By Rachel Plunkett
All water on Earth is connected—in the ocean, lakes, rivers, streams, and glaciers—and changes to these water resources can have a major impact on people's lives. The ocean dominates Earth's surface. Just as the heart circulates blood and regulates the body's temperature, the ocean controls the circulation of heat and moisture throughout the climate system. When we burn fossil fuels, such as coal, oil, and natural gas, excess carbon dioxide is released into the atmosphere and builds up, acting like a heat-trapping blanket. This puts stress on the ocean, which damages its ability to regulate the climate system and maintain stability. National marine sanctuaries are marine protected areas in U.S. ocean and Great Lakes waters and are affected by the changes in Earth's energy and water cycles.
The impacts from human-caused climate change are happening now, and while we have a good understanding of what the large-scale effects of climate change are likely to be, there are differences in the rate and extent of change from place to place. Your national marine sanctuaries and marine national monuments, which are scattered across the United States, offer excellent opportunities to research and understand these changes and how the effects vary from place to place. As new information and insights are gathered, we will be able to respond adaptively to better manage sanctuary resources. In 2020, we published a new series, National Marine Sanctuary Climate Change Impacts Profiles, highlighting changes that are already occurring within the National Marine Sanctuary System, the threats these changes pose to habitats, wildlife, and cultural resources, and how these changes are projected to continue impacting sanctuaries and the people who depend on them.
The living and nonliving resources in sanctuary waters are vulnerable to climate change impacts such as ocean acidification, rising water temperatures, and increasing storm intensity. These changes can affect wildlife, food webs, and the integrity of heritage resources. As average ocean temperatures rise worldwide, we are seeing more extreme temperature events in certain areas. Some species are more vulnerable to these changes than others. In Gray's Reef National Marine Sanctuary, researchers believe that continuing trends of increased ocean temperatures could cause red snapper to become more common in the sanctuary, while species like black sea bass may become less abundant. But what about flora and fauna that can't swim, such as kelps and corals? These organisms in particular are greatly impacted by more frequent and intense ocean heatwaves. Intense heatwaves lead to reductions in kelp forests, while prolonged periods of extreme heat cause corals to expel the microscopic algae living inside their tissues—an event known as coral bleaching—which can eventually cause corals to starve. In both kelp forests and coral reefs throughout the National Marine Sanctuary System (and beyond), these changes are leading to a loss of biodiversity and ecosystem function.
The ocean absorbs much of the excess carbon dioxide in the atmosphere, changing the chemistry of the water. The change in chemistry increases the acidity of the water and reduces the concentration of carbonate, a compound needed for shellfish, corals, and some sponges to grow and strengthen their skeletal components; similar to how humans need calcium to build and strengthen bones. This is known as ocean acidification. At Cordell Bank National Marine Sanctuary, studies have shown that higher ocean acidity affects the reproductive success of krill, which are important primary consumers in the marine food web there. Increased ocean temperatures also have a negative impact on krill populations and other zooplankton, and these changes are partly responsible for mass mortalities of seabirds and marine mammals that have occurred along the entire West Coast in recent years. Sanctuary researchers are also concerned that sand lance, an important part of the food web in Stellwagen Bank National Marine Sanctuary, may be impacted by climate change. Sand lance are a pencil-sized forage fish and a favorite food of humpback whales, sharks, seals, seabirds, and other ocean predators. Researchers are studying how increasing temperatures and ocean acidification will impact the development and growth of sand lance, which could impact the ecology of sand lance predators.
These effects are not just limited to marine waters—freshwater bodies feel the wrath of climate change as well. In Thunder Bay National Marine Sanctuary, increasing acidity can cause corrosion on metal parts of shipwrecks. Additionally, weather patterns around the world are being altered by climate change. Changes to wind and evaporation impact rainfall, causing more frequent and prolonged droughts in some areas, and in turn more rainfall in other parts of the world. Droughts can lead to lower lake levels, which can cause shipwrecks in shallow water to be overexposed to the elements and degrade faster than normal.
America's national marine sanctuaries and monuments are recognized as "sentinel sites." The routine monitoring and coordinated environmental observations and applied science by government, tribal, academic, and citizen scientists taking place within sanctuary waters allows for investigation of changing ecosystem resources and conditions over time. Each sanctuary faces a unique suite of threats that present challenges to resource management. The work being done within each of these sentinel sites provides early warning capabilities, allowing us to respond more quickly and efficiently than would be possible in other locations.
For example, Olympic Coast National Marine Sanctuary was designated as a sentinel site for ocean acidification in late 2019 in response to growing concern over the potential impacts of ocean acidification to marine ecosystems and local economies. Coordinated monitoring, research, outreach, and public engagement efforts have catalyzed the interest and involvement of partners to work together to collectively address the increasing threat of ocean acidification in Washington's outer coastal waters.
Elsewhere, Papahānaumokuākea Marine National Monument and Greater Farallones National Marine Sanctuary are participants in NOAA's Sentinel Site Program through Cooperative Management Teams and are focused on sea level rise. There are other special projects to monitor ocean acidification in sanctuaries, such as Cheeca Rocks Reef (data buoy MPACO2) in Florida Keys National Marine Sanctuary and the ocean acidification studies taking place in National Marine Sanctuary of American Samoa.
In addition to conducting research on climate change within sanctuary waters, our staff are also working to educate the public through programs and outreach products across the National Marine Sanctuary System. Communicating about climate change is important to increase the general public's understanding of the many threats and changing conditions within each sanctuary and monument, and throughout the water bodies that connect the sanctuary system. Docents from sanctuary visitor centers and partner institutions use NOAA's innovative Science on a Sphere® to communicate the global and local impacts of climate change in a way that is engaging, informative, and fun.
Individual sanctuary sites have their own unique programs as well. National Marine Sanctuary of American Samoa incorporates climate change messaging into their outreach to local communities through initiatives such as the Sanctuary Summer Science in the Village program and is developing a community-facing web portal with information about the local impacts of climate change. At Stellwagen Bank National Marine Sanctuary, staff work with whale watch naturalists to help them communicate climate change information to the over 500,000 people each year who go on whale watch tours.
We hope that learning a bit more about the work our staff and partners have been doing (and will continue to do) throughout the National Marine Sanctuary System gives you reason for hope. As a team of scientists, policy experts, educators, and communicators who are dedicated to studying, protecting, and promoting the natural and cultural resources within your national marine sanctuaries and marine national monuments, we do what we do because we have hope for the future—and you should too! There's so much you can do to help out with these efforts, from volunteering your time as a citizen scientist, to perfecting your climate change communication skills. After all, caring for our ocean is not any one person's responsibility, it is a community effort.