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Collaboration with new scholar and NOAA Ocean Acidification Program Show Potenital

This past month, NCCOS welcomed a new Hollings Scholar, Madison Uetrecht, who will study the effects of ocean acidification on oyster growth under Dr. Beth Turner over the summer months. They visited Mook Sea Farm, where Uetrecht will conduct out-planting experiments with juvenile oysters to assess whether shell growth and calcification changes during different field ocean acidification (OA) conditions.

Dr. Turner is the NOAA lead on a recently funded mini-grant from the NOAA Ocean Acidification Program for citizen science workshops through the Northeast Coastal Acidification Network. Monitoring guidance for coastal acidification developed by EPA will guide workshop participants in demonstrations and hands-on activities to monitor conditions in local estuaries.

Continue reading ‘Collaboration with new scholar and NOAA Ocean Acidification Program Show Potenital’

Impacts of climate change on fish and shellfish in the coastal and marine environments of Caribbean Small Island Developing States (SIDS)

The commercially important fish and shellfish of Caribbean SIDS have been considered in four groups based on environment and following the typical division of fishery groups used in this region.

There is a dearth of research and long-term datasets on the impacts of climate change on Caribbean marine environments and the important fishery resources. Most research to date has been outside of the Caribbean and has examined the impacts of one or two stressors in short-term ex situ experiments which are unlikely to accurately reflect the true complexity of long-term in situ impacts of climate change in the region. There is a need to consider the combined effects of climate change stressors
(direct and indirect) on both individuals and ecosystems, together with the synergistic effects of other chronic anthropogenic stressors in the region.

We consider the reef-associated shallow shelf group to be the most vulnerable of the four fishery groups given: 1) the already apparent negative climate change impacts on their critical habitats; 2) the overexploited state of most reef-associated fishery stocks; 3) the already degraded state of their nearshore habitats as a result of other anthropogenic activities; and 4) their biphasic life history, requiring the ability to settle in specific benthic nursery habitat from a pelagic early life stage.

We consider the most resilient group, over the short-term, to be the oceanic pelagic species that generally show fewer negative responses to the climate change stressors given that they: 1) are highly mobile with generally good acid-base regulation; 2) have an entirely pelagic lifecycle; 3) have less vulnerable reproductive strategies (i.e. they have extended spawning seasons and over broad areas); and 4) are generally exposed to fewer or less severe anthropogenic stressors.

This summary is provided with the following important caveat: “Any attempt to report on what has already happened to fish and shellfish resources in the Caribbean, based on direct evidence, will be strongly biased by the fact that there is a lack of monitoring and directed research examining fish and shellfish species-level impacts of climate change in this region. As such, any conclusions drawn from direct evidence alone will likely misrepresent the true nature and extent of the climate change impacts on the coastal and marine fish and shellfish resources within the Caribbean to date.”

Continue reading ‘Impacts of climate change on fish and shellfish in the coastal and marine environments of Caribbean Small Island Developing States (SIDS)’

Impacts of physical environments in the coastal and marine environments of Caribbean Small Island Developing States (SIDS)

Temperature – sea surface temperature has risen by more than 1 °C over the last 100 years. Future temperature rises will have impacts on hurricanes, rainfall, coral reefs and wider marine ecosystems.

Hurricanes – The IPCC (IPCC AR5 WG1) found strong evidence for an increase in the frequency and intensity of the strongest tropical hurricanes since the 1970s in the North Atlantic.

El Niño- Understanding the influence of the El Niño – Southern Oscillation (ENSO) phenomenon on Caribbean’s marine environment and timescales of variability is key to understanding how climate has been changing; projecting these relationships and ENSO itself into the future becomes vital to understand the fingerprint of global warming in the region.

Precipitation – there are a wide range of projections for future precipitation change in the area with some models finding increases in the coming century while most suggest a drier future for the region.

Ocean surface aragonite saturation state (Ωarg) has declined by around 3% in the Caribbean region relative to pre-industrial levels.

Climate variability – the Caribbean region needs a smaller increase in temperature for its conditions to become distinct (climate emergence) from the envelope of climate variability over the last hundred years, compared with the rest of the world.

Continue reading ‘Impacts of physical environments in the coastal and marine environments of Caribbean Small Island Developing States (SIDS)’

Impacts of ocean acidification in the coastal and marine environments of Caribbean Small Island Developing States (SIDS)

Oceans have absorbed one third of the carbon dioxide (CO2) released to the atmosphere from human activities causing the seawater pH to decrease by 0.1 units since the Industrial Revolution.

There is certainty that ocean acidification caused by anthropogenic activities is currently in progress and will increase in accord with rising atmospheric CO2 concentrations. There is medium confidence that these changes with significantly impact marine ecosystems.

Throughout the Caribbean small islands, ocean acidification effects could be exacerbated due to local processes within coastal zones. Ocean surface aragonite saturation state (Ωarg) has declined by around 3% in the Caribbean region relative to pre-industrial levels potentially already impacting tropical marine calcifying organisms. In addition to the effect on living organisms, ocean acidification is likely to diminish the structural integrity of coral reefs through reduced skeletal density, loss of calcium carbonate, and dissolution of high-Mg carbonate cements which help to bind the reef. This would make coastal areas of the Caribbean small islands increasingly more vulnerable to the action of waves and storm surge. This is likely to have knock-on effects to the tourism sector, fisheries and coastal infrastructure.

More studies about the present and projected impacts of ocean acidification on Caribbean small islands are necessary in order to evaluate alternative adaptive strategies accounting for the different island’s environmental, socioeconomic, and political settings.

Continue reading ‘Impacts of ocean acidification in the coastal and marine environments of Caribbean Small Island Developing States (SIDS)’

Impacts of climate change on coral in the coastal and marine environments of Caribbean Small Island Developing States (SIDS)

Coral reefs are integral to life in the Caribbean – providing protection from storms, sustaining national economies and livelihoods through tourism and fishing, and supporting culture, recreation and biodiversity conservation. Over a decade ago, their value was estimated at US$3.1 – 4.6 billion each year.

Climate change is already impacting coral reefs in the Caribbean, through coral bleaching, disease outbreaks, ocean acidification and physical damage from stronger hurricanes. Coral beaching is the most visible, wide-spread and iconic manifestation of climate change on reefs, with major events in the Caribbean in 1998, 2010 and 2015/16. The extent of bleaching and associated mortality varies by location and event, but has resulted in some mortality. Coral disease has already significantly altered the community composition of reefs in the Caribbean, and is projected to result in increasing frequency of outbreaks as seas warm. The lack of a centralized database to coordinate reef monitoring information, hampers efforts to measure these effects.

Ocean acidification is a direct chemical result of increased carbon dioxide, but it has a variety of different responses in different reef organisms. Corals are the brick foundations of the reef, with crustose coralline algae as their mortar. Both these critical functional groups are already being affected by the reduced pH of surface water, making it more difficult to calcify and grow.

Future impacts are expected to follow and accelerate on these trends.

By 2040–2043 projections are for the onset of annual severe bleaching, which would likely result in significant coral mortality. Disease outbreaks are predicted to become annual events several years earlier. Projections for future ocean acidification result in ocean carbonate saturation levels potentially dropping below those required to sustain coral reef accretion by 2050. Cutting emissions in CO2 (within RCP6.0) would buy many coral reefs a couple of decades more time before the worst impacts occur, but it delays rather than mitigates the threats posed to coral reefs by acidification and bleaching (Maynard et al, 2016).

National leaders of the Caribbean need to adamantly fight for CO2 emissions reductions, and ensure their reef management agencies take all precautionary measures needed to reduce local stress on their reefs to buy them additional time and resiliency potential for withstanding the stress of climate change.

Continue reading ‘Impacts of climate change on coral in the coastal and marine environments of Caribbean Small Island Developing States (SIDS)’

High resolution microscopy reveals significant impacts of ocean acidification and warming on larval shell development in Laternula elliptica

Environmental stressors impact marine larval growth rates, quality and sizes. Larvae of the Antarctic bivalve, Laternula elliptica, were raised to the D-larvae stage under temperature and pH conditions representing ambient and end of century projections (-1.6°C to +0.4°C and pH 7.98 to 7.65). Previous observations using light microscopy suggested pH had no influence on larval abnormalities in this species. Detailed analysis of the shell using SEM showed that reduced pH is in fact a major stressor during development for this species, producing D-larvae with abnormal shapes, deformed shell edges and irregular hinges, cracked shell surfaces and even uncalcified larvae. Additionally, reduced pH increased pitting and cracking on shell surfaces. Thus, apparently normal larvae may be compromised at the ultrastructural level and these larvae would be in poor condition at settlement, reducing juvenile recruitment and overall survival. Elevated temperatures increased prodissoconch II sizes. However, the overall impacts on larval shell quality and integrity with concurrent ocean acidification would likely overshadow any beneficial results from warmer temperatures, limiting populations of this prevalent Antarctic species.

Continue reading ‘High resolution microscopy reveals significant impacts of ocean acidification and warming on larval shell development in Laternula elliptica’

Ice Acidification: A review of the effects of ocean acidification on sea ice microbial communities

Sea ice algae are naturally exposed to a wider range of pH and CO2 concentrations than marine phytoplankton. While climate change and ocean acidification (OA) will impact pelagic communities, their effects on sea ice microbial communities remains unclear.

Sea ice contains several distinct microbial communities, which are exposed to differing environmental conditions depending on their depth within the ice. Bottom communities mostly experience relatively benign bulk ocean properties, while interior brine and surface communities experience much greater extremes.

Most OA studies have examined the impacts on single sea ice algae species in culture. Although some studies examined the effects of OA alone, most also examined the effects of OA and either light, nutrients or temperature. With few exceptions, increased CO2 concentration caused either no change or an increase in growth and/or photosynthesis. In situ studies of brine and surface algae also demonstrated a wide tolerance to increased and decreased pH and showed increased growth at higher CO2 concentrations. The short time period of most experiments (< 10 days) together with limited genetic diversity (i.e. use of only a single strain), however, has been identified as a limitation to the broader interpretation of results.

While there have been few studies on the effects of OA on marine bacterial communities in general, impacts appear to be minimal. In sea ice also, the few reports available suggest no negative impacts on growth or community richness.

Sea ice ecosystems are ephemeral, melting and re-forming each year. Thus, for some part of each year organisms inhabiting the ice must also survive outside of the ice, either as part of the phytoplankton or as resting spores on the bottom. During these times, they will be exposed to the full range of co-stressors that pelagic organisms experience. Their ability to continue to make a major contribution to sea ice productivity will depend not only on their ability to survive in the ice but also on their ability to survive the increasing seawater temperatures, changing distribution of nutrients and declining pH forecast for the water column over the next centuries.

Continue reading ‘Ice Acidification: A review of the effects of ocean acidification on sea ice microbial communities’


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Ocean acidification in the IPCC AR5 WG II

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