Download or read book Modeling Phytoplankton Community Response to Nutrient Loading and Climate Change in a Shallow Temperate Estuary written by Sara A. Blachman and published by . This book was released on 2016 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: Phytoplankton account for at least half of all primary production in estuarine waters and are at the center of biogeochemical cycles and material budgets. Environmental managers use water column chlorophyll-a (chl-a) concentrations as a basic water quality indictor, as the problems of eutrophication and hypoxia are intrinsically linked to excessive phytoplankton growth. Evidence suggests that the distribution and frequency of harmful algal blooms may be increasing worldwide. For the most part, phytoplankton communities follow a standard seasonal pattern, with specific groups dominating the assemblage during the time of year when environmental conditions correspond to their requisites for growth. However, climate change will result in incremental but consistent shifts in some environmental factors known to affect phytoplankton production and biomass accumulation. Mean surface temperatures in North American mid-Atlantic coastal and estuarine regions are steadily rising, and the frequency and severity of drought and storm events are projected to fluctuate, potentially increasing the severity of extreme weather events. Anthropogenically-induced nutrient loading, especially from non-point sources, is one of the largest consistent contributors to coastal marine eutrophication. The consequences of changes in these environmental factors to estuarine ecosystems and phytoplankton community dynamics are unclear. Because different phytoplankton groups respond to environmental changes in distinctive ways, some classes thrive during periods of environmental stability and others at times of temporary or sustained disturbance. To predict how phytoplankton and therefore water quality might respond to changes in climate and land use, we built mathematical phytoplankton kinetics sub-models that differentiate phytoplankton groups using taxonomic classes with well-defined functional characteristics. Then we integrated them into a reduced-complexity estuarine ecosystem model. The sub-models were designed to simulate daily biomass of diatoms, dinoflagellates, cyanobacteria, and raphidophytes in the New River Estuary, NC. We calibrated and validated the model using data collected from 2007 – 2012 through the Aquatic Estuarine monitoring module of the Defense Coastal/Estuarine Research Program. The model was a relatively good predictor of total chl-a and primary production, and a fair predictor of group dynamics. The model was employed in heuristic simulations of changes in temperature, nutrient loading, and freshwater delivery to predict their effects on overall phytoplankton biomass, productivity, and community composition. Increases in temperature had a modest effect on mean daily simulated phytoplankton production and chl-a, but considerably decreased the relative abundance of diatoms and simultaneously increased the relative abundance of cyanobacteria. The seasonal phenology of phytoplankton abundance also shifted in response to increased temperatures: chl-a concentrations were larger in the winter and spring and smaller in the summer and fall. The model was most sensitive to changes in the watershed nutrient load. Nutrient influx had a dramatic effect on the temporal and spatial extent of phytoplankton blooms. The relative abundance of dinoflagellates and raphidophytes increased in response to elevated nutrient loading, regardless of whether load was increased directly as in nutrient simulations or indirectly as in freshwater simulations. Initially, greater freshwater discharge increased total chl-a, productivity, and the frequency of phytoplankton blooms. However, these relationships leveled off or were reversed as flow continued to increase due to greater rates of flushing and light attenuation. Results demonstrated how models like this can be important tools for both heuristic understanding and environmental management. A benefit of this model is how easy it is to update to other estuarine systems through the re-parameterization of the phytoplankton groups.

Download or read book The Ecology of Phytoplankton written by C. S. Reynolds and published by Cambridge University Press. This book was released on 2006-05-04 with total page 437 pages. Available in PDF, EPUB and Kindle. Book excerpt: This important new book by Colin Reynolds covers the adaptations, physiology and population dynamics of phytoplankton communities. It provides basic information on composition, morphology and physiology of the main phyletic groups represented in marine and freshwater systems and in addition reviews recent advances in community ecology.

Download or read book Nutrient and Grazing Control of Estuarine Phytoplankton Growth and Community Composition written by Emily K. Cira and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Estuarine phytoplankton growth is often controlled by nitrogen availability. In addition to overall nitrogen loads, nitrogen form (organic vs. inorganic) is an important factor affecting estuarine phytoplankton growth and community composition. Recent studies have shown that in addition to nitrogen availability, trophic cascades and relaxation of grazing pressure may also be important for phytoplankton bloom formation in estuaries. With a goal of better understanding how nitrogen availability and grazing pressure interact to control estuarine phytoplankton growth and community composition, we examined the individualistic as well as the combined effects of nitrogen (varying availability and form) and grazing pressure on estuarine phytoplankton growth and community composition in the Neuse River Estuary, North Carolina, USA. During each of three sampling events (June 2011, August 2011, March 2012) natural phytoplankton assemblages were manipulated with added nitrogen (as urea or nitrate) and reduced grazing pressure (by filtering out zooplankton grazers). Treatments were incubated for 48 hours in an experimental pond, and subsamples taken daily to assess phytoplankton growth responses to treatments through chlorophyll a, diagnostic photopigments and cell enumerations. The effects of nitrogen additions and reduced grazing pressure varied throughout the events. In June, only nitrogen addition stimulated phytoplankton community growth (chlorophyll a), while in August, only grazing reduction had a significant impact on community growth. Neither treatment had a significant effect on community growth in March, as the phytoplankton community faced phosphorus-limitation and decreased grazing pressure associated with cooler winter/spring temperatures. While both treatments did not continuously effect overall phytoplankton growth throughout all experiments, there were always effects seen in some diagnostic photopigments, indicating varying taxa-specific responses to treatments throughout the year, which can be explained by shifts in phytoplankton community composition and environmental factors. These results demonstrate the importance of both bottom-up (nutrient availability and form) and top-down (grazing) controls in a temperate, eutrophic estuary. Results also hint at the potential for other factors (i.e. light and phosphorus-limitation) to play a role in phytoplankton growth as well. Phytoplankton growth, biomass and community dynamics are relevant indicators of environmental change and this study highlights the need to consider the potential interactive effects of controlling factors for proper management of estuarine ecosystems. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/151400

Download or read book A Practical Handbook of Seawater Analysis written by John D. Strickland and published by . This book was released on 1977 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Clean Coastal Waters written by National Research Council and published by National Academies Press. This book was released on 2000-08-17 with total page 422 pages. Available in PDF, EPUB and Kindle. Book excerpt: Environmental problems in coastal ecosystems can sometimes be attributed to excess nutrients flowing from upstream watersheds into estuarine settings. This nutrient over-enrichment can result in toxic algal blooms, shellfish poisoning, coral reef destruction, and other harmful outcomes. All U.S. coasts show signs of nutrient over-enrichment, and scientists predict worsening problems in the years ahead. Clean Coastal Waters explains technical aspects of nutrient over-enrichment and proposes both immediate local action by coastal managers and a longer-term national strategy incorporating policy design, classification of affected sites, law and regulation, coordination, and communication. Highlighting the Gulf of Mexico's "Dead Zone," the Pfiesteria outbreak in a tributary of Chesapeake Bay, and other cases, the book explains how nutrients work in the environment, why nitrogen is important, how enrichment turns into over-enrichment, and why some environments are especially susceptible. Economic as well as ecological impacts are examined. In addressing abatement strategies, the committee discusses the importance of monitoring sites, developing useful models of over-enrichment, and setting water quality goals. The book also reviews voluntary programs, mandatory controls, tax incentives, and other policy options for reducing the flow of nutrients from agricultural operations and other sources.

Download or read book Uncovering Mechanisms of Phytoplankton Response to Climate Change written by Gwenn M. Miller Hennon and published by . This book was released on 2015 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: Phytoplankton are responsible for approximately half the primary production on earth, fueling marine food webs and driving the cycling of carbon and inorganic nutrients in the oceans. Climate change is predicted to alter the marine environment by elevating carbon dioxide, increasing temperature, and decreasing the availability of inorganic nutrients in the surface ocean where phytoplankton dominate. To predict phytoplankton productivity and abundance in the future requires an understanding of the mechanisms of phytoplankton response to these environmental changes. Here we investigate how a model phytoplankton, Thalassiosira pseudonana, acclimates to increasing carbon dioxide through physiological and gene expression changes, and how picophytoplankton communities in the tropical Atlantic respond to variations in temperature and nutrient availability. By uncovering mechanisms of phytoplankton response to environmental variables we gain new insights into predicting how marine food webs and biogeochemical cycles may be altered by climate change.

Download or read book Plankton Ecology written by Ulrich Sommer and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: All relevant ecological aspects of plankton, especially seasonal changes in the species composition, the role of competition for limiting resources in species replacements, the role of parasitism, predation and competition in seasonal succession are treated in detail considering phytoplankton, zooplankton and bacteroplankton. In addition to its use as a valid reference book for plankton ecology, this monograph may well be used as a model for other kinds of ecological communities.

Download or read book Treatise on Estuarine and Coastal Science written by and published by Academic Press. This book was released on 2012-03-06 with total page 4604 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of estuaries and coasts has seen enormous growth in recent years, since changes in these areas have a large effect on the food chain, as well as on the physics and chemistry of the ocean. As the coasts and river banks around the world become more densely populated, the pressure on these ecosystems intensifies, putting a new focus on environmental, socio-economic and policy issues. Written by a team of international expert scientists, under the guidance of Chief Editors Eric Wolanski and Donald McClusky, the Treatise on Estuarine and Coastal Science, Ten Volume Set examines topics in depth, and aims to provide a comprehensive scientific resource for all professionals and students in the area of estuarine and coastal science Most up-to-date reference for system-based coastal and estuarine science and management, from the inland watershed to the ocean shelf Chief editors have assembled a world-class team of volume editors and contributing authors Approach focuses on the physical, biological, chemistry, ecosystem, human, ecological and economics processes, to show how to best use multidisciplinary science to ensure earth's sustainability Provides a comprehensive scientific resource for all professionals and students in the area of estuarine and coastal science Features up-to-date chapters covering a full range of topics

Download or read book Spatiotemporal Dynamics of Phytoplankton Biomass and Community Succession for Driving Factors in a Meso Eutrophic Lake written by Jing Cao and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The dual effects of climate change and nutrient load on lake phytoplankton blooms, both caused by human activities, have attracted much attention. However, their roles and synergistic effects on phytoplankton biomass and community historical succession are not well understood, especially for meso-eutrophic plateau lakes. In this study, a multi-year (1997-2022) monthly dataset including hydro-chemical and meteorological indicators of the meso-eutrophic plateau lake Erhai in China, was used to explore the contributions of climate change and nutrient load on phytoplankton biomass variation and community succession. Phytoplankton biomass increased from 1997 to 2006, slowly decreased from 2006 to 2015, then increased again from 2015 to 2022, according to a generalised additive model (GAM). Alongside warming, carbon, nitrogen and phosphorus nutrients are key drivers of long-term interannual variation in phytoplankton biomass and historical succession of the phytoplankton community. The extensive blooms in recent years were strongly associated with both organic matter accumulation and global warming. Phytoplankton biomass in northern and southern districts was greater than in central areas, with Cyanophyta and Pyrrophyta dominating in the north and Chlorophyta prevalent in the south. Since 2015, phytoplankton diversity has increased significantly, and biomass has declined in the southern district but increased markedly in the northern district. Spatial heterogeneity was caused by the spatial distribution of nutrients and the buoyancy regulation capacity of cyanobacteria. The results demonstrate that bloom mitigation responds strongly to nitrogen and phosphorus control in meso-eutrophic lakes. Given the accumulation of organic matter in recent years, synergistic control of organic matter and total nitrogen and phosphorus could effectively reduce the risk of cyanobacterial and dinoflagellate blooms.

Download or read book The Effect of Rising Carbon Dioxide on Communities of Freshwater Phytoplankton written by Egor Katkov and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Human activities, such as CO2 emissions are altering aquatic ecosystems in ways that are not fully understood. Because phytoplankton are essential organisms, forming the base of pelagic aquatic food webs, I focus on this group to help us understand how lake ecosystems respond to anthropogenic change. Specifically, I focus on the response of total phytoplankton biomass and community composition to increasing pCO2 in concert with (1) nutrient enrichment, (2) increasing temperatures, and (3) organismal evolution.In the first chapter, I investigated whether CO2 can act as a co-limiting resource that can promote phytoplankton growth and alter community composition across different times of the year. I conducted experiments using mesocosms suspended in a temperate mesotrophic lake, and designed them to evaluate the interactive effects of nitrogen, phosphorus, and CO2 enrichment in the months of July, August, October, April and June. I found that, in some seasons, CO2 acted as a co-limiting factor with phosphorus when nitrogen was also added. The phytoplankton community was affected by all three resources in diverse ways at different times of the year. I concluded that CO2 can affect the community composition and be a co-limiting factor for freshwater phytoplankton communities, especially when other resources are abundant, as is typical in eutrophic lakes.In chapter two, I investigated the interactive effect of CO2 and temperature on phytoplankton and zooplankton communities, two highly inter-related factors in the context of climate change. In the same lake as Chapter 1, I ran a single mesocom experiment in late Fall over four weeks. I did not detect an interactive effect between CO2 and temperature, although both factors had independent and additive effects on the phytoplankton community, and temperature altered zooplankton community composition. Additionally, CO2 altered the stoichiometry of the seston, which has been shown in other studies to affect zooplankton food quality. I concluded that, although no evidence for interactive effects was found, CO2 and temperature can have independent and additive effects across and multiple trophic levels in freshwater ecosystems.The third chapter deals with the evolutionary potential of phytoplankton species responding to changing atmospheric CO2 concentrations. I developed an eco-evolutionary model where phytoplankton growth depends on the influx of atmospheric CO2 and carbon uptake kinetics can evolve to trade off maximum carbon flux for affinity. At equilibrium, I found that populations adapted by optimizing carbon uptake to environmental conditions, which, in modelled monocultures, allowed populations to reach higher biomass, and in multi-species communities, allowed certain species to gain an unexpected advantage over others. The biomass increases depended on the species-specific parameters and concentrations of atmospheric CO2 and initial HCO3. I concluded that evolution in the context of changing pCO2 can affect community composition and generate greater biomass increases than expected from CO2 co-limitation alone.In sum, I found that biomass and composition of freshwater phytoplankton communities can be affected by increases in pCO2, by co-limitation, potentially in concert with factors like temperature, and evolution. One key observation and conclusion across all chapters of this thesis is the ecological and evolutionary effects of CO2 are generally small (compared to eutrophication) and may be involved in complex interactions. Such small effect sizes may seem to make it unnecessary to study the effects of enriched CO2. However, the fact that pCO2 concentrations are increasing worldwide, that even a small but large-scale effect can be significant, and that freshwaters are fragile but essential ecosystems, at the mercy of countless potentially interacting human activities, emphasizes the importance of understanding the impact of high pCO2 on freshwater communities"--

Download or read book Modeling the Plankton Enhancing the Integration of Biological Knowledge and Mechanistic Understanding written by Christian Lindemann and published by Frontiers Media SA. This book was released on 2017-12-28 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: In light of climate change and allied changes to marine ecosystems, mathematical models have become an important tool to examine processes and predict phenomena from local through to global scales. In recent years model studies, laboratory experiments and a better ecological understanding of the pelagic ecosystem have enabled advancements on fundamental challenges in oceanography, including marine production, biodiversity and anticipation of future conditions in the ocean. This research topic presents a number of studies that investigate functionally diverse organism in a dynamic ocean through diverse and novel modeling approaches.

Download or read book On the Response of Marine Phytoplankton to Changing Nutrient and Light Conditions written by Katherine Rose Marie Mackey and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Marine phytoplankton are photoautotrophic microorganisms that synthesize organic biomass from mineral nutrients and form the base of the marine food web. Marine phytoplankton are increasingly being recognized as important contributors to biogeochemical cycling of chemical elements, including carbon (C), and therefore play a role in controlling Earth's climate. A relatively recent estimate suggests that while the upper 100 meters of the ocean contains less than 1 percent of the total global photosynthetic biomass, this small fraction of the marine environment accounts for nearly 50 percent of global primary production, the process by which atmospheric carbon dioxide is incorporated into biomass through photosynthesis. Nutrients and light affect phytoplankton growth, and their availability exerts considerable control on phytoplankton distributions in the ocean and their contribution to biogeochemical cycles. The global supply, distribution, and availability of nutrients in the ocean are driven by a range of physical and biological factors. However, light availability is determined primarily by attenuation within the water column. The ability of a phytoplankton group to respond to changes in nutrient and light availability ultimately determines whether that group will persist, or whether community succession will permit different, more ecologically competitive groups to prevail. The overarching goal of this dissertation is to identify and understand how responses to changing resource availability influence the competitive success of phytoplankton, and to increase our understanding of how phytoplankton affect biogeochemical cycling of C and other important nutrients in the ocean. The dissertation includes an Introduction (Chapter 1), and seven research chapters (Chapters 2-8) covering separate bodies of work, each focusing on a different topic as outlined below. In Chapter 1, general background information is provided about nutrient and light regimes in the ocean, and about the basic biology and ecology of phytoplankton. Chapter 2 (entitled: The phosphorus cycle) provides an overview of the phosphorus (P) cycle including sources, sinks, and transport pathways of P in the environment, microbially-mediated processes and their genetic regulation, methods for assessing environmental P concentrations and microbial phosphate status, and a discussion of microbial responses to anthropogenic changes to the P cycle. This chapter was published in 2009 in The Encyclopedia of Microbiology, 3rd Edition, edited by Moselio Schaechter, Elsevier. Chapter 3 is entitled: Phosphorus availability, phytoplankton community dynamics, and taxon-specific phosphorus status in the Gulf of Aqaba, Red Sea. The study uses a novel cell stain to show that (1) coexisting groups of phytoplankton exposed to identical phosphate levels may have a different phosphate status, and (2) although increased alkaline phosphatase activity can serve as an indicator of phosphate limitation, it does not necessarily confer a competitive advantage to cells in oligotrophic waters, where smaller cell size may provide a more important competitive edge. The affinity of individual groups of phytoplankton for P may help determine community composition and lead to seasonal community succession as P availability changes dramatically throughout the year. This chapter was published in 2007 in Limnology and Oceanography 52: 873-885. Chapter 4 is entitled: Nitrogen cycling in oligotrophic waters: the influence of light and substrate availability. This study demonstrates that two major processes contribute to formation of nitrite maxima in the Gulf of Aqaba: (i) spatially segregated microbial oxidation of ammonium and nitrite during nitrification; and (ii) incomplete nitrate reduction to ammonium by light-limited phytoplankton. Field data and stable isotope (N-15) tracer experiments show that physical and biological characteristics of the water column determine which of the two nitrite formation processes becomes dominant at a given season and depth. Rates are reported for major N transformation reactions occurring in the N cycle. This chapter is currently in review with Limnology and Oceanography. Chapter 5 is entitled: Picophytoplankton responses to changing nutrient and light regimes during a bloom. In the Red Sea, the spring bloom is characterized by a rapid increase in photosynthetic biomass. Nutrient addition experiments and in situ monitoring show that picoeukaryotes and Synechococcus have a bloomer growth strategy, have higher P requirements relative to N, and are responsible for the majority of photosynthetic biomass in surface waters. In contrast, light limited populations show rapid photoacclimation and community shifts following stratification. The traditional interpretation of "bloom" dynamics (i.e. increase in biomass) may therefore be confined to surface waters where light is not limiting, while other acclimation processes are more ecologically relevant at depth. This chapter was published in 2009 in Marine Biology 156: 1531-1546. Chapter 6 is entitled: A photosynthetic strategy for coping in a high light, low nutrient environment. This chapter reports field observations from the Atlantic and Pacific Oceans that show the reduction of oxygen is important for preserving photosynthetic efficiency in oligotrophic waters where low Fe levels may limit PSI and cytochrome b6f biogenesis. Despite midday photoinhibition (depression in the maximum photochemical yield, Fv/Fm), cells do not show a decreased capacity for carbon dioxide fixation. Instead, the fraction of oxidized functional PSII reaction centers increases at midday, counteracting the loss of functional centers stemming from photoinhibition. This process was not apparent in the coastal phytoplankton populations monitored in this study, and may be a strategy unique to open ocean phytoplankton. This chapter was published in 2008 in Limnology and Oceanography 53: 900-913. Chapter 7 is entitled: The influence of atmospheric nutrients on primary productivity in a coastal upwelling region. This chapter is the first study to quantify the role of atmospheric deposition in supporting productivity an upwelling-dominated system (coastal California). Soluble nutrient measurements from locally-collected aerosols, oceanographic and atmospheric data from long-term monitoring programs and the MODIS satellite record, and laboratory culture experiments are used. The aerosol-Chlorophyll a relationship is significant in the summer, and is stronger at offshore locations than near the coast. Atmospheric nutrient sources are more important during El Niño periods when upwelling is suppressed, a phenomenon that may become more common due to climate warming. During high deposition non-upwelling periods aerosol N could support up to 20 percent of new production. Expanding our analysis to other regions, we find that atmospheric deposition may support up to 8 percent of production annually in other major coastal upwelling regions around the world. This chapter is currently in review with Global Biogeochemical Cycles. Chapter 8 is entitled: Toxicity of metals on marine Synechococcus. Atmospheric deposition of aerosols to the surface ocean is a source of nutrients for phytoplankton. However, this study demonstrates that atmospheric aerosols also contain components like copper (Cu), which are toxic to some phytoplankton above certain threshold levels. Incubations of natural phytoplankton assemblages with local aerosols show that metal toxicity can cause a major shift in phytoplankton community composition, suggesting that atmospheric aerosols may play a larger role in controlling phytoplankton species distributions than previously believed. Specific metal toxicity threshold concentrations were determined based on laboratory culture experiments with coastal and oceanic strains of Synechococcus, and oceanic strains are more susceptible to metal toxicity at lower concentrations and for a larger number of metals. A portion of this chapter was published as part of a larger study that also included a global model for Cu deposition in aerosols that was published in 2009 in The Proceedings of the National Academy of Science 106: 4601-4605 Chapter 9 discusses ideas for future work. The dissertation provides valuable information about how phytoplankton respond to resource availability in a number of different marine environments. The physical environment is shown to play an important role in determining nutrient and light availability over short term periods (e.g. transient exposure to high light during mixing, episodic delivery of aerosol nutrients) as well as over predictable seasonal cycles (e.g. deep convective mixing and stratification). Physiological acclimation of individual phytoplankton to these perturbations allows each species to survive over a broader range of conditions, increasing their competitive advantage. Similarly, succession allows the phytoplankton community as a whole to thrive over the broadest possible range of environmental conditions. This dissertation also shows that phytoplankton play an important role in the P and N cycles by generating organic substrates from inorganic substrates. In doing so, phytoplankton contribute substantially to primary production in coastal and open ocean habitats, and form and important link between the biotic and abiotic environment.

Download or read book Ecology Conservation and Restoration of Tidal Marshes written by Arnas Palaima and published by Univ of California Press. This book was released on 2012-09-08 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: The San Francisco Bay, the biggest estuary on the west coast of North America, was once surrounded by an almost unbroken chain of tidal wetlands, a fecund sieve of ecosystems connecting the land and the Bay. Today, most of these wetlands have disappeared under the demands of coastal development, and those that remain cling precariously to a drastically altered coastline. This volume is a collaborative effort of nearly 40 scholars in which the wealth of scientific knowledge available on tidal wetlands of the San Francisco Estuary is summarized and integrated. This book addresses issues of taxonomy, geomorphology, toxicology, the impact of climate change, ecosystem services, public policy, and conservation, and it is an essential resource for ecologists, environmental scientists, coastal policymakers, and researchers interested in estuaries and conserving and restoring coastal wetlands around the world.

Download or read book Mathematical Modeling of Phytoplankton in Lake Ontario written by Robert V. Thomann and published by . This book was released on 1976 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Water Resources in a Variable and Changing Climate written by Simon Beecham and published by MDPI. This book was released on 2018-10-04 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Water Resources in a Variable and Changing Climate" that was published in Water

Download or read book Mathematical Modeling of Phytoplankton in Lake Ontario written by Robert V. Thomann and published by . This book was released on 1975 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Phytoplankton Community Structure Response to Groundwater borne Nutrients in the Inland Bays DE written by Daniel M. Torre and published by . This book was released on 2016 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: We conducted a series of experiments, coupling seepage meters directly to phytoplankton enclosure experiments to determine the impacts of groundwater-borne nutrients on biomass and response in community structure of phytoplankton. To assess the impacts of groundwater-borne nutrients, we measured chlorophyll a concentrations as a proxy for overall biomass and used genetic sequencing techniques to characterize the phytoplankton community structure. Groundwater carried a high N load to the estuary with NO3- up to 295 μmol/L, and NH4 + up to 55 μmol/L. As a result treatment mesocosms had NO 3- concentrations up to 55.5 μmol/L and NH 4+ up to 4.0 μmol/L, while control mesocosms received filtered seawater, and were thus relatively low in nutrients (24.2 μmol/L NO3- and ∼2 μmol/L NH4 +). In June the highest chlorophyll a concentrations occurred after 3.5 days, with significant differences between control mesocosms (4.3±0.2 mg/L), groundwater amended mesocosms (7.0±0.6 mg/L), and mesocosms receiving groundwater across the sediment-water interface (10.9±0.2 mg/L). In August, biomass peaked after 3 days and showed larger variation across treatment groups with groundwater amended mesocosms reaching significantly higher values (36.6±2.0 mg/L) than mesocosms receiving groundwater across the sediment-water interface (18.7±4.8 mg/L), which showed significantly different values than both controls and phosphate amended mesocosms (11.9±0.7 and 9.9±0.2 mg/L respectively). Community gene sequence data showed that species assemblage was also impacted by availability of nutrients, with significant differences in community structure for mesocosms receiving nutrients vs control mesocosms in both June and August experiments. Several harmful algal species also proliferated in high nutrient treatments, including Cylindrotheca closterium, Karlodinium veneficum, Nitzschia ovalis, and Heterocapsa sp. Our study demonstrates the importance groundwater-borne nutrients play in structuring the phytoplankton community, and the potential impacts of nutrient loading through groundwater transport. More research is needed to further identify spatial and temporal differences in groundwater-borne nutrient discharge and response of phytoplankton community structure.