. Coast watch. Marine resources; Oceanography; Coastal zone management; Coastal ecology. SEA SCIENCE. Brant Touchette examines eelgrass growing in controlled environments. "Eelgrass doesn't follow that model. Just why it has not evolved a mechanism to shut down at night is a question for another day," he muses. Contributing factors A widespread eelgrass die-off stunned scientists in the early 1930s. The so-called "Wasting Disease" decimated about 90 percent of all eelgrass in northern Atlantic waters. On the east coast, the eelgrass growing range extends from the Arctic Cir
. Coast watch. Marine resources; Oceanography; Coastal zone management; Coastal ecology. SEA SCIENCE. Brant Touchette examines eelgrass growing in controlled environments. "Eelgrass doesn't follow that model. Just why it has not evolved a mechanism to shut down at night is a question for another day," he muses. Contributing factors A widespread eelgrass die-off stunned scientists in the early 1930s. The so-called "Wasting Disease" decimated about 90 percent of all eelgrass in northern Atlantic waters. On the east coast, the eelgrass growing range extends from the Arctic Circle to North Carolina. Scientists have proposed many theories as to the cause — bacteria, fungus, and mold. But the literature records several previous eelgrass declines, and some suggest that periodic sunspots might be to blame. Others have correlated periods of above average precipitation with the decline, while still others have suggested the decline could be drought-related. Another theory points to increased water temperatures as a contributing culprit — something that Touchette also considered in his recent research. His lab experi- ments show that an increased temperature can reduce eelgrass shoot density by about 40 percent. Tempera- ture also may decrease leaf and root develop- ment, and may alter internal carbon and nitrogen compositions. But Touchette is not ready to draw any correlation between global warming and the current decline of eelgrass. "The jury is still out on that," he says. However, he is willing to stick his neck out and name names when it comes to contributing factors to nutrient loading and eelgrass loss. "There is an obvious need to control point and nonpoint pollution. Better stormwater management is a big step, since historically storms mean high concentrations of nitrogen in runoff," Touchette says. Also, sediments, which begin as ammonia compounds, may oxidize into nitrate in the water column. A National Research Council
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