• Warming Waters
    Even a minute change in ocean temperature can devastate species such as algae, plants, and animals.

    Photograph by Edward Mattis, MyShot

    Old-Timer
    The Chesapeake Biological Laboratory is the oldest state-supported marine laboratory on the East Coast.

    By Stuart Thornton

    Thursday, November 4, 2010

    From the end of a pier jutting into Maryland’s Patuxent River, scientists at the Chesapeake Biological Laboratory have determined that the region’s water temperatures are warming.

    According to David Secor, a professor from the University of Maryland Center for Environmental Science who works at the facility, the surface waters at the end of the pier have increased 3 degrees Fahrenheit since people began collecting data from the site in 1938.

    Secor believes if little action is taken to slow global warming, the Chesapeake Bay could have summer water temperatures comparable to Florida’s by the year 2100. Global warming is the increase in the average temperature of the Earth’s air and oceans. The release of carbon emissions into the atmosphere, mostly through industrial agriculture and burning fossil fuels, probably contributes to global warming.

    “If we do nothing—which is probably the simplest way to think about this—in 50 year’s time, we are looking at at least a 3-degree Fahrenheit rise,” he says. “In 80 years time we could be looking at a 6- to 8-degree Fahrenheit change.”

    The Chesapeake Bay is an estuary off the Atlantic Ocean that stretches north into the states of Virginia and Maryland and supports a variety of animal and plant species. More than 100 rivers and streams from New York, Delaware, Pennsylvania, and West Virginia flow into the bay.

    The plants and animals of the Chesapeake Bay have supported people since the first European settlers arrived in the area more than 500 years ago. Oysters, fish, crabs, and wild rice were part of the diet of the Powhatan, the Native Americans of the region. Chesapeake Bay still produces more fish and shellfish than any other estuary in the United States. The blue crab, the “state crustacean” of Maryland, is the most important fishery in the area.

    Secor admits at this time he can only predict what might happen to the region’s ecology and economy as the bay’s temperatures continue to climb. He thinks that climate change might cause declines in species that are already stressed by disease and poor water quality.

    Hot Water for Fishes and Plants

    Secor says he suspects that Atlantic sturgeon and shortnose sturgeon will be affected by the changes in the Chesapeake Bay. Sturgeon are huge fish, native to most rivers that feed the Chesapeake Bay, including the James and the Susquehanna rivers. Sturgeon, a cold-water fish also native to Russia, are mostly harvested for their eggs, or caviar. Sturgeon are a benthic species, meaning they live near the bottom of rivers.

    Sturgeon are particularly sensitive to pollution. Runoff from farms and industry, as well as overfishing, have threatened sturgeon populations in the Chesapeake Bay region.

    “The combination of warm water and maybe frequent droughts, which are in the offing in the future, could be the final nail in the coffin for species like sturgeon,” Secor says.

    Secor also suspects that fish that thrive in cooler waters, including shad and striped bass, could experience decreases in population brought about by a warmer climate.

    “These species are already very stressed by water quality, by watershed development, by impervious surfaces, by dams,” he says. “A stress like warming could produce a threshold condition that causes very rapid declines in these species.”

    According to Bill Dennison, the vice president for science application at the University of Maryland Center for Environmental Science, the Chesapeake Bay’s rising water temperatures could also change the makeup of the region’s plant communities. He cites an unusually warm summer in 2005 that caused a mass die-off of eelgrass, a marine plant that is commonly found along the mouths of tributaries that flow into the bay from Virginia.

    If eelgrass were to die out in the Chesapeake Bay due to warming water temperatures, its disappearance would affect other species in the region.

    “Blue crabs and peeler crabs go into the grass to molt, so when they lose that protection they are more susceptible to predation,” Dennison says.

    According to Secor, increasing water temperatures in the bay can also cause species there, including striped bass, shad and river herring, to misread environmental cues.

    “These species migrate into the Chesapeake Bay according to certain reproduction and feeding schedules,” he says. “With warming, those schedules can get miscued due to environmental conditions.”

    Invasive Species

    The Chesapeake Bay’s changing water temperatures might affect more than just native plants and animals. The change could also make conditions more favorable for non-native or invasive species.

    Secor points to recent sightings of manatees in the Chesapeake Bay as an example of a species from a warmer climate appearing. Manatees, an endangered species, are marine mammals usually found in tropical waters of the Caribbean Sea. More sightings of manatees in the Chesapeake Bay area could be a sign of the animal moving northward due to changing water conditions. The bay ecosystem, including marine grasses on which manatees feed, may not be able to support the animals.

    Secor says the parasites that cause the oyster diseases MSX and Dermo seem to flourish in the warmer and drier conditions that are part of global warming, the latest instance of climate change on Earth.

    With warming waters, more exotic species could become prevalent. “We sometimes see things like piranhas [in the Chesapeake Bay] that people release from aquariums,” Secor says. “Currently, when we come across one, we can be confident that winter temperatures will kill those fish. If winters become milder, then some of these invasives that are introduced through the aquarium trade could take hold.”

    Reinventing Ecosystems

    At this point, Secor admits he doesn’t know how the Chesapeake Bay will change as its waters warm.

    “There’s a lot of discussion about what is the ecosystem [is] going to look like,” he says. “We just can’t say we are going to look just like a South Carolina estuary or a North Carolina estuary or something like that. What we will be doing is kind of reinventing these systems. There will be some species that can adapt to these trends most assuredly, and then others that will be colonizing into the Chesapeake.”

  • Term Part of Speech Definition Encyclopedic Entry
    agriculture Noun

    the art and science of cultivating the land for growing crops (farming) or raising livestock (ranching).

    Encyclopedic Entry: agriculture
    benthic Adjective

    having to do with the bottom of a deep body of water.

    blue crab Noun

    crustacean with a greenish body and blue legs, native to North America.

    carbon emission Noun

    carbon compound released into the air through the burning of fossil fuels such as coal or gas.

    caviar Noun

    delicacy made from the eggs of sturgeon or other fish.

    Chesapeake Bay Noun

    large, shallow estuary of the Susquehanna and other rivers that flow through the U.S. states of Maryland, Virginia, West Virginia, Delaware, Pennsylvania, and New York and the capital of Washington, D.C., before emptying in the Atlantic Ocean.

    climate Noun

    all weather conditions for a given location over a period of time.

    Encyclopedic Entry: climate
    climate change Noun

    gradual changes in all the interconnected weather elements on our planet.

    Encyclopedic Entry: climate change
    crustacean Noun

    type of animal (an arthropod) with a hard shell and segmented body that usually lives in the water.

    cue Noun

    hint or marker.

    dam Noun

    structure built across a river or other waterway to control the flow of water.

    Dermo Noun

    fatal disease among oysters caused by the germ Perkinsus marinus.

    drought Noun

    period of greatly reduced precipitation.

    Encyclopedic Entry: drought
    ecology Noun

    branch of biology that studies the relationship between living organisms and their environment.

    Encyclopedic Entry: ecology
    economy Noun

    system of production, distribution, and consumption of goods and services.

    ecosystem Noun

    community and interactions of living and nonliving things in an area.

    Encyclopedic Entry: ecosystem
    eelgrass Noun

    type of seagrass with long, thin leaves. Also called tape grass.

    endangered species Noun

    organism threatened with extinction.

    Encyclopedic Entry: endangered species
    estuary Noun

    mouth of a river where the river's current meets the sea's tide.

    Encyclopedic Entry: estuary
    exotic species Noun

    non-native species.

    facility Noun

    a building or room that serves a specific function.

    fishery Noun

    industry or occupation of harvesting fish, either in the wild or through aquaculture.

    fossil fuel Noun

    coal, oil, or natural gas. Fossil fuels formed from the remains of ancient plants and animals.

    global warming Noun

    increase in the average temperature of the Earth's air and oceans.

    Encyclopedic Entry: global warming
    impervious surface Noun

    boundary that does not allow water to penetrate it.

    invasive species Noun

    type of plant or animal that is not indigenous to a particular area and causes economic or environmental harm.

    Encyclopedic Entry: invasive species
    manatee Noun

    threatened marine mammal native to the Caribbean Sea and Atlantic Ocean.

    migrate Verb

    to move from one place or activity to another.

    molt Verb

    to shed fur, skin, feathers, or other body covering.

    MSX Noun

    (multi-nucleated sphere unknown) fatal disease among oysters caused by the germ Haplosporidium nelsoni.

    offing Noun

    part of a body of water that touches the horizon.

    overfish Verb

    to harvest aquatic life to the point where species become rare in the area.

    pier Noun

    platform built from the shore and extending over water.

    piranha Noun

    carnivorous, freshwater fish native to South America. Also called caribe.

    pollution Noun

    introduction of harmful materials into the environment.

    Encyclopedic Entry: pollution
    Powhatan Noun

    people and culture native to the mid-Atlantic region of the U.S.

    predation Noun

    behavior of one animal feeding on another.

    prevalent Adjective

    common or widespread.

    river Noun

    large stream of flowing fresh water.

    Encyclopedic Entry: river
    runoff Noun

    overflow of fluid from a farm or industrial factory.

    Encyclopedic Entry: runoff
    settler Noun

    person who migrates and establishes a residence in a largely unpopulated area.

    shad Noun

    type of fish, related to the herring.

    shellfish Noun

    any aquatic animal that has a shell.

    stress Verb

    to strain or put pressure on.

    sturgeon Noun

    type of marine or freshwater large, long, bony fish.

    susceptible Adjective

    able to be influenced to behave a certain way.

    threshold Noun

    point in a process that must be met to start a new stage in the process.

    tributary Noun

    stream that feeds, or flows, into a larger stream.

    Encyclopedic Entry: tributary
    tropical Adjective

    existing in the tropics, the latitudes between the Tropic of Cancer in the north and the Tropic of Capricorn in the south.

    watershed development Noun

    construction or preparation of land for housing, industry, or agriculture near a river or flood plain.

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