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Chesapeake Bay ecosystem recovery may be model for South Texas

Pristine but vulnerable, the Lower Laguna Madre Bay stretches from Corpus Christi to South Padre Island, Texas, and is vulnerable to pollutant run-off from area rivers and streams.
Nitrogen, phosphorus pollutants causing stress in Coastal Texas bay and estuaries

For all the good and productive benefits of modern agriculture, like feeding the world and providing lasting sustenance for a growing population, there is a dark side–as there generally is for all things good and worthy.

The ancient Chinese referred to it as yin yang, the dark and the bright side of every human endeavor; the good and the bad, or the point and counter point of just about every aspect of our often-complicated human experience.

We don't need to look far for prime examples of the good and bad of life. For instance, the introduction of the Internet and the World Wide Web, an incredible tool that has given billions instant access to information at the touch of a button and use of a keyboard. While more information can be found across the Internet than is contained in any single library or museum or laboratory in the world, it has also opened the doors to scams, viruses, cyber bullies and predators. Television and electronic gaming has given us full color entertainment and also taken our kids off the playground and into the easy chair, often a roadblock to exercise, good health and real-world discovery.

It doesn't stop there; Cell phones give us wireless connections and can promote brain cancer. Modern medicines have given us effective pain killers and antibiotics, and opioid addiction and immune deficiencies.

Pesticides and fertilizers have increased agricultural production and food security but has had a negative impact on the environment–and that brings us to a great divide of opinions about the positive-versus-the-negative aspects, or the yin and yang of their widespread use in farming.

In the early days of the use of chemicals in agriculture, both natural and synthetic varieties, the positive results of their use became obvious. But before long, even farmers began to recognize the dangers associated with their overuse in an attempt to control things like pest and weed pressure and diseases. In recent times, agricultural producers have not only recognized the dangers and responsibility of chemical use, they have taken broad steps to participate in efforts to correct it.

Recognition and Control Efforts

As far back as 1983 federal legislators, with the support of state governments, environmentalists and agricultural industry leaders, passed legislation in the form of an environmental act known as the Chesapeake Bay Program, a comprehensive mandate to restore the environmental damages caused in the bay system by pollutants. One of the primary focuses of the Act was to reduce pollution from excess nutrients like nitrogen and phosphorus, the force behind what came to be known as dead zones, the darkening waters of the bay system that added to the rapid decline and  destruction of bay-grasses and marine life.

By monitoring the environmental effects of pollutants in the Chesapeake Bay, similar federal and multi-state action followed involving dead zones that began developing in the Gulf of Mexico, primarily caused by nitrogen and phosphorus that had leached from agricultural fields thousands of miles away up and down the Mississippi River and its tributaries. Still a work in progress, much the same as the Chesapeake Bay Program, the Mississippi River Program, an effort to reduce pollutants that caused Gulf Hypoxia, a condition that reduces oxygen in the water, was initiated and continues today with great contributions from the agricultural sector.

These hypoxic conditions are created when pollutants, in the form of nutrients created by nitrogen and phosphorus, filters into the river and promotes the rapid and excessive growth of algae that eventually reach the bays and finally the Gulf of Mexico where it depletes oxygen in the water before sinking to the bottom and decays. The result creates the so-called Gulf Dead Zones at depths that kills grasses and marine life, the largest such dead zones in the world.

Recent Study Shines Light on Effective Efforts

In more recent years, these growing hypoxic zones have responded to cleanup efforts, though the restoration work is a slow process. While more cleanup and time will be required to significantly reduce the levels of pollutants that cause the hypoxic effect, a new and most recent study has added to our collective knowledge of better and more effective ways to achieve success in the effort to restore damaged bay and ocean systems.

The new study, which was published this month in the “Proceedings of the National Academy of Sciences,” could serve as a restoration model for damages not only in the Gulf of Mexico but along the once-pristine and delicate bay system located along the Texas coast, including in the Bay of Corpus Christi, the larger Laguna Madre that stretches across 90 miles of the coastline, and a string of other saltwater bays up and down the coast from Kingsville to Port Arthur.

“The estuaries surrounding Corpus Christi are very similar to those that feed into the Chesapeake Bay system. About 80 percent of Texas seagrasses are found in the Laguna Madre and these ‘coastal canaries’ are the first to disappear when an ecosystem is under stress,” said Dr. Christopher Patrick, assistant professor of life sciences at Texas A&M University-Corpus Christi. “Thanks to this study, we have the opportunity to put these measures in place to proactively protect our ecologically and economically important marine ecosystems as we head towards economic growth in the coming years.”

Patrick, who co-authored the study along with 13 other experts across the nation, found that a 23 percent reduction of nitrogen and an eight percent reduction of phosphorus resulted in a four-fold increase in the abundance of Submerged Aquatic Vegetation (SAV) in the Chesapeake Bay since restoration efforts began. This ecosystem recovery is an unprecedented event; based on the breadth of data available and a sophisticated data analysis, it is the biggest resurgence of underwater grasses ever recorded in the world.

“I am proud of our team of young and experienced researchers who worked in a collaborative environment to produce these exciting results,” said Dr. Robert “J.J.” Orth of the Virginia Institute of Marine Science at the College of William and Mary and senior co-author. “I really feel the torch is being passed to a next generation of scientists who bring both the passion and knowledge needed to continue the vital work of marine science required to keep our Chesapeake Bay flourishing.”

The researchers employed advanced analytical tools to definitively show how the reduction of excess pollutants like nitrogen and phosphorus are the cause of this ecosystem recovery. To link land use and Chesapeake Bay status, researchers analyzed data in two different ways: one focusing on the cascade of nutrients from the land to the waterways and one showing what happens to SAV once the nutrients are in the water.

“[We] have had the distinct privilege of facilitating research that confirms a direct correlation between conservation actions undertaken by a broad partnership and ecosystem responsiveness that is leading to positive ecological outcomes,” said Dr. William Dennison of University of Maryland Center for Environmental Science and senior co-author.

These findings are a collaborative effort between: Texas A&M-Corpus Christi, the Bigelow Laboratory for Environmental Science, Virginia Institute of Marine Science, University of Maryland Center for Environmental Science, Environmental Protection Agency Chesapeake Bay Program, U.S. Geological Survey, National Socio-Environmental Synthesis Center, St. Mary’s College of Maryland, Smithsonian Environmental Research Center and Maryland Department of Natural Resources.

“These efforts began before I was even born, but we are at a stage now where the all these different threads can be pulled together to unveil a picture of unprecedented success,” said Dr. Jonathan Lefcheck of the Bigelow Laboratory for Ocean Science and lead author.

TAGS: Water
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