The Effects Of Light Temperature And Ocean Acidification On The Physiology And Ecology Of Tropical Crustose Coralline Algae
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The Effects Of Light Temperature And Ocean Acidification On The Physiology And Ecology Of Tropical Crustose Coralline Algae
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Author : Amy A. Briggs
language : en
Publisher:
Release Date : 2016
The Effects Of Light Temperature And Ocean Acidification On The Physiology And Ecology Of Tropical Crustose Coralline Algae written by Amy A. Briggs and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.
The Effects Of Ocean Acidification Elevated Temperature And Herbivory On Tropical Crustose Coralline Algae
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Author : Maggie Dorothy Johnson
language : en
Publisher:
Release Date : 2011
The Effects Of Ocean Acidification Elevated Temperature And Herbivory On Tropical Crustose Coralline Algae written by Maggie Dorothy Johnson and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.
Ocean Acidification
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Author : National Research Council
language : en
Publisher: National Academies Press
Release Date : 2010-09-14
Ocean Acidification written by National Research Council and has been published by National Academies Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010-09-14 with Science categories.
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.
Investigating The Photophysiology Of A Tropical Crustose Coralline Alga At Different Depths Under Ocean Acidification Conditions
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Author : Ashtyn Lynné Isaak
language : en
Publisher:
Release Date : 2021
Investigating The Photophysiology Of A Tropical Crustose Coralline Alga At Different Depths Under Ocean Acidification Conditions written by Ashtyn Lynné Isaak and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021 with categories.
Ocean acidification (OA) negatively affects marine calcifying organisms and can alter many chemical and physiological processes. Crustose coralline algae (CCA), such as Porolithon onkodes, are important structural calcifying components on coral reefs and they grow across a range of depths. This research investigated the interactive effects of light quantity, spectral quality and pCO2 on P. onkodes to determine if CCA are impacted differentially by OA as a function of depth. In the first experiment, I tested the effects of increased pCO2 on Porolithon onkodes collected from two different depths. Light filters were utilized to simulate light quality at shallow back reef environments at 2-m depth and deeper fore reef environments at 17-m depth in manipulative mesocosm experiments at both ambient and elevated pCO2 treatments (400 μatm pCO2 and 1000 μatm pCO2). Results of this experiment showed no effects of OA on photosynthesis, respiration, calcification, or most photosynthetic pigment concentrations (except for phycoerythrin). Photosynthesis also did not differ between depths suggesting that photosynthesis in this species is not stimulated by blue wavelengths of light and may saturate at low levels of photon flux density (PFD). However, samples from shallow water calcified 64.7% faster than samples from the deep environment over the experiment, which is likely due to increased PFD and also indicates that photosynthesis and calcification may not be as tightly coupled as previously thought. The second set of experiments investigated the differences in photochemical efficiency of P. onkodes under OA conditions in a mesocosm experiment, and also by changes in algal orientation in relation to sunlight at different depths in a field experiment. The effective quantum yield of photosynthetic energy conversion (fluorescence yield), and the relative rate of electron transport through PSII (rETR) were quantified using a PAM fluorometer. Fluorescence yield was greatest in low-PFD environments in both the mesocosm and field experiments by 29.8% - 46.4% compared to the high-light environments. rETR were between 11.0% - 49.4% less than samples from high-PFD compared to low-PFD environments. OA at 1000 μatm pCO2 compared to 400 μatm pCO2 resulted in a decrease of fluorescence yield by 6.7% in the deep treatment, and by 21.7% in the high-PFD environment, which may be attributed to decreases in phycoerythrin pigment concentration. Overall, this study suggests that increased PFD is more important than spectral quality for P. onkodes, and although this study found no effects of OA on photosynthesis, respiration, or calcification rates, it did impact the concentration of the photosynthetic pigment phycoerythrin in low-PFD environments. Decreases in phycoerythrin in elevated pCO2 in low-PFD environments suggests that P. onkodes may be more impacted by OA in a fore reef compared to a back reef environment. Future studies should conduct longer experimental periods to determine if this pattern will ultimately result in decreases in photosynthesis and calcification.
Coralline Algae Globally Distributed Ecosystem Engineers
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Author : Laurie Carol Hofmann
language : en
Publisher: Frontiers Media SA
Release Date : 2020-07-08
Coralline Algae Globally Distributed Ecosystem Engineers written by Laurie Carol Hofmann and has been published by Frontiers Media SA this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020-07-08 with categories.
The Effect Of Ocean Acidification On The Ecology Of Two Tropical Crustose Coralline Algae Phylum Rhodophyta
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Author : Joshua Caraher-Fergusson Manning
language : en
Publisher:
Release Date : 2017
The Effect Of Ocean Acidification On The Ecology Of Two Tropical Crustose Coralline Algae Phylum Rhodophyta written by Joshua Caraher-Fergusson Manning and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.
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.
The Effects Of Nutrient Addition And Ocean Acidification On Tropical Crustose Coralline Algae
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Author : Bridget Francine Shayka
language : en
Publisher:
Release Date : 2018
The Effects Of Nutrient Addition And Ocean Acidification On Tropical Crustose Coralline Algae written by Bridget Francine Shayka and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with categories.
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.
The Combined Effects Of Ocean Acidification With Water Flow And Temperature On Tropical Non Calcareous Macroalgae
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Author : Maureen Ho
language : en
Publisher:
Release Date : 2016
The Combined Effects Of Ocean Acidification With Water Flow And Temperature On Tropical Non Calcareous Macroalgae written by Maureen Ho and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.
The vulnerability of coral reefs has substantially increased in the past few decades due to accelerating human-driven global change. The effects of ocean acidification (OA) and global warming individually and interactively have resulted in varying degrees of responses in benthic reef organisms. For non-calcareous macroalgae, the physiological and ecological responses to physical environmental changes can alter their relative abundances, which are often used as an indicator of the overall coral reef status. To better understand how fleshy macroalgae will respond to various physical parameters, three separate experiments were conducted from June 2014 to July 2015 in Moorea, French Polynesia. An important physical driver in transferring nutrients and dissolved gases to benthic reef organisms is water motion. In 2014, I tested the hypothesis that increased water motion and elevated pCO2 would benefit Amansia rhodantha (a CO2 user) more than Dictyota bartayresiana and Lobophora variegata (HCO3- users). The highest and lowest growth rates were at the intermediate and highest flow speed, respectively, for all three species. A. rhodantha exhibited the greatest reduction in biomass at reduced flow under ambient pCO2, indicating high sensitivity to mass transfer and carbon limitation. In 2015, the interactive effects of temperature and OA were tested in a two-part study on the metabolic (i.e. photosynthesis and respiration) and growth responses of D. bartayresiana and A. rhodantha. The first study in January 2015 showed that net photosynthesis in both species was affected by high pCO2 but not temperature, and the combination of temperature and OA affected respiration rates. In the second study in July 2015, metabolic rates were affected by temperature but not pCO2. Net photosynthesis and respiration of A. rhodantha were highest under OA conditions at 27.5 oC, but were reduced at 30 oC. There was no effect on metabolic rates of D. bartayresiana across all temperature treatments. The relative growth rates for D. bartayresiana were higher than A. rhodantha in the first study, while both species exhibited varying responses to treatments in the second study. Lastly, from May to June 2015, massive Porites spp. was paired with D. bartayresiana in competitive interactions at low and high flow speeds under ambient and elevated pCO2 levels. I tested the hypothesis that increased water flow would increase algal growth rates, enhancing the competitive ability of the alga against the coral. For corals, I predicted that OA and reduced water flow would negatively affect the corals, thus increasing susceptibility to algal overgrowth. Net calcification and the photosynthetic efficiency of corals were used as a proxy for fitness and health status, respectively, however neither was affected by water flow or OA. On the contrary, growth rates of D. bartayresiana were significantly reduced under low flow. The negative effects of reduced water motion on macroalgae may potentially compromise the ability of the alga to compete. The variation in water motion can affect resource acquisition and when combined with OA, can have significant implications on species interactions. These results indicate the importance of water motion in influencing macroalgal growth and provide insights to the varying responses in fleshy macroalgae to global change. Furthermore, their physiological responses may be attributed to their different carbon uptake strategies, as A. rhodantha was more sensitive to reduced flow and temperature than D. bartayresiana.
The Combined Effects Of Ocean Acidification With Fleshy Macroalgae And Filamentous Turfs On Tropical Crustose Coralline Algae
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Author : Lansing Yun Perng
language : en
Publisher:
Release Date : 2019
The Combined Effects Of Ocean Acidification With Fleshy Macroalgae And Filamentous Turfs On Tropical Crustose Coralline Algae written by Lansing Yun Perng and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019 with categories.
The Combined Effects Of Ocean Acidification With Morphology Water Flow And Algal Acclimation On Metabolic Rates Of Tropical Coralline Algae
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Author : Sarah Merolla
language : en
Publisher:
Release Date : 2017
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 has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017 with categories.
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.