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Book Microzooplankton Grazing Growth and Gross Growth Efficiency are Affected by PCO2 Induced Changes in Phytoplankton Biology

Download or read book Microzooplankton Grazing Growth and Gross Growth Efficiency are Affected by PCO2 Induced Changes in Phytoplankton Biology written by Kelly Still and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accumulating evidence shows that ocean acidification (OA) alters surface ocean chemistry and, in turn, affects aspects of phytoplankton biology. However, very little research has been done to determine if OA-induced changes to phytoplankton morphology, physiology and biochemistry may indirectly affect microzooplankton, the primary consumers of phytoplankton. This is one of the first studies to explore how OA may indirectly affect microzooplankton ingestion, population growth and gross growth efficiency (GGE). I hypothesized 1) that the physiology, biochemistry and morphology of the phytoplankton Rhodomonas sp. would be directly affected by elevated pCO2 and 2) that pCO2-induced changes in Rhodomonas sp. would affect grazing, growth rates, and GGE in microzooplankton consumers. To test my first hypothesis, I cultured the ecologically important phytoplankton, Rhodomonas sp., semi-continuously for 17 days under three pCO2 treatments (400ppmv, 750ppmv and 1000ppmv). During this time I characterized Rhodomonas sp. cell size, C:N, cellular total lipids, growth rate, cellular chlorophyll a concentrations and carbohydrates. Rhodomonas sp. cell bio-volume and total cellular lipids were the only aspects of Rhodomonas sp. found to be significantly affected by pCO2. On average, Rhodomonas sp. cell bio-volume increased by ~60% and ~100% and total cellular lipids increased by 36% and 50% when cultured under moderate and high pCO2 treatments, respectively, compared to the ambient treatment. To test my second hypothesis, the pCO2-acclimated Rhodomonas sp. were fed to four microzooplankton species, two tintinnid ciliates (Favella ehrenbergii (recent name change to Schmidingerella sp.) and Coxliella sp.) and two heterotrophic dinoflagellates (Gyrodinium dominans and Oxyrrhis marina). Two experimental designs were used to test whether microzooplankton grazing and growth are affected by OA through changes in prey state. My data confirm my hypothesis that microzooplankton grazing is affected by OA-induced changes to their prey. In three out of the four grazers tested, short term ingestion rates were either higher or non-linear when grazers fed on moderate and high pCO2 acclimated Rhodomonas sp., compared to the ambient treatment cells. Using multiple linear regression models to test for the factors that explain the observed variation in microzooplankton short term ingestion rates across pCO2 treatments, prey cell bio-volume explained 43, 82 and 88% of the variability in short term grazing rates for O. marina, G. dominans and F. ehrenbergii, respectively. In contrast to the short term grazing results, I found that during long term grazing experiments, G. dominans and Coxliella sp. grazed ambient pCO2 acclimated Rhodomonas sp. significantly faster than moderate and high cultured cells. O. marina demonstrated a non-linear feeding response in both short and long term grazing experiments, where O. marina ingested moderate pCO2 acclimated Rhodomonas sp. faster than ambient and high pCO2 acclimated prey. Microzooplankton growth rates were higher for all microzooplankton species when feeding on Rhodomonas sp. cultured under moderate and high pCO2 compared to ambient pCO2 diets. G. dominans and Coxliella sp. were the only grazers that demonstrated a difference in GGE across treatments, showing increased GGE when feeding on prey cultured under elevated pCO2. These findings validate my hypothesis that OA-induced changes in Rhodomonas sp. morphology and biochemistry affects microzooplankton grazing and growth. If the alteration of phytoplankton morphology and nutritional quality observed in this study is wide spread across phytoplankton taxa under OA, and this, in turn, affects microzooplankton grazing and growth dynamics as seen here, it will serve as a mechanism to alter future biogeochemical processes in pelagic marine food webs.

Book Taxon specific Analysis of Microzooplankton Grazing Rates and Phytoplankton Growth Rates Estimated from Chromatographic Pigment Analysis

Download or read book Taxon specific Analysis of Microzooplankton Grazing Rates and Phytoplankton Growth Rates Estimated from Chromatographic Pigment Analysis written by Tye Y. Waterhouse and published by . This book was released on 1992 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Effects of Nutrient Input and Microzooplankton Grazing on Phytoplankton Productivity in the Grand Bay Estuary Mississippi

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.

Book The influence of nutrient addition on growth rates of phytoplankton groups and microzooplankton grazing rates in a mesocosm experiment

Download or read book The influence of nutrient addition on growth rates of phytoplankton groups and microzooplankton grazing rates in a mesocosm experiment written by L. SCHLUTER and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book The Role of Microzooplankton and Mesozooplankton Grazing During the Planktothrix dominated Cyanobacterial Blooms in Sandusky Bay Lake Erie

Download or read book The Role of Microzooplankton and Mesozooplankton Grazing During the Planktothrix dominated Cyanobacterial Blooms in Sandusky Bay Lake Erie written by Matthew R. Kennedy and published by . This book was released on 2020 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the role of internal top-down trophic grazing interactions from zooplankton is necessary to better determine cyanobacterial algal bloom establishment as a parallel to more common investigation into the role of changes in nutrient concentrations, or bottom-up enrichment, on bloom structure and function. Bi-weekly samples were collected from two locations in Sandusky Bay, Lake Erie between March 2019 to October 2019 to capture pre-bloom, early-bloom, and late-bloom conditions. For microzooplankton analysis, dilution experiments were conducted to determine grazing rates using previously established methods. Mesozooplankton grazing rates were determined by concentrating natural populations to 8 times ambient levels, then measuring phytoplankton growth rate changes. After 24 hours samples for both experiments were collected for analysis of total chlorophyll É1 pigment concentration using fluorometry and analysis of chlorophyll É1 pigment concentration as well as phytoplankton community structure using a BBE Fluoroprobe. Phytoplankton cell enumeration using light microscopy was also conducted to determine cyanobacterial cell densities. This research also provided additional insights into correlations of chlorophyll É1 data analysis between fluorometry and BBE Fluoroprobes. Results indicated that microzooplankton were actively grazing on the overall phytoplankton community in the majority of experiments conducted and that microzooplankton grazing rates were not negatively affected by increases in cyanobacterial density. In contrast mesozooplankton grazing rates were extremely low or no grazing was seen in the majority of experiments. Overall, this study indicated that while microzooplankton can play an important role, mesozooplankton grazing may not, in the top-down control of Planktothrix-dominated blooms in Sandusky Bay, Lake Erie.

Book Sensitivity of Phytoplankton to Climate Change

Download or read book Sensitivity of Phytoplankton to Climate Change written by Miriam Seifert and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Marine phytoplankton constitutes about half of the primary production on Earth. It forms the base of the marine food web and is a pivotal player in the marine biological carbon pump. The primary environmental drivers that control phytoplankton growth are temperature, nutrient availability, light, and the concentration of inorganic carbon species. Ongoing climate change modifies these drivers, leading to a warming, high-CO2 ocean with altered nutrient availabilities and light regimes. Changes in phytoplankton productivity and community composition resulting from these newly emerging environmental states in the ocean have important implications for the marine ecosystem and carbon cycling. Biogeochemical ocean models are used to investigate how marine primary production may be affected by future climate change under different emission scenarios. Phytoplankton growth rates in models are typically determined by functions describing growth dependencies on temperature, light, and nutrients. However, a large body of laboratory studies on phytoplankton responses to environmental drivers reveals two points that are usually not considered in current biogeochemical models. Firstly, phytoplankton growth can be considerably modified by the state of the carbonate system. Changes in inorganic carbon species concentrations can be either growth-enhancing (CO2(aq) and bicarbonate are substrates for photosynthesis), or growth-dampening (increasing CO2(aq) levels lead to a shift in the carbonate equilibria and result in a pH decrease, a process which is called ocean acidification). Functions describing this growth dependence of phytoplankton on the carbonate system have not been implemented in large-scale ocean biogeochemical models so far. Secondly, growth responses towards one driver can be modified if the level of another driver is changing. Functions including these so-called interactive driver effects partly exist in models (e.g. the response to varying light levels may depend on the nutrient limitation term). However, the large number of laboratory studies on multiple driver effects has never been used to constrain driver interactions in large-scale ocean biogeochemical models. This holds especially true for the findings of growth responses to driver interactions that include ocean acidification, which make up the largest share of laboratory experiments. This thesis aims to investigate sensitivities of marine phytoplankton to changing CO2(aq) levels as well as to interactive effects between CO2 and other environmental drivers. A comprehensive and reproducible literature search in combination with a statistical analysis (Publication I) reveals that increasing CO2(aq) levels robustly dampen the growth-increasing effects of warming and improving light conditions. In addition, the results show that the calcifying phytoplankton group of coccolithophores experiences the strongest negative effects by ocean acidification compared to other phytoplankton groups. A second study (Publication II) examines the effects of mechanistically described carbonate system dependencies on primary production and community composition in a model. To this end, carbonate system dependencies of phytoplankton growth and and coccolithophore calcification are implemented into the global biogeochemical ocean model REcoM. The study shows that responses to ocean acidification cascade on growth responses to other drivers, which partly balance or counteract the direct impact of the carbonate system on growth rates. In addition, warming is identified as the main driver of the observed recent increase of coccolithophore biomass in the North Atlantic. A final study (Publication III) investigates the interactive effects between CO2 and temperature as well as between CO2 and light on phytoplankton biomass and community composition in a high emission scenario. For the parametrization in REcoM, growth responses to interacting drivers as synthesized in Publication I are used. The decrease of global future phytoplankton biomass and net community production by the end of the century is similar in simulations with and without driver interactions (-6% and -8%, respectively). However, phytoplankton responses to future climate conditions are considerably modified on a regional scale and the share of individual phytoplankton groups in the community changes both globally and regionally when accounting for multiple driver effects. Globally, diatoms and coccolithophores are impacted more and small phytoplankton less severely by future oceanic conditions when accounting for driver interactions. Future projections of the Southern Ocean phytoplankton community are modified most dramatically with the new interactive growth formulation, as diatoms and coccolithophores become less and small phytoplankton more abundant, while it is the other way round in simulations without driver interactions. The thesis highlights 1) that the carbonate system is a critical growth-modifying driver for phytoplankton in a high-CO2 ocean, which can furthermore modify growth responses to other drivers substantially, and 2) that driver interactions have considerable effects on climate-change induced alterations in the phytoplankton community as well as on regional biomass changes in a future ocean.

Book Marine Microzooplankton are Indirectly Affected by Ocean Acidification Through Direct Effects on Their Phytoplankton Prey

Download or read book Marine Microzooplankton are Indirectly Affected by Ocean Acidification Through Direct Effects on Their Phytoplankton Prey written by Kasey Kendall and published by . This book was released on 2015 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book The Effect of Rising Carbon Dioxide on Communities of Freshwater Phytoplankton

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"--

Book Toxicant induced Changes in Zooplankton Communities and Consequences for Phytoplankton Development

Download or read book Toxicant induced Changes in Zooplankton Communities and Consequences for Phytoplankton Development written by Robbert Gerbrand Jak and published by . This book was released on 1997 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book The Ecology of Phytoplankton

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.