a news stream provided by the Ocean Acidification International Coordination Center (OA-ICC)
Thanks to carbon emissions, our oceans are turning to acid. It’s dissolving the shells of oysters and attacking global shorelines – damaging ecosystems that suck more carbon dioxide from ocean waters than all the world’s vehicles spew into the air. In this first report of the series “Coast vs. Climate”, VOA’s Veronica Balderas Iglesias explores the “evil twin” of climate change – and how to remedy it.
Continue reading ‘Evil twin of climate change, and how to stop it (text & video)’A small subset of marine microbial enzymes and surface transporters have a disproportionately important influence on the cycling of carbon and nutrients in the global ocean. As a result, they largely determine marine biological productivity and have been the focus of considerable research attention from microbial oceanographers. Like all biological catalysts, the activity of these keystone biomolecules is subject to control by temperature and pH, leaving the crucial ecosystem functions they support potentially vulnerable to anthropogenic environmental change. We summarize and discuss both consensus and conflicting evidence on the effects of sea surface warming and ocean acidification for five of these critical enzymes [carbonic anhydrase, ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), nitrogenase, nitrate reductase, and ammonia monooxygenase] and one important transporter (proteorhodopsin). Finally, we forecast how the responses of these few but essential biocatalysts to ongoing global change processes may ultimately help to shape the microbial communities and biogeochemical cycles of the future greenhouse ocean.
Continue reading ‘The enzymology of ocean global change’Ocean warming and acidification pose serious threats to cold-water corals (CWCs) and the surrounding habitat. Yet, little is known about the role of natural short-term and seasonal environmental variability, which could be pivotal to determine the resilience of CWCs in a changing environment. Here, we provide continuous observational data of the hydrodynamic regime (recorded using two benthic landers) and point measurements of the carbonate and nutrient systems from five Lophelia pertusa reefs in the Langenuen Fjord, southwestern Norway, from 2016 to 2017. In this fjord setting, we found that over a tidal (<24 h) cycle during winter storms, the variability of measured parameters at CWC depths was comparable to the intra-annual variability, demonstrating that single point measurements are not sufficient for documenting (and monitoring) the biogeochemical condiotions at CWC sites. Due to seasonal and diurnal forcing, parts of the reefs experienced temperatures up to 4 ◦C warmer (i.e., >12 ◦C) than the mean conditions and high CT concentrations of 20 µmol kg−1 over the suggested threshold for healthy CWC reefs (i.e., >2170 µmol kg−1 ). Combined with hindcast measurements, our findings indicate that these shallow fjord reefs may act as an early hotspot for ocean warming and acidification. We predict that corals in Langenuen will face seasonally high temperatures (>18 ◦C) and hypoxic and corrosive conditions within this century. Therefore, these fjord coral communities could forewarn us of the coming consequences of climate change on CWC diversity and function.
Continue reading ‘Cold-water coral reefs in the Langenuen Fjord, Southwestern Norway—a window into future environmental change’
Dear Users,
The OA-ICC has supported the ocean acidification community by maintaining the ocean acidification news stream and OA-ICC bibliographic database for nearly 10 years. This year in light of the increased importance of the virtual space in the time of COVID-19, we dedicated additional resources to update and grow our site, enhancing the tools available to our community. In addition to updating the Bibliographic Database, which now contains more than 8,800 scientific papers on ocean acidification, we have developed new guides and features on the site which you may be interested in.
These include:
We invite you to explore the site and benefit from the additional resources made available to the ocean acidification community. If you are interested in collaborating with the OA-ICC projects, programs and events, please contact us at oa-icc@iaea.org.
Kind regards,
OA-ICC team
We are happy to inform you that the latest version of the OA-ICC bibliographic database, now containing more than 8,800 scientific articles, books and more on ocean acidification, is available for public use on Zotero and for download on pCloud. The database is no longer available on Mendeley because the public groups feature has been discontinued, but you may still download the database and add it to your Mendeley library.
We have also created a new user guide and a page on our methodology to improve your experience using the bibliographic resources. You may find our user guide and more information on OA-ICC bibliographic resources, including the biological response data portal, on our new bibliographic database page. This page includes our updated friendly user’s guide, featuring explanations to our custom keywords with links to clear examples. In addition, we will be sharing a tutorial on navigating the bibliographic resources soon.
Continue reading ‘OA-ICC bibliographic database updates and user guide’Highlights
Abstract
It is expected that by 2050 human population will exceed nine billion leading to increased pressure on marine ecosystems. Therefore, it is conjectured various levels of ecosystem functioning starting from individual to population-level, species distribution, food webs and trophic interaction dynamics will be severely jeopardized in coming decades. Ocean warming and acidification are two prime threats to marine biota, yet studies about their cumulative effect on marine fish and shellfishes are still in its infancy. This review assesses existing information regarding the interactive effects of global environmental factors like warming and acidification in the perspective of marine capture fisheries and aquaculture industry. As climate change continues, distribution pattern of species is likely to be altered which will impact fisheries and fishing patterns. Our work is an attempt to compile the existing literatures in the biological perspective of the above-mentioned stressors and accentuate a clear outline of knowledge in this subject. We reviewed studies deciphering the biological consequences of warming and acidification on fish and shellfishes in the light of a molecule to ecosystem perspective. Here, for the first time impacts of these two global environmental drivers are discussed in a holistic manner taking into account growth, survival, behavioural response, prey predator dynamics, calcification, biomineralization, reproduction, physiology, thermal tolerance, molecular level responses as well as immune system and disease susceptibility. We suggest urgent focus on more robust, long term, comprehensive and ecologically realistic studies that will significantly contribute to the understanding of organism’s response to climate change for sustainable capture fisheries and aquaculture.
Continue reading ‘Combined effects of ocean warming and acidification on marine fish and shellfish: a molecule to ecosystem perspective’The carbonate chemistry was investigated in the semiarid eutrophic Araruama Lagoon (Brazil), one of the largest hypersaline coastal lagoons in the world. Spatial surveys during winter and summer periods were performed, in addition to a diurnal sampling in summer. The hypersaline waters have higher concentrations of total alkalinity (TA) and dissolved inorganic carbon (DIC) than the seawater that feed the lagoon, due to evaporation. However, TA and DIC concentrations were lower than those expected from evaporation. Calcium carbonate (CaCO3) precipitation partially explained these deficits. The negative correlation between the partial pressure of CO2 (pCO2) and chlorophyll a (Chl a) indicated that DIC was also consumed by primary producers. The uptake by photosynthesis contributes to 57–63% of DIC deviation from evaporation, the remaining credited to CaCO3 precipitation. Marked pCO2 undersaturation was prevalent at the innermost region with shallow, confined, and phytoplankton-dominated waters, with a strong enrichment of heavier carbon isotope (δ13C-DIC up to 5.55%), and highest pH (locally counter-acting the process of ocean acidification). Oversaturation was restricted to an urbanized region, and during night-time. The lagoon behaved as a marked CO2 sink during winter (− 15.32 to − 10.15 mmolC m−2 day−1), a moderate sink during summer (− 5.50 to − 4.67 mmolC m−2 day−1), with a net community production (NCP) of 93.7 mmolC m−2 day−1 and prevalence of net autotrophic metabolism. A decoupling between CO2 and O2 exchange rate at the air–water interface was attributed to differences in gas solubility, and high buffering capacity. The carbonate chemistry reveals simultaneous and antagonistic actions of CaCO3 precipitation and autotrophic metabolism on CO2 fluxes, and could reflect future conditions in populated and semiarid coastal ecosystems worldwide.
Continue reading ‘Eutrophication overcoming carbonate precipitation in a tropical hypersaline coastal lagoon acting as a CO2 sink (Araruama Lagoon, SE Brazil)’Coral reefs are one of the most biodiverse and ecologically important ecosystems on the planet, but they are increasingly threatened by ocean acidification and warming. Changes in environmental factors can cause the coral to expel their endosymbiotic community of single-celled dinoflagellates (family: Symbiodiniaceae), leaving them more vulnerable to disease and mortality. One proposed method through which coral can acclimatize to the fluctuations in ocean temperature is by shuffling their Symbiodiniaceae community compositions to increase the relative proportions of temperature-tolerant symbionts. However, the effects of ocean acidification on Symbiodiniaceae community compositions are still unknown. Here, I present data from a two-year mesocosm experiment investigating the effects of long-term exposure to ocean acidification and warming on Symbiodiniaceae community composition in eight common species of Hawaiian coral. Coral were collected from six geographically distinct locations around O’ahu and exposed to predicted end-of-century temperature and pH conditions for two years. Next Generation Sequencing (NGS) of the ribosomal internal transcribed spacer 2 (ITS2) region of the Symbiodiniaceae provided detailed insight into the distinct symbiont types and the changes in community composition resulting from environmental stressors. Our findings indicate that temperature is a more significant driver of changes to the Symbiodiniaceae community compositions than pH in Hawaiian corals. We additionally demonstrate that the changes in symbiont communities in response to experimental temperature and pCO2 conditions arise from the shuffling of current symbionts and the incorporation of novel symbionts from the environment, which has implications for future coral resilience against climate change.
Continue reading ‘How do coral reefs respond to climate change? Investigating the role of Symbiodiniaceae community composition on coral performance under long-term exposure to warming and acidification’Excessive CO2 emissions isn’t just an atmospheric problem, it’s changing the chemistry of our oceans through ocean acidification and impacting ocean life.
Continue reading ‘The ocean’s chemistry is changing. Why does it matter? (video)’Highlights
Abstract
The intestinal microflora is critical for the health of hosts by affecting their nutrient absorption and immune response. Increasing evidences demonstrate that environmental stress can lead to the dysbiosis of intestinal microflora, which increases the susceptibility of host to pathogens. Ocean acidification (OA) is one of the greatest environmental threats for marine mollusks with the negative effects on growth and calcification, but its impact on intestinal microflora is poorly understood. In the present study, the intestinal microflora of the Pacific oyster Crassostrea gigas reared at seawater with pH values of 8.1 (control group), 7.8 (AC78 group) and 7.4 (AC74 group) were characterized and compared using 16S rRNA gene sequencing. The composition of oyster intestinal microflora changed significantly after acidification, while no significant difference of α-diversity was observed between the control and acidification groups. At the phylum level, the relative abundance of Firmicutes decreased in acidification groups, and the Firmicutes/Bacteroides ratio in AC78 and AC74 groups were 0.53 and 0.31-fold of that in the control group, respectively. At the genus level, the intestinal microflora was dominated by Mycoplasma, which was significantly enriched in the two acidification groups. LEfSe analysis showed that Mycoplasma was one of the most discriminative biomarkers in the AC78 group, while Alteromonadales, Amphritea, Salinirepens and Alteromonas were the biomarker taxa in the AC74 group. The functional prediction results indicated that the pathways related to protein and nucleic acid synthesis were enriched in the two acidification groups, while those related to carbohydrate catabolism were blocked in the AC78 group but enhanced in the AC74 group. These results suggested that the relative abundance of probiotic bacteria decreased upon ocean acidification, which favored the proliferation of pathogenic species in the intestine of oysters. The increased consumption of nutrients caused by microflora proliferation would aggravate the susceptibility of oysters to pathogens. Under greater OA stress, the intestinal microflora would enhance the competition for energy source with their hosts, consequently posing a great challenge to the host health. The information contributed to the better understanding of the oyster-microflora interactions under environmental stress.
Continue reading ‘Impact of ocean acidification on the intestinal microflora of the Pacific oyster Crassostrea gigas’Human inputs of pollutants to the atmosphere and subsequent deposition may decrease pH in the coastal waters. Significant rate of decrease in pH and increase in pCO2 by 3–5 times is noticed in the coastal Bay of Bengal (BoB) than the low-latitude global ocean trends in the last few decades. We provide evidence for the first time for a rapid decrease in surface water pH due to atmospheric deposition of pollutants in the coastal BoB. The decrease in pH in the coastal BoB over the last decade is associated with concomitant increase in aerosol optical depth (AOD), total suspended particles (TSP) in air, sulfate and nitrate concentrations in TSP. This study suggests that contamination of surface coastal BoB by atmospheric pollutants not only acidifies surface ocean but also potentially amplifies CO2 emission with immediate implications to regional weather and climate.
Continue reading ‘Elevated acidification rates due to deposition of atmospheric pollutants in the coastal Bay of Bengal’Climate change is a global persistent threat to fish and fish habitats throughout North America. Climate-induced modification of environmental regimes, including changes in streamflow, water temperature, salinity, storm surges, and habitat connectivity can change fish physiology, disrupt spawning cues, cause fish extinctions and invasions, and alter fish community structure. Reducing greenhouse emissions remains the primary mechanism to slow the pace of climate change, but local and regional management agencies and stakeholders have developed an arsenal of adaptation strategies to help partially mitigate the effects of climate change on fish. We summarise common stressors posed by climate change in North America, including (1) increased water temperature, (2) changes in precipitation, (3) sea level rise, and (4) ocean acidification, and present potential adaptation strategies that fishery professionals may apply to help vulnerable fish and fisheries cope with a changing climate. Although our adaptation strategies are primarily from North America, they have broader geographic applicability to fish and aquatic biota in other jurisdictions. These strategies provide opportunities for managers to mitigate the effects of climate change on fish and fish habitat while needed global policies to reduce greenhouse gas emissions emerge, which may offer more lasting solutions.
Continue reading ‘Climate change effects on North American fish and fisheries to inform adaptation strategies.’Many shallow coastal systems experience diel fluctuations in dissolved oxygen (DO) and pH that can intensify throughout the summer season and expose estuarine organisms to repeated episodes of coastal hypoxia and acidification. In temperate regions, larval release of the economically important blue crab Callinectes sapidus occurs in the summer, and while the earliest stage (zoea I) larvae are susceptible to persistent low DO and low pH conditions, their sensitivity to diel fluctuations is unknown. Here, a series of short-term (≤96 h) experiments were conducted to investigate the survival of C. sapidus zoea I larvae exposed to a range of diel cycling hypoxic and acidified conditions and durations. Two experiments comparing a diel cycling DO/pH treatment (fluctuating from ∼30% air saturation to ∼103% averaging ∼66%/and from pH ∼7.26 to ∼7.80 averaging ∼7.53) to a static low DO/pH treatment (∼43%/∼7.35), a static moderate DO/pH treatment (∼68%/∼7.59), and a static control treatment (∼106%/∼7.94) indicated that survival in the diel cycling treatment was significantly lower than the moderate treatment (p < 0.05) by 75 and 48% over 96 and 48 h, respectively, despite comparable mean experimental DO/pH values. Three other experiments aimed at identifying the effective minimum duration of low DO/low pH to significantly depress larval survival under diel cycling conditions revealed that 8 h of low DO/low pH (∼28%/∼7.43) over a 24-h diel cycle consistently decreased survival (p < 0.05) relative to control conditions by at least 55% regardless of experimental duration (72-, 48-, and 24-h experiments). An increase in DO beyond saturation to supersaturation (160%) and pH beyond normocapnic to highly basified (8.34) conditions during the day phase of the diel cycle did not improve survival of larvae exposed to nocturnal hypoxia and acidification. Collectively, these experiments demonstrate that diel cycling does not provide newly hatched C. sapidus larvae a temporal refuge capable of ameliorating low DO/pH stress, but rather is more lethal than chronic exposure to comparable average DO/pH conditions. Given that larvae exposed to a single nocturnal episode of moderate hypoxia and acidification experience significantly reduced survival, such occurrences may depress larval recruitment.
Continue reading ‘Brief episodes of nocturnal hypoxia and acidification reduce survival of economically important blue crab (Callinectes sapidus) larvae’Eutrophic coastal regions are highly productive and greatly influenced by human activities. Primary production supporting the coastal ecosystems is supposed to be affected by progressive ocean acidification driven by increasing CO2 emissions. In order to investigate the effects of high pCO2 (HC) on eutrophic plankton community structure and ecological functions, we employed 9 mesocosms and carried out an experiment under ambient (∼410 ppmv) and future high (1000 ppmv) atmospheric pCO2 conditions, using in situ plankton community in Wuyuan Bay, East China Sea. Our results showed that HC along with natural seawater temperature rise significantly boosted biomass of diatoms with decreased abundance of dinoflagellates in the late stage of the experiment, demonstrating that HC repressed the succession from diatoms to dinoflagellates, a phenomenon observed during algal blooms in the East China Sea. HC did not significantly influence the primary production or biogenic silica contents of the phytoplankton assemblages. However, the HC treatments increased the abundance of viruses and heterotrophic bacteria, reflecting a refueling of nutrients for phytoplankton growth from virus-mediated cell lysis and bacterial degradation of organic matters. Conclusively, our results suggest that increasing CO2 concentrations can modulate plankton structure including the succession of phytoplankton community and the abundance of viruses and bacteria in eutrophic coastal waters, which may lead to altered biogeochemical cycles of carbon and nutrients.
Continue reading ‘Elevated pCO2 impedes succession of phytoplankton community from diatoms to dinoflagellates along with increased abundance of viruses and bacteria’Beginning in 2015, the United States Environmental Protection Agency’s (EPA’s) National Estuary Program (NEP) started a collaboration with partners in seven estuaries along the East Coast (Barnegat Bay; Casco Bay), West Coast (Santa Monica Bay; San Francisco Bay; Tillamook Bay), and the Gulf of Mexico (GOM) Coast (Tampa Bay; Mission-Aransas Estuary) of the United States to expand the use of autonomous monitoring of partial pressure of carbon dioxide (pCO2) and pH. Analysis of high-frequency (hourly to sub-hourly) coastal acidification data including pCO2, pH, temperature, salinity, and dissolved oxygen (DO) indicate that the sensors effectively captured key parameter measurements under challenging environmental conditions, allowing for an initial characterization of daily to seasonal trends in carbonate chemistry across a range of estuarine settings. Multi-year monitoring showed that across all water bodies temperature and pCO2 covaried, suggesting that pCO2 variability was governed, in part, by seasonal temperature changes with average pCO2 being lower in cooler, winter months and higher in warmer, summer months. Furthermore, the timing of seasonal shifts towards increasing (or decreasing) pCO2 varied by location and appears to be related to regional climate conditions. Specifically, pCO2 increases began earlier in the year in warmer water, lower latitude water bodies in the GOM (Tampa Bay; Mission-Aransas Estuary) as compared with cooler water, higher latitude water bodies in the northeast (Barnegat Bay; Casco Bay), and upwelling-influenced West Coast water bodies (Tillamook Bay; Santa Monica Bay; San Francisco Bay). Results suggest that both thermal and non-thermal influences are important drivers of pCO2 in Tampa Bay and Mission-Aransas Estuary. Conversely, non-thermal processes, most notably the biogeochemical structure of coastal upwelling, appear to be largely responsible for the observed pCO2 values in West Coast water bodies. The co-occurrence of high salinity, high pCO2, low DO, and low temperature water in Santa Monica Bay and San Francisco Bay characterize the coastal upwelling paradigm that is also evident in Tillamook Bay when upwelling dominates freshwater runoff and local processes. These data demonstrate that high-quality carbonate chemistry observations can be recorded from estuarine environments using autonomous sensors originally designed for open-ocean settings.
Continue reading ‘Integrating high-resolution coastal acidification monitoring data across seven United States estuaries’Experimentally elevated pCO2 and the associated pH drop are known to differentially affect many aspects of the physiology of diatoms under different environmental conditions or in different regions. However, contrasting responses to elevated pCO2 in the dark and light periods of a diel cycle have not been documented. By growing the model diatom Phaeodactylum tricornutum under 3 light levels and 2 different CO2 concentrations, we found that the elevated pCO2/pH drop projected for future ocean acidification reduced the diatom’s growth rate by 8–25% during the night period but increased it by up to 9–21% in the light period, resulting in insignificant changes in growth over the diel cycle under the three different light levels. The elevated pCO2 increased the respiration rates irrespective of growth light levels and light or dark periods and enhanced its photosynthetic performance during daytime. With prolonged exposure to complete darkness, simulating the sinking process in the dark zones of the ocean, the growth rates decreased faster under elevated pCO2, along with a faster decline in quantum yield and cell size. Our results suggest that elevated pCO2 enhances the diatom’s respiratory energy supplies to cope with acidic stress during the night period but enhances its death rate when the cells sink to dark regions of the oceans below the photic zone, with implications for a possible acidification-induced reduction in vertical transport of organic carbon.
Continue reading ‘Elevated pCO2 enhances under light but reduces in darkness the growth rate of a diatom, with implications for the fate of phytoplankton below the photic zone’Highlights
Abstract
Pharmaceuticals found in human wastes are emergent pollutants that are continuously released into aquatic systems. While exposure to pharmaceuticals alone could adversely impact aquatic organisms, few studies have considered the interactive effects of pharmaceuticals and the future environmental conditions, such as decreasing pH due to ocean acidification. Given the bioavailability of many pharmaceuticals is dependent on these physical conditions, we investigated the effect of environmentally-relevant concentrations of fluoxetine (10 and 100 ng L−1) under ambient (pH 8.0) and reduced pH conditions (pH 7.7) on physiology, behavior, and DNA integrity of larval sea urchins (Heliocidaris crassispina). Notably, the negative impacts of fluoxetine exposure were attenuated by reduced pH. Larvae exposed to both reduced pH and fluoxetine exhibited lower levels of DNA damage compared to those exposed to only one of the stressors. Similar antagonistic interactions were observed at the organismal level: for example, fluoxetine exposure at 10 ng L−1 under ambient pH increased the percentage of embryos at later developmental stages, but such effects of fluoxetine were absent at pH 7.7. However, despite the modulation of fluoxetine impacts under ocean acidification, control larvae performed better than those exposed to either stressor, alone or in combination. We also observed that pH alone impacted organismal behaviors, as larvae swam slower at reduced pH regardless of fluoxetine exposure. Our findings highlight the need to consider multi-stressor interactions when determining future organismal performance and that multiple metrics are needed to paint a fuller picture of ecological risks.
Continue reading ‘Near future ocean acidification modulates the physiological impact of fluoxetine at environmental concentration on larval urchins’Ocean acidification typically reduces the calcification rates of massive Porites spp. corals, but increasing seawater temperatures (below the stress and bleaching threshold) can offset this effect. Here, we use δ11B to reconstruct the pH of the calcification media (pHECM) used to precipitate the skeleton in poritid corals cultured over a range of seawater pCO2 and at 25 °C and 28 °C. Increasing temperature had no significant effect on pHECM at high pCO2 although corals increased their calcification rates. pHECM was reduced at 28 °C compared to 25 °C at low seawater pCO2, although calcification rates remained constant. Increasing calcification rates could reflect the positive influence of temperature on aragonite precipitation rate, an increase in calcification media saturation state or a change in the concentration/behaviour of the skeletal organic matrix. The two temperatures utilized in this study were within the seasonal range at the coral collection site and do not represent a heat stress scenario. Increasing seawater temperatures may promote calcification in some corals in the future but are unlikely to benefit the majority of corals, which are already living close to their maximum thermal tolerance limits.
Continue reading ‘Resolving the interactions of ocean acidification and temperature on coral calcification media pH’Learn more about the Fisheries and Oceans Climate Change and Ocean Acidification Laboratory (FOCCOAL). This state-of-the-art system, developed by DFO scientists at the Pacific Biological Station, allows tight control of both seawater pH and temperature.
Continue reading ‘Fisheries and Oceans Climate Change and Ocean Acidification Laboratory (FOCCOAL)(text & video)’Date: 30 August – 3 September 2021
Location: online
Date: 2 September 2021
Title: Interactive effects of ocean acidification and UV radiation on aquatic primary production
Time: 15:40 – 16:05
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Title: Photophysiological response of marine phytoplankton under ocean acidification conditions
Time: 16:45 – 17:00
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Title: Effects of ocean acidification in photophysiology of marine bacteria from two different marine habitats
Time: 17:00 – 17:05
Continue reading ’19th Congress of the European Society for Photobiology’
