The flow of groundwater into oceans might be invisible to the naked eye but can have major impacts on coral reef health.
On World Oceans Day, we are highlighting the surprising role that groundwater plays in near-shore ocean ecosystems:
🪸 When groundwater flows into the ocean, these persistent, cooler plumes can potentially counteract the exposure of corals to elevated and rising sea-surface temperatures that cause coral bleaching, protecting them from thermal stress.
🐠 However, coastal groundwater can also introduce substances from land, including nutrients, toxins, pathogens, and other pollutants that can stress or kill corals.
🐚 The flux of groundwater into coral reef ecosystems is highly variable, being controlled by geology, climate, land use, and ocean dynamics. Groundwater movement to the ocean also responds to changes in sea level, precipitation, and coastal groundwater withdrawals.
As part of the USGS Coral Reef Project, the USGS Pacific Coastal and Marine Science Center is conducting geophysical and geochemical research to address questions about coastal groundwater-to-reef flow and the resulting coral reef health, with the goal of informing management decisions related to planning and implementing activities in priority watershed-coral reef systems.
Read more about USGS research in coral reefs:
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📷 1: Thermal infrared image of two USGS researchers standing on the coast and looking up over a coastal groundwater plume that is non-visible to the naked eye but is shown in this thermal image from temperature differences between the cooler (blue) groundwater and warmer (pink) ocean water over the coral reefs.
📷 2: USGS physical scientist installs a special buoy in the waters of the National Park of American Samoa on Ofu in the Manuʻa Islands Group. The special buoy, developed by USGS scientists, measures radon on the reef, which is a marker of submarine groundwater.
📷 3: A healthy coral reef in the Tumon Bay Marine Preserve off Tumon, Guam, showing several different species of fish swimming over a high coral cover reef composed of hard and soft coral species.
#WorldOceansDay #Groundwater #CoralReefs
ALT Thermal infrared image of two USGS researchers standing on the coast and looking up over a coastal groundwater plume that is non-visible to the naked eye but is shown in this thermal image from temperature differences between the cooler (blue) groundwater and warmer (pink) ocean water over the coral reefs.
ALT USGS physical scientist installs a special buoy in the waters of the National Park of American Samoa on Ofu in the Manuʻa Islands Group. The special buoy, developed by USGS scientists, measures radon on the reef, which is a marker of submarine groundwater.
ALT A healthy coral reef in the Tumon Bay Marine Preserve off Tumon, Guam, showing several different species of fish swimming over a high coral cover reef composed of hard and soft coral species.