Ocean acidification: Pacific conversations with SPREP

In June this year, the Pacific islands are amplifying their voice at the United Nations Ocean Conference at the UN Headquarters in New York, focusing on Sustainable Development Goal 14 – Life Below Water.

This Pacific Conversation discusses ocean acidification and its impacts on Pacific species, providing you with more information to help make a difference in our region.

Did you know that a lower pH, the potential of hydrogen, makes the ocean a louder place? By 2050, under conservative projections of ocean acidification, sounds could travel as much as 70% farther in some ocean areas. This means ocean acidification affects whales and other animals, not just coral reefs and shellfish.

The ocean absorbs about 25% of the CO2 that we emit. If we had to pay for it, the value of this ‘ocean service’ to the global economy is USD 60 to 400 billion annually (EPOCA).

By taking up our extra CO2, the ocean has acidified by 30% since the start of the Industrial Revolution. The current rate of decrease is 0.02 units per decade, faster than any rate in the past 300 million years. Projections show that by 2060, seawater acidity could have increased by 120%.

Continue reading ‘Ocean acidification: Pacific conversations with SPREP’

Net community metabolism and seawater carbonate chemistry scale non-intuitively with coral cover

Coral cover and reef health have been declining globally as reefs face local and global stressors including higher temperature and ocean acidification (OA). Ocean warming and acidification will alter rates of benthic reef metabolism (i.e., primary production, respiration, calcification, and CaCO3 dissolution), but our understanding of community and ecosystem level responses is limited in terms of functional, spatial, and temporal scales. Furthermore, dramatic changes in coral cover and benthic metabolism could alter seawater carbonate chemistry on coral reefs, locally alleviating or exacerbating OA. This study examines how benthic metabolic rates scale with changing coral cover (0-100%), and the subsequent influence of these coral communities on seawater carbonate chemistry based on mesocosm experiments in Bermuda and Hawaii. In Bermuda, no significant differences in benthic metabolism or seawater carbonate chemistry were observed for low (40%) and high (80%) coral cover due to large variability within treatments. In contrast, significant differences were detected between treatments in Hawaii with benthic metabolic rates increasing with increasing coral cover. Observed increases in daily net community calcification and nighttime net respiration scaled proportionally with coral cover. This was not true for daytime net community organic carbon production rates, which increased the most between 0 to 20% coral cover and then less so between 20% to 100%. These differences in scaling resulted in larger diel variability in seawater carbonate chemistry as coral cover increased. To place the results of the mesocosm experiments into a broader context, in situ seawater carbon dioxide (CO2) at three reef sites in Bermuda and Hawaii were also evaluated; reefs with higher coral cover experienced a greater range of diel CO2 levels, complementing the mesocosm results. The results from this study highlight the need to consider the natural complexity of reefs and additional biological and physical factors that influence seawater carbonate chemistry on larger spatial and longer temporal scales. Coordinated efforts combining various research approaches (e.g. experiments, field studies, and models) will be required to better understand how benthic metabolism integrates across functional, spatial, and temporal scales, and for making predictions on how coral reefs will respond to climate change.

Continue reading ‘Net community metabolism and seawater carbonate chemistry scale non-intuitively with coral cover’

What a decade (2006-15) of journal abstracts can tell us about trends in ocean and coastal sustainability challenges and solutions

Text mining and analytics may offer possibilities to assess scientists’ professional writing and identify patterns of co-occurrence between words and phrases associated with different environmental challenges and their potential solutions. This approach has the potential to help to track emerging issues, semi-automate horizon scanning processes, and identify how different institutions or policy instruments are associated with different types of ocean and coastal sustainability challenges. Here I examine ecologically-oriented ocean and coastal science journal article abstracts published between 2006 and 2015. Informed by the Institutional Analysis and Development (IAD) framework, I constructed a dictionary containing phrases associated with 40 ocean challenges and 15 solution-oriented instrument or investments. From 50,817 potentially relevant abstracts, different patterns of co-occurring text associated with challenges and potential solutions were discernable. Topics receiving significantly increased attention in the literature in 2014-15 relative to the 2006-13 period included: marine plastics and debris; environmental conservation; social impacts; ocean acidification; general terrestrial influences; co-management strategies; ocean warming; licensing and access rights; oil spills; and economic impacts. Articles relating to global environmental change were consistently among the most cited; marine plastics and ecosystem trophic structure were also focal topics among the highly cited articles. This exploratory research suggests that scientists’ written outputs provide fertile ground for identifying and tracking important and emerging ocean sustainability issues and their possible solutions, as well as the organizations and scientists who work on them.

Continue reading ‘What a decade (2006-15) of journal abstracts can tell us about trends in ocean and coastal sustainability challenges and solutions’

Bacterial community responses during a possible CO2 leaking from sub-seabed storage in marine polluted sediments

Carbon capture and storage (CCS) is a viable option to reduce high concentrations of CO2 and mitigate their negative effects. This option has associated risks such as possible CO2 leakage from the storage sites. So far, negative effects deriving from a CO2 release have been reported for benthic macrofauna in both polluted and nonpolluted sediments. However, bacterial communities has no considered. In this work, risk assessment was carried out in order to evaluate the possible effects in a contaminated area considering bacterial responses (total number of cells, respiring activity, changes in the bacterial community composition and diversity). Four microcosms were placed into an integrated CO2 injection system with a non-pressurized chamber to simulate four different pH treatments (pH control 7.8, 7, 6.5 and 6). Results showed an impact on bacterial communities because of the CO2 treatment. Changes in respiring activity, community composition groups and diversity were found. This study highlights the use of respiring bacteria activity not only as bioindicator for environmental risk assessment and monitoring purposes but also as a bioindicador during a CO2 leakage event or CO2 enrichment process among all the responses studied.

Continue reading ‘Bacterial community responses during a possible CO2 leaking from sub-seabed storage in marine polluted sediments’

Acidification et réchauffement extrêmement rapides en Méditerranée nord-occidentale (in French)

Ayant analysé une série temporelle de haute fréquence acquise dans la rade de Villefranche-sur-Mer, des chercheurs du Laboratoire d’océanographie de Villefranche (LOV/OOV, UPMC / CNRS) et de l’Institut des relations internationales et du développement durable (Sciences Po, Paris) ont mis en évidence les changements très rapides qu’a connu l’eau de mer dans cette région entre 2007 et 2015. L’augmentation de la température y a été plus rapide que partout ailleurs dans l’océan global et celle de son acidité l’une des plus élevées jamais mesurées dans l’océan. En conséquence, plusieurs organismes sont affectés, ce qui pourrait altérer la chaîne alimentaire méditerranéenne.

Les mers et océans sont affectés de multiples manières par les activités humaines. Il est bien établi que les rejets de gaz carbonique (CO2) par les activités humaines entraînent un réchauffement. Environ 25 % de ces rejets sont absorbés par l’océan, soit 26 millions de tonnes de CO2. Cela permet de limiter les changements climatiques, mais au prix d’un bouleversement de la chimie de l’eau de mer, notamment une augmentation de son acidité.

Continue reading ‘Acidification et réchauffement extrêmement rapides en Méditerranée nord-occidentale (in French)’

Impact of climate change on direct and indirect species interactions

Recent marine climate change research has largely focused on the response of individual species to environmental changes including warming and acidification. The response of communities, driven by the direct effects of ocean change on individual species as well the cascade of indirect effects, has received far less study. We used several rocky intertidal species including crabs, whelks, juvenile abalone, and mussels to determine how feeding, growth, and interactions between species could be shifted by changing ocean conditions. Our 10 wk experiment revealed many complex outcomes which highlight the unpredictability of community-level responses. Contrary to our predictions, the largest impact of elevated CO2 was reduced crab feeding and survival, with a pH drop of 0.3 units. Surprisingly, whelks showed no response to higher temperatures or CO2 levels, while abalone shells grew 40% less under high CO2 conditions. Massive non-consumptive effects of crabs on whelks showed how important indirect effects can be in determining climate change responses. Predictions of species outcomes that account solely for physiological responses to climate change do not consider the potentially large role of indirect effects due to species interactions. For strongly linked species (e.g. predator-prey or competitor relationships), the indirect effects of climate change are much less known than direct effects, but may be far more powerful in reshaping future marine communities.

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A good Kiwi isn’t acidic: how ocean acidification is affecting the New Zealand economy

In a country that houses a mere 4 million people, it is no wonder that agriculture has become the main facet of New Zealand’s economy. However, while the sheep and produce have flourished from land protection laws, marine life has struggled in recent years due to an increase in oceanic carbon levels. In an area of the Pacific that is so rich in coral reefs, Great White breeding areas, and a plethora of fish species, any upset of the natural preexisting chemical balance has a tangible impact. New Zealand is dealing with a crisis with huge economic and ecological ramifications. I study the exact adverse effects that ocean acidification has had on the economy of New Zealand. The scientific process of how ocean acidification occurs is a building block of this understanding as well as the Gross Domestic Product (GDP) of the country. The rise of marine pH levels is inextricably linked to the downturn of prosperity in New Zealand’s agricultural sector. My solutions address stricter policies in regards to fishing and emissions regulations to augment the regulation of established New Zealand commercial fishing laws. In this thesis, my goal is to highlight that ocean acidification is a climate problem that affects the entire New Zealand population. By putting these effects into economic terms, I hope to urge change in the “business as usual” way countries conduct themselves, starting with policy makers whose focus is growing their GDP. To illustrate this point effectively, I utilize the disciplines of chemistry, economics, and politics to analyze the trends and consequences of ocean acidification.

Continue reading ‘A good Kiwi isn’t acidic: how ocean acidification is affecting the New Zealand economy’


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Ocean acidification in the IPCC AR5 WG II

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