What Do Algae, Corn, and Summer Vacation Have in Common? – The Equation: Blog of the Union of Concerned Scientists (blog)


The Equation: Blog of the Union of Concerned Scientists (blog)

What Do Algae, Corn, and Summer Vacation Have in Common?
The Equation: Blog of the Union of Concerned Scientists (blog)
Have any summer vacation plans that include swimming, fishing, or walks on the beach? If so, lucky you. But, if you're headed to the East Coast, Great Lakes, Gulf of Mexico, or any number of our nation's lovely ocean or lake escapes around late July

Project to reduce risk of harmful algal blooms in ponds and lakes

A new project to help identify and remediate harmful algal blooms could make Pennsylvania ponds and lakes safer for people and animals. With a grant from the Penn State-based Pennsylvania Water Resources Research Center, trained Penn State Extension educators will collect data to help determine the abundance of these blooms and conduct workshops and other outreach activities to educate and assist pond and lake owners.

‘Real food’: U. commits to a dining-hall overhaul – Salt Lake Tribune


Salt Lake Tribune

'Real food': U. commits to a dining-hall overhaul
Salt Lake Tribune
Four student researchers at the University of California, Santa Cruz, discovered that some reportedly local ingredients had traveled farther than the contractor revealed, said Tim Galarneau, education coordinator at the Center for Agroecology and

Effects of habitat types and within lake environmental gradients on the diversity of chironomid assemblages

Publication date: Available online 30 May 2015
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Diána Árva , András Specziár , Tibor Erős , Mónika Tóth
Understanding the distribution of biotic diversity across various spatial scales and environmental gradients is important from fundamental, practical and conservation biological aspects. We applied a hierarchical diversity partitioning framework to quantify the variability of sample level α- and β 1 -diversity, and environment related β 2 -diversity of benthic chironomid assemblages within and among a priori defined habitat types, and along the gradients of individual environmental factors in a large and shallow lake (Lake Balaton, Hungary). Taxon richness (both additive and multiplicative) and Shannon index based diversity approaches yielded highly concordant results. The α-diversity was much lower and β 1 -diversity higher than predicted by null model and both measures varied substantially among habitat types and along most individual environmental gradients. The β 2 -diversity indicated a marked variability of taxon (identified at species to genus level) pool among habitat types and higher than predicted taxon turnover along all examined environmental gradients. Moreover, the observed β 2 -diversity varied greatly among individual environmental gradients. The difference between the expected and observed β 2 -diversity values suggests that taxon turnover was most influential (in decreasing order) along the algae coverage gradient, the lake bed substratum gradient and the macrophyte coverage gradient among others. We argue that within-lake environmental heterogeneity and its effect on the taxon richness should receive more attention in biodiversity assessment and conservation. Management could benefit from the identification of within lake gradients along which taxonomic turnover maximizes.

Dynamics and sources of dissolved organic carbon during phytoplankton bloom in hypereutrophic Lake Taihu (China)

Publication date: Available online 29 May 2015
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Linlin Ye , Xiaodong Wu , Bo Liu , Dezhi Yan , Fanxiang Kong
To establish the influence of phytoplankton blooms on the dynamics and sources of dissolved organic carbon (DOC) in Lake Taihu, the concentrations and stable carbon isotope values (δ13C) of DOC and particulate organic carbon (POC) were analyzed, along with environmental factors, including water temperature, chlorophyll a (Chl a ) concentration, phytoplankton community and total bacterial abundance, from March to August 2013 at five sites in Lake Taihu. Significant differences were observed in the DOC concentrations and δ13C DOC values at the sampling sites. On average, the proportion of DOC in the total organic carbon (TOC) pool ranged from 30% ± 10% to 81% ± 7%. POC was positively associated with both Chl a concentration and cyanobacteria biomass, suggesting that cyanobacteria blooms contribute to the POC pool in Lake Taihu. Depleted 13C in DOC relative to POC was observed in August, indicating that DOC was partially derived from POC in August. However, Chl a explained only 40% of the variation in DOC in the entirety of Lake Taihu, and at two sites far from the estuary, the contribution of allochthonous carbon was less than 50% in August. These results suggested a greater influence of allochthonous sources on the DOC pool. Moreover, the biodegradability of DOC was further determined by the total dissolved carbohydrates to DOC ratio (TCHO/DOC), specific UV absorbance (SUVA 254 ), and the concentrations of bioavailable DOC (BDOC). On average, 17% of the variation in DOC was attributable to the BDOC pool, and the BDOC concentration correlated positively with Chl a , cyanobacteria biomass, and total bacterial abundance, suggesting that cyanobacteria – derived DOC is biodegradable and is preferentially utilized by bacteria.

Decomposition of macrophytes in a shallow subtropical lake

Publication date: Available online 19 May 2015
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Cristiane Carvalho , Luiz Ubiratan Hepp , Cleber Palma-Silva , Edélti Faria Albertoni
Submerged macrophyte detritus is a major component of the organic matter entering shallow lakes. Plant litter decomposition is a complex process that is mediated by microorganisms and some invertebrates. However, the role that aquatic organisms play in the decomposition of macrophytes in shallow subtropical lakes is unclear. This study compared the decomposition rates of Potamogeton pectinatus and Chara zeylanica in a shallow lake (southern Brazil) and assessed the fungal biomass and the macroinvertebrate community associated with the detritus. Aliquots of both species were incubated in litter bags and placed in the lake. After 1, 7, 20, 40, 60, and 80 days of incubation, one set of litter bags was removed from the lake. In a laboratory, plant material was washed for the determination of decomposition rates, chemical characterisation, and quantification of microorganisms and invertebrates. After 80 days of incubation, there was no C. zeylanica detritus, with a decomposition that was four times faster than that of P. pectinatus . The chemical composition was also different between the two detritus, with P. pectinatus showing a higher concentration of nitrogen, phosphorus, organic matter, polyphenols, and carbon. The fungal biomass was similar between the two species. In total, 7,502 invertebrates belonging to 27 taxa were sampled in this study. The composition and abundance of invertebrates was different between the two species. In conclusion, the chemical structure of the macrophyte species studied was important for the microorganisms’ and invertebrates’ colonisation. In addition, leaching had an important function in the initial degradation process.

It’s time for the “spring flush”… of pesticides

What, you may ask, is the "spring flush?" In late spring and early summer,  large concentrations of herbicides are flushed from croplands. These chemicals — like the herbicide atrazine — then get transported far and wide through surface water systems.

Herbicides are water-soluble and thus have the potential to leach into groundwater supplies as well as streams, lakes and other surface waters. Atrazine is a frequently found contaminant in drinking water supplies throughout the Corn Belt, and every year the spring flush raises concerns over the potential of atrazine spikes in drinking water supplies.

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Underwater light climate, thermal and chemical characteristics of the tropical soda lake Chitu, Ethiopia: Spatio-temporal variations

Publication date: May 2015
Source:Limnologica – Ecology and Management of Inland Waters, Volume 52
Author(s): Tadesse Ogato , Demeke Kifle , Brook Lemma
Soda lakes are known for their extreme environmental conditions and unique assemblage of biota and provide great ecological and economic values. Although they are highly sensitive to environmental changes, soda lakes are among the least frequently studied inland water bodies. In this study, temporal and spatial (vertical) patterns of underwater light climate, thermal and chemical characteristics of a little known soda were studied. Parameters of underwater light climate showed light-limited conditions with more marked inter-monthly variations, associated with the accumulation of Arthrospira biomass in the shallow trophogenic zone. Water column conditions indicated superficial thermal stratification (0–3 m depths) with weak temperature gradients and weak mixing pattern. Dissolved oxygen (DO) varied considerably among months, ranging from subsurface supersaturation on certain occasions to persistent deoxygenation of most of the water column on other occasions, with the variations being attributable to the high productivity, high metabolic rates of microbes and weak vertical mixing. Alkalinity, conductivity and pH were generally high with moderate temporal and vertical variations, which were presumably associated with precipitation, evaporation and high algal biomass. In most cases, CO 3 2−:HCO 3 was high (>1), suggesting lower concentration of HCO 3 . Most of the major algal nutrients showed considerable inter-monthly and vertical variations. NO 3 and NH 3 in the euphotic zone were often very low or undetectable while soluble reactive phosphate (SRP) and total phosphorus (TP) were considerably high throughout the study period. The observed dramatic increase in the levels of NH 3 and SRP with depth is attributable to internal loading, which is enhanced by increased microbial activities and largely anoxic water column. The concentration of SiO 2 was remarkably low, which was probably due to organic matter accumulation within the lake that tends to preclude internal loading. In general, the notable temporal and vertical variations in physicochemical parameters, associated chiefly with the lake’s productivity, microbial activity, anoxic water column and meteorological conditions, probably suggest that Lake Chitu is sensitive to perturbations and that any environmental changes occurring in the lake are likely to affect the key planktonic alga ( Arthrospira ) and its ecosystem values.

Long-chain n-alkenes in recent sediment of Lake Lugu (SW China) and their ecological implications

Publication date: May 2015
Source:Limnologica – Ecology and Management of Inland Waters, Volume 52
Author(s): Zhang Yongdong , Su Yaling , Liu Zhengwen , Chen Xiangchao , Yu Jinlei , Di Xiaodan , Jin Miao
Long-chain n -alkenes showing a predominance of n -C 25:1 and n -C 27:1 were detected in recent sediment of Lake Lugu, an oligotrophic alpine lake in Yunnan Province, SW China. The abundances of n -C 25:1 and n -C 27:1 alkenes varied considerably in the sediment core, most obviously in showing higher values during the period of 1821–1982, followed by a significant decrease between 1982 and 2012. Such variations were similar to those of long-chain 1,15-alkyl diols, biomarkers of eustigmatophytes, and a significant correlation was observed between n -C 25:1 (or n -C 27:1 ) alkene and C 32 1,15-alkyl diol in the sediment core. This correlation and the fact that long-chain n -alkenes in some eustigmatophytes (e.g., Nannochloropsis sp.) were dominated by C 25 and C 27 compounds indicates that eustigmatophytes were the most likely contributor of the long-chain n -alkenes (especially the n -C 25:1 and n -C 27:1 alkenes) in Lake Lugu sediment. Chlorophytes, on the other hand, cannot be excluded as a possible contributor of the long-chain n -alkenes because these algae are common in Lake Lugu and they are known to biosynthesize n -C 27:1 alkene. Productivities for some species of eustigmatophytes and chlorophytes considerably decreased when the lake water was heavily influenced by catchment soil erosion and anthropogenic sewage inputs.

Climate driven changes in the submerged macrophyte and phytoplankton community in a hard water lake

Publication date: Available online 3 April 2015
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Wojciech Ejankowski , Tomasz Lenard
We studied the changes in the submerged aquatic vegetation (SAV) and phytoplankton community in a hard water lake during different meteorological conditions. We hypothesised that variations in climatic conditions (precipitation and temperature) can influence the physicochemical parameters of water and, in turn, affect SAV and phytoplankton development. The investigations were performed in Lake Rogóźno (the West Polesie region, Eastern Poland) over 10 years from 2003 to 2013. The physicochemical parameters, the structure of macrophytes and the phytoplankton community in the dry (2003-2006, DP) and wet periods (2007-2013, WP) were analysed. Between the dry and wet periods, the water colour and the concentration of dissolved organic carbon (DOC) increased considerably, whereas water conductivity decreased. Other parameters (concentration of nutrients, water reaction and transparency) were comparable during both periods. When the precipitation and water level were low (DP), charophytes dominated the SAV and cyanobacteria dominated the phytoplankton community. After the precipitation and water level increased (WP), the charophyte population declined and the vascular plants and bryophytes dominated. Furthermore, flagellated algae belonging to the dinophytes and cryptophytes were the most numerous in the phytoplankton community. These changes in the SAV and phytoplankton were linked with the variations of physicochemical parameters determined by the total precipitation and mean air temperature in March.

Morphometric variation of the oriental river prawn (Macrobrachium nipponense) in Taiwan

Publication date: Available online 20 March 2015
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Po-Cheng Chen , Tzong-Der Tzeng , Chun-Han Shih , Ta-Jen Chu , Ying-Chou Lee
Morphometric differences were used to elucidate the stock geographic variations and phylogeography of Macrobrachium nipponense in Taiwan. Eight samples were collected from three estuaries (Tamsui River Estuary [TSE], Kaoping River Estuary [KPE], and Houlung River Estuary [HLE]) and five reservoirs (Shimen Reservoir [SMR], Mingde Reservoir [MDR], Deji Reservoir [DJR], Tsengwen Reservoir [TWR], and Chengqing Lake Reservoir [CLR]). Twelve morphometric measurements were size-standardised by the allometric method and analysed via cluster analysis and canonical variate analysis (CVA). Randomisation tests were used to verify the morphometric variation between groups. The results clustered the eight samples into a minimum of three groups. The first group included four reservoir samples (i.e. DJR, MDR, CLR, and TWR); the second included the SMR sample, and the third comprised the remaining estuarine samples (i.e. TSE, HLE, and KPE). Morphometric variation among the three groups was significant for each sex. Significant differences between these three groups may be derived from evolutionary origins, geographic events or environmental adaption which was discussed in the paper. The difference between multivariate allometric coefficients in both sexes and sites were also tested based on the eight group data sets, and the result showed that the difference between sexes was significant.

A sensitivity analysis of lake water level response to changes in climate and river regimes

Publication date: March 2015
Source:Limnologica – Ecology and Management of Inland Waters, Volume 51
Author(s): Ali Torabi Haghighi , Bjørn Kløve
Lake water level regimes are influenced by climate, hydrology and land use. Intensive land use has led to a decline in lake levels in many regions, with direct impacts on lake hydrology, ecology and ecosystem services. This study examined the role of climate and river flow regime in controlling lake regimes using three different lakes with different hydraulic characteristics (volume-inflow ratio, CIR). The regime changes in the lakes were determined for five different river inflows and five different climate patterns (hot-arid, tropical, moderate, cold-arid, cold-wet), giving 75 different combinations of governing factors in lake hydrology. The input data were scaled to unify them for lake comparisons. By considering the historical lake volume fluctuations, the duration (number of months) of lake volume in different ‘wetness’ regimes from ‘dry’ to ‘wet’ was used to develop a new index for lake regime characterisation, ‘Degree of Lake Wetness’ (DLW). DLW is presented as two indices: DLW 1 , providing a measure of lake filling percentage based on observed values and lake geometry, and DLW 2 , providing an index for lake regimes based on historical fluctuation patterns. These indices were used to classify lake types based on their historical time series for variable climate and river inflow. The lake response time to changes in hydrology or climate was evaluated. Both DLW 1 and DLW 2 were sensitive to climate and hydrological changes. The results showed that lake level in high CIR systems depends on climate, whereas in systems with low CIR it depends more on river regime.

Quick class credit available at Iowa Lakeside Laboratory – Iowa State Daily

Quick class credit available at Iowa Lakeside Laboratory
Iowa State Daily
“It's a sort of cram or crash course,” said Kathleen Delate, ISU professor of horticulture, who will be teaching a two-week course on agro-ecology at the Lakeside Laboratory this summer. “But on the other hand, [students] get so much more time in the

Inventive water harvesting helps Kenya balance rain extremes – Reuters

Inventive water harvesting helps Kenya balance rain extremes
Reuters
Amos Wekesa, an environment and climate change advisor with Vi Agroforestry, a Swedish development agency working with farmers in East Africa's Lake Victoria basin, said such water harvesting efforts "are some of the most tested methods of ensuring …

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Inventive water harvesting helps Kenya balance rain extremes – Yahoo News

Inventive water harvesting helps Kenya balance rain extremes
Yahoo News
Amos Wekesa, an environment and climate change advisor with Vi Agroforestry, a Swedish development agency working with farmers in East Africa's Lake Victoria basin, said such water harvesting efforts "are some of the most tested methods of ensuring …

Inventive water harvesting helps Kenya balance rain extremes – Yahoo! Maktoob News

Inventive water harvesting helps Kenya balance rain extremes
Yahoo! Maktoob News
Amos Wekesa, an environment and climate change advisor with Vi Agroforestry, a Swedish development agency working with farmers in East Africa's Lake Victoria basin, said such water harvesting efforts "are some of the most tested methods of ensuring …

and more »

Inventive water harvesting helps Kenya balance rain extremes – Reuters UK

Inventive water harvesting helps Kenya balance rain extremes
Reuters UK
Amos Wekesa, an environment and climate change advisor with Vi Agroforestry, a Swedish development agency working with farmers in East Africa's Lake Victoria basin, said such water harvesting efforts "are some of the most tested methods of ensuring …

and more »

Influence of nitrate and dissolved organic carbon loading on the interaction of Microcystis aeruginosa and heterotrophic bacteria from hyper-eutrophic lake (Taihu Lake, China)

Publication date: Available online 20 January 2015
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Du Jingjing , Ma Xu , Pu Gaozhong , Kong Xiangshi , Akbar Siddiq , Jia Yanyan , Tian Xingjun
To investigate the interaction between cyanobacteria and heterotrophic bacteria under gradients of glucose and nitrate, a cyanobacterial strain of Microcystis aeruginosa was grown in microcosms with and without a freshwater bacterial mixture, which was collected from Lake Taihu. Concentrations of glucose (1350, 975, 600, 300, 150, and 37.5 μmol C L−1) and nitrate (150, 300, and 9000 μmol N L−1) were used in a range of combinations giving 9 different treatments of glucose:nitrate. In the microcosm without the bacterial mixture, M . aeruginosa abundance gradually increased with days in all treatments. However, M. aeruginosa had much lower density in some treatments with the bacterial mixture. The difference in M. aeruginosa growth could be explained by competition with bacteria in the cultures in which these were added. The abundance of M. aeruginosa and bacteria when grown together was nearly equal and the number of the bacterial species was highest in the treatment with 300 μmol C L−1 and 150 μmol N L−1. Our results suggest that at this glucose:nitrate ratio M . aeruginosa and the bacterial mixture maintain a balance, and bacteria maintain diversity. In conclusion, we propose that dissolved organic carbon and nitrate availability fundamentally affects the structure as well as stoichiometry of pelagic associations.

Spatial Arrangement and Metrics of Freshwater Coastal Rock Pools Applied to Amphibian Conservation

Publication date: Available online 17 January 2015
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Alexander T. Egan , Leonard C. Ferringtona Jr. , Toben Lafrançois , Mark B. Edlund , Jenna McCullougha
Coastal habitats are an ecotone between aquatic and terrestrial ecosystems. Depressions on volcanic bedrock shores of Lake Superior form small pool habitats that are influenced to various degrees by their spatial context and that relate to differences in mechanisms of disturbance. A total of 71,931 coastal pools were mapped and measured, and amphibian occupants were identified along 48 km of shoreline at Isle Royale National Park, where coastal rock pool habitats were abundant. Generally, mean depth of pools was 0.11 m, with a mean surface area of 0.6 m2, although maximum measurements were 1.5 m and 378 m2, respectively. Three strongly defined zones occurred, with bedrock near the lake having a low slope and more numerous, smaller, and shallower pools; bedrock near the forest edge had a steeper slope and fewer, larger, and deeper pools; and a median zone occurring between. A single offshore location, Passage Island, had nearly 63% of all pool abundance. Two amphibian species were typical of coastal pools, the chorus frog ( Pseudacris triseriata ) and blue-spotted salamander ( Ambystoma laterale ), while spring peeper ( Pseudacris crucifer ) was uncommon and probably incidental to coastal habitats. These three species were significantly more abundant in mid-shore pools. Four other amphibian species were only rarely detected. Both coastal habitat density and chorus frog abundance were highest at localities directly adjacent to an international shipping lane. As a result of intriguing spatial distributions and potential for impacts from coastal pollution, chorus frog in particular reveals that coastal ecology can be unique from inland contexts and have important management implications at the land-water interface.

Human waterborne protozoan parasites in freshwater bivalves (Anodonta anatina and Unio tumidus) as potential indicators of fecal pollution in urban reservoir

Publication date: Available online 6 December 2014
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Anna Słodkowicz-Kowalska , Anna C. Majewska , Piotr Rzymski , Łukasz Skrzypczak , Anna Werner
The presence of environmentally robust dispersive stages of intestinal protozoan parasites in waters represents an important public health threat since these pathogens have caused numerous outbreaks related to either drinking or recreational waters. The purpose of this study was to evaluate the presence of Cryptosporidium oocysts, Giardia and Blastocystis cysts, and microsporidian spores in mussels collected from municipal reservoir, Lake Malta (Poland, Europe). Two species of freshwater bivalves ( Anodonta anatina and Unio tumidus ) were tested for the enteropathogens. A direct wet smear and smears stained with chromotrope 2R, Ziehl-Neelsen and iron hematoxylin made from each pellet of the hemolymph, gills and gastrointestinal homogenates of mussels were examined microscopically. In the study the immunofluorescence antibody test kit MERIFLUOR Cryptosporidium/Giardia was also used for all bivalve samples. None of investigated parasites were found in U. tumidus . In A. anatina , Cryptosporidium oocysts and Blastocystis cysts were detected in 15.4 and 5.1% of mussel samples, respectively. The present results indicate contamination of Lake Malta with Cryptosporidium and Blastocystis , which is important from the point of view of public health threats because of different human uses of studied reservoir.

Fish distribution patterns and habitat availability in lakes Moreno Este and Moreno Oeste, Patagonia, Argentina

Publication date: November 2014
Source:Limnologica – Ecology and Management of Inland Waters, Volume 49
Author(s): Magalí Rechencq , Pablo Horacio Vigliano , Patricio Jorge Macchi , Gustavo Enrique Lippolt
Andean Patagonian lakes are ultraoligotrophic and deep, have simple food webs and low fish diversity and abundance. In this work the distributional abundance data of fish was studied in two interconnected Andean Patagonian lakes with varying proportions of contrasting habitat types. Hydroacoustic data (120 kHz) were used to analyze fish abundance and habitat use during the mixis and stratification periods. Three types of habitat (near shore, surface pelagic and deep pelagic) and two groups of fish, based on size (Big Fish >12 cm total length and Fish Larvae and Small Fish <12 cm total length) were defined. The distribution of both fish groups in these lakes revealed differences in habitat use for each lake and period. Fish group abundance was related to the availability of habitat types, according to the morphology of each lake. The Big Fish group showed preference for the near shore habitat during lake stratification and always appeared as individual targets. The Fish Larvae and Small Fish group used mainly the pelagic habitat during mixis, where they formed dense sound scattering layers. However, during lake stratification many individual targets from this group were found both in pelagic and near shore habitats, which would seem to indicate a change in distributional behavior. This is possibly associated with niche changes in the Galaxiids ( Galaxias spp), a key component of Northern Patagonian lake food webs. Lakes like Moreno Oeste, which are morphologically and structurally more complex, could have more diverse fish ensembles with higher abundances. In contrast, lakes of simple morphology with low development of near shore habitats and ample deep zones, like Lake Moreno Este, could present lower Big Fish abundance. The contrasting habitat availability between lakes accounts for the abundances and distribution patterns of each fish group. While in these lakes fish assemblage species composition could depends on the environmental filter, the particular structure of a fish assemblage in terms of the proportional abundances of species depends on proportional habitat type availability. We can speculate that in Andean Patagonian lakes Galaxiids mediate a habitat coupling process critical for the transfer of energy and matter in oligotrophic lakes. We may also consider that the Small Puyen in this type of lake is a keystone prey species that relieves predation pressure on other potential prey. The existence of deep pelagic habitats in numerous deep lakes in the Northern Patagonian Andean region provides not only daytime refuge for Galaxiids, which allows them to maintain their high numbers in the lakes, but could also, in the long term, act as a Galaxiid source for other water bodies.

Unraveling the ‘landscape approach’: Are we on the right track? – Center for International Forestry Research (press release) (blog)


Center for International Forestry Research (press release) (blog)

Unraveling the 'landscape approach': Are we on the right track?
Center for International Forestry Research (press release) (blog)
Lake Sentani landscape, Papua, Indonesia. Balancing multiple land uses among multiple stakeholders — a landscape approach — is gaining some traction as a useful management tool, despite inherent challenges. Mokhammad Edliadi/CIFOR photo.

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Effects of internal phosphorus loading on nutrient limitation in a eutrophic reservoir

Publication date: Available online 6 September 2014
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Stephen J. Nikolai , Andrew R. Dzialowski
While lake and reservoir management has historically focused on controlling external nutrient loads to improve water quality, internal mechanisms can also contribute to the processes of eutrophication. We assessed how the release of phosphorus (P) from anoxic sediments in the hypolimnion of a eutrophic reservoir affected epilimnetic nutrient concentrations and ratios. We also conducted nutrient bioassay experiments to determine if water column total nitrogen:total P (TN:TP) ratios could be used to predict nutrient limitation in the reservoir. We estimated that anoxic sediments from the lacustrine zone of the reservoir released 7.1 mg P/m2/day into the reservoir during stratification. This internal load was an important source of P to the epilimnion of the reservoir that helped to lower TN:TP ratios and create N limiting conditions following thermocline erosion. With respect to the enrichment bioassays, we found that nutrient limitation varied both spatially and temporally in the reservoir with observed periods of no nutrient limitation, N limitation, P limitation, and N and P co-limitation. However, corresponding water column TN:TP ratios correctly identified the limiting nutrient in less than 50% of the nutrient bioassays. As such, total nutrient ratios should be used with caution when trying to predict nutrient limitation in individual systems.

Internal waves and mixing in a stratified reservoir: insights from three-dimensional modeling

Publication date: Available online 2 September 2014
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Serghei A. Bocaniov , Christian Ullmann , Karsten Rinke , Kevin G. Lamb , Bertram Boehrer
In this study, the 3-dimensional (3D) Estuary and Lake Computer Model (ELCOM) was used to model a mid-sized reservoir (Rappbode Reservoir, Germany) during the period of summer stratification to identify and illustrate the source of internal waves as well as to characterize the water exchange between the hypolimnion and epilimnion under different wind speed conditions with a focal point on one episode of high and sustained winds. The modeling revealed that wind stress was the key driver of the observed internal waves while the role of water withdrawal was negligible. Our results also showed that within the range of wind speeds considered, wind-induced upwelling greatly enhanced mixing between the hypolimnion and epilimnion with a rate that varies approximately as the square of the wind speed. This numerical correlation affirmed that processes connected to wind stress, i.e. internal waves or direct upwelling, were responsible for the mixing of the hypolimnetic water into the surface water rather than direct input of turbulent kinetic energy.

A typology for fish-based assessment of the ecological status of lowland lakes with description of the reference fish communities

Publication date: Available online 21 August 2014
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): David Ritterbusch , Uwe Brämick , Thomas Mehner
We compared the potential of different lake typologies to discriminate fish communities in least disturbed sites. The typologies tested were based on morphometric and geographical descriptors. The best discrimination was achieved by distinguishing three lake types according to depth and mixis regime: polymictic lakes, stratified lakes with less than 30 m of maximum depth and deep, stratified lakes with maximum depths above 30 m. We conclude that the proposed typology is appropriate for a system to assess the ecological status of German lakes with the fish fauna according to the Water Framework Directive and might well be transferable to other European assessment systems. The fish communities in all lake types were similar and dominated by few fish species. Perch and roach were the most abundant ones, followed by ruffe, bream, rudd and pike. The fish communities in least disturbed sites might be used as reference conditions in future fish-based assessment systems.

Hydrological connectivity as most probable key driver of chlorophyll and nutrients in oxbow lakes of the Bug River (Poland)

Publication date: March 2014
Source:Limnologica – Ecology and Management of Inland Waters, Volume 46
Author(s): Lech Kufel , Szymon Leśniczuk
Concentrations of chlorophyll, dissolved inorganic nitrogen and phosphorus, total phosphorus and suspended solids were analysed in 10 oxbow lakes of the Bug River in spring and summer. According to their connectivity with the river, all lakes were divided into 3 categories – lakes connected with the river channel but separated from the floodplain inputs, lakes connected with the river but receiving inputs from the floodplain and totally isolated lakes. Connected lakes showed significantly higher concentrations of available nutrients and chlorophyll but the relationship between the two variables was weak in the spring and non-existent in the summer. Suspended solids were also more abundant in connected than in isolated lakes. Analyses of the proportion of chlorophyll and particulate phosphorus in suspension led us to the conclusion that water movement in connected lakes inhibited sedimentation and kept algae in the water column. Isolated oxbow lakes devoid of wind-driven mixing were more susceptible to algal sedimentation which would explain the differences observed between the two lake categories.

A floodplain-scale lake classification based on characteristics of macroinvertebrate assemblages and corresponding environmental properties

Publication date: Available online 20 July 2014
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Baozhu Pan , Hongzhu Wang , Haijun Wang
Floodplain lakes have been experiencing great pressures by human activities, and ecological functions in different types of lakes show different degrees of degradation. For facilitating conservation and management of different types of floodplain lakes, it is necessary to classify the lakes into similar groups according to certain standards. In this study, on basis of consideration of macroinvertebrate assemblages and corresponding environmental properties, the Yangtze floodplain lakes were classified into three major types grouping five groups of lakes: 1) river-disconnected lakes (algal lakes, macrophytic-algal transition lakes, and macrophytic lakes), 2) semi-connected lakes (oxbow lakes), 3) river-connected lakes. The classification of floodplain lakes mainly reflects the gradients of trophic and hydrological connectivity. The key factors structuring macroinvertebrate assemblages in the Yangtze floodplain lakes were mainly hydrological (connectivity rating, water depth), trophic (total phosphorus, macrophytes biomass) and morphometric (development of lake shoreline). Among the floodplain lakes, ecological status of river-connected lakes, where biodiversity, biomass and production of macroinvertebrates reached maxima, has been confirmed to be the best. From the view of conservation and management of the entire floodplain lakes, it is suggested that protecting the remnants of river-connected lakes, controlling eutrophication and linking disconnected lakes freely with the mainstream are crucial.

Permaculture practices let nursery thrive off grid – San Francisco Chronicle

Permaculture practices let nursery thrive off grid
San Francisco Chronicle
BLOOMINGTON, Ind. (AP) — Not far from Lake Monroe is the hard-nosed, disease-resistant Asian pear tree. The tree sits in a row of plants and neighbors the nitrogen-rich false California indigo, the heavy pollinator foxtail lily, the nutrient-rich lamb

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Permaculture practices let nursery thrive off grid – Fairfield Citizen

Permaculture practices let nursery thrive off grid
Fairfield Citizen
BLOOMINGTON, Ind. (AP) — Not far from Lake Monroe is the hard-nosed, disease-resistant Asian pear tree. The tree sits in a row of plants and neighbors the nitrogen-rich false California indigo, the heavy pollinator foxtail lily, the nutrient-rich lamb
Ecological sanctuary: Permaculture principles help Monroe County nursery stay Greenfield Daily Reporter



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Reproductive traits and conservation needs of the endemic gammarid Laurogammarus scutarensis (Schäferna, 1922) from the Skadar Lake system, Balkan Peninsula

Publication date: Available online 4 May 2014
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Michał Grabowski , Karolina Bącela-Spychalska , Vladimir Pešić
Europe is one of the global hotspots of freshwater amphipod diversity with a number of endemic species yet many of European freshwater ecosystems are under extreme anthropogenic pressure. Studying the biology and ecology of endemic species may substantially help to assess risk of extinction and define proxies for their conservation. Laurogammarus scutarensis is a Balkan endemic and the only species within the genus Laurogammarus G. Karaman 1984. Its distribution is restricted to temperature-stable, cool waters of the springs, streams and lower sections of a few rivers emptying to the north-western part of the Skadar Lake in Montenegro–an area under heavy anthropogenic pressure in recent years. We examined life history of the species in a limnocrene spring with year-round stable temperature (10 °C ± 0.5) by estimating its population structure over a year, fecundity, reproductive period and relationship between photoperiod and reproduction. These parameters were compared to those of other gammarids, including invasive species, in order to estimate the role of photoperiod in shaping life history of L. scutarensis , and to give insight into the possible conservation needs for that species. Our results show that the species is univoltine and its reproduction continues round the year. However, its intensity is synchronised with seasonal day length changes with the highest share of females breeding in spring and early summer. The population sex structure is strongly female biased in most of the year. Number of eggs laid depends positively on the female body length; however the mean brood size (15.53 eggs) of L. scutarensis is rather low when compared to other species. Also partial fecundity and mean body length at which individuals start to reproduce indicate that its reproductive potential is much lower than that of many other gammarid species, including those colonizing many European water bodies in recent years. Concluding, the studied life history traits of L. scutarensis combined with its very narrow distribution range and peculiar thermal requirements reported in the literature provide as with the hint to define the species as vulnerable to threats posed by the habitat degradation and competition with other species. Taking into account the risk of invasion by alien species and progressive habitat loss, we are of the opinion that L. scutarensis should be recognised as an endangered species and that a conservation plan should be implement to prevent its possible extinction.

Panel Discussion on Climate Disruption to Be Held April 17 at ECC Training … – The Missourian

Panel Discussion on Climate Disruption to Be Held April 17 at ECC Training
The Missourian
Also joining in the discussion will be Dr. Johann Bruhn, professor emeritus at the University of Missouri Center for Agroforestry and Brian Ettling, a seasonal park ranger at Crater Lake National Park. Ettling is co-founder of Climate Reality-St. Louis

Parramatta in the frame for western Sydney documentaries – Parramatta Sun

Parramatta in the frame for western Sydney documentaries
Parramatta Sun
… had planned scenes at Lake Parramatta and Parramatta River and would explore ideas of environmental awareness and sustainability through interviews with community members for and against initiatives like permaculture, community gardens and seed …

and more »

Modelling Lake Kivu water level variations over the last seven decades

Publication date: Available online 13 March 2014
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Fabrice A. Muvundja , Alfred Wüest , Mwapu Isumbisho , Mwenyimali B. Kaningini , Natacha Pasche , Päivi Rinta , Martin Schmid
This study aimed at analysing the hydrological changes in the Lake Kivu Basin over the last seven decades with focus on the response of the lake water level to meteorological factors and hydropower dam construction. Historical precipitation and lake water levels were acquired from literature, local agencies and from global databases in order to compile a coherent dataset. The net lake inflow was modelled using a soil water balance model and the water levels were reconstructed using a parsimonious lake water balance model. The soil water balance shows that 370 mm yr−1 (25%) of the precipitation in the catchment contributes to the runoff and baseflow whereas 1100 mm yr−1 (75%) contributes to the evapotranspiration. A review of the lake water balance resulted in the following estimates of hydrological contributions: 55%, 25%, and 20% of the overall inputs from precipitation, surface inflows, and subaquatic groundwater discharge, respectively. The overall losses were 58% and 42% for lake surface evaporation and outflow discharge, respectively. The hydrological model used indicated a remarkable sensitivity of the lake water levels to hydrometeorological variability up to 1977, when the outflow bed was artificially widened.

Impact of epilimnetic phosphorus supply and food web structure on phosphorus binding forms in settling material and sediments in a thermally stratified lake

Publication date: Available online 8 February 2014
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Rychła Anna , Gonsiorczyk Thomas , Hupfer Michael , Kasprzak Peter
Knowledge about the contribution of food web structure and nutrient concentration in lakes to phosphorus (P) sedimentation and remobilization at the sediment surface is still poor. Using four large enclosures placed in a eutrophic, thermally stratifying lake, we studied the effects of the structure of the planktonic food web (with and without planktivorous fish, ±F treatments) and nutrient concentration (with and without fertilisation, ±N treatments) on P sedimentation. We investigated the total P content and P binding forms in settling material (TP SM ) and of the uppermost 1 cm sediment layer (TP Sed ) during three consecutive stratification periods (2005–2007). Additionally, epilimnetic P (SRP Epi , TP Epi ), chlorophyll a and biomass of total crustacean and Daphnia were measured. On a seasonal scale, Daphnia biomass tended to negatively influence chlorophyll a, sedimentation rate of total particulate matter and of P, but the latter two criteria did not differ significantly between treatments due to large fluctuations within each enclosure. The contents of TP SM and loosely adsorbed P in settling material decreased in the following order:–F/ + N > +F/ + N > –F/–N > +F/–N, indicating greater effects of nutrient addition than of food web structure. In sediments, organically bound P was 9–23% higher in–F variants compared to the corresponding +F treatments, thus indicating an effect of food web structure. Furthermore, positive correlations between SRP Epi , TP Epi , TP SM , TP Sed , sediment reductant-soluble P and calcite bound P revealed an effect of the epilimnetic P concentration on P sedimentation and specific P binding forms. Compared to the composition of different P binding forms in the settling material, a considerable decrease of loosely adsorbed P (12–26%) and reductant-soluble P (14–21%), as well as an increase of organic P (14–26%) were observed in the uppermost 1cm-layer of the sediments in all treatments. We conclude that both nutrient enrichment (+N) and food web structure (–F) enhance the P sedimentation and P content at the sediment surface. However, in addition to food web effects on organic P content in settling matter and sediments, factors like iron concentration and calcite precipitation might be of importance for P sedimentation and storage in sediments in complex systems such as lakes.

Tahoe Food Hub raises more than $28K in crowdfund campaign – Tahoe Daily Tribune

Tahoe Food Hub raises more than $28K in crowdfund campaign
Tahoe Daily Tribune
It contributes food regularly to Project MANA, North Lake Tahoe's hunger relief organization and provides tours and workshops on four-season growing methods at its Sierra Agroecology Center and Growing Dome. Learn more by visiting tahoefoodhub.org.

The role of food availability and phytoplankton community dynamics in the seasonal succession of zooplankton community in a subtropical reservoir

Publication date: Available online 1 February 2014
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Chun-Wei Chang , Fuh-Kwo Shiah , Jiunn-Tzong Wu , Takeshi Miki , Chih-hao Hsieh
Seasonal patterns of zooplankton succession have been explained by physical factors such as temperature and precipitation. While the influence of biological factors, such as food availability and composition, has been recognized in theory, how food availability and composition affect the seasonal succession of zooplankton communities, especially in tropical/subtropical lakes, is still unclear and under debate. In this study, we applied multivariate analyses to a 3-year time series of physicochemical factors, various food sources (primary and bacterial production), and phytoplankton and zooplankton species composition in a subtropical reservoir in Taiwan. Our results demonstrated that (i) in addition to physical factors, seasonal variation of food availability partly explains zooplankton seasonal succession. In particular, inter-annual variation of food availability proved more important than physical factors in determining the inter-annual variation in the magnitude of seasonal succession. Specifically, limited food supply amplifies the magnitude of seasonal variation of zooplankton community biomass and composition; (ii) a stronger association between zooplankton and phytoplankton was found between their species composition rather than their biomass, implying a strong interaction between zooplankton and phytoplankton at the community level.

Effects of limnoecological changes on the Ostracoda (Crustacea) community in a shallow lake (Lake Çubuk, Turkey)

Publication date: Available online 30 January 2014
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Okan Külköylüoğlu , Necmettin Sarı , Muzaffer Dügel , Şükran Dere , Nurhayat Dalkıran , Cem Aygen , Sırma Çapar Dinçer
We sampled Lake Çubuk, a shallow lake in Bolu (Turkey), for 26 months to investigate the effect of limnoecological changes on the composition of ostracod species. Seventeen ostracod species were identified from the six stations sampled between 2008 and 2010. Numbers of species and individuals were both significantly reduced during 2010, which corresponded to a 3 m water level increase. Ostracod Watch Model (OWM) displayed distinct seasonal occurrences of five species (Candona neglecta, Cypria ophtalmica, Cypridopsis vidua, Limnocythere inopinata, Fabaeformiscandona cf. japonica) when Physocypria kraepelini was the only species encountered all year round. Approximately 77.2% of the relationship between species and environmental variables was expressed by the first two axes of Canonical Correspondence analyses (CCA). Electrical conductivity and water temperature (P = 0.002) were the most influential variables on species. There was a significant negative correlation of seven species to conductivity. Of those, (F. cf. japonica and C. vidua) showed a significant positive correlation to water temperature, while C. candida was negatively correlated to water temperature (P < 0.05). Candona neglecta was the only species to show a positive correlation to dissolved oxygen. Tolerance limits for the most common species were higher than the mean water temperatures, but lower than mean levels of electrical conductivity. Finding the ratio of noncosmopolitan to cosmopolitan species “pseudorichness” as 1.13 suggested significant role of cosmopolitan species to species diversity.

Hydrological connectivity as most probable key driver of chlorophyll and nutrients in oxbow lakes of the Bug River (Poland)

Publication date: Available online 29 January 2014
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Lech Kufel , Szymon Leśniczuk
Concentrations of chlorophyll, dissolved inorganic nitrogen and phosphorus, total phosphorus and suspended solids were analysed in 10 oxbow lakes of the Bug River in spring and summer. According to their connectivity with the river, all lakes were divided into 3 categories–lakes connected with the river channel but separated from the floodplain inputs, lakes connected with the river but receiving inputs from the floodplain and totally isolated lakes. Connected lakes showed significantly higher concentrations of available nutrients and chlorophyll but the relationship between the two variables was weak in the spring and non-existent in the summer. Suspended solids were also more abundant in connected than in isolated lakes. Analyses of the proportion of chlorophyll and particulate phosphorus in suspension led us to the conclusion that water movement in connected lakes inhibited sedimentation and kept algae in the water column. Isolated oxbow lakes devoid of wind-driven mixing were more susceptible to algal sedimentation which would explain the differences observed between the two lake categories.

Kenya’s water towers sustainability key to rivers, lakes survival: experts – Coastweek

Kenya's water towers sustainability key to rivers, lakes survival: experts
Coastweek
“As a non-government organization which is championing for the sustainable utilization of the environmental resources, we sensitize communities and farmers on the necessity of practicing agro-forestry,” he says. “Sensitizing them on the need to shift

No differences between littoral fish community structure of small natural and gravel pit lakes in the northern German lowlands

Publication date: Available online 10 January 2014
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Matthias Emmrich , Svenja Schälicke , Daniel Hühn , Christian Lewin , Robert Arlinghaus
Habitat loss has been identified as a major contributor to declining freshwater biodiversity, resulting in a high thread level among European fishes. Non-natural ecosystems such as pit lakes may compensate habitat loss by providing new habitat for aquatic organisms. We compared the structure of the littoral fish communities of 18 natural and 19 gravel pit lakes located in the northern German lowlands to evaluate whether artificial lakes managed by angling clubs host similar communities as typically observed in natural lakes. The fish community structure was analyzed between the lake types and along gradients of lake morphometry, productivity and littoral complexity. Although the gravel pit lakes differed in morphology (characterized by steeper littoral slopes and less structured littoral habitat), differences in fish community structure between the natural and gravel pit lakes were weak and mainly related to differences in the abundance of the dominant species perch, roach and rudd. Both lake types had similar species richness, community diversity and hosted several small-bodied and endangered species. To conclude, fish communities characteristic of small natural lakes may serve as reference for the development of gravel pit lakes. Moreover, our study reveals that recreational-fisheries management of gravel pit lakes does not result in artificial communities that deviate strongly from the communities present in natural lakes. Therefore, nature conservation and fisheries management goals can be reconciled in relation to fish in small artificial lakes managed by angling clubs.

Key drivers for phytoplankton composition and biomass in an Ethiopian highland Lake

Publication date: Available online 14 December 2013
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Tadesse Fetahi , Michael Schagerl , Seyoum Mengistou
We studied the temporal phytoplankton community pattern of the deep crater lake Hayq in the highlands of Ethiopia from October 2007 to October 2008. Earlier sporadic surveys indicated that the phytoplankton community was predominantly characterized by heavy diatoms, which characteristically suffer from rapid sedimentation. The trophic status of Lake Hayq was reported to have changed from oligotrophic to eutrophic in 1992. The present study addresses the potential reasons for the diatom dominance as well as causes of the trophic change. Net and integrated water samples were used for determination of physico-chemical parameters and phytoplankton biovolumes. Our results revealed that diatoms and chlorophytes dominated during most of the study period in Lake Hayq and seem to be favored by the mixing regime of the water body, which can be described as partial atelomixis with daily mixing of the epilimnion maintaining the algae within the euphotic depth via regular re-suspension. However, the epilimnion may be decoupled from the hypolimnion by a seasonal chemocline. Nutrients were not limiting in the lake with an overall mean concentration of soluble reactive phosphorus of 22 μg L−1 and total phosphorus of 58 μg L−1 and of dissolved inorganic nitrogen of 305 μg L−1, with ammonium being the primary form. In the 1940-ies only diatoms were reported, but since the 1990’s other phytoplankton groups and taxa have become relevant. Canonical correspondence analysis showed that chlorophytes were mainly associated with nutrients and rainfall, euglenophytes with elevated alkalinity and the diatoms with silica and zooplankton. Chlorophyll a as measure of total phytoplankton biomass was significantly influenced by seasonality and underwater light supply, reflecting the significant role of atelomixis in persistent occurrence of heavy taxa in the epilimnion. The lake is still categorized as a eutrophic system, demonstrating that the trophic change reported in 1992 was not short-lived. In addition to changes in the catchment the eutrophication process was probably primarily triggered by a previous introduction of Tilapia in the lake, causing a cascading effect in the food-web interactions. This implied that the phytoplankton composition and biomass of this tropical deep tropical lake can be controlled through biomanipulation, as has been demonstrated for temperate lakes.

Food webs of the Paraná River floodplain: assessing basal sources using stable carbon and nitrogen isotopes

Publication date: Available online 11 December 2013
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Mercedes Rosa Marchese , Miguel Saigo , Florencia Lucila Zilli , Soledad Capello , Melina Devercelli , Luciana Montalto , Graciela Paporello , Karl Matthias Wantzen
Food webs in floodplain ecosystems may be based on a variety of aquatic, terrestrial or amphibious food resources. Here, we determined which of the basal resources mostly contribute to the food webs in a floodplain lake of the Middle Paraná River using isotopic composition of C and N (δ13 C and δ15 N) of potential food sources in the Paraná floodplain (Argentina). We analyzed if organic matter sources isotope of C and N differ between flooding and low water seasons, and analyzed the isotopic niche representations of consumers in order to characterize niches width and intraguilds overlapping. To estimate the contribution of different sources of carbon to primary consumers, we measured the stable isotopic compositions of bottom sediment organic matter, coarse particulate organic matter, biofilm, suspended particulate organic matter, epiphyton, phytoplankton, C3 and C4 macrophytes and riparian tree leaves, benthic macroinvertebrates, aquatic orthopterans and fishes in dry and flooding seasons. The packages Stable Isotope Analysis and the Stable Isotope Bayesian Ellipses algorhythm in R were calculated to compare the C and N isotopic variability between the primary consumers and their sources. The energy sources available for benthic organisms mainly originated from autochthonous sources based on the C3 photosynthesis pathway. The isotopic signatures of sources and primary consumers did not differ significantly between low and high water seasons. Our results demonstrated a higher contribution to primary consumers of C3 macrophytes and low contributions of C4 for herbivores; biofilm and benthic organic matter for gatherer collectors (Oligochaeta and Chironominae); epiphyton for ephemeropterans, amphipods and fishes, whereas biofilm was the most important source for mussels.

Negative influence of burial stress on plant growth was ameliorated by increased plant density in Polygonum hydropiper

Publication date: Available online 1 November 2013
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Feng Li , Yonghong Xie , Yinyin Liu , Yue Tang , Xinsheng Chen , Zhengmiao Deng , Jiayu Hu , Na Liu
Sedimentation and density are important factors influencing the growth of wetland plants. The aim of this study was to elucidate the role of plant density in acclimation to burial stress by investigating the growth, biomass allocation, and carbohydrate contents of Polygonum hydropiper L. var. flaccidum , one of the dominant species in the Dongting Lake wetland, China. Experimental treatments, conducted in a greenhouse, combined three plant densities (16, 144, and 400 plants m−2) with two burial depths (0 and 15 cm) in a factorial design. Greater burial depth and higher plant density had negative effects on biomass accumulation and plant height with some exceptions. Plant growth, although lower at higher densities in general, was unaffected by burial depth at medium and high densities, indicating that the negative effect of burial stress was ameliorated by increased plant density. Deeper burial led to higher stem mass fraction only in the low-density treatment. Belowground mass fraction increased significantly with increasing density in both burial treatments. Moreover, higher density and deeper burial led to higher soluble sugar content but lower starch content. These data indicate that higher density facilitates acclimation of P. hydropiper to burial stress through increased soluble sugar content.

Assessment of the vulnerability of Lithuanian lakes to expansion of Gonyostomum semen (Raphidophyceae)

Publication date: Available online 31 October 2013
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Jūratė Karosienė , Jūratė Kasperovičienė , Judita Koreivienė , Irma Vitonytė
Invasions in aquatic ecosystems can have negative ecological and economic effects. It is important to identify the impacts of non-native species in order to evaluate the outcomes of invasion processes and implement measures of management. A biopollution assessment method (BPL, or biopollution level index) was applied to measure the impact of Gonyostomum semen (Raphidophyceae) on the lakes of Lithuania. It occurred in humic, lobelia and eutrophic lakes. G. semen , comprising abundance up to 1.05 × 106 cells L−1 and biomass up to 24.8 mg L−1, was assigned as an invasive species that caused recognisable changes on phytoplankton communities, habitats and ecosystem functioning. The dominance of G. semen shifted phytoplankton composition from the prevailing small chrysophytes and green algae to the raphidophyte and large dinophytes being dominant. The assessment for the lakes revealed the highest biopollution level (BPL = 3, strong impact) for the lakes in the northern part, and moderate biopollution (BPL = 2, moderate impact) for the other regions of Lithuania.

Information night for indigenous knowledge course and Ojibwe Nation field study

An information night for the spring semester course “Exploring Indigenous Ways of Knowing in the North American Context” and Maymester field study (CED 497B and 497C) will be held at 5:30 p.m. Thursday, Nov. 7, in 113 Thomas Building on the University Park campus of Penn State. This program offers students an opportunity to learn about the history, culture and ways of life of the Red Lake, Leech Lake and White Earth Ojibwe Nations in northern Minnesota through an unforgettable, immersive field study experience.

Geochemical evidence of human impacts on deep Lake Fuxian, southwest China

Publication date: Available online 24 October 2013
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Wen Liu , Jinglu Wu , Haiao Zeng , Long Ma
Human activities in Lake Fuxian and its catchment have caused environmental changes that are preserved in the geochemical records of lake sediments. Human activities responsible for the environmental changes include agriculture, mining, industrial development, and fishery management. To elucidate human impacts on this deep water body during the past several decades, two short sediment cores were collected from the lake, dated by 137Cs, and analyzed for several geochemical variables (total organic carbon (TOC), total nitrogen (TN), δ13C and heavy metals). The multi-proxy geochemical and isotopic evidence can be used to divide the limnological record into a 3-part history. Although increasing inputs of chromium (Cr) had begun as early as the 1950s, human activities, including heavy metal contamination, apparently had little effect on lacustrine production, as δ13C, TOC, TN and TOC/TN were relatively constant until the 1980s. Mining and industry have generated large amounts of heavy metal elements such as Zn, Pb and Cd that have been deposited into the lake since the 1980s, increasing to their highest concentrations over the last decades. Zn, Pb and Cd probably were released by industrial processes such as the manufacture of cement. Cr concentrations increased at site FB, but declined at site FZ, most likely due to the closer proximity of site FB to the source of metal production. From the middle of the 1980s, the decreased δ13C, and increased TOC, TN and TOC/TN suggest a broad change in lake ecology. In the 1980s, a new fish species was introduced into Lake Fuxian and fish yields increased quickly, which may mark the beginning of a change in ecosystem structure.

Implementing ecological potential of lakes for the Water Framework Directive–Approach in Flanders (northern Belgium)

Publication date: Available online 24 October 2013
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Luc Denys , Jeroen Van Wichelen , Jo Packet , Gerald Louette
The European Water Framework Directive stipulates that artificial and heavily modified water bodies must reach good ecological potential, as opposed to good ecological status as required for natural water bodies, if certain hydrological and morphological pressures cannot be removed. We propose to obtain these objectives from the conditions expected once all feasible mitigating measures have been taken but relative to the internationally agreed quality goals for natural lakes. This allows a more objective, consistent and transparent definition of the possible deviation from the ultimate quality level than prevalent methods, in particular those considering the improvement expected from future measures. A level of functional integrity should be endeavored that minimizes the probability of undesired phenomena and negative consequences for biodiversity objectives embodied by the Habitats Directive. This remains a difficult exercise, but as a first approximation, constraints for the secondary alteration of lake hydrochemistry and the consequent potential for development of submerged vegetation can be considered. Six case studies illustrate possible procedures, which may be further refined to include additional relations between hydromorphological pressures, physical-chemical conditions and biota as knowledge develops or circumstances require.

Ali saved, joined a Sacco, grew vegetables to buildPublish Date: Oct 07, 2013 – New Vision


New Vision

Ali saved, joined a Sacco, grew vegetables to buildPublish Date: Oct 07, 2013
New Vision
Around 2011, a group of people from the city working on a project called Health of People and the Environment in the Lake Victoria Basin (HOPE-LVB) taught us about Agro-forestry, now I also plant food crops and trees on the same piece of land that has

Growth, abundance, morphometric and metabolic parameters of three populations of Diplodon chilensis subject to different levels of natural and anthropogenic organic matter input in a glaciar lake of North Patagonia

Publication date: January 2014
Source:Limnologica – Ecology and Management of Inland Waters, Volume 44
Author(s): Iara Rocchetta , Betina J. Lomovasky , Maria S. Yusseppone , Sebastián E. Sabatini , Flavia Bieczynski , María C. Ríos de Molina , Carlos M. Luquet
Three populations of Diplodon chilensis (Hiridae, Bivalvia) from North Patagonia (Lacar lake, Argentina) have been studied to determine how organic matter (OM) influence their growth, density, morphometric and metabolic parameters in two pristine sites (Yuco and Nonthué) and in a growing touristic locality (San Martín de los Andes Bay, site SMA) affected by urban discharges. In Nonthué (chemical and biological oxygen demand ratio COD/BOD ratio of 4.7), a dense neighboring forest provides higher quantities of vegetal detritus compared to Yuco, while in SMA the OM input increase is related to anthropogenic impact, mainly sewage discharges, which is more biodegradable (COD/BOD ratio of 1.7). Our results show that population’s size distribution and growth rates are affected positively by increased OM, independently of its natural or anthropogenic origin. The modal shell length interval for SMA and Nonthué is two-fold higher (70 mm), in agreement to the growth rate increase ( k = 0.079), compared to Yuco (35 mm, k = 0.045). The morphometric relationships between size–size and size–mass show a higher slope for SMA and Nonthué, which underline allometric differences between these two populations and the Yuco’s one. The lower population densities in both sites (SMA 33 ind./m2 and Nonthué 76 ind./m2) compare to Yuco (176 ind./m2) and the absence of individuals younger than 7 and 5 years old, respectively, in SMA and Nonthué could be related to the higher allochthonous OM content in the sediments and total suspended solids in water. Increased OM due to urban pollution in SMA bivalves leads to higher oxidative damage to lipids, which is not counterbalanced by the higher detoxification enzyme glutathione-S-transferase activity. Hence, we can conclude that pollution would explain the drastic reduction in population density, probably related to a high impair in the juvenile’s survival/recruitment, the higher observed mortality and the lower population longevity. When increased OM is supply by the forest, like in Nonthué, this has less negative effect on population density and no effect on longevity at all. However, a negative effect of oxygen depletion due to increased OM (either anthropogenic or natural) on juvenile survival cannot be discarded, but further studies should be carried out to support this idea.

All eyes on chlorpyrifos

Here in Minnesota, the state Department of Agriculture (MDA) just announced a review of Best Management Practices (BMPs) for all agricultural insecticides, but with a special focus on chlorpyrifos.

Why chlorpyrifos? Like many places around the globe, Minnesota has alarmingly high levels of chlorpyrifos in our lakes and rivers. And while chemical build-up in the environment is never a good thing, with chlorpyrifos it's especially troubling because of its well-documented harms to children's health.

read more

Energy resources and feeding guild structure of macroinvertebrate assemblages in the hyporheic zone of calcite depositing lake outlets

Publication date: January 2014
Source:Limnologica – Ecology and Management of Inland Waters, Volume 44
Author(s): Marko Miliša , Marija Ivković , Renata Matoničkin Kepčija
We investigated the distribution of particulate organic matter (POM) and its relation to flow velocity and tufa deposition rates (TDR) in the 4–10 cm deep zone at tufa barriers. We expected surface conditions affect the hyporheic zone, even in habitats with non-moving substrate in calcite depositing lake outlet streams. Additionally, we analyzed feeding guild structure of macroinvertebrate assemblages against environmental conditions, food resources and predatory abundance. Overall, more POM was deposited in the hyporheic zone of slow flow and low TDR habitats. Mean energy stored in the hyporheic POM was 163.4 kJ dm−3. While least abundant in mass, coarse POM represented the majority of organic matter energy stock. Coarse particles accumulated more at fast flow habitats and finer particles accumulated more at slow flow habitats. We propose that fast flow partly flushes small particles and partly macroinvertebrate fauna ingests and converts them to larger particles (fecal pellets) and transports them to the hyporheic zone. Collector gatherers dominated the assemblages (76%) and as passive filterers (4%) they thrived at fast flow sites. Grazers were the second dominant feeding guild (14%) and were more abundant at slow flow sites. Surface flow and predation pressure were the most important controls of hyporheic assemblage structuring. POM content was not as important. We propose that in the stable, non-moving tufa hyporheic zone food is plenty for the scarce fauna so macroinvertebrates are more reactive to predatory pressure. Moog’s functional feeding guild allocation system, while more complex, proved more suitable for our analyses than classification system derived from Cummins’.

Eutrophication impacts littoral biota in Lake Ohrid while water phosphorus concentrations are low

Publication date: Available online 25 September 2013
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Susanne C. Schneider , Magdalena Cara , Tor Erik Eriksen , Biljana Budzakoska Goreska , Alma Imeri , Lirika Kupe , Tatjana Lokoska , Suzana Patceva , Sonja Trajanovska , Sasho Trajanovski , Marina Talevska , Elisabeta Sarafilovska Veljanoska
Eutrophication has traditionally been measured as increased phosphorus concentrations. In some lakes, however, such as transboundary Lake Ohrid situated between Macedonia and Albania, pelagic phosphorus concentrations are low, in spite of known sources of nutrient input. We assumed that littoral biota may be more responsive to phosphorus load than water chemistry, and studied nearshore water chemistry, macrophytes, diatoms and macroinvertebrates at 30 sites around the lake, analyzing functional groups as well as standard eutrophication metrics. We hypothesized that the incorporation of nutrients into benthic biomass will conceal correlations between water phosphorus concentrations and biological eutrophication metrics, but that analysis of functional groups in addition to eutrophication metrics may help draw a plausible picture of how phosphorus is transferred through the food web. Water total phosphorus concentrations in the Lake Ohrid littoral were generally low, while all three analyzed organism groups indicated at least some degree of eutrophication. This shows that littoral biota are more sensitive indicators of nutrient input than hydrochemistry. The abundance of the benthic alga Cladophora sp. correlated positively with water total phosphorus concentrations, indicating that P-loading at local scales may be an important driver of Cladophora biomass. In contrast, none of the biotic metrics (macrophyte index, diatom index, and macroinvertebrate ICM) correlated with ambient water P-concentrations. We argue that this is not a sign of poorly working biological metrics, but a consequence of ecosystem processes in the lake littoral. Analysis of macrophyte and benthic algae abundance, and macroinvertebrate feeding types together with the biotic metrics suggests a meso- to slightly eutrophic littoral ecosystem where nutrient supply is incorporated into macrophyte and benthic algae biomass, and transferred through the food web from benthic algae to grazers, and from macrophytes to shredders and gatherers. Macroinvertebrate filter feeders correlate negatively with water total phosphorus concentrations, suggesting they remove phosphorus from the water. Our results indicate that the combined use of classical biological eutrophication metrics and functional groups may be a way to not only distinguish between oligotrophic and eutrophic ecosystems, but in addition give information as to whether or not nutrient input and nutrient removal in an ecosystem are balanced. This may eventually also give information about ecosystem functioning and ecosystem stability, and thus provide a basis for the development of “second generation” metrics for ecosystem assessment.

Chemocline erosion and its conservation by freshwater introduction to meromictic salt lakes

Publication date: Available online 19 September 2013
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Bertram Boehrer , Uwe Kiwel , Karsten Rahn , Martin Schultze
Salinity stratification has been documented in two meromictic lakes in detail. We present seven years of field data on the salinity stratification of meromictic lakes Wallendorfer See and Rassnitzer See forming in the pits of the former lignite mine Merseburg-Ost in the Central German Mining District. Mainly from groundwater inflows, salinity stratified meromictic residual lakes had formed before freshwater was introduced intentionally over a period of two years to fill the pits more rapidly close to the final water level. From the observations, changes in the salinity stratification were interpreted in terms of deposited potential energy. Freshwater introduction (capping) was quantified in terms of potential energy. Thus the evolution of the salinity profiles was explained and their residual shapes became understandable as a consequence of the flooding procedure. Based on the quantitative estimates of energy deposited in the stratification during deep recirculation in winter, prospective statements could be made about the further evolution of the monimolimnia.

Algal diets and natural xenobiotics impact energy allocation in cladocerans. II. Moina macrocopa and Moina micrura

Publication date: January 2014
Source:Limnologica – Ecology and Management of Inland Waters, Volume 44
Author(s): Rihab Bouchnak , Christian E.W. Steinberg
In freshwater lakes, changing mineral and biochemical food qualities as well as exposure to natural xenobiotics, such as humic substances (HSs) are common challenges to life history traits of zooplankters. In this contribution, we tested the bottom-up effect of different food qualities alone and in concert with exposure to increasing HS concentrations in a clone of each Moina micrura (inhabitant of Brazilian coastal lagoons) and Moina macrocopa (invasive species). Carbon, nitrogen, and phosphorus contents, fatty acid (FA) and the amino acid (AA) patterns of three coccal green algae of the summer aspect in the lagoons were analyzed. All algae were deficient in P, differed in their content of α-linolenic acid (ALA), histidine, and arginine and were lacking long-chained polyunsaturated fatty acids (PUFAs >C18). M. micrura did not grow on Desmodesmus armatus . Maximal mean lifespan and total lifespan reproduction were achieved on Pseudokirchneriella subcapitata . M. macrocopa fed all algae offered. Multiple regressions showed that ALA triggered longevity and the P-content reproduction. Exposure to HSs revealed that M. micrura reduced either its lifespan on Monoraphidium minutum or its reproduction on P. subcapitata . Conversely in M. macrocopa , lifespan on M. minutum was extended by a factor of 1.7 and offspring numbers increased by 1.4 upon HS exposure. On D. armatus an originally very low reproductive output increased maximal by a factor 4.6. Relating HS-mediated lifespan and offspring modulations of the 1.08 mM exposure to food components, it appears that ALA controls lifespan modulation even under HS stress, whereas offspring modulation seems to be controlled by C and total AA content. This indicates that, upon HS exposure, the investment of energy in body maintenance or reproduction would depend at least partly on the biochemical composition of the food available. This also shows that even short-chained dietary PUFAs may play a major role in keeping lipid peroxidation low. A comparison of the two Moina species tested revealed that M. macrocopa has the capacity to outcompete M. micrura , since it had the greater clutch size, never reduced the reproductive output upon HS-exposure, and fed all diets offered.

Pittsburgh is at the forefront of an unruly food movement: Permaculture – Pittsburgh Post Gazette

Pittsburgh is at the forefront of an unruly food movement: Permaculture
Pittsburgh Post Gazette
"I guess they call me 'The Original Gangsta' of Pittsburgh permaculture," he jokes as he plucks a near-ripe berry from one of the bushes at Three Sisters Farm, Mr. Frey's five acres in Sandy Lake, Mercer County. More guru than gangsta, Mr. Frey is one

3rd Annual Farm to Fork Dinner Takes Place September 15 – Tickets Now Available

Join us for the Third Annual Farm to Fork Benefit Dinner, a gourmet field dinner on the landmark UC Santa Cruz Farm to celebrate the work of the Center for Agroecology and Sustainable Food Systems (CASFS) and support the CASFS Apprenticeship’s training of new organic farmers and gardeners.

The event will take place on Sunday, the 15th of September with a reception and tour starting at 3 pm and dinner starting at 4 pm. Dinner will feature a 5-course meal created with organic ingredients from the UCSC Farm & Garden and other local organic farms and ranches. The entrée portion of the menu will offer locally raised meat or fish, and all courses will include full vegetarian options. Fine wines will accompany the meal.

The evening will also include a silent auction; check back soon for examples of auction items.

Tickets for the event are $125 per person and are available online at the Brown Paper Tickets site.
If you prefer to purchase your tickets by mail, send a check for $125 per ticket made payable to UC Regents to: UCSC Farm, 1156 High Street, Santa Cruz, CA, 95064, attn: Benefit Dinner. Please include contact information.
For more information, call 831.459-3240 or email casfs@ucsc.edu. Proceeds will support the CASFS Apprenticeship in Ecological Horticulture program.

Personal and corporate sponsorships for the dinner are available. Please contact us at arblake@ucsc.edu or (831) 459-3857 for details of sponsorship options.

The contribution of seeds to the recruitment of a Nymphoides peltata population

Publication date: January 2014
Source:Limnologica – Ecology and Management of Inland Waters, Volume 44
Author(s): Wei Huang , Kaining Chen , Xian Shi , Kuixiao Ren , Wenchao Li
The Nymphoides peltata population expands quickly in Lake Taihu, China. One question addressed in this study is whether the seeds of N. peltata contribute to this expansion. The buoyancy and germination of N. peltata seeds and the development of N. peltata seedlings were studied, using seeds collected from Lake Taihu. The results indicated that a low wind velocity of 2.4–3.0 m s−1 had a slightly negative effect on seed buoyancy. After 19 and 67 h of gentle stirring, 50% and 90%, respectively, of the N. peltata seeds had sunk. Few seeds floated again after sinking, but these refloating seeds sank soon with the disturbance. The N. peltata seeds did not germinate without stratification, but the stratification of seeds for a two-week period resulted in a high germination rate (63.3%) at a light intensity of 20 μmol photons m−2 s−1. Both the light and stratification treatments stimulated the seeds germination. The seeds did not germinate in sediment at depths greater than 0.25 cm. A high germination rate (74%) was observed for the seeds that laid on the water–sediment interface; however, nearly all of the germinated seeds floated on the water surface after germination. Only a small fraction (14%) of the buoyant seedlings could re-establish in shallow water (less than 3 cm). In the eighth week of the experiments, the buoyant seedlings that failed to re-establish rotted. When grown in low light intensity conditions, the N. peltata seedlings had smaller cotyledons, shorter primary roots, and weak development of adventitious roots. Sufficient light was important for both seed germination and seedling development. It was found that sexual reproduction is likely to have little direct contribution to the rapid expansion of N. peltata towards the centre of this large shallow lake.

Incubation, hatching and survival of eggs of Atlantic salmon (Salmo salar) in spawning redds influenced by groundwater

Publication date: Available online 1 July 2013
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Svein Jakob Saltveit , Åge Brabrand
Many west coastal and northern Norwegian rivers run through deep, confined valleys with permeable layers of glacial and alluvial deposits. Groundwater flows through these permeable layers and enter lakes and rivers as underwater seepage and springs. Groundwater inflow to inland Norwegian rivers may constitute 40–100% of total water discharge during low flow periods in late summer and winter. Juvenile salmonids may take advantage of groundwater upwellings and actively seek out such patches. In regulated rivers groundwater influx may create refuges during low flow or hydropeaking episodes. The importance of groundwater for salmon redd site selection and egg survival is also clear, although less known and documented in regulated rivers. Eggs of Atlantic salmon ( Salmo salar ) are deposited in redds in river bed gravels lacking fine sediments and with high oxygen levels. Egg development is therefore dependent on the interaction of a number of environmental factors such as groundwater influx, oxygen and temperature. Atlantic salmon in the regulated River Suldalslågen, Western Norway, spawn relatively late compared to other Norwegian rivers, with a peak in early January. Newly emerged fry are found from the end of May to the beginning of June, i.e. “swim up” one month earlier than expected using models for egg and alevin development and river water temperatures. The most plausible explanation is that groundwater has a higher and more stable temperature than surface river water. In field experiments, fertilized salmon eggs were placed in boxes close to natural spawning redds in the river bed at sites influenced and those not influenced by groundwater. A difference of up to 40 days in 50% hatching was found, and “swim up” occurred at the end of May in boxes influenced by groundwater. Preliminary studies have revealed that groundwater also plays an important role in survival of salmon eggs in the River Suldalslågen when dewatered in winter. Eggs placed in boxes in groundwater seepage areas during winter in the dewatered river bed survived even when covered by ice and snow. The survival from fertilization until 30 April, one month before hatching, was 91%, the same survival as found for eggs placed in boxes in the wetted river bed. However, mortality from fertilization to hatching was higher compared to the eggs placed in wetted river bed, 57 and 91% respectively. Groundwater creates a horizontal and vertical mosaic of temperatures in spawning redd areas leading to potentially greater variation in spawning sites, time of hatching and “swim up”. This is likely to increase egg survival during low flow periods in regulated rivers. In conclusion, the interaction between groundwater and surface river water should therefore be considered when managing fish populations in regulated rivers.

Optical properties and light penetration in a deep, naturally acidic, iron rich lake: Lago Caviahue (Patagonia, Argentina)

Publication date: Available online 3 June 2013
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Gustavo D. Baffico
The optical properties and light climate in the deep and extremely acid Lake Caviahue have been studied in order to better understand its characteristics and the possible influence upon the phytoplankton community. The absorption coefficients for the dissolved fraction were maximal in the ultraviolet (UV) region and the water absorption spectra showed a shoulder around 300 nm, which was attributed to the concentration of Fe(III). No radiation was detected in the water column below 360 nm. The depth of the 1% incident radiation was dependent of wavelength, showing its maximum of 13.3 m at 565 nm, compared to 1.7 m and 4.8 m at 400 nm and 700 nm, respectively. Phytoplankton biomass was low and showed an almost constant profile with depth despite the relative darkness of the water column. Optical climate of Lake Caviahue is not typical of high elevation lakes but is more similar to low elevation shallow lakes of the Andean region. The chemical composition of the water, mainly Fe oxidation state and concentration, is the responsible for the high attenuation of the UV radiation (UVR). Living organisms are protected of UVR because Lake Caviahue waters are a shield against UV-B.

Bussi communities and preserving Lake VictoriaPublish Date: May 31, 2013 – New Vision


New Vision

Bussi communities and preserving Lake VictoriaPublish Date: May 31, 2013
New Vision
“Each family is given seedlings to plant in an effort to promote agro-forestry and encourage the communities to replace the trees they harvest for timber, firewood and other uses,” Kabiswa explains. The project has helped establish 50 model households

Aquatic macrophyte diversity assessment: Validation of a new sampling method for circular-shaped lakes

Publication date: Available online 10 May 2013
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Mattia M. Azzella , Carlo Ricotta , Carlo Blasi
We propose and validate a new sampling method to assess the presence, abundance and distribution of macrophytes in circular-shaped lakes according to the requirements of the Water Framework Directive (WFD2000/60/EC). The results of the macrophyte survey, and in particular of macrophyte diversity, obtained using this method are also discussed. The sampling is based on randomly selected transects homogeneously distributed around the perimeter of the lake. The number of transects is proportional to the lake’s size. The method was validated on six Italian volcanic lakes using computational resampling procedures on a total of 126 transects. Using resampling procedures, we show that the proposed approach identifies more than 75% of the overall species richness through a moderate sampling effort. According to our results, Charophytes dominate aquatic vegetation in Italian volcanic lakes. Species diversity is highest at shallow depths, whereas the most abundant species, such as Chara polyacantha , are located at an intermediate depth between the shoreline and the maximum growing depth.

Small-scale patterns of meiofauna in a bryophyte covered tufa barrier (Plitvice Lakes, Croatia)

Publication date: Available online 25 April 2013
Source:Limnologica – Ecology and Management of Inland Waters
Author(s): Tvrtko Dražina , Maria Špoljar , Biserka Primc , Ivan Habdija
Meiobenthic fauna is complex and essential part of the stream benthos and it is known as intermediaries from bacteria to higher trophic levels. However, the dynamics and mechanisms regulating this community at small-scale largely have been neglected. This study was carried out to determine meiofaunal dynamics in a small scale-patterns influenced by flow velocity and other abiotic and biotic factors. We examined meiofauna within bryophytes on a tufa barrier in Plitvice Lakes National Park using a detailed taxonomic approach of various meiofaunal groups and their feeding guilds. We choose three microhabitats (slow, medium, fast) differing significantly in flow velocity above bryophytes. Bdelloid rotifers were the most abundant group in microhabitat with highest flow velocity, while in other two microhabitats nematodes and monogonont rotifers prevailed in abundance. Data on environmental variables and main meiofaunal taxa and feeding guilds were analyzed using redundancy analysis. This analysis indicated that microfilter feeding guild (e.g. bdelloid rotifers) was strongly affected by interaction of flow velocity and POM fractions. Other feeding guilds were influenced by temperature, oxygen and/or pH and did not prefer high flow velocity. Suction-feeder nematodes and microfilter-feeder rotifers were dominant on temporal and spatial scale, indicating their good adaptations on frequently disturbed conditions that prevailed on bryophyte covered tufa barrier. Our results provide comprehensive survey of diversity, density as well as trophic structure of meiofauna in aquatic bryophytes. Differences in meiofaunal composition and density between three microhabitats suggest that the meiofauna is relevant indicator of environmental changes even at small-scale pattern.

The unique environment of the most acidified permanently meromictic lake in the Czech Republic

Publication date: Available online 8 April 2013
Source:Limnologica – Ecology and Management of Inland Waters

Changes in the water properties and biological characteristics of the highly acidic Hromnice Lake (Western Bohemia) were investigated. This 110-year-old lake, formed as a consequence of the mining of pyritic shales, is permanently meromictic. Two chemoclines separate an extremely acidic (pH ~ 2.6) mixolimnion from a metal-rich anoxic monimolimnion. The absence of spring mixolimnetic turnover due to ice melting and very slow heat propagation through the chemocline with a 6-month delay were observed. Extreme mixolimnetic oxygen maxima (up to 31 mg l−1) in phosphorus-rich lake (PO 4 3− up to 1.6 mg l−1) well correlated with outbursts of phytoplankton. Phytoplankton consist of several acido-tolerant species of the genera Coccomyxa , Lepocinclis , Chlamydomonas and Chromulina . Surface phytoplankton biomass expressed as chlorophyll- a varies from 2 to 140 μg l−1. Multicellular zooplankton are almost absent with the exception of Cephalodella acidophila , a small rotifer occurring in low numbers. Large red larvae of the midge Chironomus gr. plumosus were found at the bottom close to the shore, with larvulae in the open water. Developmental stages (protonemata) of a moss, resembling filamentous algae, dwell in the otherwise plant-free littoral zone.

Harvard students offer conservation, community concepts to county – Highlands Today

Harvard students offer conservation, community concepts to county
Highlands Today
Sophomore Li Murphy said they got a "crash course" in the local ecology with tours of scrublands, the MacArthur Agro Ecology Research Center and a night walk where they saw many alligators. They visited area lakes and interviewed local fishermen, she

Macroinvertebrate metrics and their integration for assessing the ecological status and biocontamination of Lithuanian lakes

Available online 28 February 2013
Publication year: 2013
Source:Limnologica – Ecology and Management of Inland Waters

We present an assessment system for determining the ecological status (eutrophication and land use pressures) and non-indigenous macroinvertebrate species (NIMS) specific deviation from naturalness of Lithuanian lakes, using semi-quantitative sampling of littoral macroinvertebrates. This system includes two integrated indices, the multimetric Lithuanian Lake Macroinvertebrate Index (LLMI) and the Fauna Autochthony Index (FAI). The LLMI, developed for the assessment of ecological status, averages four metrics: the conventional Average Score Per Taxon (ASPT) and the first Hill’s number (H 1 ), as well as the newly validated number of Coleoptera, Ephemeroptera and Plecoptera taxa (#CEP) and the proportion of Coleoptera, Odonata and Plecoptera individuals (COP). Furthermore, the metrics of biocontamination were transformed into the WFD-compliant FAI for the NIMS-specific naturalness evaluation. The LLMI had significant correlations with total phosphorus, total nitrogen, chlorophyll a , biochemical oxygen demand, water transparency, the morphoindex and the combined trophomorphoindex. Relationships between the LLMI or its core metrics and biocontamination were not found; thus the LLMI and the FAI are not interdependent and have the advantage of separately accounting for pressures requiring different management techniques. Variation of the LLMI and the FAI did not differ between stony/pebbly and vegetated littoral mesohabitats suggesting that any of the mesohabitats or a multihabitat sampling technique can be suitable for a reliable evaluation of lake status. Aquatic beetles revealed themselves as good indicators of the trophic status, while caddisflies and conventional macroinvertebrate metrics ETO and EPT proved unworkable. The ineffectiveness of the latter metrics may be due to the relatively low trophic level in most of the studied lakes which resulted in an increment of caddisfly metrics with an increase of nutrient loads, as well as due to the susceptibility of caddisflies to the invasive species, the zebra mussel Dreissena polymorpha and amphipod Pontogammarus robustoides .

Soap pesticide found in MN lakes

Minnesota lakes contains triclosan, say researchers. An anti-bacterial pesticide found in soap, toothpaste and many other products, triclosan is currently being (slowly) evaluated by both EPA and FDA. Meanwhile, many companies have already pulled it from their list of ingredients in response to concerns about the chemical's health and environmental harms.

University of Minnesota scientists analyzed sediment from eight lakes to understand trends in contaminant levels over time. They found that levels of triclosan and its byproducts have gone up steadily since the chemical entered the market in the 1970s.

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