Coastal ecosystems – marshes, bogs, swamps, seagrass beds and mangroves among them – provide a wide range of beneficial services that have all too often been unknown to or ignored, including serving as carbon sinks. A ¨blue carbon¨ study by non-profit Restore America's Estuaries puts numbers on the amount of atmospheric carbon dioxide (CO2) seagrasses, marshes and mangroves in the Tampa Bay area absorb – an estimated 74 million metric tons per year until 2100.
Wetlands the world over have been and continue to be lost at a rapid rate due to human activities, such as dredging, draining and in-filling. It's estimated that their loss releases some 450 million metric tons of CO2 into the atmosphere on average every year, along with a variety of other beneficial services these ecosystems have provided human and other living communities over the millennia.
The Tampa Bay ecosystem is unique in that it's one of the few in the U.S. where substantial natural areas of seagrass, marsh and mangrove haven't fallen prey to development and other impacts associated with population growth and industrial-age economic development. The study "reinforces the importance of restoring coastal habitats in Tampa Bay and around the nation to buffer the effects of rising seas and a changing climate," the non-profit explains in a press release.
Addressing threats to coastal communities
Tampa Bay managers have been working to restore some balance by restoring critical types of more natural estuary habitats since thousands of acres were lost due to development that took place from the 1950s to early 1990s. Contributing to such efforts, Restore America's Estuaries (RAE) enlisted conservation agencies Tampa Bay Estuary Program and Tampa Bay Watch to carry out their study. As RAE explains:
"The study highlights the substantial contribution that Tampa Bay coastal habitats provide for capturing and storing carbon, and provides new data to help local organizations and agencies understand what actions are needed most to help the Bay mitigate the effects of sea-level rise, while continuing to improve habitat health and the Bay’s overall environmental and economic integrity."
Coastal shorelines account for just 10 percent of the land area of the lower 48 U.S. states yet just shy of 4 in 10 Americans (39 percent) lived on them as of 2010, according to the National Oceanic and Atmospheric Administration (NOAA).
Coastal shoreline cities and communities in Florida, the U.S. and worldwide are threatened in a variety of ways as sea levels rise and extreme weather events occur with greater frequency as the climate warms. Shorelines are being eroded more rapidly, taking homes, businesses and property with them. Freshwater aquifers and reservoirs are being threatened as saltwater incursions increase and intensify. Valuable habitats, such as coral reefs, are being lost and the makeup of commercial fish and other populations of marine species are changing as species migrate in response to changing environmental conditions.
In Tampa Bay, much of the marsh and mangrove habitat is vulnerable to drowning as sea level rises, according to Save America's Estuaries' research report. Provided water quality is good enough, seagrass beds may take their place.
Maintaining the qualify of seawater will be critical to maintaining Tampa Bay's fisheries and quality of life. And by setting aside upland area we can provide critical areas for marsh and mangrove habitats to migrate to, the report authors point out.
“There is an opportunity for coastal managers to use this data to plan for sea-level rise,” principal investigator Steve Crooks, director of Climate Change Services for Environmental Science Associates, was quoted. “By targeting vulnerable areas for conservation and restoration, we can improve habitat diversity and health in Tampa Bay.”
Coastal habitat conservation
Project researchers modeled the response of coastal habitats to future sea-level rise and offer recommendations that can help Tampa Bay and coastal communities across the U.S. and beyond prepare for and address the coming changes. Among them:
- Actions that enhance tidal wetland resilience, e.g. enabling habitats to accrete (build up) vertically and keep pace with sea-level rise;
- Conserving upland areas to allow coastal habitat migration in response to rising seas;
Prioritizing vulnerable areas for restoration and/or acquisition, such as areas that are more susceptible to flooding; and
- Maintain (or improve where necessary) water quality to allow seagrass expansion into newly flooded coastal lands where marsh and mangrove are unable to persist.
- "Over the past two decades, the Tampa Bay community has made great progress in improving the health of Tampa Bay’s waters," Executive Director of the Tampa Bay Estuary Program Holly Greening said.
"We want to ensure that progress will not be lost as a result of sea-level rise. The data and model provided by this study will help us chart a course forward that protects the work our public and private sector partners have collectively accomplished over the past 45 years."
Extraordinary returns on investment
In April 2014 the Center for American Progress (CAP) and Oxfam released a report for which a research team evaluated the returns and benefits of three coastal ecosystem restoration projects on different U.S. coasts. Analyzing the data gathered, the project team found that for every $1 million invested in carrying out the projects:
- $15 in net economic benefits was created for every dollar spent.
- 17 jobs were created on average – almost double the 8.9 created per $1 million invested in offshore oil and gas development.
- Projects provide increased protection from storm surges, improved coastal recreation opportunities, and health benefits from increased levels of filter feeders, such as oysters.
As NOAA (National Oceanographic and Atmospheric Administration) Assistant Secretary of Commerce for Conservation and Management Mark Schaefer elaborated in a news release.
“We learned in a nutshell that there’s a win-win, if not a win-win-win, opportunity that presents itself when you invest in conservation. The economic benefits are remarkable … there’s a direct connection between what we’re doing to enhance the environment and what we’re doing to enhance economic opportunity.”
*Image credits: 1), 2): Restore America's Estuaries, ¨Tampa Bay Blue Carbon Assessment,¨ June 2016; 3) Center for American Progress, Oxfam