Download or read book Effects of Differential Grazing and Phosphorus Recycling on Phytoplankton Community Dynamics written by Hans J. Hartmann and published by . This book was released on 1987 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Biology of Cladocera written by V. Korínek and published by Springer Science & Business Media. This book was released on 2013-04-17 with total page 319 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the Second International Symposium on Cladocera, Tatranska Lomnicá, Czechoslovakia, September 13-20, 1989
Download or read book Effects of Acid Precipitation on Aquatic Resources written by and published by . This book was released on 1982 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dissertation Abstracts International written by and published by . This book was released on 1987 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Nutrient Input and Microzooplankton Grazing on Phytoplankton Productivity in the Grand Bay Estuary Mississippi written by Gary Christopher Baine (II.) and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: The estuarine system at Grand Bay National Estuarine Research Reserve in Mississippi is a near pristine wetland home to a diversity of flora and fauna. While seasonal fluctuations in water quality are well understood, less is known about the coupled dynamics of water quality and phytoplankton production. Light availability, nutrient levels, and grazing are key factors regulating phytoplankton. Previous studies have revealed Grand Bay to primarily be limited by nitrogen rather than phosphorus or light. Since then extended phosphate inputs from the neighboring Mississippi Phosphates fertilizer plant have occurred provoking the following question: will the phosphate inputs affect the growth and structure of the phytoplankton communities? This study is investigating the effects of inputs of an array of nutrients (ammonium, nitrate, silicon, and phosphate) on phytoplankton growth, community structure, and production over an annual cycle. Phytoplankton production was monitored as biomass (chlorophyll a concentration) and 14C-bicarbonate fixation. Specific comparisons were made between NH4+ and NO3- to distinguish any preference to different forms of nitrogen (N); however, no preference was observed. Interestingly, the manner in which phytoplankton responded to N additions show that not only is N the limiting nutrient, but that limitation is being exacerbated by excess phosphate (P). Furthermore, this is the first study showing that phytoplankton growth in Bangs Lake was controlled by microzooplankton grazing in all but two months of the study when water temperatures were coolest.
Download or read book Research in Fisheries written by University of Washington. School of Fisheries and published by . This book was released on 1987 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Memorie dell Istituto italiano di idrobiologia dott Marco de Marchi written by and published by ISE CNR. This book was released on 1991 with total page 566 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Spatial and Temporal Dynamics of Phytoplankton Living in Deep Chlorophyll Maxima written by Cornelia L. Sawatzky and published by . This book was released on 2001 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Plankton Dynamics in Mesotrophic Highland Reservoirs of the Colorado River System Texas written by Mary Anne Wallace and published by . This book was released on 2011 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Various ecological and limnological factors affect plankton dynamics and nutrient processing in clear, hard water subtropical reservoirs where temperature and light usually are conducive to year-round phytoplankton growth. Selected reservoirs in the Highland Lakes system that are currently under a point-source discharge ban, yet are slated for future wastewater discharges, were studied by collecting natural plankton assemblages from the surface-mixed layer at various uplake to near-dam sites in the larger reservoir, Lake Lyndon B. Johnson (LBJ), and from the near-dam sites in the two smaller reservoirs, Inks Lake and Lake Marble Falls. My questions were: how do the nutrients, nitrogen (N) and phosphorus (P), affect phytoplankton growth; and to what extent, seasonally, does zooplankton grazing impact phytoplankton, since phytoplankton mortality is a major loss factor of productivity and biomass from the photic zone? Nutrient bioassays were prepared by initially pre-sieving the water to remove adult zooplankton (>150 micron) and with the following treatments: control (no nutrients added); nitrogen (N); phosphorus (P); and N+P. The monthly bioassays were incubated 5-7 d in a growth chamber set at reservoir temperature and seasonal photoperiods. Phytoplankton growth was measured using daily in vivo fluorescence, and by initial and final extracted chlorophyll (Chl a). Phytoplankton growth rates differed statistically among treatments and generally were negligible in the controls and increased four-fold in the N+P treatments. In the single nutrient treatments (N or P), significant interactions occurred with N-limitation during the warmer, stratified months, and P-limitation during the cooler months when the vertical water column was fully mixed. Phytoplankton mortality due to zooplankton grazing was assessed seasonally with natural zooplankton assemblages that were collected by vertical net tows at the near-dam sites of each reservoir. Once in the lab, a density gradient was prepared by adding progressively higher numbers of zooplankton (grazers) to each treatment (0-3X) and incubated from 24-48 h with the ambient phytoplankton assemblages collected from the near-surface mixed layer at various reservoir sites. The 0X treatment had no grazers added to the water and served as a control to assess the phytoplankton growth rate in the absence of grazers. The 1X treatment had about 7-10 grazers, the 2x had about 20 grazers, and the 3X had about 30 grazers added to the ambient phytoplankton assemblages. The grazing rate was determined by the change in phytoplankton growth between 0 and 3X treatments, with phytoplankton growth rate plotted as a linear function of zooplankton density. N and P were added to all treatments at approximately half the concentration of the [NP] in the nutrient bioassays to allow for phytoplankton growth and to dampen the effects of nutrient regeneration by zooplankton. Phytoplankton mortality due to zooplankton grazing was significant by the reservoir copepod-dominated assemblages. In post-analysis, the phytoplankton growth rates in the controls were compared to the overall grazing rates to determine seasonal patterns of growth versus grazing, by season and site. In spring, phytoplankton growth exceeded zooplankton grazing from all sites except one site, and at all but two sites in the late summer. In the fall, winter, and early summer, zooplankton grazing rates were equal to or exceeded growth rates at most sites. Currently, the Highland Lakes' phytoplankton communities are constrained by both ambient nutrient limitation and zooplankton grazing. This study serves as an important assessment of primary producers and secondary consumers in subtropical reservoirs, prior to potential system eutrophication. The ecological and limnological processes studied here also may be useful as indicators to assess ecosystem health, climate, and anthropogenic changes within the context of aquatic food web ecology, limnology, and biogeochemical cycling.
Download or read book Phytoplankton Growth and the Effects of Zooplankton Grazing in a Phosphorus Limited System written by Richard David Pridmore and published by . This book was released on 1979 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Phytoplankton Community Composition Effects on Phosphorus Sedimentation Dynamics in Lake Erie written by Sunniva Bruce Ronzio and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1986 with total page 1140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Index to American Doctoral Dissertations written by and published by . This book was released on 1986 with total page 606 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Decreased Phosphorus Loading on the Phytoplankton Dynamics of Eutrophic Long Lake Washington written by Gwen Pebles Burr and published by . This book was released on 1979 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Previous investigations of eutrophic Long Lake, Washington have shown the major source of algal nutrients to be the city of Spokane's primary sewage treatment effluent. Excess nutrients have promoted large algal standing crops that ultimately decomposed creating extensive hypolimnetic anoxia. To address the problem of excess nutrient loading, an advanced wastewater treatment facility was built by the city of Spokane to remove at least 85 percent of the phosphorus from municipal wastewater. The facility began operation 22 August 1977 and phosphorus removal was initiated 15 December 1977. This investigation has revealed an 80 percent decline in orthophosphate concentrations throughout the reservoir since the initiation of advance wastewater treatment. Orthophosphate concentrations at spring overturn (0.02 mg 1−1) were 20 percent of 1977 spring concentrations. Overall hypolimnetic anoxia has declined by 75 percent. Phytoplankton species composition and seasonal succession showed little change. Although decreased phytoplankton biovolume was exhibited early in the 1978 growing season as a result of decreased nutrient loading to the reservoir, an overall increase was observed due to an isolated bloom of Microcystis aeruginosa Kutz. in September. This resulted in a shift in class dominance from the Bacillariophyceae, seen in all previous years of study, to the Cyanophyceae in 1978. It appeared that a change in nutrient limitation from nitrogen to phosphorus, as determined by algal assay, and decreased heavy metal toxicityto the test alga, Selenastrum capricornutum, may be in part responsible for the predominance of M. aeruginosa. Mean chlorophyll aö concentrations and primary productivity were not distorted by the impact of the M. aeruginosa bloom. Mean annual chlorophyll concentrations have declined significantly from 14.12 mg m−3 in 1977 to 8.79 mg m−3 in 1978. The correlation between chlorophyll aö concentration and phytoplankton biovolume remained positive in spite of the high biovolume observed in September of 1978. Primary productivity also showed a significant decline from 1.45 g C m−2 day−1 in 1977 to 0.88 g C m−2 day−1 in 1978. Fluctuations in phytoplankton standing crop during 1978 appeared to be affected by zooplankton grazing as well as nutrient concentrations. A good correlation existed between decreased phosphorus loading and mean annual chlorophyll aö concentration. This indicated that phosphorus loading gave a reasonable estimate of chlorophyll aö standing crop. Decreases in phosphorus loading, chlorophyll aö concentrations, primary productivity, orthophosphate concentrations and hypolimnetic anoxia indicate the reversion of eutrophic Long Lake, Washington to more mesotrophic conditions"--Document.
Download or read book Oil in the Sea III written by National Research Council and published by National Academies Press. This book was released on 2003-03-14 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the early 1970s, experts have recognized that petroleum pollutants were being discharged in marine waters worldwide, from oil spills, vessel operations, and land-based sources. Public attention to oil spills has forced improvements. Still, a considerable amount of oil is discharged yearly into sensitive coastal environments. Oil in the Sea provides the best available estimate of oil pollutant discharge into marine waters, including an evaluation of the methods for assessing petroleum load and a discussion about the concerns these loads represent. Featuring close-up looks at the Exxon Valdez spill and other notable events, the book identifies important research questions and makes recommendations for better analysis ofâ€"and more effective measures againstâ€"pollutant discharge. The book discusses: Inputâ€"where the discharges come from, including the role of two-stroke engines used on recreational craft. Behavior or fateâ€"how oil is affected by processes such as evaporation as it moves through the marine environment. Effectsâ€"what we know about the effects of petroleum hydrocarbons on marine organisms and ecosystems. Providing a needed update on a problem of international importance, this book will be of interest to energy policy makers, industry officials and managers, engineers and researchers, and advocates for the marine environment.
Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1986 with total page 690 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ocean Acidification written by National Research Council and published by National Academies Press. This book was released on 2010-09-14 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ocean has absorbed a significant portion of all human-made carbon dioxide emissions. This benefits human society by moderating the rate of climate change, but also causes unprecedented changes to ocean chemistry. Carbon dioxide taken up by the ocean decreases the pH of the water and leads to a suite of chemical changes collectively known as ocean acidification. The long term consequences of ocean acidification are not known, but are expected to result in changes to many ecosystems and the services they provide to society. Ocean Acidification: A National Strategy to Meet the Challenges of a Changing Ocean reviews the current state of knowledge, explores gaps in understanding, and identifies several key findings. Like climate change, ocean acidification is a growing global problem that will intensify with continued CO2 emissions and has the potential to change marine ecosystems and affect benefits to society. The federal government has taken positive initial steps by developing a national ocean acidification program, but more information is needed to fully understand and address the threat that ocean acidification may pose to marine ecosystems and the services they provide. In addition, a global observation network of chemical and biological sensors is needed to monitor changes in ocean conditions attributable to acidification.
