November 2004 ( Vol. 43 No. 1 )
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Our Ocean. Our Planet. Our Future.
Where the Rivers Meet the Sea
Estuaries are the borderlands between salt and freshwater environments, and they are incredibly diverse both biologically and physically. The diversity and the high energy of the ecosystem make estuaries remarkably resilient.
The Coastal Ocean Institute
We are all stewards of the coastal ocean. For some of us, the connection to the sea is clear and immediate; for others, it is subtle and distant. But whether you live on waterfront property or in a land-locked hamlet, your everyday activities affect this most sensitive and most threatened portion of the world?s oceans.
Robo-Sailors
In the mid-1990s, the Navy began funding research for small, robotic vehicles to perform unmanned reconnaissance in coastal waters. At WHOI, that helped spark the development of REMUS (Remote Environmental Monitoring UnitS), designed and built by Chris von Alt, Ben Allen, and colleagues in the Oceanographic Systems Laboratory.
New Instrument Sheds Light on Bioluminescence
Bioluminescence is ubiquitous in the oceans, and especially prevalent in coastal regions where nutrients are abundant and life thrives. Yet scientists have little basic understanding of how bioluminescence is influenced by water temperatures, depths, seasons, geographic locations, even different times of day.
The Cacophony on the Coast
Unlike light, sound travels efficiently through water, and the Navy uses sound to monitor what's going on in the ocean. To understand the sound messages transmitted through the seas, you need to understand the medium through which they are transmitted.
Where Are Mines Hiding on the Seafloor?
Eternally and incessantly, waves and currents stir up sand from the seafloor near the coast. Sediments get suspended in the ocean, carried onshore and off, and deposited elsewhere. In the process, objects on the seafloor—natural and unnatural—can get buried and uncovered.
For the Navy, the Coast Isn't Clear
Every so often, circumstances can conspire to make a battleship turn on a dime. Fifteen years ago, two geopolitical events prompted the U.S. Navy to abruptly change long-standing research priorities and steer rapidly in a new direction.
A Fatal Attraction for Harmful Algae
Estuaries are the borderlands between salt and freshwater environments, and they are incredibly diverse
both biologically and physically. The diversity and the high
energy of the ecosystem make estuaries remarkably resilient.
With a better understanding of these systems, we can reverse
their decline and restore the ecological richness of these
valuable, albeit muddy, environments.
Rites of Passage for Juvenile Marine Life
The childhood of a barnacle is fraught with challenges. It hatches in shallow waters close to shore as a tiny larva, no bigger than a speck of dust. Currents sweep it to deeper, choppy waters, sometimes miles offshore. In these proving grounds each larva floats, at the mercy of hungry fish and swift ocean currents. Billions of larvae?including fish, lobsters, clams, starfish, and sea cucumbers?begin life this way. Only a few survive and return to shore, where they settle on rocks or sandy seafloor to become adults. Why larvae make their offshore journey remains unclear, but we are beginning to uncover the intricacies of their return trip?learning how waves, currents, eddies, tides, and other phenomena bring larvae back toward the shore.
Red Tides and Dead Zones
The most widespread, chronic environmental problem in the coastal ocean is caused by an excess of chemical nutrients. Over the past century, a wide range of human activities—the intensification of agriculture, waste disposal, coastal development, and fossil fuel use—has substantially increased the discharge of nitrogen, phosphorus, and other nutrients into the environment. These nutrients are moved around by streams, rivers, groundwater, sewage outfalls, and the atmosphere and eventually end up in the ocean.
Water Flowing Underground
Groundwater discharge appears to be an important factor for determining the chemistry of the coastal ocean. As fresh groundwater flows toward the sea, it rises up over denser, salty water. The fresh and salty water mix along the interface, and the resulting fluid discharges at the shoreline. This interface between underground water masses has recently been described as a "subterranean estuary," a mixing zone between fresh and salty water analogous to the region where a river meets the ocean.
Rising Sea Levels and Moving Shorelines
Changes to the shoreline are inevitable and inescapable. Shoals and sandbars become islands and then sandbars again. Ice sheets grow and shrink, causing sea level to fall and rise as water moves from the oceans to the ice caps and back to the oceans. Barrier islands rise from the seafloor, are chopped by inlets, and retreat toward the mainland. Even the calmest of seas are constantly moving water, sand, and mud toward and away from the shore, and establishing new shorelines.
The Growing Problem of Harmful Algae
Harmful algal blooms are natural and they are not new. But ocean scientists are growing concerned that they are now all too common. The unprecedented growth of human activities in coastal watersheds—including agriculture, aquaculture, industry, housing, and recreation—has drastically increased the amount of fertilizer flowing into coastal waters and fueled unwanted algal growth.
Oil in Our Coastal Back Yard
On September 16, 1969, the barge Florida ran aground off Cape Cod, rupturing its hull and spilling 189,000 gallons of No. 2 fuel oil. Winds and waves pushed the oil onto the beaches and marshes of West Falmouth, Massachusetts, carrying with it dead lobsters, scup, and cod.
Shaping the Beach, One Wave at a Time
For years, scientists who study the shoreline have wondered at the apparent fickleness of storms, which can devastate one part of a coastline, yet leave an adjacent part untouched. How can this be? The answer lies in the physics of the nearshore region?the stretch of sand, rock, and water between the dry land behind the beach and the beginning of deep water far from shore.
Down on the Farm...Raising Fish
Aquaculture, or fish farming, is changing how we think about one of our main sources of protein. With many fish stocks shrinking due to overfishing or environmental degradation, aquaculture holds the promise of more reliable and more sustainable seafood production. The economic and social benefits could be significant for both consumers and producers.
Mixing Oil and Water
In recent decades scientists have made substantial progress in understanding how oil enters the oceans, what happens to it, and how it affects marine organisms and ecosystems. This knowledge has led to regulations, practices, and decisions that have helped us reduce sources of pollution, prevent and respond to spills, clean up contaminated environments, wisely dredge harbors, and locate new petroleum handling facilities.
Which Way Will the Wind Blow?
Wind energy is the fastest-growing sector of the global electric power industry, and several companies have proposed to build large wind turbines and utility-scale electric power-generating facilities in the coastal waters of the United States. Such facilities could change the way people use the ocean, and the public is divided over the costs and benefits. The environmental and economic benefits of renewable, nonpolluting sources of energy are clear. But there may be side effects from the placement of modern wind farms in the ocean, including the degradation of seascapes, impacts on birds and marine animals, and the disruption of existing patterns of human use of the ocean. The laws and regulations related to the placement of wind turbines in the ocean are at best rudimentary and inchoate; at worst, they are non-existent. Marine scientists and engineers can make an important contribution to this growing public debate by clarifying our understanding of the nature of these side effects. They might also inform public policies that balance the value of various ocean resources with the rights and interests of all who wish to use them.
The Grass is Greener in the Coastal Ocean
Stretching from inland rivers and bays to the edge of the continental shelf, the coastal ocean accounts for about 10 percent of the ocean's surface area. Yet this relatively small sliver of ocean contains about half of all the microscopic plants adrift in our seas.