Acidification

Increasing temperatures, carbon levels, and ocean acidity have negative impacts on marine systems.
In addition climate change, the buildup of carbon dioxide in the atmosphere has also been linked to changes in the chemistry of the oceans.

How is the Ocean Becoming More Acidic?

Measurements made over the last few decades have demonstrated that ocean carbon dioxide levels have risen in response to increased carbon dioxide in the atmosphere, leading to an increase in acidity (that is, a decrease in pH).

Ocean acidification is the result of an increase in carbon dioxide absorption by ocean water and the corresponding decrease in pH. As seawater becomes less alkaline – or more acidic – less calcium carbonate is available for corals, shellfish, and other sea life to build their shells and skeletons. Threats to ecosystems and species due to ocean acidification will be wide-ranging across the marine food web and associated coastal communities, but include significant changes in the chemical composition of coastal ecosystems.  NOAA reports that increased absorption of carbon dioxide into the ocean has already begun to reduce calcification rates in reef-building and reef-associated organisms.

Implications for Land Trusts

Ocean acidification has been linked to the disturbance of food webs and changing species distributions. Together with other biogeochemical changes, increasing ocean acidification may compromise the health of marine ecosystems as well as negatively impact many ocean goods and services and the communities that rely on them. These changes especially threaten marine organisms that build their structures calcium carbonate – such as corals, clams, oysters, and crustaceans – because more energy is required to build their shells, making less energy available for important biological processes such as growing, reproducing, and responding to stress.  Researchers from the Woods Hole Oceanographic Institute found that some shelled-species faired better than others to increasing carbonic acid, however, overall impacts to ecosystems such as coral or oyster reefs appear to be negative, as research shows these systems are becoming increasingly threatened.

As coral and oyster reefs are degraded, the health of these systems and the plants and animals that depend on them becomes increasingly vulnerable. Additionally, these reef systems play important roles reducing the risk of coastal communities from natural hazards such as storms, flooding, and erosion. The USGS supported research published in Nature recent research that finds:

• Coral reefs provide substantial protection against natural hazards by reducing wave energy by an average of 97 percent.
• The reef crest, or shallowest part of the reef where the waves break first, dissipates 86 percent of wave energy on its own.
• The median cost for building artificial breakwaters is USD $19,791 per meter, compared to $1,290 per meter for coral reef restoration projects.

These findings make a strong case for the value of conservation of intact reef systems. The fact that over 7 million people live near reef systems in the United States provides additional basis for restoring degraded reef systems in order to enhance their wave attenuation potential, which can substantial reduce the vulnerability of coastal ecosystems and the communities in coastal areas.

Tips for Planning: What Land Trusts Are Doing

Cooperatively Working Towards Conservation Goals.

Land trusts are responding to on-the-ground impacts of ocean acidification in various ways. Some groups are engaging in coral reef restoration work, and many more are undertaking advocacy and education to help raise awareness to this growing management challenge. In addition to employing strategic conservation planning to reduce risks and enhance resilience, some land trusts are also supporting efforts to mitigate greenhouse gas emissions to reduce the extent of future climate change.

Land trusts must determine the right planning approach for their organization, however, more and more, conservation organizations are working with their communities to identify opportunities to reduce vulnerabilities and prepare for changing temperatures. Agencies are making similar strides to implement projects that reduce risks and plan for resilience by incorporating adaptation, mitigation, and engagement into their strategic goals and objectives. For example, the U.S. Fish and Wildlife Service’s Strategic Plan for Responding to Accelerating Climate Change identifies seven planning and development goals to support sustainable landscapes. Conservation groups are increasingly partnering with agencies as well as other nonprofits and for-profit organizations to respond to this global challenge at local levels.

Building resilience for multiple management objectives.

Resilience describes the ability of a system to persist through extreme change. By working to identify and reduce potential threats land managers can build resilience and achieve multiple management objectives. Assessing vulnerabilities is a critical step in the strategic conservation planning process that helps land trusts identify key threats to resources. Adaptive management planning enables conservation practitioners to implement interventions to reduce vulnerabilities and to monitor and revise strategies as new information becomes available. There is no one-size-fits-all solution to addressing management challenges associated with warming average temperatures, however, planning that acknowledges vulnerabilities can help land trusts better achieve their conservation objectives.

Learn More

• 2008 Monaco Declaration
• Climate Change Indicators in the United States: Ocean Acidity, EPA
• Critical Issues of Ocean Acidification, National Geographic
• IPCC Workshop on Impacts of Ocean Acidification on Marine Biology and Ecosystems
• NOAA Pacific Marine Estuary Laboratory:
  • Implementation of the Nonal Coral Reef Action Strategy – Report to Congress
  • Ocean Acidification
  • OA Educational Tools
  • Observations & Data
  • Additional Resources
• Ocean Acidification, NRDC
• Ocean Acidification, Woods Hole Oceanographic Institute
• Ocean Acidification Threatens Our Oceans, 2010, WWF
• The effectiveness of coral reefs for coastal hazard risk reduction and adaptation, Nature Communications
• Written Testimony: Effects of Climate Change and Ocean Acidification on Living Marine Resources, S. Doney, 2007