Bsa Environmental Services

Beachwood, OH, United States

Bsa Environmental Services

Beachwood, OH, United States
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Catalano M.J.,University of Florida | Catalano M.J.,Michigan State University | Allen M.S.,University of Florida | Schaus M.H.,Virginia Wesleyan College | And 2 more authors.
Hydrobiologia | Year: 2010

We evaluated a biomanipulation program to test for short-term changes in water quality (chlorophyll a, Secchi depth, total phosphorus) and macrozooplankton biomass following partial removal of omnivorous gizzard shad Dorosoma cepedianum. The removal occurred at a eutrophic subtropical lake, and responses were compared to an unmanipulated control lake using a before-after-control-impact paired series analysis. The removal reduced the biomass of large (>300 mm) gizzard shad by 75% over 2 years via a subsidized commercial gill net fishery. However, the total population biomass of gizzard shad was reduced by approximately 32% from an average pre-manipulation biomass of 224 kg ha-1 due to the size selectivity of the gear, which did not effectively capture small fish (<300 mm). No significant short-term changes in chlorophyll a concentration, Secchi depth, total phosphorus concentration or macrozooplankton biomass were detected following biomanipulation. The partial removal may have fallen short of the biomass reduction required to cause ecosystem responses. Our results suggest that moderate omnivore removals (i.e., <40% biomass reduction) will have little short-term benefits to these lakes, and future manipulations should use a less size-selective gear to achieve a larger total biomass reduction. © 2010 Springer Science+Business Media B.V.

Havens K.E.,University of Florida | Beaver J.R.,Bsa Environmental Services
Hydrobiologia | Year: 2011

Crustacean zooplankton data were compiled from long-term observational studies at seven large shallow Florida lakes, to determine whether there are general characteristics in regard to species composition, body size, and biomass. In particular, we examined whether patterns in body size and species richness fit empirical models developed by Stanley Dodson. The lakes included range in size from 125 to 1730 km2 and encompass mesotrophic to hyper-eutrophic conditions. We found that zooplankton biomass was strongly dominated by one species of calanoid copepod-Arctodiaptomus dorsalis. Large daphnids were absent, and Cladocera assemblages were dominated by small taxa such as Ceriodaphnia, Chydorus, and Eubosmina. The total number of species of pelagic cladocerans (8-12) was consistent with Dodson's predictions based on lake area. The average size of crustacean zooplankton in Florida lakes is small in comparison with temperate communities. A. dorsalis is the smallest calanoid copepod in North America, and the mean length of Cladocera (0.6 mm) is consistent with Dodson's results that size decreases from temperate to tropical zones. Total biomass of crustacean zooplankton was very low, ratios of zooplankton to phytoplankton biomass (0.01-0.1) are among the lowest reported in the literature, and the zooplankton displayed short-lasting early spring peaks in biomass. Cladocera were almost entirely absent in spring and summer. Factors known to occur in Florida lakes, which appear to explain these characteristics of biomass, include intense fish predation and high summer water temperature. © 2010 Springer Science+Business Media B.V.

Havens K.E.,University of Florida | Beaver J.R.,Bsa Environmental Services | East T.L.,South Florida Water Management District | Work K.,Stetson University | And 6 more authors.
Freshwater Biology | Year: 2012

We examined 7-12years of monthly to quarterly historical data from 15 lakes in FL, U.S.A. to determine the extent and outcome of invasion by the alien cladoceran Daphnia lumholtzi Sars. The alien species was found in 10 of the 15 lakes, including Florida's three largest lakes: Okeechobee, George and Apopka. All the surveyed lakes had resident populations of the smaller native species Daphnia ambigua Scourfield. In most of the lakes, D. ambigua occurred seven to ninefold more often in plankton samples than D. lumholtzi, and at 10- to 100-fold higher maximal densities. One exception was a small lake in central Florida (Lake Jesup), where D. lumholtzi attained high densities on several occasions in the 10years of sampling. In Lake Okeechobee, where data were of sufficient quality and quantity to perform statistical analyses, the results of canonical correlation analysis indicated that high densities of D. lumholtzi were correlated with lower concentrations of suspended solids, high algal biomass and higher temperature, whereas the opposite conditions were correlated with high densities of D. ambigua. Based on the majority of data, D. lumholtzi has successfully invaded many lakes in Florida, yet it has not become a substantive component of the zooplankton. Additional research is needed to determine whether resources, fish predation or some other factor is responsible for this outcome of invasion. © 2011 Blackwell Publishing Ltd.

Havens K.E.,University of Florida | Beaver J.R.,Bsa Environmental Services | Casamatta D.A.,University of North Florida | East T.L.,South Florida Water Management District | And 4 more authors.
Journal of Plankton Research | Year: 2011

Hurricanes Frances and Jeanne passed over Lake Okeechobee, Florida, in September 2004 and Hurricane Wilma in October 2005. The storms created large waves, strong currents, high wind seiches and uplifted over 3 million metric tons (collectively) of sediments into the water column. Suspended solid concentrations increased five-fold and there were substantial changes in the plankton. Unlike previously documented effects of hurricanes in the open ocean and estuaries, where increased nitrogen inputs stimulate primary productivity, the hurricanes resulted in substantial reductions in biomass of bacteria, phytoplankton and phototrophic nanoflagellates, both in pelagic and near-shore habitats. Increases in macro-zooplankton biomass were observed in both habitats. There were sustained large increases in dissolved inorganic nitrogen and phosphorus in the water column after the hurricanes, coincident with large declines in mean irradiance in the mixed layer. Further, results from laboratory bioassays that exposed the phytoplankton to nutrient additions and a controlled light gradient indicate that the community shifted from being frequently nitrogen limited to most commonly light limited after the storms. The results confirm that the major driver of plankton food-web dynamics in this system is light availability, and that the primary mechanism of change caused by hurricanes is an accentuation of light limitation via greatly increased sediment re-suspension. There additionally was evidence of food-web-mediated effects where the loss of submerged vegetation and increased turbidity reduced the density and efficiency of visually feeding fishes, leading to a significant increase in biomass of macro-zooplankton. © The Author 2011. Published by Oxford University Press. All rights reserved.

Beaver J.R.,Bsa Environmental Services | Casamatta D.A.,University of North Florida | East T.L.,South Florida Water Management District | Havens K.E.,University of Florida | And 4 more authors.
Hydrobiologia | Year: 2013

We demonstrate a major ecological change in a large lake ecosystem in response to a series of extreme weather events. Phytoplankton community dynamics in subtropical Lake Okeechobee are described from 2000 through early 2008 with emphasis on inter-relationships among phytoplankton populations and associated environmental variables in this large, shallow eutrophic lake. The lake experienced the physical effects of three hurricanes in 2004-2005, which caused massive sediment resuspension, near total elimination of submerged aquatic vegetation, elevated biologically available nutrients and total suspended solids, and lower water transparency. Patterns of long-term co-dominance by nitrogen (N)-fixing cyanobacteria and meroplanktonic diatoms abruptly changed to dominance by only meroplanktonic diatoms. The planktonic cyanobacteria genera Anabaena and Planktolyngbya both decreased approximately an order of magnitude in the post-hurricane period despite large surpluses of bioavailable nutrients. Meroplanktonic diatoms (mostly Aulacoseira spp.) declined approximately 20%, perhaps because of superior competitive ability for light in a polymictic, turbid water column. Canonical Correspondence Analysis (CCA) suggested that reduction in planktonic cyanobacteria after compression of the photic zone and the persistence of meroplanktonic diatoms were related to light utilization traits for the key algal taxa and indicated that pre-existing light limitation and crustacean grazing pressure were intensified in the post-hurricane period. © 2013 Springer Science+Business Media Dordrecht.

Havens K.E.,University of Florida | Beaver J.R.,Bsa Environmental Services
Hydrobiologia | Year: 2013

We examined crustacean zooplankton data (excluding nauplii) from 15 shallow lakes in south and central Florida, spanning a range of sizes and Chlorophyll-a concentrations. Each dataset was comprised of monthly samples from 2 years (6 lakes), or monthly to quarterly samples from 10 or 12 years (9 lakes). We quantified relationships between the zooplankton to phytoplankton biomass ratio (BZ:BP) and measurements of BZ and BP at three levels of resolution: (1) sampling events; (2) seasonal means; and (3) period-of-record means and medians. For individual sampling events, variations in ZB explained most of the variation in BZ:BP and ratios were little affected by changes in BP. Seasonal declines in BZ:BP corresponded with declines in BZ, were not related to declines in biomass of edible algae, and happened in spring-summer when earlier studies indicated high densities of planktivorous fish. Period-of-record means and medians did not identify any relationships between the biomass ratio and either BZ or BP, suggesting that processes affecting the ratio operate at shorter time scales than multiple years. Short-term and seasonal changes in BZ:BP in Florida may be controlled by predation. Testing this hypothesis will require coincident sampling of plankton and fish over a number of years or experimental studies. © 2012 Springer Science+Business Media Dordrecht.

Beaver J.R.,Bsa Environmental Services | Jensen D.E.,U.S. Army | Casamatta D.A.,University of North Florida | Tausz C.E.,Bsa Environmental Services | And 6 more authors.
Hydrobiologia | Year: 2013

We assessed if the qualitative and quantitative aspects of plankton composition in reservoirs of the middle Missouri River were influenced by hydrologic variability. Phytoplankton and zooplankton communities in six reservoirs of this highly regulated system were sampled between 2004 and 2011 during historic drought, subsequent recovery, and a 100-year flood event. The reservoir system encompasses a broad latitudinal gradient of decreasing depth, decreasing water residence time and increasing trophic state. Phytoplankton communities of the upper three reservoirs were co-dominated by planktonic and meroplanktonic diatoms during the drought, recovery, and flood periods, but the proportion of more silicified meroplanktonic diatoms increased in the lower three reservoirs as water residence time decreased. Peak phytoplankton biovolume usually occurred during spring/early summer and was associated with increased hydrologic inflows and outflows. Zooplankton biomass of the reservoir system was dominated by Daphnia spp., but all zooplankton groups decreased as inflows and outflows accelerated during the recovery and flood periods. Rotifer abundances were higher under turbulent conditions associated with dam operations. Canonical correlation analyses suggested that temperature, water residence time, station depth, and water clarity explained more variance in the structures of phytoplankton and zooplankton communities than bioavailable nutrient parameters. © 2012 Springer Science+Business Media Dordrecht.

Beaver J.R.,Bsa Environmental Services | Tausz C.E.,Bsa Environmental Services | Renicker T.R.,Bsa Environmental Services | Holdren G.C.,Bureau of Reclamation | And 6 more authors.
Freshwater Biology | Year: 2014

Summary: We tested whether the crustacean zooplankton species composition and size structure (which are important determinants of energy flow in plankton food webs) during late summer in reservoirs would be related to ecoregional designations, catchment land use, temperature and latitude. We also examined whether the predictions of decreasing cladoceran body size with decreasing latitude (as observed for natural lakes) would be valid for reservoirs. Zooplankton samples were collected in late summer 2010 from 102 western U.S. reservoirs distributed over three major ecoregions from 32.5 to 48.6°N latitude. Large-bodied cladocerans (Daphnia pulex complex) and cyclopoid copepods (Diacyclops thomasi) were found in deeper, cooler reservoirs with forested catchments (Northwestern Forested Mountains). Small-bodied cladocerans (Daphnia retrocurva, Diaphanosoma spp. and Chydorus sphaericus) and cyclopoid copepods (Tropocyclops prasinus) were more common in productive reservoirs in catchments influenced by agriculture (Great Plains). Small-bodied cladocerans (Bosmina longirostris) dominated the otherwise modest crustacean zooplankton in reservoirs located in catchments dominated by evergreen shrub vegetation with limited forestation (Western Xeric). Calanoid copepods also displayed clear distribution by ecoregion. Increasing water temperature and decreasing latitude were associated with smaller mean Daphnia and cladoceran body lengths and lower absolute biomass of daphniids. Daphniids were rare or absent in warm waters (i.e. below 36o N latitude and/or from sites located <500 m altitude). Species composition and mean body size of the cladoceran zooplankton were consistent with the feeding habits of the common planktivorous fish - salmon (Oncorhynchus spp.) and lake trout (Salvelinus spp.) in the Northwestern Forested Mountains, gizzard shad (Dorosoma cepedianum) in the Great Plains and threadfin shad (Dorosoma petenense) in the Western Xeric ecoregion. Our study indicates that the taxonomic composition and size structure of the cladoceran zooplankton in reservoirs are highly connected to ecoregional attributes such as catchment land use, temperature and latitude as has been observed for natural lakes. © 2014 John Wiley & Sons Ltd.

Beaver J.R.,Bsa Environmental Services | Scotese K.C.,Bsa Environmental Services | Minerovic A.D.,Bsa Environmental Services | Buccier K.M.,Bsa Environmental Services | And 2 more authors.
Inland Waters | Year: 2012

We describe characteristics of phytoplankton communities of Ohio reservoirs with emphasis on the interrelationships among cyanobacterial populations, land use within 3 ecoregions, and associated environmental variables. We collected 59 phytoplankton samples from 25 mostly productive reservoirs located within 3 distinct ecoregions corresponding to intense agricultural land use (Eastern Corn Belt Plains), intermediate forestation and intermediate agricultural land use (Erie Drift Plain), and heavily forested land (Western Allegheny Plateau) between May and October 2008-2010 and May and June 2011. Cyanobacteria populations peaked in late summer months and were dominated by nitrogen-fixing taxa only in Western Allegheny Plateau and Erie Drift Plain sites, which commonly included Anabaena, Anabaenopsis, Aphanizomenon, and Cylindrospermopsis. Canonical correlation analysis suggests that the qualitative and quantitative characteristics of phytoplankton populations in Ohio reservoirs are strongly influenced by underlying land use practices. Coarse resolution at the ecoregion scale can be valuable in describing potential cyanobacteria composition where detailed nutrient budgets are not available for particular reservoirs and lakes. © International Society of Limnology 2012.

Beaver J.R.,Bsa Environmental Services | Manis E.E.,Bsa Environmental Services | Loftin K.A.,U.S. Geological Survey | Graham J.L.,U.S. Geological Survey | And 2 more authors.
Harmful Algae | Year: 2014

A statistically significant association was found between the concentration of total microcystin, a common class of cyanotoxins, in surface waters of lakes and reservoirs in the continental U.S. with watershed land use using data from 1156 water bodies sampled between May and October 2007 as part of the USEPA National Lakes Assessment. Nearly two thirds (65.8%) of the samples with microcystin concentrations ≥1.0. μg/L (n= 126) were limited to three nutrient and water quality-based ecoregions (Corn Belt and Northern Great Plains, Mostly Glaciated Dairy Region, South Central Cultivated Great Plains) in watersheds with strong agricultural influence. canonical correlation analysis (CCA) indicated that both microcystin concentrations and cyanobacteria abundance were positively correlated with total nitrogen, dissolved organic carbon, and temperature; correlations with total phosphorus and water clarity were not as strong. This study supports a number of regional lake studies that suggest that land use practices are related to cyanobacteria abundance, and extends the potential impacts of agricultural land use in watersheds to include the production of cyanotoxins in lakes. © 2014 Elsevier B.V.

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