Sunday, November 29, 2015

NOAA awards will help improve projections of acidification impacts in changing coastal waters

Awards of $1.3 million this year, totaling $4.1 million over three years, will focus on understanding the combined effects of ocean acidification, low oxygen and nutrient pollution on economically and ecologically important species in coastal habitats.

It is clear that our ocean is becoming more acidic as a result of carbon dioxide seeping into open ocean surface waters. But closer to shore things become a bit murky, as other factors can also change the chemistry of coastal waters. In these waters which are home to many important marine organisms on which coastal communities rely, scientists will be working to shed light on the potential impacts of acidification and other stresses.

Scientists measure water quality in the Corpus Christi Bay area. Photo credit: Larry Hyde

There are distinct factors that create these stresses and drive acidification in coastal areas. “It is crucial that we understand how the ocean chemistry is changing in different places, and how it will affect commercial fisheries and critical marine habitats in valued coastal communities,” said Libby Jewett, Ph.D., director of NOAA’s Ocean Acidification Program. These awards will allow studies of the coastal water chemistry on the US west coast, in the Gulf of Mexico and the Chesapeake Bay to take place over the next few years.  

These near shore waters are not only home to valued marine organisms, but are also susceptible to the effects of land based activities. Many coastal areas are experiencing stresses including low oxygen levels and increased nutrient runoff from land into coastal waters. Increased nutrient runoff causes blooms of tiny marine plants or algae. When the algal blooms decompose, deeper coastal waters can become depleted of oxygen. This process also increases carbon dioxide concentrations in the water, which leads to further acidification in localized areas. Additionally, rains not only bring freshwater into the near shore waters, but other sources of carbon. All of these factors: nutrient pollution, low oxygen, and increased freshwater contribute to coastal acidification.    

“Acidification, nutrient pollution and low oxygen may fundamentally change these coastal ecosystems. With these and other threats to our coasts, it is imperative that we build better tools for predicting these changes. These projections will inform decisions about fisheries management, protection of coral reefs, and agricultural practices,” said Dr. Libby Jewett. Within NOAA, the Ocean Acidification Program (OAP) and the National Centers for Coastal Ocean Science  are partnering to answer fundamental questions about how acidification will interact with other coastal stressors to impact marine resources. “These new projects expand the ability of coastal communities to better understand and respond to the very serious threat of acidification to the world's ocean, estuaries and Great Lakes" said Dr. Libby Jewett.

Understanding how these three stressors interact will allow for better informed marine resource and coastal land management. Dr. James McWilliams of the University of California Los Angeles and  lead investigator for the California Current project explained that “The motivation is to understand the potential negative effects of low oxygen and acidification on the base of the food web in this highly productive ecosystem.  We are particularly interested in understanding how regional pollution management practices can have outcomes locally.” This research will help determine which areas of the California Current are particularly vulnerable to low oxygen and acidification.

View of the Chesapeake Bay from above, including bathymetry, illustrating the deep central channels of the Bay (dark blue) and many shallow tributaries (yellow-orange). The project led by Dr. Testa at University of Maryland will focus on nutrient and carbon dynamics in both the deep, central basin, as well as the tributaries. Image credit: Jeremy Testa using Google Earth)

In Texas, short term coastal acidification events have been noticed in the local estuaries. Researchers at Texas A&M University-Corpus Christi note that the events have become longer and longer. This research team, led by Dr. Paul Montagna at Texas A&M University Corpus Christi, will be investigating how drought and land use change affect coastal acidification. They will then use that information to predict how future acidification and changes in rain patterns will impact the estuarine ecosystems of Texas.

On the US east coast, Dr. Jeremy Testa is leading a project in the Chesapeake Bay focused on the Eastern oyster, one of the bay’s most economically and culturally important species. “Attempts to restore the Eastern oyster in Chesapeake Bay could be affected by future changes,” Testa said. “In this project we hope to understand what role oyster reefs play in the cycling of nutrients and carbon and how these cycles may help or harm the restoration of oyster reefs.  We are also interested in discovering which regions of the bay are least vulnerable to acidification and might be ideal for oyster reef restoration.”

This research and the models developed from these projects will allow scientists to better understand acidification of our coastal waters driven by increasing atmospheric carbon dioxide and amplified by local processes.  With information about the drivers behind and projected impacts to different coastal ecosystems, coastal and land-based resource managers will have tools to better manage our valued coastal resources.