Recently in Wetlands Category

Plant Releases Toxic Chemicals Into Soil

A team led by Harsh Bais has determined that Phragmites employs a strategy known as allelopathy, in which plants release toxic chemicals into the soil to deter other plants from growing close to them.

Phragmites australis, ranks as one of the world's most invasive plants.

The invasive strain, which hails from Eurasia, overtakes its "native" cousin, which has lived in North America for the past 10,000 years, ironically by provoking the native plant to "take itself out," through a combination of microbial and enzymatic activity in the soil.

Phragmites Reeds in Wetlands

In soil studies at the Delaware Biotechnology Institute, a center for life sciences research at UD, scientists discovered that invasive Phragmites produces elevated levels of a benign compound, a precursor of gallic acid known as gallotannin, relative to its native cousin.

However, when this gallotannin, a polymeric phenol, is attacked by tannase produced through enzymatic activity by native plants and rhizospheric microbes, toxic gallic acid is produced and released in the root zone, exacerbating the invasive Phragmites' noxiousness.

"The tannins are like partners in crime in the process," Bais said.

He noted that Hanson and Kumar collected microbes present on the root surface of the plants and revealed that the "bugs" cleave the polymer (gallotannin) to release the monomer (gallic acid) because the microbes are using the tannins as a carbon source.

"It's like a two-way highway," Bais said, "the plant is working with bacteria to secrete gallic acid into the soil."

Bais says that the microbial population is the same in the native versus the invasive Phragmites. The invasive variety simply secretes more gallotannins into the soil than its native cousin, putting the native plant at a disadvantage in turf battles between the two strains.

Phragmites has overtaken millions of acres of wetlands in the United States, thanks to the aggressive, invasive strain of the plant that came on the scene some 200 years ago from Eurasia.

The exotic species has displaced the non-aggressive native variety of the plant, relegating the native strain to isolated patches and wetland margins along the Atlantic coast.

"Now we have a way to remedy the sick soil," Bais said. "After years of research, we have identified a mechanism that may lead to a solution to the Phragmites invasion."

The research was supported by the University of Delaware Research Foundation (UDRF). Gurdeep Bains's involvement in the study was made possibly by a BOYSCAST Fellowship from the Department of Science and Technology, India.

SOURCE: Newswise

Spiders that live near water may be an effective warning system for contaminants in aquatic ecosystems, according to a new USGS and U.S. Environmental Protection Agency study.

Scientists examined PCB (polychlorinated biphenyls) levels in shoreline-living spiders at Lake Hartwell, a Superfund site in South Carolina, and used this information to map contaminant concentrations in lake sediment.

Spiders are indicators of ecosystem recovery from PCB contamination

Future monitoring studies will use the spiders as indicators of ecosystem recovery from PCB contamination. Researchers also made risk maps for a spider-eating bird, the Carolina wren, which could be exposed to PCBs through eating spiders.

Food Chain Transfers Contaminants

These spiders rely heavily on adult aquatic insects for food and play a key ecological role in the transfer of contaminants between water and land ecosystems. In spite of this, they are underused as a sentinel species at contaminated sediment sites.

SOURCE:  USGS

Nutrient Delivery to the Gulf of Mexico Among Highest Measured in 30 years!


Too many nutrients, which are essential for plant growth, are not necessarily a good thing. Excessive nutrients can be harmful by decreasing the amount of oxygen in the water, also known as hypoxia.

This can result in an area experiencing stress or death of near or bottom dwelling organisms called a hypoxic zone, or "dead zone."

Hypoxia, along with overfishing, habitat loss and toxic contamination, can significantly impact the Gulf of Mexico coastal region, an important resource for the Nation providing about 1.2 billion pounds of fresh seafood every year.

The amount of nutrients transported from the Mississippi River Basin to the Gulf during the spring is a major factor controlling the size of the hypoxic zone. The northern Gulf of Mexico hypoxic zone is the second largest in the world, and threatens the economic and ecological health of one of the nation's largest and most productive fisheries.

Nutrients can come from many sources, such as fertilizers applied to agricultural fields, golf courses, and suburban lawns; atmospheric contributions; erosion of soils containing nutrients; and sewage treatment plant discharges.

USGS releases estimates of nutrients from the Mississippi and Atchafalaya Rivers to the Gulf of Mexico in early June each year. The estimates are used by the National Oceanic and Atmospheric Administration, Louisiana Universities Marine Consortium, and other researchers to predict the areal extent of the hypoxic zone. 

The amount of nutrients delivered to the Gulf each spring depends, in large part, on precipitation and the resulting amounts of nutrient runoff and streamflow in the Mississippi-Atchafalaya River Basin. Streamflows in spring 2009 were about 17 percent above average over the last 30 years. Last year's elevated levels were most likely due to the flooding during the spring.

States and Federal partners serving on the Gulf of Mexico Hypoxia Taskforce are trying to reduce nutrients transported to the Gulf to reduce the size of hypoxic zone to less than 5,000 square kilometers by 2015. Tracking nutrient levels every year is important to determine if partners are on target with that goal.

Predictions of the size of the 2009 hypoxic zone reflects USGS estimates of about 295,000 metric tons of nitrogen (in the form of nitrate) delivered in April and May 2009 to the northern Gulf. In 2008, the hypoxic zone exceeded 20,000 square kilometers, an area similar in size to the state of New Jersey. Spring delivery of nitrogen in 2009 was about 23% lower than what was measured in 2008, but still about 11% above the average from 1979 to 2009.

USGS has monitored streamflow and water quality in the Mississippi River Basin for decades, to access more information visit the USGS nutrient flux webpage.

For more than 125 years, the USGS has served as the Nation's water monitoring agency, including flow and (or) quality in selected streams and rivers across the U.S. Access data from more than 7,400 streamgages, many of which provide real-time data in 15 minute increments at the USGS WaterWatch site.

For an even larger variety of USGS data, such as for ground water and water quality, access the National Water Information System Web Interface, which contains over 1.5 million sites, and averages over 25 million hits per month. 

The Performance Information and Visualization and Outreach Tool (PIVOT) module for the National Estuary Program (NEP) highlights common habitat degradation and loss problems faced by National Estuary communities around the country.

PIVOT's interactive graphics, maps and photos are designed to help users better understand the issues and visually track progress toward achieving habitat restoration goals in the 28 National Estuary Programs.

An interactive graphic shows how everyday human activities along the coast increase pressures on natural habitat and can impact the health of our estuaries in other ways as well.

Links are provided to information about watersheds, maps, and performance measures useful for reporting progress toward improving the health of coastal watersheds.

Performance Indicators Visualization and Outreach Tool (PIVOT)

The National Estuary Program works with local communities to improve the health of our nation's estuaries. Community support and involvement is fundamental to the success of these efforts. Through an extensive stakeholder planning process, NEP communities develop comprehensive conservation and management plans, or CCMPs. These plans serve as documentation of the communities' environmental goals for their estuaries and watersheds as well as blueprints for achieving those goals. As this is a long-term process, keeping the community well informed and connected with plan activities and progress is critical to keeping the plan a vital, living process for the community.

Performance reporting is not only essential for garnering and maintaining community support, it is often mandated. Enabling legislation or other laws—federal or local—may require responsible agencies to report on what progress they are making toward established goals. For the National Estuary Program, several pieces of federal legislation weigh in on performance reporting.

28 National Estuary Programs

Each of the 28 National Estuary Programs was charged with developing and implementing a Comprehensive Conservation and Management Plan (CCMP) which establishes priorities for activities, research, and funding for the estuary. The CCMP serves as a blueprint to guide future decisions and actions and addresses a wide range of environmental protection issues including water quality, habitat, fish and wildlife, pathogens, land use, and introduced species to name a few. The CCMP is based on a scientific characterization of the estuary and is developed and approved by a broad-based coalition of stakeholders.

Comprehensive Estuary Conservation and Management Plans

Over the years, hundreds of thousands of miles of river corridors and millions of acres of wetlands have been damaged throughout the nation. Restoration seeks to return some of these ecosystems to their approximate pre-disturbance conditions.

The ecological and societal benefits of river corridor and wetlands restoration are substantial:

Rivers transport water, sediment, and nutrients from the land to the sea, play an important role in building deltas and beaches, and regulate the salinity and fertility of estuaries and coastal zones. Rivers serve as corridors for migratory birds and fish, and provide habitat to many unique species of plants and animals, including federally endangered and threatened aquatic species. According to the 1985 National Survey of Fishing, Hunting, and Wildlife -Associated Recreation (U.S. DOI, Fish and Wildlife Service, 1988), 38.4 million fishermen spent $17.8 billion for non-Great Lakes freshwater fishing in 1985, with 45 percent of reported anglers fishing in rivers and streams.

Wetlands provide food, protection from predators, and other vital habitat factors for many of the nation's fish and wildlife species, including endangered and threatened species. In addition, wetland ecotypes have economic value associated with recreational, commercial, and subsistence use of fish and wildlife resources and they remove pollutants from overland flows before they reach our lakes, rivers and bays.

Wetlands intercept storm runoff and release floodwaters gradually to downstream systems. When wetlands are converted to systems without water retention capacity, downstream flooding problems increase.

From 1982 to 1992, a total of 768,700 acres of wetlands were gained as a result of restoration activities around the nation (USDA, 1997). Likewise, numerous miles of rivers and streams were restored in our nations watersheds over the same time period. When properly planned, executed and managed, restoration works; its success can be attributed to the hard work and dedication of practitioners, scientists, and others who seek to heal damaged natural systems and improve our communities.

Learn more about restoration of wetlands:

EPA Wetlands, oceans & Watersheds

Learn! Explore! Take Action!

Celebrate the vital importance of wetlands to the Nation's ecological, economic, and social health.

May, American Wetlands Month is also a great opportunity to discover and teach others about the important role that wetlands play in our environment and the significant benefits they provide - improved water quality, increased water storage and supply, reduced flood and storm surge risk, and critical habitat for plants, fish, and wildlife.

In organizing its activities this year, EPA is placing special emphasis on encouraging Americans to:

1. Learn about wetlands. This is a great time to better understand what a wetland is, where wetlands can be found, and the importance of wetlands. Activities may include reading and studying about wetland areas, drawing maps or illustrations of wetlands, and identifying native species found in wetlands. Information on wetlands and the important benefits they provide is available on this website, through EPA's wetland fact sheet series, or by visiting the websites of our partners.
2. Explore a wetland near you. Unless you live in the most extreme climate zones, there is a good chance a scenic wetland exists nearby for you to visit and explore during American Wetlands Month and throughout the year. To find a wetland near you, consult your local parks department, state natural resource agency, or the United States Fish and Wildlife Service (http://www.fws.gov/refuges). If you live in the Washington, DC area, a guide has been created to highlight wetlands and wildlife sanctuaries.
3. Take action to protect and restore wetlands. Support and promote wetlands informing community members about wetlands' vital roles, "adopting" a wetland, joining a local watershed group, or participating in a wetland monitoring, restoration, or cleanup project. There are many other actions Americans can take to help conserve wetlands.To learn more about what you can do to help protect and restore these valuable natural resources in your state or local area, visit http://www.epa.gov/owow/wetlands/awm/#you.