© Ytterstad, Nordland, Norway

Acidification: Winners, losers and ecosystem impacts

1 October 2018

This article originally appeared in The Circle: Arctic biodiversity in the spotlight. The Circle shares perspectives from across the Arctic, and the views expressed here are not necessarily those of WWF. See all Circle issues here.

The ecological and socio-economic impacts of ocean acidification and warming will be considerable without large reductions in carbon emissions—and nowhere will the effects be more apparent than in the Arctic. This conclusion is based on the results of the 2018 Arctic Ocean Acidification Assessment, which will be presented at the 2018 Conservation of Arctic Flora and Fauna (CAFF) Arctic Biodiversity Congress in a session co-chaired by Richard Bellerby, Emily Osborne and Claudia Gelfond Roche.

The fastest rates of ocean acidification in the world—and the largest net changes in pH that we can observe today—have been detected in the Arctic Ocean. These shifts in ocean chemistry have an impact on marine ecosystems, in turn affecting both ocean resources and northern economies. The 2018 Arctic Ocean Acidification Assessment, conducted by the Arctic Monitoring and Assessment Programme with an update to the 2013 assessment, presents the chemical, biological and socio-economic impacts of ocean acidification through a series of regionally focused case studies.

Complex responses from marine ecosystems

Increasingly acidifying ocean conditions can affect marine organisms in a variety of ways. Some may experience altered growth, development or behaviour if exposed to low pH at certain life stages. Others may experience indirect effects, such as changes in their food web structures or predator–prey relationships.
This mixed response tells us that some organisms will be winners and others will be losers—an outcome that ultimately means we can expect a more complex array of impacts on marine ecosystems. The 2018 Arctic Ocean Acidification Assessment highlights some of these intricate interactions and underscores the difficulty of predicting how ecosystems may respond to change. But case studies like those of the Barents Sea cod fishery, Norwegian urchin harvesting and Greenland shrimp fisheries may shed some light on the regional challenges and socio-economic effects of ocean acidification in distinct Arctic areas.

For example, the case study of Norwegian urchin harvesting identifies the synergistic impacts of ocean acidification and warming on the potential harvestable urchin population and kelp regrowth in northern Norway. Considered a delicacy in some cuisines, urchins have been explored as an emerging fishery that could benefit kelp forest regrowth. Projecting the impacts of an acidifying, warming ocean on the urchin population and kelp growth in a variety of future CO2 emissions and ocean acidification scenarios can help us figure out the best harvesting strategies for both.

Anticipating the socio-economic impacts

Many of the studies included in the assessment anticipate that ocean acidification will have negative socio-economic impacts on communities. This would be thanks to the drastic ecological changes that are expected as marine systems respond to acidification. But other Arctic regions may experience positive economic effects from environmental changes like rising temperatures and reduced sea ice. The assessment included studies of several Arctic regions to better understand the variety of socio-economic impacts that ocean acidification may cause.

Overall, the assessment presents a synthesis of current research showing that ocean acidification is already affecting Arctic marine ecosystems, and that as it continues, it will ultimately have significant ecological and socio-economic effects that are difficult to predict accurately. Collectively, the studies indicate that while it’s clear there will be significant changes in Arctic ocean services, our current knowledge does not allow for a high level of confidence that these projections are accurate.

Protecting and managing Arctic ecosystems and ecosystem services to the benefit of local and global societies will depend on an integrated socio-ecological understanding of the Arctic Ocean.

Richard Bellerby is a senior scientist and research coordinator at the Norwegian Institute for Water Research, Norway and director of the SKLEC-NIVA Centre for Marine and Coastal Research at East China Normal University, China.
Emily B. Osborne is a program manager at the NOAA Arctic Research Program.
Claudia Gelfond Roche is a researcher affiliated with the Ocean Acidification Research Center at the University of Alaska Fairbanks.