Restored tidal marsh at the Nisqually River Delta within Billy Frank Jr. National Wildlife Refuge, Washington.
What are wetlands?
Wetlands are transitional areas, sandwiched between permanently flooded deepwater environments and well-drained uplands, where the water table is usually at or near the surface or the land is covered by shallow water. They include mangroves, marshes (salt, brackish, intermediate, and fresh), swamps, forested wetlands, bogs, wet prairies, prairie potholes, and vernal pools. In general terms, wetlands are lands where saturation with water is the dominant factor determining the nature of soil development and the types of plant and animal communities living in the soil and on its surface. The single feature that most wetlands share is soil or substrate that is at least periodically saturated with or covered by water.
Learn more: USGS Wetland and Aquatic Research Center
Related
Why are wetlands important?
What is the Brown Marsh phenomenon?
How would sea level change if all glaciers melted?
What are the long-term effects of climate change?
Why is elevation data so important to forecasting hurricane impact?
Restored tidal marsh at the Nisqually River Delta within Billy Frank Jr. National Wildlife Refuge, Washington.
Salt marsh in coastal Massachusetts (Cape Cod) during USGS field work on estuarine ecosystems.
Salt marsh in coastal Massachusetts (Cape Cod) during USGS field work on estuarine ecosystems.
A white heron flying across a marsh in York County, Virginia.
A white heron flying across a marsh in York County, Virginia.

Brown patches and brown stems show stress in this phagmites (roseau cane) stand in Pass A Loutre Wildlife Management Area, a tract of state-owned land in Louisiana's bird foot delta, where the Mississippi River meets the Gulf of Mexico. An ongoing phragmites was first discovered in spring 2017 and blamed on an invasive scale insect from Asia.
Brown patches and brown stems show stress in this phagmites (roseau cane) stand in Pass A Loutre Wildlife Management Area, a tract of state-owned land in Louisiana's bird foot delta, where the Mississippi River meets the Gulf of Mexico. An ongoing phragmites was first discovered in spring 2017 and blamed on an invasive scale insect from Asia.

- Wetlands are hotspots for mercury methylation and export of methylmercury to aquatic foodwebs.
- Rice is the most abundant wetland type in California and globally in temperate and tropical latitudes.
- Wetlands are hotspots for mercury methylation and export of methylmercury to aquatic foodwebs.
- Rice is the most abundant wetland type in California and globally in temperate and tropical latitudes.
A family of Trumpeter Swans sits on the earthen berm enclosing a restored wetland unit at the Ottawa National Wildlife Refuge. Photo Credit: USGS.
A family of Trumpeter Swans sits on the earthen berm enclosing a restored wetland unit at the Ottawa National Wildlife Refuge. Photo Credit: USGS.

--The South Bay Salt Pond Restoration Project
By Laura Valoppi, Lead Scientist
--The South Bay Salt Pond Restoration Project
By Laura Valoppi, Lead Scientist
Slideshow of images related to USGS wetlands research.
Slideshow of images related to USGS wetlands research.
This video describes causes of wetland loss in the Mississippi River Delta.
This video describes causes of wetland loss in the Mississippi River Delta.

Wetlands in the prairie pothole region of North American, while often appearing as being isolated from each other, are interconnect to each through a variety of ways including temporary surface-water flows, long-term groundwater flows, and biotic movements.
Wetlands in the prairie pothole region of North American, while often appearing as being isolated from each other, are interconnect to each through a variety of ways including temporary surface-water flows, long-term groundwater flows, and biotic movements.

This video describes research being conducted by Dr. Karen McKee, USGS Research Ecologist, and her university partner, Dr. Julia Cherry. Their goal is to better understand the effects of sea-level rise and other global change factors on coastal wetlands in the Mississippi River Delta. This region contains over 40% of the U.S.
This video describes research being conducted by Dr. Karen McKee, USGS Research Ecologist, and her university partner, Dr. Julia Cherry. Their goal is to better understand the effects of sea-level rise and other global change factors on coastal wetlands in the Mississippi River Delta. This region contains over 40% of the U.S.

This video describes research conducted by Dr. Karen McKee, USGS Research Ecologist, and her university partners, Dr. Irv Mendelssohn (Louisiana State University) and Dr. Mark Hester (University of Louisiana). They are studying the effects of hurricanes on marsh and mangrove wetlands in the Mississippi River Delta, which contains over 40% of the U.S.
This video describes research conducted by Dr. Karen McKee, USGS Research Ecologist, and her university partners, Dr. Irv Mendelssohn (Louisiana State University) and Dr. Mark Hester (University of Louisiana). They are studying the effects of hurricanes on marsh and mangrove wetlands in the Mississippi River Delta, which contains over 40% of the U.S.
USGS scientists deliver a variety of science in the effort to restore wetlands to over 25,000 acres in San Francisco Bay. "Wetland Revival" shows how science is contributing to the transformation of once industrial salt producing ponds into more natural habitat. The program was completed in 2008. USGS General Information Product 61.
USGS scientists deliver a variety of science in the effort to restore wetlands to over 25,000 acres in San Francisco Bay. "Wetland Revival" shows how science is contributing to the transformation of once industrial salt producing ponds into more natural habitat. The program was completed in 2008. USGS General Information Product 61.
Long Island marsh water
Long Island marsh water
Dr. Lee Foote, National Wetlands Research Center, studies a Louisiana marshland.
Dr. Lee Foote, National Wetlands Research Center, studies a Louisiana marshland.
Knowledge gaps and opportunities in water-quality drivers of aquatic ecosystem health
Everglades Depth Estimation Network (EDEN)—A decade of serving hydrologic information to scientists and resource managers
Desert wetlands—Archives of a wetter past
Trends and causes of historical wetland loss in coastal Louisiana
Wetland fire remote sensing research--The Greater Everglades example
Integrated monitoring of ecological conditions in wetland-upland landscapes
The Cottonwood Lake study area, a long-term wetland ecosystem monitoring site
Methods for processing and imaging marsh foraminifera
USGS research on Florida's isolated freshwater wetlands
Estuaries of the Greater Everglades Ecosystem: Laboratories of Long-term Change
Hydrology and Ecology of Freshwater Wetlands in Central Florida - A Primer
Potential consequences of saltwater intrusion associated with Hurricanes Katrina and Rita
Related
Why are wetlands important?
What is the Brown Marsh phenomenon?
How would sea level change if all glaciers melted?
What are the long-term effects of climate change?
Why is elevation data so important to forecasting hurricane impact?
Restored tidal marsh at the Nisqually River Delta within Billy Frank Jr. National Wildlife Refuge, Washington.
Restored tidal marsh at the Nisqually River Delta within Billy Frank Jr. National Wildlife Refuge, Washington.
Salt marsh in coastal Massachusetts (Cape Cod) during USGS field work on estuarine ecosystems.
Salt marsh in coastal Massachusetts (Cape Cod) during USGS field work on estuarine ecosystems.
A white heron flying across a marsh in York County, Virginia.
A white heron flying across a marsh in York County, Virginia.

Brown patches and brown stems show stress in this phagmites (roseau cane) stand in Pass A Loutre Wildlife Management Area, a tract of state-owned land in Louisiana's bird foot delta, where the Mississippi River meets the Gulf of Mexico. An ongoing phragmites was first discovered in spring 2017 and blamed on an invasive scale insect from Asia.
Brown patches and brown stems show stress in this phagmites (roseau cane) stand in Pass A Loutre Wildlife Management Area, a tract of state-owned land in Louisiana's bird foot delta, where the Mississippi River meets the Gulf of Mexico. An ongoing phragmites was first discovered in spring 2017 and blamed on an invasive scale insect from Asia.

- Wetlands are hotspots for mercury methylation and export of methylmercury to aquatic foodwebs.
- Rice is the most abundant wetland type in California and globally in temperate and tropical latitudes.
- Wetlands are hotspots for mercury methylation and export of methylmercury to aquatic foodwebs.
- Rice is the most abundant wetland type in California and globally in temperate and tropical latitudes.
A family of Trumpeter Swans sits on the earthen berm enclosing a restored wetland unit at the Ottawa National Wildlife Refuge. Photo Credit: USGS.
A family of Trumpeter Swans sits on the earthen berm enclosing a restored wetland unit at the Ottawa National Wildlife Refuge. Photo Credit: USGS.

--The South Bay Salt Pond Restoration Project
By Laura Valoppi, Lead Scientist
--The South Bay Salt Pond Restoration Project
By Laura Valoppi, Lead Scientist
Slideshow of images related to USGS wetlands research.
Slideshow of images related to USGS wetlands research.
This video describes causes of wetland loss in the Mississippi River Delta.
This video describes causes of wetland loss in the Mississippi River Delta.

Wetlands in the prairie pothole region of North American, while often appearing as being isolated from each other, are interconnect to each through a variety of ways including temporary surface-water flows, long-term groundwater flows, and biotic movements.
Wetlands in the prairie pothole region of North American, while often appearing as being isolated from each other, are interconnect to each through a variety of ways including temporary surface-water flows, long-term groundwater flows, and biotic movements.

This video describes research being conducted by Dr. Karen McKee, USGS Research Ecologist, and her university partner, Dr. Julia Cherry. Their goal is to better understand the effects of sea-level rise and other global change factors on coastal wetlands in the Mississippi River Delta. This region contains over 40% of the U.S.
This video describes research being conducted by Dr. Karen McKee, USGS Research Ecologist, and her university partner, Dr. Julia Cherry. Their goal is to better understand the effects of sea-level rise and other global change factors on coastal wetlands in the Mississippi River Delta. This region contains over 40% of the U.S.

This video describes research conducted by Dr. Karen McKee, USGS Research Ecologist, and her university partners, Dr. Irv Mendelssohn (Louisiana State University) and Dr. Mark Hester (University of Louisiana). They are studying the effects of hurricanes on marsh and mangrove wetlands in the Mississippi River Delta, which contains over 40% of the U.S.
This video describes research conducted by Dr. Karen McKee, USGS Research Ecologist, and her university partners, Dr. Irv Mendelssohn (Louisiana State University) and Dr. Mark Hester (University of Louisiana). They are studying the effects of hurricanes on marsh and mangrove wetlands in the Mississippi River Delta, which contains over 40% of the U.S.
USGS scientists deliver a variety of science in the effort to restore wetlands to over 25,000 acres in San Francisco Bay. "Wetland Revival" shows how science is contributing to the transformation of once industrial salt producing ponds into more natural habitat. The program was completed in 2008. USGS General Information Product 61.
USGS scientists deliver a variety of science in the effort to restore wetlands to over 25,000 acres in San Francisco Bay. "Wetland Revival" shows how science is contributing to the transformation of once industrial salt producing ponds into more natural habitat. The program was completed in 2008. USGS General Information Product 61.
Long Island marsh water
Long Island marsh water
Dr. Lee Foote, National Wetlands Research Center, studies a Louisiana marshland.
Dr. Lee Foote, National Wetlands Research Center, studies a Louisiana marshland.