Assessing the vulnerability of marine invertebrates to ocean acidification (OA) requires an understanding of critical thresholds at which developmental, physiological, and behavioral traits are affected. To identify relevant thresholds for echinoderms, we undertook a three-step data synthesis, focused on California Current Ecosystem (CCE) species. First, literature characterizing echinoderm responses to OA was compiled, creating a dataset comprised of >12,000 datapoints from 41 studies. Analysis of this data set demonstrated responses related to physiology, behavior, growth and development, and increased mortality in the larval and adult stages to low pH exposure. Second, statistical analyses were conducted on selected pathways to identify OA thresholds specific to duration, taxa, and depth-related life stage. Exposure to reduced pH led to impaired responses across a range of physiology, behavior, growth and development, and mortality endpoints for both larval and adult stages. Third, through discussions and synthesis, the expert panel identified a set of eight duration-dependent, life stage, and habitat-dependent pH thresholds and assigned each a confidence score based on quantity and agreement of evidence. The thresholds for these effects ranged within pH from 7.20 to 7.74 and duration from 7 to 30 days, all of which were characterized with either medium or low confidence. These thresholds yielded a risk range from early warning to lethal impacts, providing the foundation for consistent interpretation of OA monitoring data or numerical ocean model simulations to support climate change marine vulnerability assessments and evaluation of ocean management strategies. As a demonstration, two echinoderm thresholds were applied to simulations of a CCE numerical model to visualize the effects of current state of pH conditions on potential habitat.
Continue reading ‘Synthesis of thresholds of ocean acidification impacts on echinoderms’Archive Page 245
Synthesis of thresholds of ocean acidification impacts on echinoderms
Published 20 May 2021 Science ClosedTags: biological response, BRcommunity, echinoderms, growth, individualmodeling, modeling, morphology, mortality, performance, physiology, reproduction, review
House of Representatives passes rep. Bill Posey’s Bipartisan lagoon initiatives
Published 20 May 2021 Media coverage Closed
BREVARD COUNTY, FLORIDA – Representative Bill Posey’s (R-Rockledge) legislation—the National Estuaries and Acidification Research Act or NEAR Act—aimed at fighting coastal acidification and helping estuaries like our Indian River Lagoon—passed the House of Representatives with bipartisan support.
“Estuaries are some of most diverse ecosystems in the country, and because estuaries are places where freshwater mixes with salt water from the oceans, preserving this delicate balance is necessary but also challenging,” said Rep. Bill Posey. “This critical legislation will help protect our estuaries by ensuring that we continue to study and monitor the effects of coastal acidification.”
Specifically, the NEAR Act directs the National Academies of Science Ocean Study Board to conduct a two-year study examining the science of ocean acidification and its impact on our estuaries.
The goal of the NEAR Act is to create a better understanding of coastal acidification, so we can better manage and mitigate its effects on our nation’s estuaries and other natural treasures.
Continue reading ‘House of Representatives passes rep. Bill Posey’s Bipartisan lagoon initiatives’Title: 10 years of ocean acidification science at NOAA: Reflections and opportunities
Presenter(s): Dwight Gledhill, Deputy Director, NOAA Ocean Acidification Program
Date & Time: 2 June 2021 3:00 pm – 4:00 pm ET
Location: Webinar
Sponsor(s): Ocean Acidification Program, jennifer.mintz@noaa.gov
Remote Access: Register via Google meet at: https://attendee.gotowebinar.com/register/65158573617431566
Abstract: In 2009, the Federal Ocean Acidification Research and Monitoring Act called for a program within NOAA to monitor, research and understand the impacts of ocean acidification to better prepare society.The NOAA Ocean Acidification Programs is celebrating ten years of interdisciplinary science conducted across NOAA, academic institutions and industry. During this presentation, we’ll reflect on the important questions and information we had ten years ago, what we’ve learned, and where we’re going with our NOAA partners.
Bio(s): Dr. Gledhill serves as the Deputy Director of the NOAA Ocean Acidification Program office in Silver Spring, MD. Previously he was an associate scientist with the UM/RSMAS Cooperative Institute of Marine & Atmospheric Sciences (CIMAS) with NOAA’s Atlantic Oceanographic & Meteorological Laboratory Ocean Chemistry Division where he advanced ocean acidification research primarily related to monitoring and understanding the process of ocean acidification within coral reef ecosystems. He was instrumental in establishing ocean acidification time-series in La Parguera, Puerto Rico, and the Florida Keys National Marine Sanctuary. He also has worked on the development of a satellite-based ocean acidification data synthesis products for the Greater Caribbean Region.. Gledhill has also been a contributor to numerous strategic planning documents related to ocean acidification within NOAA including the recent NOAA Ocean, Coastal, and Great Lakes Research Plan. Gledhill received his M.S. and Ph.D. from the Department of Oceanography at Texas A&M University in 2005 where he primarily investigated carbonate mineral kinetics in complex electrolyte solutions as well the sediment biogeochemistry associated with methane clathrates in the Northern Gulf of Mexico.
NOAA STAR, 14 April 2021. More information.
Date: Wednesday 9 June 2021
Time: 7:00pm to 8:00pm
Location: Online via MS Teams
Audience: Public, Staff and students
Created by: Sophie Belau-Conlon shbc@st-andrews.ac.uk
Organised by: Museums Learning and Access Team
Spaces available: 17
The ocean covers most of our planet, yet even small changes in PH levels have a big effect on it.
Explore the effect of acid on our ocean by creating your own piece of art using a unique process. You’ll be guided by an expert in the approach and materials will be posted to you in advance.
The event will be held on Microsoft Teams and the link will be emailed to participants in advance. All skill levels welcome.
Please note that materials can only be posted within the UK.
Free but booking is essential.
Continue reading ‘Acidic ocean online art workshop’Webinar: communities of ocean action on ocean acidification (video)
Published 19 May 2021 Presentations ClosedCorals swap in heat-resistant algae to better cope with global warming
Published 19 May 2021 Press releases Closed
Some corals can swap out the algae that live inside their tissues for different strains that are more heat tolerant – and these coral species have a better chance of surviving global climate change in the coming decades.
When sea temperatures are too high, corals expel the microscopic algae living in their tissues. This is what occurs during coral bleaching. Losing algae in this way is harmful for the corals because the algae normally provide oxygen for them and remove their waste products. However, marine biologists have previously discovered that when some corals are exposed to warmer temperatures, they can swap the algae inside their tissues for strains that have a higher thermal tolerance.
Cheryl Logan at California State University in Monterey Bay and her colleagues have developed a model to simulate how these corals – and other coral species – will respond to global warming and ocean acidification. They applied their model to 1925 coral reefs around the world under four different climate scenarios.
Continue reading ‘Corals swap in heat-resistant algae to better cope with global warming’Quantifying global potential for coral evolutionary response to climate change
Published 19 May 2021 Science ClosedTags: adaptation, BRcommunity, corals, globalmodeling, modeling, otherprocess, protists
Incorporating species’ ability to adaptively respond to climate change is critical for robustly predicting persistence. One such example could be the adaptive role of algal symbionts in setting coral thermal tolerance under global warming and ocean acidification. Using a global ecological and evolutionary model of competing branching and mounding coral morphotypes, we show symbiont shuffling (towards taxa with increased heat tolerance) was more effective than symbiont evolution in delaying coral-cover declines, but stronger warming rates (high emissions scenarios) outpace the ability of these adaptive processes and limit coral persistence. Acidification has a small impact on reef degradation rates relative to warming. Global patterns in coral reef vulnerability to climate are sensitive to the interaction of warming rate and adaptive capacity and cannot be predicted by either factor alone. Overall, our results show how models of spatially resolved adaptive mechanisms can inform conservation decisions.
Continue reading ‘Quantifying global potential for coral evolutionary response to climate change’Coastal eutrophication drives acidification, oxygen loss, and ecosystem change in a major oceanic upwelling system
Published 19 May 2021 Science ClosedTags: abundance, biogeochemistry, biological response, chemistry, methods, modeling, North Pacific, otherprocess, photosynthesis, phytoplankton, primary production, regionalmodeling, respiration
Significance
We conduct a modeling study of the effects of enhanced coastal nutrient export from human activities on the carbon, nitrogen, and oxygen cycles of the Southern California Bight, in the context of emerging global climate change. The modeling approach used is innovative in the breadth of its scope, and simulations are generally consistent with local measurements. The human effects on the regional ecosystem from coastal nitrogen inputs of 23 million people are substantial, leading to significant increases in the photosynthesis and biomass of phytoplankton and increased oxygen loss and acidification of the water column. These changes are likely to compress habitat for a variety of marine organisms, with cascading ecological effects and implications for marine resources and water-quality management.
Abstract
Global change is leading to warming, acidification, and oxygen loss in the ocean. In the Southern California Bight, an eastern boundary upwelling system, these stressors are exacerbated by the localized discharge of anthropogenically enhanced nutrients from a coastal population of 23 million people. Here, we use simulations with a high-resolution, physical–biogeochemical model to quantify the link between terrestrial and atmospheric nutrients, organic matter, and carbon inputs and biogeochemical change in the coastal waters of the Southern California Bight. The model is forced by large-scale climatic drivers and a reconstruction of local inputs via rivers, wastewater outfalls, and atmospheric deposition; it captures the fine scales of ocean circulation along the shelf; and it is validated against a large collection of physical and biogeochemical observations. Local land-based and atmospheric inputs, enhanced by anthropogenic sources, drive a 79% increase in phytoplankton biomass, a 23% increase in primary production, and a nearly 44% increase in subsurface respiration rates along the coast in summer, reshaping the biogeochemistry of the Southern California Bight. Seasonal reductions in subsurface oxygen, pH, and aragonite saturation state, by up to 50 mmol m−3, 0.09, and 0.47, respectively, rival or exceed the global open-ocean oxygen loss and acidification since the preindustrial period. The biological effects of these changes on local fisheries, proliferation of harmful algal blooms, water clarity, and submerged aquatic vegetation have yet to be fully explored.
Continue reading ‘Coastal eutrophication drives acidification, oxygen loss, and ecosystem change in a major oceanic upwelling system’Dynamics of bacterial communities during a seasonal hypoxia at the Bohai Sea: coupling and response between abundant and rare populations
Published 19 May 2021 Science ClosedTags: abundance, biogeochemistry, biological response, BRcommunity, chemistry, community composition, field, molecular biology, North Pacific, otherprocess, prokaryotes
Marine bacterial community plays a vital role in the formation of the hypoxia zone in coastal oceans. Yet, their dynamics in the seasonal hypoxia zone of the Bohai Sea (BHS) are barely studied. Here, the 16S rRNA gene-based high-throughput sequencing was used to explore the dynamics of their diversity, structure, and function as well as driving factors during the gradual deoxygenation process in the BHS. Our results evinced that the bacterial community was dominated by Proteobacteria, followed by Bacteroidetes, Firmicutes, Actinobacteria, and Cyanobacteria, etc. The abundant subcommunity dominated in the number of sequences (49%) while the rare subcommunity dominated in the number of species (99.61%). Although abundant subcommunity accounted for most sequences, rare subcommunity possessed higher diversity, richness and their population dramatically changed (higher turnover) during the hypoxia transition. Further, co-occurrence network analysis proved the vital role of rare subcommunity in the process of community assembly. Additionally, beta diversity partition revealed that both subcommunities possessed a higher turnover component than nestedness and/or richness component, implying species replacement could explain a considerable percentage of community variation. This variation might be governed by both environmental selection and stochastic processes, and further, it influenced the nitrogen cycle (PICRUSt-based prediction) of the hypoxia zone. Overall, this study provides insight into the spatial-temporal heterogeneity of bacterial and their vital role in biogeochemical cycles in the hypoxia zone of the BHS. These findings will extend our horizons about the stabilization mechanism, feedback regulation, and interactive model inside the bacterial community under oxygen-depleted ecosystems.
Continue reading ‘Dynamics of bacterial communities during a seasonal hypoxia at the Bohai Sea: coupling and response between abundant and rare populations’10.5 US symposium on harmful algae: emerging voices and blooming careers – May 25-27, 2021
Published 19 May 2021 Events ClosedDate: May 27, 2021
Time: 10:45-11:30 am
Location: virtual
Title: Harmful algal blooms and ocean acidification: defining a research agenda
Presenter:
Halle Berger
Department of Marine Sciences, University of Connecticut, Groton, CT 06340
National Oceanic and Atmospheric Administration (NOAA), Silver Spring, MD 20910
Harmful algal blooms (HABs) and ocean acidification (OA) are threats to marine ecosystems and human communities. HABs and OA have common drivers in coastal areas and often co-occur in space and time. Although many studies have provided insight into HAB dynamics, only a few of these have included OA. Similarly, OA studies have examined biogeochemistry and impacts to marine resources and have started to expand into multi-stressor studies, but less is known about the influences of HAB-OA interactions and cascading impacts to coastal ecosystems and economies.
The NOAA Ocean Acidification Program (OAP) and National Centers for Coastal Ocean Science (NCCOS) Competitive Research Program (CRP) held a virtual workshop to identify research needs at the intersection of HABs and OA.
Description:
This presentation will focus on the regional and national grand challenges, research priorities, and research products highlighted at the workshop. Research areas of high priority at the national level include modeling for prediction, attribution, and sensitivity testing; leveraging monitoring assets to measure HAB and OA parameters simultaneously; data management to foster integration; data product development; and enhanced communication and outreach efforts. Importantly, the workshop identified a need for increased collaboration between HAB and OA scientists. Interdisciplinary approaches will be required to disentangle the complexities of HAB-OA interactions and address stakeholder needs. This effort will be facilitated by the NOAA OAP and NCCOS CRP through the development of a community of practice and a federal funding opportunity.
Bio:
Halle Berger is a 2021 Sea Grant Knauss Marine Policy Fellow serving as a Coastal Stressors Program Coordinator with the NOAA Ocean Acidification Program and National Centers for Coastal Ocean Science Competitive Research Program. She is working on building a research community to address the overlapping challenges between harmful algal blooms and ocean acidification. Halle is also currently a PhD Student at the University of Connecticut. Her research assesses the vulnerability of important shellfisheries to changing ocean conditions.
Plenary Session will be followed by a Q&A panel with Halle and NOAA Program Managers Quay Dortch, Maggie Broadwater and Erica Ombres.
Continue reading ‘10.5 US symposium on harmful algae: emerging voices and blooming careers – May 25-27, 2021’Chapter 5 – Effect of climate change on marine ecosystems
Published 18 May 2021 Science ClosedTags: biological response, corals, education, fish, fisheries, phanerogams, review
The impacts of anthropogenic climate change are already discernible throughout the ocean, from the equator to the poles, and from the surface to abyssal depths. Further climate change impacts are inevitable; however, their damage to marine organisms and ecosystems, and the services they provide, can be greatly reduced if greenhouse gas emissions are rapidly reduced. This review covers six main climate-related drivers (warming, acidification, deoxygenation, sea level rise and storm events, sea ice loss, stratification, and nutrient supply) and their impacts on 13 marine ecosystems, broadly defined. Seven of these are near-shore (coral reefs, kelp ecosystems, seagrass meadows, rocky and sandy intertidal, saltmarshes, estuaries, and mangroves) and six are in shelf seas and the open ocean (shelf sea benthos, upper ocean plankton, fish and fisheries, cold water corals, ice-influenced ecosystems, and the deep seafloor). Three cross-cutting issues are emphasized: that climate change impacts are not single factors, but interact together and with other human pressures in a multistressor context; that there are fast and slow climate processes in the ocean, with overall temporal uncertainties relating to future societal behavior; and that there can be high spatial heterogeneity in marine ecosystem impacts and vulnerabilities.
Continue reading ‘Chapter 5 – Effect of climate change on marine ecosystems’Effects of ocean acidification on transcriptomes in Asian seabass juveniles
Published 18 May 2021 Science ClosedTags: biological response, fish, growth, laboratory, molecular biology, performance, physiology
Ocean acidification is changing the fate of marine organisms. It is essential to predict the biological responses and evolutionary processes driven by ocean acidification, to maintain the equilibrium of the marine ecosystem and to facilitate aquaculture. However, how marine organisms, particularly the marine fish species, respond to ocean acidification, is still poorly understood. Consequences of ocean acidification on finfish aquaculture are largely not well known. We studied the effects of ocean acidification for 7 days on growth, behaviour and gene expression profiles in the brain, gill and kidney of Asian seabass juveniles. Results showed that growth and behaviour were not affected by short-term ocean acidification. We found tissue-specific differentially expressed genes (DEGs) involving many molecular processes, such as organ development, growth, muscle development, ion homeostasis and neurogenesis and development, as well as behaviours. Most of the DEGs, which were functionally enriched in ion homeostasis, were related to calcium transport, followed by sodium/potassium channels. We found that genes associated with neurogenesis and development were significantly enriched, implying that ocean acidification has also adversely affected the neural regulatory mechanism. Our results indicate that although the short-term ocean acidification does not cause obvious phenotypic and behavioural changes, it causes substantial changes of gene expressions in all three analysed tissues. All these changes of gene expressions may eventually affect physiological fitness. The DEGs identified here should be further investigated to discover DNA markers associated with adaptability to ocean acidification to improve fish’s capability to adapt to ocean acidification.
Continue reading ‘Effects of ocean acidification on transcriptomes in Asian seabass juveniles’Identification of miRNAs in sea urchin Strongylocentrotus purpuratus larvae response to pH stress
Published 18 May 2021 Science ClosedTags: biological response, echinoderms, laboratory, molecular biology, morphology, physiology, reproduction
MicroRNAs (miRNAs) are a class of small, endogenous, non‐coding RNAs that regulate gene expression through transcriptional repression of messenger RNA. They play significant roles in many physiological and biochemical processes in eukaryotes. Ocean acidification can impact the development, survival, growth and physiology of many marine organisms. Here, we performed miRNA transcriptome analysis of the sea urchin Strongylocentrotus purpuratus larvae exposed to CO2‐driven seawater acidification. We generated 10.6 and 10.8 million clean reads from the malformed S. purpuratus larva after CO2 treatment and the larvae with the normal bone development respectively. A total of 682 conserved and 17 novel miRNAs were identified. Target genes of the differential expression miRNAs were also predicted, which contained growth‐related genes (collagenase, collagen and HSP70‐binding protein 1), spicule formation‐related gene (carbonic anhydrase transcript variant X1) and skeletogenesis‐related genes (breast carcinoma amplified sequence 2). Target genes of the differentially expressed miRNAs were used to perform KEGG pathway analysis and were found to be involved in the proteasome and oxidative phosphorylation. These results provide a relatively large number of miRNAs transcriptome resource and provide a foundation for further analyses on the functional and molecular mechanisms of S. purpuratus larvae impacted by ocean acidification.
Continue reading ‘Identification of miRNAs in sea urchin Strongylocentrotus purpuratus larvae response to pH stress’Coastal processes modify projections of some climate-driven stressors in the California Current System (update)
Published 18 May 2021 Science ClosedTags: North Pacific, regionalmodeling
Global projections for ocean conditions in 2100 predict that the North Pacific will experience some of the largest changes. Coastal processes that drive variability in the region can alter these projected changes but are poorly resolved by global coarse-resolution models. We quantify the degree to which local processes modify biogeochemical changes in the eastern boundary California Current System (CCS) using multi-model regionally downscaled climate projections of multiple climate-associated stressors (temperature, O2, pH, saturation state (Ω), and CO2). The downscaled projections predict changes consistent with the directional change from the global projections for the same emissions scenario. However, the magnitude and spatial variability of projected changes are modified in the downscaled projections for carbon variables. Future changes in pCO2 and surface Ω are amplified, while changes in pH and upper 200 m Ω are dampened relative to the projected change in global models. Surface carbon variable changes are highly correlated to changes in dissolved inorganic carbon (DIC), pCO2 changes over the upper 200 m are correlated to total alkalinity (TA), and changes at the bottom are correlated to DIC and nutrient changes. The correlations in these latter two regions suggest that future changes in carbon variables are influenced by nutrient cycling, changes in benthic–pelagic coupling, and TA resolved by the downscaled projections. Within the CCS, differences in global and downscaled climate stressors are spatially variable, and the northern CCS experiences the most intense modification. These projected changes are consistent with the continued reduction in source water oxygen; increase in source water nutrients; and, combined with solubility-driven changes, altered future upwelled source waters in the CCS. The results presented here suggest that projections that resolve coastal processes are necessary for adequate representation of the magnitude of projected change in carbon stressors in the CCS.
Continue reading ‘Coastal processes modify projections of some climate-driven stressors in the California Current System (update)’Staff chemist position in carbonate chemistry and ocean acidification (Sarasota, Florida)
Published 18 May 2021 Jobs ClosedThe Ocean Acidification Program at Mote Marine Laboratory seeks a staff chemist/lab manager with a minimum of 2 years of experience in carbonate chemistry, including experimental seawater ocean acidification facilities. This position will be located in Sarasota, Florida at the Mote Marine Laboratory main campus and will report directly to the Ocean Acidification Program Manager, Dr. Emily R. Hall. General duties to be performed include working with the indoor research-focused acidification experimental system OASys (Ocean Acidification System), coastal and marine field work, and laboratory analyses. This includes sample collection, monitoring, and analysis of total seawater alkalinity, dissolved inorganic carbon, spectrophotometric pH, and other water quality parameters. The staff chemist performs statistical data analyses to process carbonate chemistry data, manage data storage, and write reports. Tasks also include maintaining the dry ocean acidification (OA) laboratory, keeping track of and ordering all supplies and materials, keeping all OA-related work organized, instrument maintenance, mercuric chloride hazardous waste disposal, data entry, some animal husbandry, and some field work (typically twice a month with other field days possible). The staff chemist will be responsible for managing and mentoring student interns year-round. This position might include longer days and weekend work.? Must be able to work in a hot/outdoor environment and lift 40 lbs. Current projects include work with acidification, harmful algae, bivalves, and seagrass. Duration is 1 year with possibility to extend depending on performance and funding.
Requirements:
- B.S. required, M.S. preferred. Preferably with a carbonate chemistry or ocean acidification background.
- Working knowledge of carbonate chemistry processes and instrumentation.
- Familiar with standard computer software (Excel, Word, etc.), data handling applications such as R, database management, and CO2Sys or CO2Calc.
- S. citizenship or foreign citizen?s U.S. work permit appropriate for the work is required
Seasonal and interannual variability of the CO2 system in the Eastern Mediterranean sea: a case study in the North Western Levantine Basin
Published 17 May 2021 Science ClosedTags: chemistry, field, Mediterranean
The seasonal variability of the carbonate system in the eastern Mediterranean Sea (EMed) was investigated based on discrete total alkalinity (AT), total dissolved inorganic carbon (CT), and pH measurements collected during three cruises around Crete between June 2018 and March 2019. This study presents a detailed description of this new carbonate chemistry dataset in the eastern Mediterranean Sea. We show that the North Western Levantine Basin (NWLB) is unique in terms of range of AT variation vs. CT variation in the upper water column over an annual cycle. The reasons for this singularity of the NWLB can be explained by the interplay between strong evaporation and the concomitant consumption of CT by autotrophic processes. The high range of AT variations, combined to temperature changes, has a strong impact on the variability of the seawater pCO2 (pCO2SW). Based on Argo float data, an entire annual cycle for pCO2SW in the NWLB has been reconstructed in order to estimate the temporal sequence of the potential “source” and “sink” of atmospheric CO2. By combining this dataset with previous observations in the NWLB, this study shows a significant ocean acidification and a decrease in the oceanic surface pHT25 of −0.0024 ± 0.0004 pHT25 units.a–1. The changes in the carbonate system are driven by the increase of atmospheric CO2 but also by unexplained temporal changes in the surface AT content. If we consider that the EMed will, in the future, encounter longer, more intense and warmer summer seasons, this study proposes some perspectives on the carbonate system functioning of the “future” EMed.
Continue reading ‘Seasonal and interannual variability of the CO2 system in the Eastern Mediterranean sea: a case study in the North Western Levantine Basin’Comparative sensitivities of zooplankton to ocean acidification conditions in experimental and natural settings
Published 17 May 2021 Science ClosedTags: abundance, biological response, BRcommunity, bryozoa, chemistry, cnidaria, community composition, crustaceans, field, laboratory, mollusks, North Pacific, otherprocess, primary production, zooplankton
Zooplankton can serve as indicators of ecosystem health, water quality, food web structure, and environmental change, including those associated with climate change and ocean acidification (OA). Laboratory studies demonstrate that low pH and high pCO2 associated with OA can significantly affect the physiology and survival of zooplankton, with differential responses among taxa. While laboratory studies can be indicative of zooplankton response to OA, in situ responses will ultimately determine the fate of populations and ecosystems. In this perspective, we compare expectations from experimental studies with observations made in Puget Sound (Washington, United States), a highly dynamic estuary with known vulnerabilities to low pH and high pCO2. We found little association between empirical measures of in situ pH and the abundance of sensitive taxa as revealed by meta-analysis, calling into question the coherence between experimental studies and field observations. The apparent mismatch between laboratory and field studies has important ramifications for the design of long-term monitoring programs and interpretation and use of the data produced. Important work remains to be done to connect traits that are sensitive to OA with those that are ecologically relevant and reliably observable in the field.
Continue reading ‘Comparative sensitivities of zooplankton to ocean acidification conditions in experimental and natural settings’Responses of Southern ocean seafloor habitats and communities to global and local drivers of change
Published 17 May 2021 Science ClosedTags: Antarctic, policy, review, socio-economy
Knowledge of life on the Southern Ocean seafloor has substantially grown since the beginning of this century with increasing ship-based surveys and regular monitoring sites, new technologies and greatly enhanced data sharing. However, seafloor habitats and their communities exhibit high spatial variability and heterogeneity that challenges the way in which we assess the state of the Southern Ocean benthos on larger scales. The Antarctic shelf is rich in diversity compared with deeper water areas, important for storing carbon (“blue carbon”) and provides habitat for commercial fish species. In this paper, we focus on the seafloor habitats of the Antarctic shelf, which are vulnerable to drivers of change including increasing ocean temperatures, iceberg scour, sea ice melt, ocean acidification, fishing pressures, pollution and non-indigenous species. Some of the most vulnerable areas include the West Antarctic Peninsula, which is experiencing rapid regional warming and increased iceberg-scouring, subantarctic islands and tourist destinations where human activities and environmental conditions increase the potential for the establishment of non-indigenous species and active fishing areas around South Georgia, Heard and MacDonald Islands. Vulnerable species include those in areas of regional warming with low thermal tolerance, calcifying species susceptible to increasing ocean acidity as well as slow-growing habitat-forming species that can be damaged by fishing gears e.g., sponges, bryozoan, and coral species. Management regimes can protect seafloor habitats and key species from fishing activities; some areas will need more protection than others, accounting for specific traits that make species vulnerable, slow growing and long-lived species, restricted locations with optimum physiological conditions and available food, and restricted distributions of rare species. Ecosystem-based management practices and long-term, highly protected areas may be the most effective tools in the preservation of vulnerable seafloor habitats. Here, we focus on outlining seafloor responses to drivers of change observed to date and projections for the future. We discuss the need for action to preserve seafloor habitats under climate change, fishing pressures and other anthropogenic impacts.
Continue reading ‘Responses of Southern ocean seafloor habitats and communities to global and local drivers of change’Energetic lipid responses of larval oysters to ocean acidification
Published 14 May 2021 Science ClosedTags: biological response, laboratory, mollusks, morphology, mortality, physiology, reproduction
Highlights
- Climate change will limit larval energy of the oysters Saccostrea glomerata and Crassostrea gigas.
- This may impact on larval survival and ultimately aquaculture of two iconic species.
- Ocean acidification reduced lipid levels across all lipid classes.
Abstract
Climate change will increase energetic demands on marine invertebrate larvae and make planktonic food more unpredictable. This study determined the impact of ocean acidification on larval energetics of the oysters Saccostrea glomerata and Crassostrea gigas. Larvae of both oysters were reared until the 9-day-old, umbonate stage under orthogonal combinations of ambient and elevated p CO 2 (340 and 856 μatm) and food was limited. Elevated p CO 2 reduced the survival, size and larval energetics, larvae of C. gigas being more resilient than S. glomerata. When larvae were fed, elevated p CO 2 reduced lipid levels across all lipid classes. When larvae were unfed elevated p CO 2 resulted in increased lipid levels and mortality. Ocean acidification and food will interact to limit larval energetics. Larvae of S. glomerata will be more impacted than C. gigas and this is of concern given their aquacultural status and ecological function.
Continue reading ‘Energetic lipid responses of larval oysters to ocean acidification’Rapid multi-generational acclimation of coralline algal reproductive structures to ocean acidification
Published 14 May 2021 Science ClosedTags: abundance, algae, biological response, Indian, laboratory, otherprocess, reproduction
The future of coral reef ecosystems is under threat because vital reef-accreting species such as coralline algae are highly susceptible to ocean acidification. Although ocean acidification is known to reduce coralline algal growth rates, its direct effects on the development of coralline algal reproductive structures (conceptacles) is largely unknown. Furthermore, the long-term, multi-generational response of coralline algae to ocean acidification is extremely understudied. Here, we investigate how mean pH, pH variability and the pH regime experienced in their natural habitat affect coralline algal conceptacle abundance and size across six generations of exposure. We show that second-generation coralline algae exposed to ocean acidification treatments had conceptacle abundances 60% lower than those kept in present-day conditions, suggesting that conceptacle development is initially highly sensitive to ocean acidification. However, this negative effect of ocean acidification on conceptacle abundance disappears after three generations of exposure. Moreover, we show that this transgenerational acclimation of conceptacle development is not facilitated by a trade-off with reduced investment in growth, as higher conceptacle abundances are associated with crusts with faster growth rates. These results indicate that the potential reproductive output of coralline algae may be sustained under future ocean acidification.
Continue reading ‘Rapid multi-generational acclimation of coralline algal reproductive structures to ocean acidification’
