Va. professor wins $700K to study growing ocean acidity

An assistant professor at Hampton University has won a prestigious science award for his groundbreaking research on the ocean’s increasing acidity and its impact on fish’s sensory systems.

Dr. Andrij Horodysky, who works in Hampton’s Marine and Environmental Science department, will get a $700,000 Faculty Early Career Development award over five years from the National Science Foundation (NSF).

Since the Industrial Revolution, the ocean has been gradually becoming more acidic– 30 percent more acidic, to be exact. That’s because it absorbs higher levels of carbon dioxide from the atmosphere.

Continue reading ‘Va. professor wins $700K to study growing ocean acidity’

Changes in coral reef community structure in response to year-long incubations under contrasting pCO2 regimes

Coral reefs are threatened by ocean acidification (OA), which depresses net calcification of corals, calcified algae, and coral reef communities. These effects have been quantified for many organisms, but most experiments last weeks-to-months, and do not test for effects on community structure. Here, the effects of OA on back reef communities from Mo’orea, French Polynesia (17.492 S, 149.826 W), were tested from 12 November 2015 to 16 November 2016 in outdoor flumes maintained at mean pCO2 levels of 364 µatm, 564 µatm, 761 µatm, and 1067 µatm. The communities consisted of four corals and two calcified algae, with change in mass (Gnet, a combination of gross accretion and dissolution) and percent cover recorded monthly. For massive Porites and Montipora spp., Gnet differed among treatments, and at 1067 µatm (relative to ambient) was reduced and still positive; for Porolithon onkodes, all of which died, Gnet was negative at high pCO2, revealing dissolution (sample sizes were too small for analysis of Gnet for other taxa). Growth rates (% cover month−1) were unaffected by pCO2 for Montipora spp., P. rus, Pocillopora verrucosa, and Lithophyllum kotschyanum, but were depressed for massive Porites at 564 µatm. Multivariate community structure changed among seasons, and the variation under all elevated pCO2 treatments differed from that recorded at 364 µatm, and was greatest under 564 µatm and 761 µatm pCO2. Temporal variation in multivariate community structure could not be attributed solely to the effects of OA on the chemical and physical properties of seawater. Together, these results suggest that coral reef community structure may be more resilient to OA than suggested by the negative effects of high pCO2 on Gnet of their component organisms.

Continue reading ‘Changes in coral reef community structure in response to year-long incubations under contrasting pCO2 regimes’

The effect of Agulhas eddies on absorption and transport of anthropogenic carbon in the South Atlantic Ocean

The South Atlantic Ocean is currently undergoing significant alterations due to climate change. This region is important to the global carbon cycle, but marine carbon data are scarce in this basin. Additionally, this region is influenced by Agulhas eddies. However, their effects on ocean biogeochemistry are not yet fully understood. Thus, we aimed to model the carbonate parameters in this region and investigate the anthropogenic carbon (Cant) content in 13 eddies shed by the Agulhas retroflection. We used in situ data from the CLIVAR/WOCE/A10 section to elaborate total dissolved inorganic carbon (CT) and total alkalinity (AT) models and reconstruct those parameters using in situ data from two other Brazilian initiatives. Furthermore, we applied the Tracer combining Oxygen, inorganic Carbon, and total Alkalinity (TrOCA) method to calculate the Cant, focusing on the 13 identified Agulhas eddies. The CT and AT models presented root mean square errors less than 1.66 and 2.19 μmol kg−1, indicating Global Ocean Acidification Observing Network climate precision. The Cant content in the Agulhas eddies was 23% higher than that at the same depths of the surrounding waters. We observed that Agulhas eddies can play a role in the faster acidification of the South Atlantic Central Water.

Continue reading ‘The effect of Agulhas eddies on absorption and transport of anthropogenic carbon in the South Atlantic Ocean’

OA-ICC bibliographic database updated

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

The database currently contains more than 5,580 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.

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A growing sensory smog threatens the ability of fish to communicate, navigate, and survive

Ocean acidification can confuse how a clownfish reacts to predators.
 V. ALTOUNIAN/SCIENCE

An 11-day-old clownfish, pale orange and about as long as a grain of rice, searches for a place to settle down on a reef. Its keen sense of smell helps it both navigate to a safe home and steer away from the mouths of predators.

In the wild, clownfish inhabit living coral reefs. But in behavioral ecologist Danielle Dixson’s laboratory at the University of Delaware in Lewes, the habitats beckoning the fish are made mostly of wires. Dixson will use the experimental setup to study how ocean acidification could alter how fish perceive and respond to their world.

Continue reading ‘A growing sensory smog threatens the ability of fish to communicate, navigate, and survive’

SOCAT version 2019 is released

SOCAT version 2019 was released on the 18th of June 2019, containing data submitted on or before 15th of January 2019. New data submissions are welcome at any time, and will be included in the next SOCAT release.

SOCAT data are released in versions. Each succeeding version contains new data sets as well as updates of older ones. The first version of SOCAT was released in 2011, the second and third version followed biennially. Automation allowed annual public releases since version 4. The latest SOCAT version (version 2019) has 25.7 million observations from 1957 to 2019 for the global oceans and coastal seas. Calibrated sensor data are also available.

Continue reading ‘SOCAT version 2019 is released’

Long-term acclimation to near-future ocean acidification has negligible effects on energetic attributes in a juvenile coral reef fish

Increased levels of dissolved carbon dioxide (CO2) drive ocean acidification and have been predicted to increase the energy use of marine fishes via physiological and behavioural mechanisms. This notion is based on a theoretical framework suggesting that detrimental effects on energy use are caused by plasma acid–base disruption in response to hypercapnic acidosis, potentially in combination with a malfunction of the gamma aminobutyric acid type A (GABAA) receptors in the brain. However, the existing empirical evidence testing these effects primarily stems from studies that exposed fish to elevated CO2 for a few days and measured a small number of traits. We investigated a range of energetic traits in juvenile spiny chromis damselfish (Acanthochromis polyacanthus) over 3 months of acclimation to projected end-of-century CO2 levels (~ 1000 µatm). Somatic growth and otolith size and shape were unaffected by the CO2 treatment across 3 months of development in comparison with control fish (~ 420 µatm). Swimming activity during behavioural assays was initially higher in the elevated CO2 group, but this effect dissipated within ~ 25 min following handling. The transient higher activity of fish under elevated CO2 was not associated with a detectable difference in the rate of oxygen uptake nor was it mediated by GABAA neurotransmitter interference because treatment with a GABAA antagonist (gabazine) did not abolish the CO2 treatment effect. These findings contrast with several short-term studies by suggesting that end-of-century levels of CO2 may have negligible direct effects on the energetics of at least some species of fish.

Continue reading ‘Long-term acclimation to near-future ocean acidification has negligible effects on energetic attributes in a juvenile coral reef fish’


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OA-ICC HIGHLIGHTS

Ocean acidification in the IPCC AR5 WG II

OUP book