Archive for November, 2019

OA-ICC bibliographic database updated

An updated version of the OA-ICC bibliographic database is available online.

The database currently contains over 5,870 references and includes citations, abstracts and assigned keywords. Updates are made every month.

The database is available as groups on Mendeley and Zotero. Subscribe online or, for a better user experience, download the Mendeley or Zotero desktop applications and sync with the group Ocean Acidification (OA-ICC) in Mendeley, or OA-ICC in Zotero. Please see the “User instructions” for further details.

Continue reading ‘OA-ICC bibliographic database updated’

Impact of growing up in a warmer, lower pH future on offspring performance: transgenerational plasticity in a pan-tropical sea urchin

Transgenerational plasticity (TGP) may be an important mechanism for marine organisms to acclimate to climate change stressors including ocean warming (OW) and ocean acidification (OA). Conversely, environmental stress experienced by one generation may have detrimental latent effects on subsequent generations. We examined TGP in the embryos and larvae of the pan-tropical sea urchin, Tripneustes gratilla, in response to OA (pH 7.77), OW (+2 °C), or both OA and OW, OAW (+2 °C, pH 7.77) using a parent (F0) generation reared in treatments from the early juvenile to the mature adult, incorporating gonadogenesis and germline differentiation. Embryos and larvae of acclimated parents were reared in all four treatments to the 2-day-old pluteus stage. Larvae from OA and OAW parents were resilient to the effects of acidification, while larvae from OW and OAW parents were more tolerant to warmer temperature (29 °C). Parental acclimation, however, had predominantly negative effects on the size of offspring with reductions in larval arm lengths by as much as 21.4%, while eggs were up to 21.8% smaller in females raised at 29 °C. We highlight the complexity and trade-offs of TGP in this first transgenerational climate change study on a marine macroinvertebrate where the F0 generation was acclimated over their reproductive life.

Continue reading ‘Impact of growing up in a warmer, lower pH future on offspring performance: transgenerational plasticity in a pan-tropical sea urchin’

Ecological effects of elevated CO2 on marine and freshwater fishes: from individual to community effects

Research over the past decade has shown that climate-change relevant CO2 levels can affect the growth, development and survival of some fishes during early life. There are also wide-ranging effects on behavior that could alter performance and survivorship of some species. Yet, there is also substantial variation in the sensitivity of fishes to elevated CO2, both among and within species. This chapter explores the current understanding of ecological effects of projected future CO2 levels on marine and freshwater fishes, including major knowledge gaps and uncertainties, and interactions with other stressors such as global warming. While laboratory experiments show that elevated CO2 can affect ecologically important traits of some species, we are not yet able to predict which species are sensitive and which are tolerant to higher CO2 levels. Moreover, the impacts of elevated CO2 on ecologically relevant traits can depend on food availability and interact with elevated temperature and other stressors in unexpected ways. New studies also demonstrate that natural CO2 variation and ecological complexity can mitigate some of the negative effects of elevated CO2 observed in simplified laboratory experiments. Finally, studies at natural CO2 seeps suggest that indirect effects of elevated CO2 on food resources and habitats may have larger effects on fish populations than the direct effects of elevated CO2 on individual performance.

Continue reading ‘Ecological effects of elevated CO2 on marine and freshwater fishes: from individual to community effects’

Space is key to monitoring ocean acidification

This week, the UN World Meteorological Organization announced that concentrations of greenhouse gases in the atmosphere have reached yet another high. This ongoing trend is not only heating up the planet, but also affecting the chemical composition of our oceans. Until recently, it has been difficult to monitor ‘ocean acidification’, but scientists are exploring new ways to combine information from different sources, including from ESA’s SMOS mission, to shed new light on this major environmental concern.

As the amount of atmospheric carbon dioxide continues to rise, our oceans are playing an increasingly important role in absorbing some of this excess. In fact, it was reported recently that the global ocean annually draws down about a third of the carbon released into the atmosphere by human activities.

Continue reading ‘Space is key to monitoring ocean acidification’

Elevated carbon dioxide and reduced salinity enhance mangrove seedling establishment in an artificial saltmarsh community

The global phenomenon of mangrove encroachment into saltmarshes has been observed across five continents. It has been proposed that this encroachment is driven in part by rising atmospheric CO2 concentration and reduced salinity in saltmarshes resulting from rising sea levels enhancing the establishment success of mangrove seedlings. However, this theory is yet to be empirically tested at the community-level. In this study, we examined the effect of CO2 and salinity on seedling growth of two mangrove species, Aegiceras corniculatum and Avicennia marina, grown individually and in a model saltmarsh community in a glasshouse experiment. We found that the shoot (210%) and root (91%) biomass of the saltmarsh species was significantly greater under elevated CO2. As a result, both mangrove species experienced a stronger competitive effect from the saltmarsh species under elevated CO2. Nevertheless, A. marina seedlings produced on average 48% more biomass under elevated CO2 when grown in competition with the saltmarsh species. The seedlings tended to allocate this additional biomass to growing taller suggesting they were light limited. In contrast, A. corniculatum growth did not significantly differ between CO2 treatments. However, it had on average 36% greater growth under seawater salinity compared to hypersaline conditions. Avicennia marina seedlings were not affected by salinity. From these results, we suggest that although CO2 and salinity are not universal drivers determining saltmarsh–mangrove boundaries, it is likely that rising atmospheric CO2 concentration and reduced salinity associated with sea level rise will enhance the establishment success of mangrove seedlings in saltmarshes, which may facilitate mangrove encroachment in the future.

Continue reading ‘Elevated carbon dioxide and reduced salinity enhance mangrove seedling establishment in an artificial saltmarsh community’

Characterization of the CO2 System in a coral reef, a seagrass meadow, and a mangrove forest in the central Red Sea

The Red Sea is characterized by its high seawater temperature and salinity, and the resilience of its coastal ecosystems to global warming is of growing interest. This high salinity and temperature might also render the Red Sea a favorable ecosystem for calcification and therefore resistant to ocean acidification. However, there is a lack of survey data on the CO2 system of Red Sea coastal ecosystems. A 1‐year survey of the CO2 system was performed in a seagrass lagoon, a mangrove forest, and a coral reef in the central Red Sea, including fortnight seawater sampling and high‐frequency pHT monitoring. In the coral reef, the CO2 system mean and variability over the measurement period are within the range of other world’s reefs with pHT, dissolved inorganic carbon (DIC), total alkalinity (TA), pCO2, and Ωarag of 8.016±0.077, 2061±58 μmol/kg, 2415±34 μmol/kg, 461±39 μatm, and 3.9±0.4, respectively. Here, comparisons with an offshore site highlight dominance of calcification and photosynthesis in summer‐autumn, and dissolution and heterotrophy in winter‐spring. In the seagrass meadow, the pHT, DIC, TA, pCO2, and Ωarag were 8.00±0.09, 1986±68 μmol/kg, 2352±49 μmol/kg, 411±66 μatm, and 4.0±0.3, respectively. The seagrass meadow TA and DIC were consistently lower than offshore water. The mangrove forest showed the highest amplitudes of variation, with pHT, DIC, TA, pCO2, and Ωarag, were 7.95±0.26, 2069±132 μmol/kg, 2438±91 μmol/kg, 493±178 μatm, and 4.1±0.6, respectively. We highlight the need for more research on sources and sinks of DIC and TA in coastal ecosystems.

Continue reading ‘Characterization of the CO2 System in a coral reef, a seagrass meadow, and a mangrove forest in the central Red Sea’

Trait‐based climate vulnerability assessments in data‐rich systems: an application to eastern Bering Sea fish and invertebrate stocks

Trait‐based climate vulnerability assessments based on expert evaluation have emerged as a rapid tool to assess biological vulnerability when detailed correlative or mechanistic studies are not feasible. Trait‐based assessments typically view vulnerability as a combination of sensitivity and exposure to climate change. However, in some locations, a substantial amount of information may exist on system productivity and environmental conditions (both current and projected), with potential disparities in the information available for data‐rich and data‐poor stocks. Incorporating this level of detailed information poses challenges when conducting, and communicating uncertainty from, rapid vulnerability assessments. We applied a trait‐based vulnerability assessment to 36 fish and invertebrate stocks in the eastern Bering Sea (EBS), a data‐rich ecosystem. In recent years, the living marine resources of the EBS and Aleutian Islands have supported fisheries worth more than US $1 billion of annual ex‐vessel value. Our vulnerability assessment uses projections (to 2039) from three downscaled climate models, and graphically characterizes the variation in climate projections between climate models and between seasons. Bootstrapping was used to characterize uncertainty in specific biological traits and environmental variables, and in the scores for sensitivity, exposure, and vulnerability. The sensitivity of EBS stocks to climate change ranged from “low” to “high,” but vulnerability ranged between “low” and “moderate” due to limited exposure to climate change. Comparison with more detailed studies reveals that water temperature is an important variable for projecting climate impacts on stocks such as walleye pollock (Gadus chalcogrammus), and sensitivity analyses revealed that modifying the rule for determining vulnerability increased the vulnerability scores. This study demonstrates the importance of considering several uncertainties (e.g., climate projections, biological, and model structure) when conducting climate vulnerability assessments, and can be extended in future research to consider the vulnerability of user groups dependent on these stocks.

Continue reading ‘Trait‐based climate vulnerability assessments in data‐rich systems: an application to eastern Bering Sea fish and invertebrate stocks’

5th Symposium on the Ocean in a High-CO2 World: First Call for Abstracts

First Call for Abstracts – 5th Symposium on the Ocean in a High-CO2 World, Lima, Peru, 7-10 September 2020

The Symposium is the place to share cutting-edge science in a rapidly developing frontier of research dealing with the science of ocean acidification and other drivers of change. The Symposium will feature keynote talks by some of the leading experts in the field, as well as special events on ocean acidification and aquaculture, carbonate chemistry, the Global Ocean Acidification Observing Network (GOA-ON), and the Latin American Ocean Acidification Network (LAOCA).

For more information on the Symposium themes, abstract submissions and meeting details, please visit the Symposium website at http://www.highco2-lima.org.

Key dates:
– 6 March 2020, abstract submission deadline
– 15 April 2020, abstract and travel support applicants notified
– 5 June 2020, early registration closes
– 21 August 2020, registration closes
– 7 September 2020, on-site registration

More information and abstract submission. 

Impacts of ocean acidification on hermit crab communities through contrasting responses of Pagurus filholi (de Man, 1887) and Clibanarius virescens (Krauss, 1843)

Ocean acidification (OA) is predicted to decrease the abundance of calcified organisms such as gastropods. Since hermit crabs utilize gastropod shell as mobile shelter, OA has indirect impacts on hermit crab population. To examine the impacts of OA on hermit crab communities, which use calcified shell as the mobile shelter, we conducted field surveys and laboratory experiments using volcanic CO2 seeps in Shikine Island, Japan. By comparing hermit crab community structures and shell availability among five intertidal rocky shores with different degrees of acidification, Paguroidea abundance and species richness were simplified in acidified areas. Rearing experiments comparing survival rates of two Paguroidea species, Pagurus filholi (de Man, 1887) and Clibanarius virescens (Krauss, 1843), at both adult and larval stages, between acidified and ambient aquaria revealed that acidified seawater reduced larval survival rate of C. virescens. Overall, the results indicated that the species-specific direct effect in elevated C. virescens larval mortality could simplify the Paguroidea species composition. In addition, such direct effect would also lead to reduction of Paguroidea abundance, along with indirect effects though a decrease in shell availability.

Continue reading ‘Impacts of ocean acidification on hermit crab communities through contrasting responses of Pagurus filholi (de Man, 1887) and Clibanarius virescens (Krauss, 1843)’

Impact of ocean acidification on the intestinal microbiota of the marine sea bream (Sparus aurata L.)

Within a scenario of increasing atmospheric CO2 and ocean acidification (OA), it is highly relevant to investigate its impacts not only on fish performance but also on fish intestinal microbiome and how that reflects on host performance and health. The main objective of this study was to establish if the intestinal microbiota of the sea bream (Sparus aurata) was affected by high level of CO2 in line with the predictions for this century. The bacterial communities of the intestinal fluid were characterized in animals kept at the present-day level of CO2 (400 μatm) and in animals switched to high CO2 (1200 μatm) for 1 month. Bacterial taxa identification was based on molecular methods, using the DNA coding for the 16S ribosomal RNA and primers targeting the regions V1–V3. Amplicons obtained from DNA samples of animals in the same tank were combined, cloned to obtain a bacterial DNA library, and the clones were sequenced. No significant differences were found between the two treatments for alpha diversity. However, beta diversity analysis revealed distinct dysbiosis in response to hypercapnia, with phylum Firmicutes absent from the bacterial communities of fish exposed to 1200 μatm CO2, whereas Proteobacteria relative abundance was increased at elevated CO2, due to the presence of Gammaproteobacteria (Vibrionaceae and Alteromonadaceae), a class not present in the control samples. This study provides a first glimpse at the impact of OA in fish intestinal microbiota and highlights potential downstream effects to the general condition of fishes under hypercapnia.

Continue reading ‘Impact of ocean acidification on the intestinal microbiota of the marine sea bream (Sparus aurata L.)’


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OA-ICC HIGHLIGHTS

Ocean acidification in the IPCC AR5 WG II

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