Papers by Bruce Sharfstein
Archiv Fur Hydrobiologie, Jan 23, 2006
... Acknowledgements The authors wish to thank ANDY RODUSkY, RYAN MAkI, KIRSTEN WORk, DAN AN-SON,... more ... Acknowledgements The authors wish to thank ANDY RODUSkY, RYAN MAkI, KIRSTEN WORk, DAN AN-SON, MATTHEw HARwELL, MICHELLE TOEPFER, and WILFREDO MATAMOROS for their technical assistance and MARk BRADY for graphical assistance. ...
Estuarine and Coastal Marine Science, May 1, 1976
Sewage wastes discharged into estuaries contain oxidizable organic matter and inorganic nutrients... more Sewage wastes discharged into estuaries contain oxidizable organic matter and inorganic nutrients from which further organic matter may be formed. This paper presents an evaluation of the total discharge of nutrients into the Lower Hudson Estuary and estimates the quantities taken up by photosynthetic organisms under summer and winter conditions. Primary production is shown not to be nutrient-limited at any time in the Lower Estuary and in a seasonally variable area of the Apex of the New York Bight. Primary production contributes a significant part of the oxidizable organic matter to the Lower Estuary. The general approach requires few input data and can be of value in assessing the impact of sewage wastes on receiving waters.
Aquatic Botany, Apr 1, 1999
Portions of the natural littoral community in a subtropical lake were enclosed in mesocosms and s... more Portions of the natural littoral community in a subtropical lake were enclosed in mesocosms and subjected to high rates of nitrogen (N) and/or phosphorus (P) loading over a 28-day period. Changes in periphyton structure and function were compared with untreated controls to evaluate limiting resource effects. Mesocosms that received only P displayed minor increases in whole-community metabolism, measured by in situ oxygen evolution during midday hours, and small increases in the chlorophyll a (CHLA) content of surface periphyton mats. Mesocosms that received only N displayed significant increases in the CHLA content of epiphyton growing on submerged stems of Eleocharis. The most striking treatment effects were observed when both P and N were added. In that case, there were highly significant increases in the CHLA content of surface periphyton mats, epiphyton associated with submerged Utricularia, and periphyton growing on artificial substrata. There also were increases in the rates of phytoplankton carbon uptake and whole-community metabolism. These results indicate that periphyton and phytoplankton were co-limited by P and N, in contrast to previous findings of strong P limitation in more pristine regions of this marsh, and in the nearby Florida Everglades. The community responses in the present study may reflect early eutrophication effects, because the study site was located in close proximity to the lake's eutrophic pelagic region.
Aquatic Botany, Apr 1, 2002
Two separate studies measured the biomass of benthic charophytes in Lake Okeechobee, a large subt... more Two separate studies measured the biomass of benthic charophytes in Lake Okeechobee, a large subtropical lake located in south-central Florida, USA. In one study, five stations in the southern region of the lake were sampled monthly or bimonthly over a 6 year period (1994-1999). A distinct seasonal pattern was observed, with maximum biomass occurring in summer and early fall. Charophyte abundance was positively related to irradiance and negatively related to water depth. A second study took place in 1999-2000, before and after a managed lake drawdown in April, 2000. This whole-ecosystem experiment was designed to lower lake stage by ∼12.5% (0.6 m). We compared charophyte biomass at 42 stations throughout the lake prior to and after this managed recession and evaluated the influence of various environmental variables on growth. This analysis indicated that the recession resulted in increased transparency/bottom irradiance and greater charophyte biomass at nearshore stations. The data are consistent with prior studies, both in Lake Okeechobee and other lakes around the world, which indicate charophyte growth and abundance are strongly influenced by irradiance. We hypothesize that a positive feedback loop resulted in Lake Okeechobee when water levels were lowered, whereby shallower water allowed greater light penetration to the bottom, resulting in increased growth of submerged charophytes. Chara, in turn, probably stabilized sediments, leading to greater transparency and a further improvement of environmental conditions for plant recruitment and growth.
The Progressive fish culturist, Jul 1, 1979
... 0.41 g) from roadside ditches in the vicinity of Sinton, Texas, and from the Aransas River be... more ... 0.41 g) from roadside ditches in the vicinity of Sinton, Texas, and from the Aransas River between Sinton and Refugio, Texas (salinity 0 to ... Bruce A. Sharfstein and Craig Chafin, The Univer-sity of Texas, Marine Science Institute, Port Aran-sas Marine Laboratory, PO Box 1267 ...
Fundamental and Applied Limnology, Dec 7, 2002
The effects of shading on morphometric and meristic characteristics of wild celery, Vallisneria a... more The effects of shading on morphometric and meristic characteristics of wild celery, Vallisneria americana, were investigated in a large outdoor tank (7.7m 3 ) using water, sediment, and plants from Lake Okeechobee, Florida. Plants were grown in peat sediments from the lake under ambient temperature (27-31°C) and photoperiod (13L: 11D). Treatments were established by differentially shading plants with varying numbers of layers of fiberglass screen; photosynthetic photon flux density ranged from 8 to 155 μmole photons m -2 s -1 , or 1.1 to 21.6% of average incident photosynthetically active solar radiation (PAR). Response variables examined included total, above-ground, and below-ground ash-free dry mass (AFDM), epiphytic AFDM, leaf area, number of leaves, mean and maximum leaf widths, and longest, average, and cumulative leaf lengths. Many of these variables indicated statistically significant treatment effects. Only mean and maximum leaf widths, and longest and average leaf lengths had no statistically significant treatment effects. With the exception of cumulative leaf length, which decreased exponentially, all significant response variables decreased linearly with decreasing PAR. Vallisneria in this subtropical lake appears to respond to shading by reducing total, above-ground, and below-ground AFDM, leaf area and number, cumulative leaf length, and its rate of growth. Shading also reduced the AFDM of its epiphytes. The apparent photosynthetic photon flux density for no net growth, measured approximately a quarter meter above the sediment surface, was found to be 29 μmole photons m -2 s -1 with 95 % confidence limits of 0 and 51 μmole photons m -2 s -1 . These results suggest that this submersed vascular angiosperm is capable of survival under conditions of low light. This may be an important adaptation, given the eutrophic condition and generally poor clarity of water in this lake.
Elsevier eBooks, 1978
: From March 1972 to June 1977, a feasibility test of a pilot scale effluent-aquaculture-tertiary... more : From March 1972 to June 1977, a feasibility test of a pilot scale effluent-aquaculture-tertiary treatment system was operated at New York City's Tallman Island Pollution Control Plant. The system was designed to remove and recycle sewage-derived inorganic nitrogen and phosphorus-containing compounds via a phytoplankton-shellfish-phycocolloid producing seaweed managed food chain. Nitrogen (nitrate, nitrite, and ammonia) removal by phytoplankton was generally close to 100%, but the combination of high nitrogen concentrations in the sewage, and productivities of the order of 0.7 g N m-2 day-1 resulted in a minimum culture area requirement of 5 hectares per MGD of sewage. Shellfish grew at rates ranging from 22% to 118% per week, wet weight, and assimilated an average of 22% of the incoming phytoplankton protein-nitrogen, necessitating the removal of nearly 80% of the original incoming nitrogen by the seaweed-effluent polishing step of the system. Seaweeds removed in excess of 90% of the dissolved inorganic nitrogen in the shellfish effluent. Maximum sustained growth rates averaged 10 g dry weight m-2 day-1, but nitrogen fixation rates were only 0.1 g nitrogen m-2 day-1 giving a treatment area requirement of 28.6 hectares per MGD. Based on these results, the potential feasibility of large-scale effluent-aquaculture-tertiary sewage treatment systems is discussed.
Freshwater Biology, Sep 1, 1999
Summary1. An in situ experiment was performed in the littoral zone of a large, subtropical lake t... more Summary1. An in situ experiment was performed in the littoral zone of a large, subtropical lake to quantify effects of phosphorus (P) and nitrogen (N) on algal biomass, productivity, nutrient content and phosphate uptake kinetics.2. We hypothesized that resident periphyton rapidly sequester added nutrients from the water column, but once a certain threshold is reached, nutrients remain in the water and permit a shift to a phytoplankton‐dominated community.3. Three duplicate sets of 1.2‐m diameter mesocosms were treated with 10, 20 or 50 μg P L−−1 in combination with 100, 200 or 500 μg N L−−1, respectively. The nutrients were added thrice weekly for 14 days, after which the treatment doses were doubled for an additional 9 days. The cumulative amounts of P and N added over the course of the study were 700 and 7000 μg L−−1, respectively. Two untreated mesocosms and two open reference sites were used as controls.4. The total P concentration in the water column of nutrient‐treated mesocosms remained low, even after prolonged high dosing. However, there was a two‐fold increase in the P content of surface algal mats and epiphyton. This indicates that some of the added P was sequestered by those components of the community. In contrast, metaphyton and epipelon displayed little or no increase in their P content. Large quantities of added P could not be accounted for in the periphyton community, and may reflect unmeasured losses to the sediments or other pools.5. Nitrogen also was depleted from the water column, but there were no significant increases in periphyton N content. Much of the added N could not be accounted for in mass balances, and may have been lost from the mesocosms through volatilization or other biochemical processes.6. Chlorophyll‐a in epiphyton increased significantly after 14 days in the highest nutrient treatment, where there also was a proliferation of Spirogyra on day 28.7. On day 28, water column samples from the highest nutrient treatment also displayed a significantly higher rate of carbon uptake, and a significantly higher concentration of midday dissolved oxygen.8. The hypothesis that phytoplankton become dominant at high nutrient loading rates was not supported. However, there were dramatic changes in community structure (increased dominance by epiphytic Spirogyra) and function (increased productivity and dissolved oxygen) in response to nutrient additions.
Archiv Fur Hydrobiologie, Oct 29, 2004
... 1989, MAKAREwICZ 1991, SCHwEIZER & HEUSEL 1992, NOZAKI 2001, WETZEL 2001) and tropica... more ... 1989, MAKAREwICZ 1991, SCHwEIZER & HEUSEL 1992, NOZAKI 2001, WETZEL 2001) and tropical systems (PAYNE 1986, TALLING & LEMOALLE ... of the photosynthetic parameters, αB (the light-limited rate of photosynthesis) and Pm B (the maximum photosynthetic rate at ...
Wetlands Ecology and Management, Jan 18, 2013
Ecological attributes of native Eleocharis cellulosa and exotic-invasive Panicum repens communiti... more Ecological attributes of native Eleocharis cellulosa and exotic-invasive Panicum repens communities were compared in the western littoral marsh of Lake Okeechobee, USA. Water quality, periphyton and macroinvertebrates were monitored for 2 years. Fish and zooplankton were monitored during the second year. Mean dissolved oxygen, pH and Secchi transparency were significantly higher in Eleocharis while total phosphorus was marginally higher in Panicum. Periphyton biomass was higher in Panicum but biovolumes were higher in Eleocharis. There were clear differences in the within-habitat periphyton assemblages, less difference in the among-habitat assemblages and moderate to clear differences in periphyton over time in both habitats. Both habitats were dominated by small omnivorous fish. Habitat and date were the most influential factors in differences among both macroinvertebrates and zooplankton, although these differences were marginal to moderate in both cases. Macroinvertebrate densities were higher in Eleocharis while zooplankton densities were higher in Panicum. These data suggest that contrary to the paradigm that Panicum is undesirable as habitat, sparse (\1,000 stems m-2) Panicum in close proximity to Eleocharis may exhibit a similar suite of ecological attributes. Both habitats also appear to contain similar food webs to nearby Everglades marsh communities.
Lake and reservoir management, Sep 1, 2005
Journal of The North American Benthological Society, Mar 1, 2001
The Florida apple snail (Pomacea paludosa) is a critical food source for the endangered snail kit... more The Florida apple snail (Pomacea paludosa) is a critical food source for the endangered snail kite, as well as other regional wildlife. However, very little information is available on the apple snail's feeding habits. To address this information gap, Florida apple snail juveniles from Lake Okeechobee, Florida, were grown in 12 indoor aquaria for 32 d. Snails were provided with freshly collected, approximately equal volumes of either a Utricularia sp./periphyton complex, an Eleocharis sp./periphyton complex, or metaphyton (loosely attached benthic algae) as food sources. Snail growth and survival were significantly higher in the Utricularia treatment than in the metaphyton treatment, but no significant differences in growth were noted between either the Utricularia vs Eleocharis or Eleocharis vs metaphyton treatments. Overall, Utricularia had the highest nutritive quality based on its relatively low C:N ratio and ash content, and high P and chlorophyll (chl) concentrations. Eleocharis had a high C:N ratio and low P content, but also had moderate chl and low ash concentrations. The metaphyton assemblage had a low C:N ratio, but high ash and low chl concentrations. Changes in snail biomass and length were positively correlated with treatment chl content and P content. Changes in snail survival were positively correlated with treatment chl content and inversely correlated with treatment ash content. Snail excreta, collected at the end of the experiment, showed significant differences in N content among all treatments, with the excreta N content of metaphyton-reared snails being twice that of the other 2 treatments. Changes in snail biomass were inversely correlated with snail excreta N content.
The Restoration Coordination and Verification (RECOVER) program activities during 2009 include de... more The Restoration Coordination and Verification (RECOVER) program activities during 2009 include development of the next system status report as well as an interactive web page on which to publish the report. The Comprehensive Everglades Restoration Plan (CERP) Monitoring and Assessment Plan (MAP) is being updated. New tools are being developed to assist with evaluating plans and assessing the status of the system. These tools include expansion of an oyster habitat suitability index for use in additional estuaries; a high-resolution hydrology model coupled with wading bird, alligator, and fish tools; a tool that allows the South Florida Water Management District to assess the ecological response of estuarine indicators to physical stressors such as salinity; and a water budget accounting system. In addition, RECOVER continues to develop new tools to assist with managing, accessing, and utilizing data collected through the MAP program. RECOVER is also working on an adaptive management guidance document for project and systemwide use. As part of the adaptive management program, RECOVER is also currently in the process of updating the Band 1 modeling conditions and developing a compilation of new scientific knowledge gained since CERP was authorized. In addition, RECOVER continues to provide support to CERP projects. BACKGROUND RECOVER is an interagency, interdisciplinary team authorized by Section 385.
Ecological Indicators, Nov 1, 2009
Fundamental and Applied Limnology, Nov 1, 2008
ABSTRACT
Water Research, Mar 1, 2008
Macroinvertebrates were monitored during the summer of 2001 at two paired reference and impact si... more Macroinvertebrates were monitored during the summer of 2001 at two paired reference and impact sites, to assess potential effects of agricultural runoff, which was back-pumped upstream into Lake Okeechobee, USA. Monitoring was conducted prior to back-pumping (Pre, April-May), during back-pumping (BP, June-September) and during the following year (Post, April-September, 2002, impact sites only). Prior to back-pumping, the macroinvertebrate communities at both impact sites differed from those at their respective reference sites. During back-pumping, differences in the macroinvertebrate communities were slightly less pronounced among the eastern pair of sites but were more pronounced at the western sites than they were prior to back-pumping. There also were marginal differences in the macroinvertebrate communities at both impact sites between the Pre and BP periods, while very little change was observed in the communities among the same periods at both reference sites. For the Post-Pre and Post-BP period comparisons, there were clear differences between the macroinvertebrate communities at the western impact site, while less pronounced differences were observed at the eastern impact site. This suggests that the Post back-pumping assemblage did not return to that observed prior to back-pumping activity. During BP, several water-quality variables appeared to be different among each of the paired sites and the correlation between water-quality variables and macroinvertebrate community structure was strong at the western sites but weaker at the eastern sites. This suggests that a combination of abiotic variables may have been influencing the community structure at the western sites while back-pumping was occurring. Macroinvertebrates at all sites reflected poor water quality, but more taxonomic changes during back-pumping were observed at the impact sites than at the reference sites. It is not known if these taxonomic changes resulted in impacts among the macroinvertebrate community or to highertrophic-level predators such as fish. If lake restoration activities result in a shift to a less pollution-tolerant macroinvertebrate community, and the anticipated reduction in future back-pumping activity does not occur, the macroinvertebrate community may return to one that is dominated by pollution-tolerant taxa in affected portions of the lake.
Hydrobiologia, Apr 1, 2004
In situ mesocosm experiments were performed under summer (1997) and winter (1999) conditions in t... more In situ mesocosm experiments were performed under summer (1997) and winter (1999) conditions in the littoral zone of a subtropical lake in Florida, USA. The objective was to quantify phosphorus (P) accumulation by various components of the community after adding pulsed doses of dissolved inorganic P. A short-term experiment also was done to quantify the rate of P loss from the water column, with simultaneous use of an inert tracer to confirm that P depletion was not due to leakage of the tanks. In the experiments, added P was rapidly removed from the water; samples collected 3-4 days after adding spikes of near 100 µg l −1 P contained little or no soluble reactive P. In the short-term experiment, we documented that the half-life of added P was approximately 6-8 h in the water column, and that the tanks were not exchanging water with the surrounding lake. Little of the added P ended up in plankton, rooted vascular plants, or sediments. The main sink for P was periphyton, including surface algal mats, benthic algal mats and detritus, and epiphyton. In the summer 1997 experiment, the periphyton was intimately associated with a non-rooted plant (Utricularia), which also may have sequestered P from the water. Structure of the littoral community varied between summer and winter, and this influenced which periphyton component accounted for most of the P removal. In regard to P mass balances, we accounted for 54% of the added P in 1997, when coarse sampling was done. In 1999, when there was more detailed sampling of the community, 92% of the added P was located in various community components. Subtropical littoral periphyton can be a large sink for P, as long as depth and underwater irradiance conditions favor its growth.
Journal of the North American Benthological Society, 1996
Uploads
Papers by Bruce Sharfstein