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.
Severe weather to the north of the region pushed a large number of ducks, geese and swans into the main portion of the Chesapeake Bay this winter, leading to a 22 percent jump in the results of Maryland’s 2014 Midwinter Waterfowl Survey.
According to the Maryland Department of Natural Resources (DNR), pilots and biologists from both DNR and the U.S. Fish and Wildlife Service (USFWS) counted more than 905,000 waterfowl during their aerial assessments of state waters this winter. The birds were easier to count this season than in winters past because a number of them were concentrated in the few ice-free, open waters of the Bay and its tributaries.
This total included 128,000 dabbling ducks and 190,300 diving ducks, representing a 76 and 94 percent jump from last winter, respectively. Indeed, the canvasback count was the highest it has been since the mid-1960s, and estimates for mallards and black ducks were the highest they have been since the mid-1970s. Survey teams also witnessed large numbers of Canada geese along the upper Bay: 512,000, 11 percent more than were witnessed in January 2013.
The USFWS Division of Migratory Bird Management pools these survey results with those from other states to get a sense of the distribution and population size of waterfowl wintering along the Atlantic Flyway. This migration route follows the Atlantic coast of North America, and this winter hosted more than 3.19 million birds. Of this total, teams counted more than 1.6 million in watershed states, including Maryland, Virginia, West Virginia, Pennsylvania, Delaware and New York.
Winter can be a wonderful season for bird watchers and wildlife seekers in the Chesapeake Bay watershed.
Parks, wildlife refuges and backyards around the region provide a range of habitats for animals that have adapted to spend the cold winter months in the mid-Atlantic.
Game species like the white-tailed deer and wild turkey are often seen in wildlife refuges and agricultural fields adjacent to wooded areas, where they can find protective cover and food. Both deer and turkeys can be found throughout the watershed year-round and are valued by the region’s many hunters.
While cold-blooded species—insects, worms, reptiles and amphibians—and some mammals—the black bear, woodchuck and chipmunk—hibernate in the winter, mammals like the muskrat, gray squirrel and fox remain active and visible year-round.
The Delmarva fox squirrel is another such mammal. The endangered species can be found in small, isolated populations on the Delmarva Peninsula, and forages for nuts, seeds and acorns in quiet wooded areas throughout the year.
The Bay is renowned for its waterfowl habitat and is visited each year by an estimated 75 percent of the waterfowl that migrate along the Atlantic flyway. According to the Maryland Department of Natural Resources (DNR), approximately 1 million ducks, geese and swans overwinter in the watershed.
The most prolific species of migratory waterfowl in the watershed is the Canada goose. Frequently seen in farm fields and near lakes, rivers and streams, they are an important game species that, because of their foraging habits, can damage farms and vital habitats when gathered in excessive numbers. A lack of natural predators and an increase in available food during winter months means that some Canada geese now reside in the area year-round.
Snow geese and tundra swans breed in the Arctic, travel down the Atlantic flyway and overwinter along the Bay. Although the white birds may look alike at first glance, snow geese are smaller and stouter and travel in large flocks. Tundra swans, on the other hand, are larger birds with long necks and black bills. Both species can be seen near open water or blanketing agricultural fields while foraging for food
Even the Bay’s shoreline remains an active habitat during the winter. From the coast, surf scoters and other sea ducks can be seen diving for buried crustaceans.
Iconic wading birds like the great blue heron and great egret make for memorable viewing experiences. Found at wildlife refuges and along rivers and streams, the long-legged birds move slowly while hunting for food, but strike quickly at fish, frogs and other prey.
Forests make up 55 percent of the watershed and in winter support several species of woodpeckers, including the red-bellied woodpecker and the yellow-bellied sapsucker.
Downy woodpeckers are the smallest of all North American woodpeckers. They can be found clinging to trees and visiting backyard feeders near wooded areas.
Several species of warblers live in the brushy areas of the watershed’s woods, but only the yellow-rumped warbler remains in the region through the winter. Warblers feed mainly on insects, but have adapted to eat fruit—particularly bayberries—during cold months.
Passerines or perching birds like the Northern cardinal, black-capped chickadee and tufted titmouse are common throughout the watershed and, thanks to their tendency to visit backyard bird feeders, can provide an accessible and rewarding wildlife viewing experience.
Each with its own unique song and behavior, birds like the Carolina wren, white-throated sparrow and white-breasted nuthatch also frequent backyard bird feeders during winter months when their natural food sources of seeds, fruit, nectar and insects are scarce.
To learn more about wildlife in the Chesapeake Bay watershed, visit our online Field Guide.
To view more photos in this set, visit the Chesapeake Bay Program Flickr page.
Images by Steve Droter. Captions by Jenna Valente.
Green roofs, porous pavement and other tools of the green infrastructure trade can be a cost-effective way to control stormwater runoff, according to a U.S. Environmental Protection Agency (EPA) report that estimates the benefits of Lancaster City’s long-term green infrastructure plan.
Image courtesy Lindsayy/Flickr
Located in south-central Pennsylvania, Lancaster City has a population approaching 60,000. Each year, combined sewer overflows send almost 750 million gallons of stormwater runoff and untreated waste into the Conestoga River, pushing excess nutrients into the tributary of the Chesapeake Bay. In an effort to combat this pollution problem, the city released a green infrastructure plan in 2011 that outlines the tree plantings, parking lot excavations and other projects that will be put in place over the next 25 years.
While the plan lists the water quality benefits the city expects to see—including the reduction of stormwater runoff by more than 1 billion gallons per year—it is, for some, an incomplete assessment. So, in a report released this week, the EPA furthered the city’s benefits analysis by addressing the additional environmental, social and economic benefits that green infrastructure can provide.
According to the report, the long-term implementation of green infrastructure in Lancaster City could save $120 million in avoided gray infrastructure capital costs and earn close to $5 million in annual benefits. Green infrastructure would reduce air pollution, energy use and stormwater runoff, and offer residents a boost in property values, recreational opportunities and other qualitative benefits. With a forecasted implementation cost of between $51.6 and $94.5 million, it is clear the benefits of green infrastructure exceed the costs.
While gray infrastructure uses tanks and pipes to trap and dispose of rainwater, green infrastructure uses soil and vegetation to manage rainwater where it falls. A combination of green and gray infrastructure has proven effective for Lancaster City, and similar plans could benefit communities across the watershed.
One reconstructed parking lot, for instance, incorporated almost 6,000 square feet of bioretention and infiltration practices on South Plum Street, with an estimated annual benefit of more than $1,100. A commercial green street in northeast Lancaster incorporated bioretention and infiltration practices as well as permeable pavement, with an estimated annual benefit of more than $2,300. And an urban park redeveloped with a host of green infrastructure practices carries an estimated annual benefit of more than $5,500.
“Valuing multiple benefits of green infrastructure ensures water management investments by the city will help… provide a safer, healthier and more prosperous community,” said Liz Deardorff, Clean Water Supply director at American Rivers, in a media release. “The results of this study affirm that green infrastructure has multiple benefits for both large and small cities needing to reduce pollution and ensure clean water.”