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Characterizing The Response Of Coralline Algae To Ocean Acidification And Nutrient Changes In The California Current System
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Book Synopsis Characterizing the Response of Coralline Algae to Ocean Acidification and Nutrient Changes in the California Current System by : Sandy Letzing
Download or read book Characterizing the Response of Coralline Algae to Ocean Acidification and Nutrient Changes in the California Current System written by Sandy Letzing and published by . This book was released on 2013 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ocean acidification (OA) has emerged as an important focus of research and policy in this decade. Ocean acidification specifically refers to changes in the inorganic carbon system in the ocean resulting from its absorption of human-released CO2 from the atmosphere. Anthropogenic atmospheric CO2 levels are rapidly increasing; much of this is dissolved and absorbed in the ocean (~30%) where it reacts with seawater altering fundamental properties including pH, pCO2 and saturation state of carbonate minerals. This change is of concern because of the potential of OA to disrupt biological processes, particularly those processes associated with calcification (Byrne, 2011; Diaz-Pilido, Anthony, Kline, Dove, & Hoegh-Guldberg, 2012). For this study, I chose to investigate red coralline algae as a model organism because OA is predicted to have effects on calcification and photosynthesis, and because of the importance of coralline algae as an ecological engineer, which can be found in shallow water habitats globally. While the response of coralline algae to OA is a serious concern, there remains very limited data on the interactions of OA with other ocean conditions (e.g., temperature, nutrients, and light) that may alter or modify the effects of low pH on coralline algae communities. One nutrient in particular, phosphorus is known to have inhibiting effects on calcification in long-term studies. My objective was to describe the short-term effects of a range of elevated pCO2 and phosphorus levels both alone, and together, on calcification and photosynthetic rates of Corallina vancouveriensis. I exposed these algae to a range of pCO2 and phosphate concentrations and measured changes in total alkalinity, pH, and DO in acute exposure trials (
Book Synopsis Characterizing the Response of Coralline Algae to Ocean Acidification by :
Download or read book Characterizing the Response of Coralline Algae to Ocean Acidification written by and published by . This book was released on 2012 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Ocean Acidification by : National Research Council
Download or read book Ocean Acidification written by National Research Council and published by National Academies Press. This book was released on 2010-10-14 with total page 163 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.
Book Synopsis Impacts of Ocean Acidification on Coralline Algae by : Chenchen Shen
Download or read book Impacts of Ocean Acidification on Coralline Algae written by Chenchen Shen and published by . This book was released on 2017 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: Oceanic uptake of rising anthropogenic CO2 emissions has caused the emergence of ocean acidification as a major threat to marine ecosystems worldwide. Along eastern boundary current systems, seawater is naturally acidified due to coastal upwelling of low pH seawater from depth. Compounded by ocean acidification, upwelling regions are expected to become increasingly corrosive to calcifying organisms, potentially forcing them beyond their physiological tolerance windows. In my dissertation, I focused on the impacts of ocean acidification on calcareous coralline algae in the California Current System. Using coralline algae in rocky intertidal habitats as model organisms, I extend the implications of ocean acidification from the organismal level to the broader community level. Global environmental change implies not only gradual changes in the mean values of environmental variables but also an increase in variability and the likelihood of rare, extreme events. In Chapter 2, I conducted a laboratory experiment to explore potential interactions between two different types of environmental stressors. Specifically, I tested the effects of elevated pCO2, including variable pCO2 treatments, and a severe desiccation event on the coralline species, Corallina vancouveriensis. I found that C. vancouveriensis growth was negatively impacted by both elevated pCO2 and desiccation stress, although their combined effects were approximately additive rather than synergistic. Furthermore, while high pCO2 at constant levels only caused small reductions in algal growth over a two-week period, these effects were exacerbated by pCO2 variability. One criticism of laboratory experiments testing species responses to environmental change is that they isolate organisms under simplified conditions. The potential of overlooking important biotic or abiotic factors present in the natural environment limits the inferences that can be made from laboratory studies. In Chapter 3, I conducted a reciprocal removal experiment at two field sites and two wave exposures to investigate potential changes in the interactions between coralline and fleshy turf-forming algae since the 1980s. I used as a baseline the results from a similar study conducted nearly 30 years ago that failed to detect spatial competition between coralline and fleshy algae. Despite the progression of ocean acidification over the last three decades, my results indicated that the lack of competition between coralline and fleshy algae persists to this day, with results consistent across both sites and wave exposures. The findings in Chapter 3 refer to present-day interactions, but in the future, ocean acidification is expected to be detrimental to coralline algae while potentially benefitting fleshy algae. Both coralline and fleshy algae form turf habitats that shelter diverse epifaunal communities. Thus, changes in the algal composition of turf habitats may lead to broader changes encompassing epifaunal communities, depending on the degree of specialization displayed in epifaunal habitat associations. In Chapter 4, I compared the abundance, richness, and community composition of epifauna between coralline and fleshy turf habitats at four sites along the Oregon-California coast. I found that epifauna were more abundant in coralline turfs due to higher turf density. However, epifaunal richness and community composition were similar between turf types, indicating high levels of redundancy in habitat provision between coralline and fleshy algae. Since most species of epifauna tended to be turf generalists, they may be resistant to the potential indirect effects of ocean acidification involving declines in coralline turf habitat. My dissertation combined a variety of standard ecological methodologies to help translate ocean acidification impacts from the organismal level to the community level. Overall, while I found that elevated pCO2 decreased coralline growth in the laboratory, evidence from the field suggested a capacity for communities to resist the effects of ocean acidification and remain resilient. In the natural environment, ocean acidification impacts may be moderated by multiple environmental variables working in different directions, the temporal dynamics of stressors allowing for periods of recovery, and species interactions having dampening effects. One way forward to unite theories of change with those of resistance is to identify ecosystem indicators and critical thresholds that may help provide a more comprehensive view of ecosystem functioning and stability in the face of global change.
Book Synopsis Oceanic Acidification by : Ronald Eisler
Download or read book Oceanic Acidification written by Ronald Eisler and published by CRC Press. This book was released on 2011-10-04 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book critically examines the available literature on oceanic acidification, including a historical review of pH and atmospheric CO2 levels over the millennia; natural and anthropogenic sources of CO2 to the atmosphere and sea surface; chemical, physical, and biological mode of action; biological effects of acidification to marine plants and an
Book Synopsis The Effects of Nutrient Addition and Ocean Acidification on Tropical Crustose Coralline Algae by : Bridget Francine Shayka
Download or read book The Effects of Nutrient Addition and Ocean Acidification on Tropical Crustose Coralline Algae written by Bridget Francine Shayka and published by . This book was released on 2018 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the global population increases, the occurrence of multiple anthropogenic impacts on valuable coastal ecosystems, such as coral reefs, also increases. These stressors can be global and long-term, like ocean acidification (OA), or local and short-term, like nutrient runoff in some areas. The combination of these stressors can potentially have additive or interactive effects on the organisms in coral reef communities. Among the most important groups of organisms on coral reefs are crustose coralline algae (CCA), calcifying algae that cement the reef together and contribute to the global carbon cycle. This thesis studied the effects of nutrient addition and OA on Lithophyllum kotschyanum, a common species of CCA on the fringing reefs of Mo'orea, French Polynesia. Two mesocosm experiments tested the individual and interactive effects of OA and short-term nitrate and phosphate addition on L. kotschyanum. These experiments showed that nitrate and phosphate addition together increased photosynthesis, OA had interactive effects with nutrient addition, and after nutrient addition ended, calcification and photosynthetic rates changed in unpredictable ways in different OA and nutrient treatments. Because the results of the first two experiments showed impacts of nutrients even after addition stopped, two more mesocosm experiments were conducted to study the changes in photosynthesis and calcification over hourly time scales more relevant to a single nutrient pulse event. These two experiments revealed the existence of diurnal variation in light-saturated photosynthetic rate, but not calcification rate, under ambient and elevated pCO2. This pattern of increased maximum photosynthesis in the middle of the day can have important implications for how the time of nutrient runoff events during the day impacts CCA physiology. Finally, a field experiment was conducted to determine the effects of short- and long-term nutrient addition on L. kotschyanum. The results showed that a series of short-term nutrient additions did not increase photosynthesis or calcification rates above those in ambient nutrient conditions, but continual nutrient enrichment for 6 weeks increased photosynthetic rates. This increase in photosynthesis under only long-term enrichment shows the need for consideration of specific nutrient addition scenarios on coral reefs when predicting how the community will be affected.
Book Synopsis Ecophysiology of Coral Reef Primary Producers by : Maggie Dorothy Johnson
Download or read book Ecophysiology of Coral Reef Primary Producers written by Maggie Dorothy Johnson and published by . This book was released on 2016 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: Natural heterogeneity and global change are key environmental drivers of ecosystem structure and function in both terrestrial and marine ecosystems. At the foundation of all food webs are the primary producers, which require macronutrients and photosynthetic substrate in order to fix inorganic carbon into organic sugars and fuel energy transfer into food webs. This dissertation is an examination of the ecophysiology, or the interaction of organismal physiology with the environment, of key benthic primary producers on coral reefs. Reef-building corals and algae are the most abundant primary producers on coral reefs, and I use coarse functional groupings categorized as reef-building corals, fleshy macroalgae, calcareous macroalgae, crustose coralline algae (CCA) and turf algae assemblages. I assessed the influence of, 1) a natural gradient in inorganic nutrient availability, and, 2) simulated global change on the ecophysiology of corals and algae by functional group. The Southern Line Islands are an archipelago of islands that span the equatorial upwelling region and demonstrate predictable heterogeneity in inorganic nutrient availability. The dominant species of corals and algae demonstrated higher pigment concentrations and photosynthetic efficiency across the archipelago as a function of increasing inorganic nutrient concentrations. This suggests that natural fluxes of inorganic nutrients have an important positive influence on primary producers. I then conducted laboratory experiments on Palmyra Atoll and in Moorea, French Polynesia to test the effects of ocean acidification (OA) and warming on different functional groups of algae. Across a suite of species, OA increased the growth of fleshy macroalgae and turf algae assemblages, but decreased growth and calcification of calcareous macroalgae and CCA. Ocean acidification had a stronger effect than warming on the biomass of turf algae assemblages. Positive effects of OA on turf algae metabolism were increased by warming. These findings suggest that fleshy and calcifying algae respond differently to global change stressors. Ocean acidification has the potential to increase growth and productivity of fleshy algae, while concurrently decreasing growth and calcification of calcifying algae. Anthropogenic activities are increasingly altering the natural environment, and the results of this dissertation improve our ability to predict the response of corals and algae to increasing exposure to nutrients, OA and warming in the near-future ocean.
Book Synopsis Ocean Acidification by : Jean-Pierre Gattuso
Download or read book Ocean Acidification written by Jean-Pierre Gattuso and published by OUP Oxford. This book was released on 2011-09-15 with total page 347 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ocean helps moderate climate change thanks to its considerable capacity to store CO2, through the combined actions of ocean physics, chemistry, and biology. This storage capacity limits the amount of human-released CO2 remaining in the atmosphere. As CO2 reacts with seawater, it generates dramatic changes in carbonate chemistry, including decreases in pH and carbonate ions and an increase in bicarbonate ions. The consequences of this overall process, known as "ocean acidification", are raising concerns for the biological, ecological, and biogeochemical health of the world's oceans, as well as for the potential societal implications. This research level text is the first to synthesize the very latest understanding of the consequences of ocean acidification, with the intention of informing both future research agendas and marine management policy. A prestigious list of authors has been assembled, among them the coordinators of major national and international projects on ocean acidification.
Book Synopsis Review of the Federal Ocean Acidification Research and Monitoring Plan by : National Research Council
Download or read book Review of the Federal Ocean Acidification Research and Monitoring Plan written by National Research Council and published by National Academies Press. This book was released on 2013-07-03 with total page 93 pages. Available in PDF, EPUB and Kindle. Book excerpt: The world's ocean has already experienced a 30% rise in acidity since the industrial revolution, with acidity expected to rise 100 to 150% over preindustrial levels by the end of this century. Potential consequences to marine life and also to economic activities that depend on a healthy marine ecosystem are difficult to assess and predict, but potentially devastating. To address this knowledge gap, Congress passed the Federal Ocean Acidification Research and Monitoring (FOARAM) Act in 2009, which, among other things, required that an interagency working group create a "Strategic Plan for Federal Research and Monitoring of Ocean Acidification." Review of the Federal Ocean Acidification Research and Monitoring Plan reviews the strategic plan on the basis of how well it fulfills program elements laid out in the FOARAM Act and follows the advice provided to the working group in the NRC's 2010 report, Ocean Acidification: A National Strategy to Meet the Challenges of a Changing Ocean. This report concludes that, overall, the plan is strong and provides a comprehensive framework for improving our understanding of ocean acidification. Potential improvements include a better defined strategy for implementing program goals, stronger integration of the seven broad scientific themes laid out in the FOARAM Act, and better mechanisms for coordination among federal agencies and with other U.S. and international efforts to address ocean acidification.
Book Synopsis Guide to Best Practices for Ocean Acidification Research and Data Reporting by :
Download or read book Guide to Best Practices for Ocean Acidification Research and Data Reporting written by and published by . This book was released on 2011 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Marine Animal Forests by : Sergio Rossi
Download or read book Marine Animal Forests written by Sergio Rossi and published by Springer. This book was released on 2017-08-15 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the last decades there has been an increasing evidence of drastic changes in marine ecosystems due to human-induced impacts, especially on benthic ecosystems. The so called “animal forests” are currently showing a dramatic loss of biomass and biodiversity all over the world. These communities are dominated by sessile suspension feeder organisms (such as sponges, corals, gorgonians, bivalves, etc.) that generate three-dimensional structures, similar to the trees in the terrestrial forest. The animal forest provide several ecosystem services such as food, protection and nursery to the associated fauna, playing an important role in the local hydrodynamic and biogeochemical cycles near the sea floor and acting also as carbon sinks. The present book focus its attention on these three dimensional animal structures including, for the first time, all the different types of animal forests of the world in a single volume.
Book Synopsis The Effects of Light, Temperature, and Ocean Acidification on the Physiology and Ecology of Tropical Crustose Coralline Algae by : Amy A. Briggs
Download or read book The Effects of Light, Temperature, and Ocean Acidification on the Physiology and Ecology of Tropical Crustose Coralline Algae written by Amy A. Briggs and published by . This book was released on 2016 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Combined Effects of Ocean Acidification with Morphology, Water Flow, and Algal Acclimation on Metabolic Rates of Tropical Coralline Algae by : Sarah Merolla
Download or read book The Combined Effects of Ocean Acidification with Morphology, Water Flow, and Algal Acclimation on Metabolic Rates of Tropical Coralline Algae written by Sarah Merolla and published by . This book was released on 2017 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: Coral reefs are currently facing multiple stressors that threaten their health and function, including ocean acidification (OA). OA has been shown to negatively affect many reef calcifiers, such as coralline algae that provide many critical contributions to reef systems. Past studies have focused on how OA independently influences coralline algae, but more research is necessary as it is expected that the effects of OA on coralline algae will vary depending on many other factors. To better understand how algal morphology, water flow, and algal acclimation interact with OA to affect coralline algae, three studies were conducted in Moorea, French Polynesia, from June 2015 to July 2016. In January 2016, I tested the hypothesis that algal individuals with higher morphological complexity would exhibit faster metabolic rates under ambient pCO2 conditions, but would also demonstrate higher sensitivity to OA conditions. For three species of crustose coralline algae, Lithophyllum kotschyanum, Neogoniolithon frutescens, and Hydrolithon reinboldii, algal individuals with more complex morphologies demonstrated faster rates of calcification, photosynthesis, and respiration in the ambient pCO2 treatment than individuals with simpler morphological forms. There also appeared to be a relationship between morphology and sensitivity to OA conditions, with calcification rates negatively correlated with higher morphological complexity. In the summers of 2015 and 2016, I conducted three experiments examining the effects of water flow and OA on different morphologies of coralline algae to test the hypotheses that increased flow would enhance metabolic rates and mitigate the effects of OA, and that algae with more complex morphologies would be more responsive to increased water flow and more sensitive to OA conditions. A field experiment investigating the effects of water flow on Amphiroa fragilissima, L. kotschyanum, N. frutescens, and H. reinboldii detected enhanced rates of calcification, photosynthesis, and respiration with increased flow, and this relationship appeared to be the strongest for the crustose algal species with the highest structural complexity. A flume manipulation examining the combined effects of water flow and OA on A. fragilissima, L. kotschyanum, N. frutescens, H. reinboldii, and Porolithon onkodes suggested that coralline algal species with high structural complexity were the most sensitive to OA conditions. Finally, A. fragilissima and L. kotschyanum were maintained in different pCO2 and water flow conditions in a long-term mesocosm experiment, which indicated that flow was unable to mitigate the effects of OA on coralline algae. In the summer of 2016, I investigated the acclimation potential of A. fragilissima and L. kotschyanum to OA, and predicted that the original treatment conditions would induce phenotypic modifications that would influence algal responses to the end treatment. There were negative effects of long-term exposure of coralline algae to elevated pCO2 conditions on calcification and photosynthesis, though partial acclimation in calcification to OA was observed. The instantaneous exposure of elevated pCO2 had negative impacts on algal calcification, but had a nominal effect on photosynthesis. No effects of long-term or instantaneous exposure to elevated pCO2 were observed for respiration. The results of these studies indicate that the coralline algal response to OA conditions will likely be complex and depend on numerous factors including water flow, morphology, and acclimation potential. Therefore, it is critical that future studies further investigate the effects of these factors; specifically examining the mechanisms that underlie these responses in order to better predict the future of coralline algae and thus coral reef ecosystems in a more acidic ocean.
Book Synopsis Fitness of Marine Calcifiers in the Future Acidifying Ocean by : Jonathan Y. S. Leung
Download or read book Fitness of Marine Calcifiers in the Future Acidifying Ocean written by Jonathan Y. S. Leung and published by Frontiers Media SA. This book was released on 2021-11-09 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Ocean Acidification on the California Coast by : Daniel Sergio Swezey
Download or read book Ocean Acidification on the California Coast written by Daniel Sergio Swezey and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As a result of human activities, the level of CO2 in the Earth's atmosphere has increased by nearly 40% since the industrial revolution. The rate of green house gas emission is accelerating, with current trends exceeding those predicted by "worst case" global climate change scenarios. The chemistry of the ocean is fundamentally changing as a result of increasing atmospheric CO2, which dissolves in seawater, making it more acidic, a process referred to as ocean acidification (OA). A rapidly expanding body of science is now being generated to understand the impact of this global environmental change. To date, most studies evaluating OA effects have centered on simplified laboratory analyses that expose single populations to short-term treatments in order to quantify responses of individuals. These designs offer a limited assessment of the degree to which phenotypic plasticity and local adaptation might influence the response of populations to OA. Moreover, as CO2 concentrations in the atmosphere continue to increase, multiple oceanographic factors such as temperature and phytoplankton concentration will also change, and it remains largely unknown as to how multiple concurrent changes in such oceanographic conditions will interact to affect organismal calcification and growth. To address these questions, I carried out studies on members of Phylum Bryozoa, a species-rich clade of calcified colonial marine invertebrates distributed throughout the global ocean. Bryozoans were selected as a model system for this work because the clade exhibits a broad array of growth and calcification strategies, and because of the relative paucity of data regarding their expected response to future acidification. In addition, bryozoans can be subdivided into genetically identical replicate clones, which can then be assigned to separate treatments, allowing variation across treatments to be uniquely partitioned into the variance components of statistical models. In order to culture bryozoans for comparative experiments, I designed and constructed a new flow-through OA system at the Bodega Marine Laboratory, capable of finely manipulating both the temperature and carbonate chemistry of seawater, allowing for controlled laboratory experiments of long duration. In Chapter 1, I performed a comparative 9-month laboratory experiment examining the effects of ocean acidification on the native Californian bryozoan Celleporella cornuta. C. cornuta was sampled from two regions of coastline that experience different oceanographic conditions associated with variation in the intensity of coastal upwelling. Under different CO2 treatments, the biology of this bryozoan was observed to be remarkably plastic. Colonies raised under high CO2 grew more quickly, invested less in reproduction, and produced skeletons that were lighter compared to genetically identical clones raised under current atmospheric values. Bryozoans held in high CO2 conditions reduced their investment in skeletal carbonate, changed the Mg/Ca ratio of skeletal walls and increased the expression of organic coverings that may serve a protective function. Differences between populations in growth, reproductive investment, and the frequency of organic covering production were consistent with adaptive responses to persistent variation in local oceanographic conditions. In Chapter 2, I tested whether skeletal mineralogy can vary plastically in some invertebrates using the cosmopolitan bryozoan Membranipora tuberculata as a model. In a 6-month laboratory experiment, I cultured genetic clones of M. tuberculata under a factorial design with varying food availability, temperature, and dissolved CO2 concentrations. Elevated food availability increased growth in colonies while cold temperatures and high CO2 induced degeneration of colony zooids. However, colonies were able to maintain equivalent growth efficiencies under cold, high CO2 conditions, suggesting a compensatory tradeoff whereby colonies increase the degeneration of older zooids under adverse conditions, redirecting this energy to the maintenance of growth. Elevated food and cold temperatures also decreased Mg concentrations in skeletal material, and this skeletal material dissolved less readily under high CO2 conditions. This suggests that these factors interact synergistically to affect dissolution potential in this and other species. Finally, in Chapter 3, I explore stable isotope values for [delta]18O and [delta]13C in the calcium carbonate structures of the bryozoan Membranipora tuberculata. Stable isotope ratios in the skeletons of various marine invertebrate taxa are widely used to reconstruct historical oceanographic conditions. I tested whether this species accurately records both temperature and pH variability during periods of coastal upwelling by analyzing [delta]18O and [delta]13C in colonies grown in the field and in controlled laboratory cultures. Field-grown colonies were out planted next to a Durafet® pH sensor, which provided a high-resolution record of the temperature and pH conditions these colonies experienced. [Delta]E13C was found to negatively co-vary with pH in both laboratory and field growth, and calculated field temperatures derived from laboratory [delta]18O temperature calibrations aligned with the records from the pH sensor. [Delta]18O[subscript]C values were more depleted under low pH in laboratory trials, which stands in contrast to patterns observed in other taxa. This may indicate that Membranipora utilizes bicarbonate ion (HCO3−) in its calcification pathway, and could help explain why many bryozoan species appear to exhibit enhanced growth under high CO2 conditions.
Book Synopsis The Effect of Ocean Acidification on the Ecology of Two Tropical Crustose Coralline Algae (phylum Rhodophyta) by : Joshua Caraher-Fergusson Manning
Download or read book The Effect of Ocean Acidification on the Ecology of Two Tropical Crustose Coralline Algae (phylum Rhodophyta) written by Joshua Caraher-Fergusson Manning and published by . This book was released on 2017 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crustose coralline algae (CCA) are important members of coral reef communities. They accrete and consolidate the calcium carbonate framework of coral reefs, and some species are an important settlement substratum for coral larvae. CCA community composition is shaped, at least in part, by herbivory and competition. However, ocean acidification (OA) is negatively affecting CCA, with potential to affect CCA responses to herbivory (wounding) and their ability to compete for space. Changes in seawater chemistry because of OA cause reductions in the recruitment, abundance, and net calcification of CCA. In this thesis, the effects of OA on net calcification, regeneration of wounds, and competition was quantified for two species of CCA common in the back reefs of Mo'orea, French Polynesia; Porolithon onkodes and Lithophyllum insipidum. Three separate experiments were conducted in four flowing seawater tanks (flumes), each set to a different target pCO2 level representative of ambient (~ 400 μatm) or predicted end of the 21 century pCO2 (~ 700, 1000, and 1300 μatm). P. onkodes, was found to be the most abundant species of CCA in the back reefs of Mo'orea, followed by L. flavescens and L. insipidum. The abundance of P. onkodes is likely a direct result of its competitive ability. P. onkodes is thicker on average than the other common CCA in the back reefs of Mo'orea, and thicker species generally become dominant in areas of intense herbivory, such as coral reefs. In a flume experiment conducted from January to March 2016, net calcification declined 85% in P. onkodes at elevated pCO2 compared to a decline of 42% in L. insipidum, indicating that P. onkodes may be more negatively affected by OA. The differential responses to OA found here could alter the outcome of competitive interactions between P. onkodes and L. insipidum, leading to changes in the abundances of these species in CCA communities. Few studies have quantified the potential for OA to interact with natural disturbances, such as wounding of the thallus by herbivores. A flume experiment conducted from May to July 2016 found that there was a 58% reduction in the rate of vertical regeneration of artificial wounds within P. onkodes at elevated pCO2. This result could have important implications for the response of P. onkodes to grazing by excavating herbivores like parrotfish and sea urchins. Inability for CCA to recover from wounding, could increase the susceptibility of CCA to further wounding. In addition, the reductions in vertical regeneration of the wounds could also be indicative of reduced vertical growth rates. CCA with thicker thalli generally outcompete thinner CCA. Reduced vertical growth rates could reduce thallus thickness, and affect the outcome of competitive interactions among CCA. A flume experiment conducted from June to July 2016 found that there was no effect of elevated pCO2 on the outcome of competitive interactions between P. onkodes and L. insipidum. It is likely that this result may have been due to the relatively short duration of this experiment (one month). There was, however, an effect of the identity of the competitor on the proportion of live tissue remaining in focal individuals of P. onkodes. The proportion of live tissue remaining in focal individuals of P. onkodes was significantly lower in intraspecific pairings than in interspecific pairings or when paired with non-living substrate (controls). This result highlights the importance of including both intraspecific and interspecific interactions in future studies of the effects of OA on competition. Experiments of longer durations may elucidate the potential for elevated pCO2 to affect competition among CCA. CCA are ecologically important members of coral reefs. Changes in the community composition of CCA on coral reefs, because of altered competitive abilities under elevated pCO2, could affect the roles that CCA play in building and maintain coral reef ecosystems.
Author :International Union for the Conservation of Nature and Natural Resources (IUCN). Global Marine and Polar Programme. Publisher :IUCN ISBN 13 :283171723X Total Pages :140 pages Book Rating :4.8/5 (317 download)
Book Synopsis Bridging the gap between ocean acidification impacts and economic valuation by : International Union for the Conservation of Nature and Natural Resources (IUCN). Global Marine and Polar Programme.
Download or read book Bridging the gap between ocean acidification impacts and economic valuation written by International Union for the Conservation of Nature and Natural Resources (IUCN). Global Marine and Polar Programme. and published by IUCN. This book was released on 2015-05-01 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Following the first international workshop on the economics of ocean acidification organized by the Centre Scientifique de Monaco and the International Atomic Energy Agency in 2010, a second international workshop was held in November 2012, which explored the level of risk, and the resilience or vulnerability of defined regions of the world ocean in terms of fishery and aquaculture species and economic impacts, and social adaptation. This report includes the findings and recommendations of the respective regional working groups and is the result of an interdisciplinary survey of ocean acidification-sensitive fisheries and aquaculture.
