Oceanography

Scientists analyzing the temperature and salt levels of the Western Mediterranean Sea between 1943 and 2000 have found that the deep water has become progressively hotter and saltier, and that, since the 1990s, this process has speeded up. Each year the temperature of the deep layer of the Western Mediterranean increases by 0.002ºC, and its salt levels increase by 0.001 units of salinity. These changes, although minimal from year to year, have been continuously and constantly occurring at a faster pace since the 1990s. The results are consistent, "but to confirm this accelerating trend, we…

What is the volume of the world's oceans? 1.332 billion cubic kilometers, according to scientists at the Woods Hole Oceanographic Institution. The researchers report that the world's total ocean volume is less than the most recent estimates by a volume equivalent to about five times the Gulf of Mexico, or about 0.3% lower than the estimates of 30 years ago. The results reveal how accurate scientists were in the past, using cruder techniques to measure ocean depth. As long ago as 1888, for example, John Murray dangled lead weights from a rope off a ship to calculate an ocean volume—the product…

Mountains that rise from the seafloor, called seamounts, represent one of the most common ecosystems on earth, say scientists from the NOAA and Texas A&M University–Corpus Christi. Their findings reverse previous beliefs about the prevalence of seamounts, which they say are "treasure troves" of marine biodiversity. The results are published in Oceanography. Although researchers have thoroughly explored some 200 seamounts and mapped and sampled a hundred others, this study is the first to estimate that more than 45,000 seamounts dot the ocean floor worldwide — a total of roughly 28.8…

Scientists have discovered a deep ocean current with a volume equivalent to 40 Amazon Rivers near the Kerguelen plateau, in the Indian Ocean sector of the Southern Ocean. Writing in Nature Geoscience, the researchers say the current – more than three kilometers below the Ocean's surface – is an important pathway in a global network of ocean currents that influence climate patterns. While earlier expeditions had detected evidence of the current system, they were not able to determine how much water the current carried. The new experiment deployed current-meter moorings anchored to the sea…

Scientists have discovered a series of 400,000-year-old asphalt volcanoes about 10 miles off the California coast, at the bottom of the Santa Barbara Channel. The largest of these undersea Ice Age domes lies at a depth of 700 feet (220 meters), too deep for scuba diving, which explains why the volcanoes have never before been spotted by humans. The discovery is documented this week in Nature Geoscience. "They're larger than a football-field-long and as tall as a six-story building," says David Valentine, a geoscientist at University of California, Santa Barbara. "They're massive features, and…

Ocean acidification is a real problem, and unless our weather breaking carbon dioxide emissions are substantially curbed, the ocean will continue to become more acidic, according to a new report by National Research Council. The long-term consequences of ocean acidification on marine life are unknown, but the problem is apparently serious enough that Hollywood celebrities need to lobby Congress over the issue. "My hope, one shared by millions of Americans, is that you, our legislators, will put aside your differences and enact climate and energy legislation that will move America to a clean…

The world's water cycle has already intensified and the changes are consistent with predictions made by the Intergovernmental Panel on Climate Change, according to  new research in the Journal of Climate. The stronger water cycle means arid regions have become drier and high rainfall regions wetter as atmospheric temperature increases. The study shows the surface ocean beneath rainfall-dominated regions has freshened, whereas ocean regions dominated by evaporation are saltier. The paper also confirms that surface warming of the world's oceans over the past 50 years has penetrated into…

the world's deepest undersea volcanic vents, known as 'black smokers' have been discovered in the Cayman Trough 3.1 Miles beneath the surface of the Caribbean Sea. Using a remotely controlled, deep-diving vehicle, scientists uncovered slender spires made of copper and iron ores on the seafloor, erupting water hot enough to melt lead, nearly half a mile deeper than anyone has seen before. Deep-sea vents are undersea springs where superheated water erupts from the ocean floor. They were first seen in the Pacific three decades ago, but most are found between one and two miles deep. Scientists…

Supervolcanoes have been blamed for multiple mass extinctions in Earth's history. But despite their global impact, their origin and triggering mechanisms have remained unexplained. New data obtained during a recent Integrated Ocean Drilling Program (IODP) expedition in the Pacific Ocean may help explain the sea floor giants' origins. In fall 2009, an international team of scientists participating in IODP Expedition 324 drilled five sites in the ocean floor. They studied the origin of the 145 million-year-old Shatsky Rise volcanic mountain chain. Located 1,500 kilometers (930 miles) east of…

Marine ecosystems could be radically altered by ocean acidification resulting from increasing levels of atmospheric CO2, say researchers presenting at the Society for General Microbiology's spring meeting. As a result of it's impact on fish stocks and erosion of coral reefs, researchers say ocean acidification could also have serious socioeconomic ramifications as well.  The team simulated ocean acidification as predicted by current trends of carbon dioxide (CO2) emissions and found that the decrease in ocean pH (increased acidity) resulted in a sharp decline of a biogeochemically…