In the wake of a mass extinction like the one that occurred 445 million years ago, a common assumption is that surviving species tend to proliferate quickly into new forms, having outlived many of their competitors.
But new research shows that tiny marine organisms called graptoloids did not begin to rapidly develop new physical traits until about 2 million years after competing species became extinct. (more…)
ANN ARBOR, Mich.— After the last ice age peaked about 18,000 years ago, levels of atmospheric carbon dioxide rose about 30 percent. Scientists believe that the additional carbon dioxide—a heat-trapping greenhouse gas—played a key role in warming the planet and melting the continental ice sheets. They have long hypothesized that the source of the gas was the deep ocean.
But a new study by a University of Michigan paleoclimatologist and two colleagues suggests that the deep ocean was not an important source of carbon during glacial times. The finding will force researchers to reassess their ideas about the fundamental mechanisms that regulate atmospheric carbon dioxide over long time scales. (more…)
Over 50 percent of the population in the United States and over 60 percent in the world live in coastal areas. Rapidly growing human populations near the ocean have massively altered coastal water ecosystems.
One of the most extensive human stressors is the discharge of chemicals and pollutants into the ocean. In the Southern California Bight, more than 60 sewage and urban runoff sources discharge over 1 billion gallons of liquid on a dry day with the two largest sources of contaminants being sewage from municipal treatment plants and urban runoff from highly modified river basins. (more…)
Despite growing awareness of the problem of plastic pollution in the world’s oceans, little solid scientific information existed to illustrate the nature and scope of the issue.
