Biology
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.
Read MoreThe 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.
Read MoreScientists Muster to Help Right Whales
It is a sad irony that we have cataloged individual photographs of the remaining North Atlantic right whales and given each of them unique numbers and sometimes names, yet still know too little about their physiology, behavior, and habitats to take effective steps toward ensuring their survival as a species.
Read MoreWhither the North Atlantic Right Whale?
“Today only a remnant of the population survives, no more than 350 whales clustered in calving and feeding grounds along the eastern seaboard of North America. Only occasional right whale sightings in the Gulf of St. Lawrence or in the waters between Iceland, Greenland, and Norway give echoes of their once substantially greater range.
Read MoreRevealing the Ocean’s Invisible Abundance
Finding minuscule life forms in a seemingly infinite ocean isn’t trivial. But in recent years, oceanographers have been developing new techniques and instruments to identify and count marine microorganisms. Year by year, we are learning more and more about them and discovering that they are even more numerous, varied, and important than we previously thought.
Read MoreShedding Light on Light in the Ocean
Light in the ocean is like light in no other place on Earth. It is a world that is visibly different from our familiar terrestrial world, and one that marine animals, plants, and microbes are adapted to in extraordinary ways. Light behaves very differently when it moves from air into water. It moves through the expansive depths of an ocean that is devoid of solid surfaces. These and other factors combine to create an environment that has no equivalent on land.
Read MoreLife in the Arctic Ocean
Capped with a formidable ice and snow cover, plunged into total darkness during the winter, buffeted by blizzard winds,and bitterly cold, the Arctic Ocean is one of the most inaccessible and yet beautiful environments on Earth. Life here endures some of the greatest extremes in light and temperature known to our planet. Yet despite these inhospitable conditions, the Arctic Ocean is teeming with life.
Read MoreThe Secret Lives of Fish
“We have found that otoliths of fish born in each of the five natal estuaries had different, unique isotope and element compositions, or “signatures.” All their lives, these fish had carried a natural tag, encoding the location where they were hatched.
Read MoreMixing 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.
Read MoreIs Life Thriving Deep Beneath the Seafloor?
In 1991, scientists aboard the submersible Alvin were in the right spot at the right time to witness something extraordinary. They had sailed into the aftermath of a very recent volcanic eruption on the seafloor and found themselves in a virtual blizzard. They were densely surrounded by flocs of white debris, composed of sulfur and microbes, which drifted more than 30 meters above the ocean bottom. The seafloor was coated with a 10-centimeter-thick layer of the same white material. This vast volume of microbes did not come from the ocean. The eruption had flushed it out from beneath the seafloor.
Read MoreThe Evolutionary Puzzle of Seafloor Life
Most of Earth’s crust is manufactured at the bottom of the sea. Deep beneath the waves and beyond our view, magma erupts along a 40,000-mile volcanic mountain chain that bisects the ocean floors and encircles the globe. The lava flowing from these mid-ocean ridges solidifies into new ocean crust that spreads out and paves the surface of our planet.
Read MoreDeep-Sea Diaspora
When spectacular biological communities were first discovered at hydrothermal vents in 1977, biologists puzzled over two main questions: How did these oases of large and abundant animals persist in the deep sea, where food is typically scarce? And how did these unusual species, which occur only at vents, manage to colonize new vents and avoid extinction when old vents shut down?
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