During summer months, Chesapeake Bay waters become home to a range of bacteria. One of the most talked-about bacteria is Vibrio, which occurs naturally in warm estuarine waters and can infect those who eat contaminated shellfish or swim with open wounds in contaminated waters. But illness can be avoided. Learn about the bacteria—and how to avoid infection—with this list of five Vibrio facts.
Image courtesy CDC/Wikimedia Commons
1. Vibrio is a naturally occurring bacteria. There are more than 80 species of Vibrio, which occur naturally in brackish and saltwater. Not all species can infect humans, but two strains that can have raised concern in the Bay watershed: Vibrio vulnificus and Vibrio parahaemolyticus. The bacteria are carried on the shells and in the bodies of microscopic animals called copepods.
2. The presence of Vibrio in surface waters is affected by water temperature, salinity and chlorophyll. Because Vibrio prefers warm waters, it is not found in the Bay during winter months. Instead, it is common in the summer and early fall. When water temperatures are warm, algae blooms form, fed by nutrients in the water. These blooms feed the copepods that carry the Vibrio bacteria. When the copepods die, Vibrio bacteria are shed into the water. As climate change increases the temperature of the Bay, both algae blooms and Vibrio could persist later in the season.
3. Vibrio infections can occur in people who eat raw or undercooked shellfish or who swim with open wounds or punctures in contaminated waters. While infections are rare, they do take place and can be particularly dangerous for people with compromised immune systems. The ingestion of Vibrio can cause vomiting, diarrhea and abdominal pain, and in some cases can infect the bloodstream. If an open wound or puncture comes into contact with the bacteria, the area around the wound can experience swelling, redness, pain, blistering and ulceration of the skin.
4. Infection can be avoided. To avoid Vibrio infection, follow these tips:
5. Vibrio symptoms can start 12 to 72 hours after exposure. If you think you’ve been infected with Vibrio, seek medical attention. Make sure to let your doctor know that you have eaten raw or undercooked shellfish or crabs or have come into contact with brackish or saltwater.
The R/V Rachel Carson is docked on Solomons Island. At 81 feet long, the red and blue research vessel stands out against the deadrise workboats that share the Patuxent River marina. Her mission today is to lead researchers from the University of Maryland Center for Environmental Science (UMCES) to the Chesapeake Bay’s dead zone.
Every summer, this so-called “dead zone” forms in the main stem of the Bay. The area of low-oxygen water is created by bacteria as they feed on algae blooms growing in nutrient-rich water. The dead zone persists through the warm summer months because the Bay is stratified into two layers: a surface layer of lighter, fresher water that mixes with the atmosphere, and a bottom layer of denser, saltier water, where oxygen depletion persists. These layers won’t mix until the cooler temperatures of autumn allow the surface waters to sink.
To find the dead zone, Director of Marine Operations and Rachel Carson Captain Michael H. Hulme takes us to one of the deep troughs that run down the center of the Bay. Geologic remnants of the ancient Susquehanna River, these troughs can reach up to 174 feet deep in an estuary whose average depth is just 21 feet. Hulme anchors offshore of Calvert Cliffs State Park.
The boat is equipped with a dynamic positioning system, which holds it in place regardless of wind or waves. This allows the captain to step away from the helm and offer his hands on deck. “Being able to hover over that [specific] latitude and longitude is what makes the Rachel Carson so unique,” said Hulme. It’s also one of the reasons the vessel is so useful to scientists, who often return to the same sampling site again and again over time.
UMCES Senior Faculty Research Assistant David Loewensteiner drops a CTD overboard. The oceanography instrument takes eight measurements per second, tracking conductivity, temperature and depth as it is lowered through the water. Connected to the ship with a cable, the CTD sends data to a laptop in the boat’s dry lab. We measure 2.04 mg/L of dissolved oxygen in surface water, and just 0.33 mg/L at 98 feet deep. Critters need concentrations of 5 mg/L or more to thrive; these are “classic dead zone” conditions.
Dead zones are bad for the Bay. Like animals on land, underwater critters need oxygen to survive. In a dead zone, immobile shellfish suffocate and those fish that can swim are displaced into more hospitable waters. “If you were a self-respecting fish and oxygen was [low], what would you do?” asked Bill Dennison, Vice President for Science Applications and Professor at UMCES. “Swim away.”
First reported in the 1930s, the appearance of the dead zone in the Bay is linked to our actions on land: as we replace forests with cities, suburbs and farms, we increase the amount of nutrients entering rivers and streams. This fuels the growth of algae blooms that lead to dead zones. “Hypoxia [or low-oxygen conditions] is driven by what we do on the watershed,” said UMCES Assistant Professor Jeremy Testa. “The Bay is naturally set up to generate hypoxia because of that [stratification] feature. That said… when there were no people here, there was not much hypoxia.”
While it is our actions on land that created the dead zone, it is our actions on land that can make the dead zone go away. Research has shown that certain pollution-reducing practices—like upgrading wastewater treatment plants, lowering vehicle and power plant emissions and reducing runoff from farmland—can improve the health of local rivers and streams. Scientists have also traced a decline in the duration of the dead zone from five months to four, which suggests that conservation practices gaining traction across the watershed could have very real benefits for the entire Bay.
To view more photos, visit the Chesapeake Bay Program Flickr page.
Images by E. Guy Stephens/Southern Maryland Photography. Captions by Catherine Krikstan.
According to evaluations released this week by the U.S. Environmental Protection Agency (EPA), Chesapeake Bay Program partners are collectively on track to meet the phosphorous and sediment reduction commitments outlined in the Bay’s “pollution diet,” or Total Maximum Daily Load (TMDL). Further reductions in nitrogen, however, will be needed if partners are to meet all of their upcoming pollution-reducing goals.
Every two years, federal agencies and the watershed jurisdictions—which include Delaware, the District of Columbia, Maryland, New York, Pennsylvania, Virginia and West Virginia—report on the progress made toward the pollution-reducing “milestones” outlined in their Watershed Implementation Plans (WIPs). These WIPs describe how each jurisdiction will reduce the nitrogen, phosphorous and sediment pollution entering rivers and streams, and are included as commitments in the partnership’s recently signed Chesapeake Bay Watershed Agreement. Jurisdictions have set a goal to have all essential pollution-reducing practices in place by 2025 in an effort to meet water quality standards in the watershed.
Nutrient and sediment pollution are behind some of the Bay’s biggest health problems. Excess nitrogen and phosphorous fuel the growth of harmful algae blooms, which result in low-oxygen dead zones that suffocate marine life. Suspended sediment blocks sunlight from reaching underwater plants and suffocates shellfish. But “best management practices” (or BMPs) like upgraded wastewater treatment technologies, improved manure management and enhanced stormwater management can help towns, cities and states lower the amount of pollution flowing into local waters.
The EPA will continue to oversee the watershed jurisdictions’ pollution-reducing efforts, and will offer further attention to some pollution sectors—including wastewater in Delaware and New York; agricultural runoff in Delaware, Pennsylvania and West Virginia; and urban and suburban runoff in Pennsylvania, Virginia and West Virginia—to ensure partners remain on track to meet their 2017 targets.
Scientists expect the Chesapeake Bay to see an above-average dead zone this summer, due to the excess nitrogen that flowed into the Bay from the Potomac and Susquehanna rivers this spring.
Dead zones, or areas of little to no dissolved oxygen, form when nutrient-fueled algae blooms die and decompose. The latest dead zone forecast predicts an early-summer oxygen-free zone of 0.51 cubic miles, a mid-summer low-oxygen zone of 1.97 cubic miles and a late-summer oxygen-free zone of 0.32 cubic miles. This forecast was funded by the National Oceanic and Atmospheric Administration (NOAA) and is based on models developed at the University of Maryland Center for Environmental Science (UMCES) and the University of Michigan.
Dead zone size depends on nutrient pollution and weather patterns. According to the U.S. Geological Survey (USGS), 44,000 metric tons of nitrogen entered the Bay in the spring of 2014. This is 20 percent higher than last spring’s nitrogen loadings, and will influence algae growth and dead zone formation this summer.
Researchers with the Maryland Department of Natural Resources (DNR) and the Virginia Department of Environmental Quality (DEQ) will measure oxygen levels in the Bay over the next few months. While a final dead zone measurement is not expected until October, DNR biologists measured a larger-than-average low-oxygen zone on their June monitoring cruise, confirming the dead zone forecast.
Raising oysters along the bed of the Potomac River could lower pollution and improve water quality, according to new findings that show “farm-raised” shellfish are a promising method of managing nutrients.
Image courtesy Robert Rheault/Flickr
Nutrient pollution from urban, suburban and agricultural runoff has long plagued the Potomac, whose watershed spans four states and the District of Columbia and has the highest population in the Chesapeake Bay region. Excess nutrients like nitrogen and phosphorous can fuel the growth of algae blooms, which block sunlight from reaching underwater grasses and create low-oxygen dead zones that suffocate marine life. While filter-feeding oysters were once plentiful in the river—capable of removing nutrients from the water—their numbers have dropped due to overfishing and disease.
In a report published in Aquatic Geochemistry, scientists with the National Oceanic and Atmospheric Administration (NOAA) and the U.S. Geological Survey (USGS) show that cultivating shellfish on 40 percent of the Potomac’s bottom would remove all of the nitrogen now polluting the river. While conflicting uses—think shipping lanes, buried cables and pushback from boaters and landowners—mean it is unlikely that such a large area would be devoted to aquaculture, putting even 15 to 20 percent of the riverbed under cultivation would remove almost half of the incoming nitrogen. The combination of aquaculture and restored reefs could provide even greater benefits.
Image courtesy Virginia Sea Grant/Flickr
Shellfish aquaculture could also have benefits outside the realm of water quality: the shellfish could serve as a marketable seafood product, while the practice could provide growers with additional income if accepted in a nutrient trading program. Even so, the report notes that aquaculture should be considered “a complement—not a substitute” for land-based pollution-reducing measures.
“The most expedient way to reduce eutrophication in the Potomac River estuary would be to continue reducing land-based nutrients complemented by a combination of aquaculture and restored oyster reefs,” said scientist and lead study author Suzanne Bricker in a media release. “The resulting combination could provide significant removal of nutrients… and offer innovative solutions to long-term persistent water quality problems.”
At present, there are no aquaculture leases in the Potomac’s main stem. But in 2008, Maryland passed a plan to expand aquaculture in the region, and in 2009, NOAA launched an initiative to promote aquaculture in coastal waters across the United States.
The duration of the Chesapeake Bay’s annual “dead zone” has declined over time, according to research published last month in the scientific journal “Limnology and Oceanography.”
First reported in the 1930s, the Bay’s dead zone, or conditions of low dissolved oxygen also known as hypoxia, results from excess nutrients, which fuel the growth of algae blooms. As these blooms die, bacteria decompose the dead algae. This decomposition process removes oxygen from the surrounding waters faster than it can be replenished, suffocating marine life. While intensified agriculture and development continue to push nutrients into rivers and streams, research by Yuntao Zhou and others shows the duration of the Bay’s dead zone decreased from five months to four months between 1985 and 2010, and the end of the hypoxic season moved up from October to September. This could suggest that efforts to manage nutrient loads—through upgrades to wastewater treatment plants, cuts to vehicle and power plant emissions and reductions to runoff from farmland—are working.
This same research showed no change in the average onset of the Bay’s dead zone or for its average volume, whose peak has moved from late to early July. In other words, while the duration of the Bay’s dead zone has declined, its size and severity have not.
While Zhou points out that nutrient pollution is the foremost factor that fuels the development of our dead zone, his research also shows that weather patterns can act as an additional driver. Northeasterly winds, for instance, can create conditions that reinforce the separation between the Bay’s fresh and saltwater, leading to larger hypoxic volumes.
The reduction of power plant emissions in the mid-Atlantic has improved water quality in the Chesapeake region, according to new research from the University of Maryland Center for Environmental Science (UMCES).
Image courtesy haglundc/Flickr
Researchers at the university’s Appalachian Laboratory have traced improvements in the water quality trends of nine forested watersheds located along the spine of the Appalachian Mountains to the Clean Air Act’s Acid Rain Program. Passed in 1990, the Acid Rain Program led to a 32 percent drop in human-caused nitrogen-oxide emissions in 20 states. As these emissions have declined, so too has the amount of nitrogen found in some Pennsylvania, Maryland and Virginia waterways.
In other words, while the Acid Rain Program only intended to reduce the air pollution that causes acid rain, it had the unintended consequence of reducing the amount of nitrogen oxide particles landing on the region’s forests, thus improving local water quality.
“Improvements in air quality provided benefits to water quality that we were not counting on,” said UMCES President Donald Boesch in a media release.
Once nitrogen oxide particles are emitted into the air, wind and weather can carry them long distances. In time, these particles fall onto the land or into the water. Nitrogen that enters rivers and streams can fuel the growth of algae blooms, which block sunlight from reaching underwater grasses and create low-oxygen “dead zones” that suffocate marine life. Scientists estimate that just over one-third of the nitrogen polluting the Bay comes from the air.
The Chesapeake Bay watershed is home to more than 17 million people, each of whom is reliant on water. But as populations grow and communities expand, we send pollutants into our rivers and streams, affecting every drop of water in the region. How, then, do so many of us still have access to clean water? The answer lies within wastewater treatment plants.
One plant, in particular, plays a pivotal role in the region’s water quality. Located in Washington, D.C., the Blue Plains Wastewater Treatment Plant has served the D.C. metropolitan area since 1983. The plant receives 40 percent of its flow from Maryland, 40 percent from the District and 20 percent from Virginia. With the capacity to treat 370 million gallons of sewage each day, it is the largest wastewater treatment plant in the world and the only one in the nation to serve multiple states.
Recently, the District of Columbia Water and Sewer Authority—also known as DC Water—made technological upgrades to Blue Plains. Evidence shows these upgrades have already accounted for reductions in nutrient pollution and a resurgence in the upper Potomac River’s bay grass beds. Indeed, putting new wastewater treatment technology in place is a critical step toward meeting the pollution limits established in the Chesapeake Bay Total Maximum Daily Load. As of 2012, 45 percent of the watershed's 467 wastewater treatment plants had limits in place that met water quality standards.
Because of spatial constraints, many of upgrades planned for Blue Plains will focus on intensifying the wastewater treatment process. According to Sudhir Muthy, innovation chief for DC Water, the more concentrated the purification process is, the more energy efficient the plant can be.
For decades, the philosophy behind wastewater treatment plants has been to imitate those clean water processes that you might see in natural systems. Lately, there has been a shift in thinking about how wastewater is treated. Murthy explains: “Now, more attention is given to using the energy created within the treatment process to run the plant. [For example,] carbon has a lot of energy and is created during the treatment process. We are trying to harness [carbon’s] energy to help the plant run in a more energy-efficient way. We are now asking: How do we optimize the use of energy within the wastewater treatment process?”
Blue Plains hopes to become energy neutral in 10 to 15 years, and upgrades to reduce pollution and save energy will continue for years to come. A new tunnel will allow both sewage and wastewater to flow from the District to the plant, where it will be treated to reduce the flow of polluted runoff into the Potomac River. And a new process will recycle “waste” heat to “steam explode” bacterial sludge, turning it into a biosolid that can be mixed with soil, used as fertilizer and generate extra revenue.
“All processes use energy,” Muthy said. “But if you can find ways to offset or recycle that energy use, then you can move towards being more efficient.”
The Chesapeake Bay’s dead zone measured near average in size this past summer, coming close to scientists’ June prediction of a smaller than average hypoxic zone in the nation’s largest estuary.
Dead zones, or areas of little to no dissolved oxygen, form when nutrient-fueled algae blooms die. The bacteria that aid in algae bloom decomposition suck up oxygen from the surrounding waters. The resulting hypoxic or anoxic conditions can suffocate marine life, shrinking the habitat available for fish, crabs and other critters.
Each summer, the Maryland Department of Natural Resources (DNR) and the Virginia Department of Environmental Quality (DEQ) collect water samples to measure the hypoxic volume of the Bay. Since 1983, this number has ranged from 15.3 to 33.1 percent. In 2013, it measured 22.1 percent: 5.6 percent higher than the previous year and just above the 21.9 percent average.
Dead zones, or areas of little to no dissolved oxygen, form when nutrient-fueled algae blooms die. As bacteria help these blooms decompose, they suck up oxygen from the surrounding waters. The resulting hypoxic or anoxic conditions can suffocate marine life.
The Chesapeake Bay Program tracks dissolved oxygen as an indicator of water quality and Bay health.
The latest NOAA-funded forecast from researchers at the University of Maryland Center for Environmental Science (UMCES) and the University of Michigan predicts an average summer hypoxic zone of 1.108 cubic miles, lower than last year’s mid-summer hypoxic zone of 1.45 cubic miles.
This predicted improvement should result from the lower than average nutrient loads that entered the Bay this spring. According to the U.S. Geological Survey (USGS), 36,600 metric tons of nutrients entered the estuary from the Potomac and Susquehanna rivers, which is 30 percent lower than average.
The Bay’s dead zones are measured at regular intervals each year by the Maryland Department of Natural Resources (DNR) and the Virginia Department of Environmental Quality. While the final dead zone measurement will not take place until October, DNR biologists measured better than average dissolved oxygen on its June monitoring cruise, confirming the dead zone forecast.
Cover crops, streamside trees and nutrient management plans: all are exceptional ways to reduce nutrient pollution in the Chesapeake Bay. And for father and son duo Elwood and Hunter Williams, restoring the Bay begins with conservation practices and a shift in mentality.
“We knew coming down the road that we needed to do a better job with keeping the water clean,” Hunter said. “We decided that if there was going to be a problem with the streams it wasn’t going to be us.”
Excess nutrients come from many places, including wastewater treatment plants, agricultural runoff and polluted air. When nitrogen and phosphorus reach waterways, they can fuel the growth of large algae blooms that negatively affect the health of the Bay. In order to reduce these impacts, the U.S. Environmental Protection Agency (EPA) has implemented a Bay “pollution diet,” known as the Total Maximum Daily Load (TMDL).
Since the passing of the TMDL, many farmers in the watershed have felt the added pressure of the cleanup on their shoulders, but for the Williams family, having the foresight to implement best management practices (BMPs) just seemed like the environmentally and fiscally responsible thing to do.
”We don’t want to get to a point where regulations are completely out of control,” Hunter explained. “Farmers know what they’re putting on the ground so we have the ability to control it. Most people who have yards don’t have a clue what they’re putting on the ground when they use fertilizer. The difference has to be made up by the farmers because we know exactly what is going on to our soil.”
The Williams family began implementing BMPs on Misty Mountain Farm in 2006 by teaming up with the Potomac Valley Conservation District (PVCD). The government-funded non-profit organization has been providing assistance to farmers and working to preserve West Virginia’s natural resources since 1943.
The PVCD operates the Agricultural Enhancement Program (AgEP), which has steadily gained popularity among chicken farmers and livestock owners located in the West Virginia panhandle and Potomac Valley. While these two districts make up just 14 percent of West Virginia’s land mass, these regions are where many of the Bay’s tributaries begin—so it is important for area landowners to be conscious of pollutants entering rivers and streams.
AgEP is designed to provide financial aid and advice to farmers in areas that the Farm Bill does not cover. PVCD is run in a grassroots fashion, as employees collaborate with local farmers to pinpoint and meet their specific needs.
“It [AgEP] has been very well received,” said Carla Hardy, Watershed Program Coordinator with the PVCD. “It’s the local, state and individuals saying, “These are our needs and this is how our money should be spent.” Farmers understand that in order to keep AgEP a voluntary plan they need to pay attention to their conservation practices.”
Hunter admits the hardest part of switching to BMPs was changing his mindset and getting on board. Originally, Hunter was looking at the Bay’s pollution problems as a whole, but with optimistic thinking and assistance from PVCD, he realized that the best way to overcome a large problem was to cross one bridge at a time.
It wasn’t long before the Williams family started to see results: fencing off streams from cattle led to cleaner water; building barns to overwinter cows allowed them to grow an average of 75 pounds heavier than before, making them more valuable to the farm.
By using BMPs, the Williams family has set a positive example for farmers across the watershed, proving that with hard work and a ‘sky is the limit’ mentality, seemingly impossible goals can be met.
Hunter points out, “We are proud to know that if you are traveling to Misty Mountain Farm you can’t say, “Hey these guys aren’t doing their part.”
Video produced by Steve Droter.
Over the past decade, smallmouth bass in five Chesapeake Bay tributaries have suffered from fish kills and perplexing illnesses—and nutrient pollution could be to blame.
According to a new report from the Chesapeake Bay Foundation (CBF), excess nitrogen and phosphorous in our rivers and streams could be behind two of the leading problems affecting smallmouth bass: first, the rapid growth of fish parasites and their hosts, and second, the expansion of large algae blooms that can lead to low-oxygen conditions and spikes in pH. When paired with rising water temperatures and ever more prevalent chemical contaminants, nutrient pollution seems to have created a “perfect storm” of factors that are making smallmouth bass more susceptible to infections and death.
Image courtesy Mr. OutdoorGuy/Flickr
In a media call, CBF President Will Baker called the smallmouth bass “the canary in the coal mine for the Bay’s rivers.” Because the fish is sensitive to pollution, problems within the population could indicate problems within the Bay.
Smallmouth bass in the Susquehanna, Monocacy, Shenandoah, Cowpasture and South Branch of the Potomac rivers have seen a string of recent health problems, from open sores and wart-like growths to abnormal sexual development. In the Susquehanna, smallmouth bass populations have plummeted so far that Pennsylvania has made it illegal to catch the fish during spawning season.
“Our fish are sick, our anglers are mad and my board and I—protectors of our [smallmouth bass] fishery—are frustrated,” said John Arway, executive director of the Pennsylvania Fish and Boat Commission. “Our bass, and our grandchildren who will fish for them, are depending on us to fix the problem.”
Image courtesy CBF
While specific causes of smallmouth bass fish kills and illnesses remain unclear, CBF has called on state and local governments to accelerate their pollution-reduction efforts in hopes of improving water quality and saving the driving force behind a $630 million recreational fishing industry. The non-profit has also called on the federal government to designate a 98-mile stretch of the Susquehanna as impaired, which would commit Pennsylvania to reversing the river’s decline.
“This is the moment in time to save fishing in our streams and rivers, as well as the jobs and quality of life that are connected to it,” Baker said.
Nutrient and sediment trends at nine Chesapeake Bay monitoring sites have shown an overall lack of improvement, according to a report released this week by the U.S. Geological Survey (USGS).
As part of the Chesapeake Bay Program’s integrated approach to assess water quality as the Bay “pollution diet” is implemented, the report tracks changes in nitrogen, phosphorous and sediment trends at monitoring stations on the Susquehanna, Potomac and James rivers, as well as six additional waterways in Maryland and Virginia.
Using data from 1985 to 2010, the USGS measured minimal changes in total nitrogen at six out of nine monitoring stations and minimal or worsening changes in phosphorous at seven out of nine monitoring stations. Using data from 2001 to 2010, the USGS measured minimal or worsening changes in sediment at eight out of nine monitoring stations.
But a lack of improvement in pollution trends doesn’t mean that pollution-reduction practices aren’t working.
While nutrient and sediment trends can be influenced by a number of factors—among them, wastewater treatment plant upgrades and changes in land use—there is often a lag time between when restoration work is done and when visible improvements in water quality can be seen. And while the nine stations monitored here are located downstream of almost 80 percent of the land that drains into the Bay, runoff and effluent from three of the watershed’s biggest cities—Baltimore, Richmond, Va., and Washington, D.C.—do not flow past them, meaning that pollution-reduction practices implemented in these areas—or put in place after 2010—are not reflected in the study’s results.
According to the report, the USGS plans to work with partners to help explain the trends and changes described in this report; initial focus will be paid to the Eastern Shore and Potomac River Basin.
Read more about nutrient and sediment loads and trends in the Bay watershed.
Nutrient and sediment levels at a number of Chesapeake Bay monitoring sites have improved since 1985, according to a report released by the U.S. Geological Survey (USGS). These improvements in long-term trends indicate pollution-reduction efforts are working.
By measuring nutrient and sediment trends and by tracking changes in water clarity, underwater grasses and other indicators of river and Bay health, the USGS and Chesapeake Bay Program partners can make a more accurate assessment of changes in our waters. This kind of on-the-water monitoring is an integral part of ensuring Bay states and the District of Columbia are meeting "pollution diet" goals.
Excess nutrients and sediment can harm fish, shellfish and underwater grasses. Nitrogen and phosphorous fuel the growth of algae blooms that later rob water of the oxygen that aquatic species need to survive; sediment clouds the water, blocking the sunlight that plants need to grow. But a number of practices, from upgrading wastewater treatment plants to reducing agricultural, urban and suburban runoff, can stop or slow nutrients and sediment from entering the Bay.
According to the USGS report, one-third of monitoring sites have shown improvement in sediment concentrations since 1985. Within the same time period, two-thirds of these sites have shown improvement in nitrogen concentrations and almost all have shown improvement in phosphorous concentrations. However, in the past decade, the majority of sites surveyed showed no significant change in nitrogen or phosphorous levels, and only a handful showed improvement in sediment trends.
This doesn't mean that pollution-reduction efforts have been in vain. Long-term trends show us that pollution-reduction efforts do have an impact; findings from the last 10 years illustrate the lag time that can exist between restoration efforts and firm evidence of restoration success.
While upgrades to wastewater treatment plants, for instance, can yield relatively quick results, the effects of consistent reduced fertilizer on farms or suburban lawns may not be visible for years.
"While we see long-term improvements in many areas of the Bay watershed, there is a lag time between implementing water-quality practices and seeing the full benefit in rivers," said USGS scientist Scott Phillips. "Which is one reason why scientists see less improvement over the past 10 years."
"Long-term trends indicate that pollution-reduction efforts are improvement water-quality conditions in many areas of the watershed," Phillips said. "However, nutrients, sediment and contaminants will need to be further reduced to achieve a healthier Bay."
Learn more about Monitoring the Chesapeake Bay Watershed.
In 2011, monitoring data collected by the Bay jurisdictions and other partners showed that dissolved oxygen concentrations in the Chesapeake fell to their lowest level in the last four years with 34 percent of the waters meeting the established DO standards for the summer months. This represents a decrease of 4 percent from the 2010 figures according to the Chesapeake Bay Program (CBP) partnership and is almost half of the higher DO values recorded a decade ago.
In spite of lower levels and in the face of many weather challenges, various Bay habitats and creatures that have been the target of restoration efforts showed resilience last year. In CBP news this March, scientists from Virginia Institute of Marine Sciences (VIMS) reported that despite a decrease in Bay grasses overall, the restored, healthy grass beds at Susquehanna Flats remained intact, widgeon grass beds grew (likely due to seed germination stimulated by lower salinities) and new grass beds were found in Virginia’s James River. In terms of fisheries, preliminary data by oyster scientists from Maryland Department of Natural Resources and NOAA showed good news, too. Experts estimate last year’s oyster survival rate was at its highest since 1985, oyster biomass increased 44 percent and oyster disease was at an all time low.
“Last year’s heavy rains and even this year’s early algae blooms and fish kills reinforce the critical importance of controlling polluted runoff reaching the Bay’s waters,” said Nick DiPasquale, Director of the Chesapeake Bay Program. “The survival rates of some oyster and grass beds in 2011 shows us that our efforts are working. By actively restoring and protecting valuable resources we can build a stronger, healthier Bay ecosystem that can withstand the forces of nature. Clearly, while we can’t control the weather, we can restore the watershed’s ability to survive its more extreme events. We know what works; we just need to do more of it.”
Experts were not terribly surprised by the final information on the Bay’s 2011 “dead zones” given the extreme weather. Between the very wet spring that sent excessive nutrients downstream, a hot, dry, early summer and more heavy rains accompanying Tropical Storm Lee and Hurricane Irene, conditions in the Chesapeake were bound to be affected.
Peter Tango, CBP Monitoring Coordinator and U.S. Geological Survey scientists explains, “The Bay ecosystem functions most effectively when fresh and salt water can mix, just like oil and vinegar need to mix to form salad dressing. A large fresh water influx such as that in 2011, along with intense heat, can result in vast differences in quantities of warm fresh and cool salt water in the Bay. These variables make it more difficult for water to mix vertically in the water column.”
In addition to vertical mixing, the dissolved oxygen levels in the Bay are also affected by what happens at the edges. Tango continues: “By the fall of last year, the Upper Bay became mostly fresh water due to rain. The Lower Bay became a hot tub due to heat,” illustrates Tango. “While the initial effects of the Tropical Storm Lee’s arrival was to mix the Bay more than usual in late summer, this combination of salinity and temperature conditions resulted in minimal levels of oxygen in bottom waters that lasted well into the fall. The delay in autumn vertical mixing and the persistent summer-like water quality conditions at the northern and southern boundaries pushed on the mid-Bay waters, resulting in what we scientists call a dissolved oxygen or ‘DO squeeze.’”
All of the Bay's living creatures – from the fish and crabs that swim through its waters to the worms that bury themselves in its muddy bottom – need oxygen to survive, although the amounts needed vary by species, season and location in the Bay. A DO squeeze challenges the health of fish, crabs, and other Bay creatures since they become compacted together – predator and prey, from north to south and bottom to top – in significantly smaller sections of water where and conditions are less-than-ideal for their survival.
A new study analyzing 60 years of water quality data shows that efforts to reduce pollution from fertilizer, animal waste and other sources appear to be helping the Chesapeake Bay’s health improve.
The study, published in the Nov. 2011 issue of Estuaries and Coasts, was conducted by researchers from The Johns Hopkins University and the University of Maryland Center for Environmental Science (UMCES).
The research team found that the size of mid- to late-summer low oxygen areas, called “dead zones,” leveled off in the Bay’s deep channels during the 1980s and has been declining ever since. This is the same time that the Bay Program formed and federal and state agencies set the Bay’s first numeric pollution reduction goals.
“This study shows that our regional efforts to limit nutrient pollution may be producing results,” said Don Boesch, president of the University of Maryland Center for Environmental Science. “Continuing nutrient reduction remains critically important for achieving bay restoration goals.”
The study also found that the duration of the dead zone – how long it persists each summer – is closely linked to the amount of nutrient pollution entering the Bay each year.
For more information about the dead zone study, visit UMCES’s website.
The U.S. Environmental Protection Agency has approved new standards to control polluted stormwater runoff from roads, buildings and other developed areas in Washington, D.C.
The District’s renewed municipal separate storm sewer system (MS4) permit requires that redevelopment projects in the city install runoff-reducing practices to slow the flow of polluted stormwater to the Anacostia and Potomac rivers and the Chesapeake Bay.
The required practices include:
Roads, rooftops, parking lots and other hard surfaces channel stormwater directly into local rivers and streams, carrying pollution and eroding streambanks. The renewed permit will help the District in meeting its Bay pollution reduction goals and Watershed Implementation Plan (WIP).
Visit the EPA’s website to learn more about the new stormwater permit and standards.
Walking my two high-spirited Boykin Spaniels, Rosebud and Daisy, has special meaning to me. I have become the self-appointed advocate for picking up pet waste in Anne Arundel County, Maryland. Many call me the “queen of poop” (with a chuckle); it’s a title of distinction, as far as I’m concerned! But you might wonder how I earned that title and why I think it is a good thing? (My parents certainly do!)
I encourage everybody to walk with their four-legged friends. It’s good for both your health and your dog’s. Many popular routes in Anne Arundel County now have pet waste stations to encourage you to pick up your dog’s poop. Picking up pet waste is critical to achieving a healthy Chesapeake Bay. Pet waste can be carried by rainwater and groundwater to the Chesapeake Bay, where it becomes harmful pollution.
I developed an interactive web site called Annapolis and Anne Arundel County Pet Walks, which maps the locations of pet waste stations in the area. You can even visit the website from your mobile device while you’re out walking your dog to find the nearest pet waste station.
If you know of a pet waste station that isn’t included on the map, or if you’d like to learn how to set up a pet waste program in your community, please contact me at firstname.lastname@example.org.
Meanwhile, please take a walk with your dog today. And remember: POOP HAPPENS…Deal with it!
What do farms, manure, and a developing technology for creating fertilizer have to do with the Chesapeake Bay? Well, almost one-quarter of the Chesapeake Bay’s 64,000 square mile watershed is agricultural land. Runoff from farmland inevitably drains into the local streams, creeks and rivers that flow to the Chesapeake Bay.
When best management practices are not implemented on agricultural lands, runoff can carry animal waste and excess fertilizer into these waterways, overloading them with nutrients, bacteria and pathogens.
A developing technology called anaerobic digestion has been proposed to reduce phosphorus runoff from many farms. Pilot studies have been conducted in several locations around the world, including at least three Chesapeake Bay watershed states.
Anaerobic digesters, or biodigesters, have become an increasingly popular tool for managing manure on farms. Biodigesters are thought to have several benefits, including reducing farm animal waste runoff, producing nitrogen-rich liquid that can be used as fertilizer, and producing phosphorus-rich solids that can be processed into mulch and other products that would reduce runoff.
Biodigesters are increasing in popularity for use with dairy farms and manure handled as a liquid, slurry or semisolid. However, a Bay Program website visitor wanted to know about the effectiveness of using biodigesters on poultry farms with litter feedstock to improve water quality in the Bay and its tributaries.
One study conducted in the Bay watershed for the Propane Education Research Council tried to determine if this method could decrease the phosphorus in the liquid effluent from the digester exit point. Unfortunately, the study concluded that this was not the case. Phosphorus was only decreased by approximately 5 percent – the same rate of reduction without the anaerobic digestion process. The council concluded that significant phosphorus reduction could be possible if a separate post-digester step was added.
According to that study, the use of biodigesters would not be an effective way for farmers to help improve water quality.
John Ignosh is a scientist with the Virginia Cooperative Extension at Virginia Tech, working on agricultural byproduct utilization. “As far as digesters [used for] litter,” he said, “there have been a few pilot projects looking at this. The main challenge is that digestion is better suited for slurry type feedstocks.”
Most discussion of anaerobic digesters is in reference to digesters using a slurry type feedstock, but Ignosh said there have been pilot projects with litter feed conducted in Maryland, Virginia and West Virginia, among other locations.
An important note is that regardless of the type of feedstock used for the biodigesters, there is not a significant reduction in nutrients from the waste. Nitrogen enters the digester as ammonium and organic nitrogen, and the ammonium is not destroyed in the digester. Instead, the organic nitrogen is converted to ammonium. So the nitrogen in the effluent from the digester typically ends up being higher than when it went in. Similarly, the microorganisms used in the digester do not consume phosphorus. Although some of the phosphorus can be converted to a soluble form, the total mass of phosphorus remains constant.
Therefore, while anaerobic digesters may be useful for producing biogas to create energy and manage waste, they do not reduce the amount of nutrients in the fertilizer or other products it might result in. So fertilizer that is made from a biodigester and is used on farmland would not decrease the amount of nitrogen and phosphorus that would run off the land. These devices also tend to be prohibitively expensive for many farms and do not provide the best benefit for the investment.
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