sexta-feira, 10 de dezembro de 2010

Cloud 'feedback' affects global climate and warming

ScienceDaily (Dec. 10, 2010) — Changes in clouds will amplify the warming of the planet due to human activities, according to a breakthrough study by a Texas A&M University researcher.

Andrew Dessler, a professor in the Department of Atmospheric Sciences, says that warming due to increases in greenhouse gases will cause clouds to trap more heat, which will lead to additional warming. This process is known as the "cloud feedback" and is predicted to be responsible for a significant portion of the warming over the next century.
Dessler used measurements from the Clouds and the Earth's Radiant Energy System (CERES) instrument onboard NASA's Terra satellite to calculate the amount of energy trapped by clouds as the climate varied over the last decade. He also used meteorological analyses provided by NASA's Modern Era Retrospective-Analysis for Research and Applications (MERRA) and by the European Center for Medium-Range Weather Forecasts.

sexta-feira, 3 de dezembro de 2010

'No fish left behind' approach leaves Earth with nowhere left to fish, study finds

ScienceDaily (2010-12-02) -- Earth has run out of room to expand fisheries, according to a new study that charts the systematic expansion of industrialized fisheries.
http://www.sciencedaily.com/releases/2010/12/101202181122.htm

sexta-feira, 26 de novembro de 2010

UK sets up Chagos Islands marine reserve


The UK government has created the world's largest marine reserve around the Chagos Islands.
By Paul Rincon 
Science reporter, BBC News
Conservationists say the area is a biodiversity hotspot
The reserve would cover a 545,000-sq-km area around the Indian Ocean archipelago, regarded as one of the world's richest marine ecosystems.
This will include an area where commercial fishing will be banned.
But islanders, who were evicted to make way for the US air base on the island of Diego Garcia, say a reserve would effectively bar them from returning.
UK Foreign Secretary David Miliband said establishing the reserve would "double the global coverage of the world's oceans under protection".
He commented: "Its creation is a major step forward for protecting the oceans, not just around BIOT [British Indian Ocean Territory] itself, but also throughout the world.
"This measure is a further demonstration of how the UK takes its international environmental responsibilities seriously."
Conservationists say the combination of tropical islands, unspoiled coral reefs and adjacent oceanic abyss makes the area a biodiversity hotspot of global importance.
The archipelago, which has been compared to the Galapagos Islands and to Australia's Great Barrier Reef, hosts the world's biggest living coral structure - the Great Chagos Bank. This is home to more than 220 coral species - almost half the recorded species of the entire Indian Ocean, and more than 1,000 species of reef fish.

sexta-feira, 19 de novembro de 2010

Busy microbial world discovered in deepest ocean crust ever explored

http://www.sciencedaily.com/releases/2010/11/101119162926.htm

ScienceDaily (Nov. 19, 2010) — The first study to ever explore biological activity in the deepest layer of ocean crust has found bacteria with a remarkable range of capabilities, including eating hydrocarbons and natural gas, and "fixing" or storing carbon.

The research, just published in the journal PLoS One, showed that a significant number and amount of bacterial forms were present, even in temperatures near the boiling point of water.
"This is a new ecosystem that almost no one has ever explored," said Martin Fisk, a professor in the College of Oceanic and Atmospheric Sciences at Oregon State University. "We expected some bacterial forms, but the long list of biological functions that are taking place so deep beneath the Earth is surprising."
Oceanic crust covers about 70 percent of the surface of the Earth and its geology has been explored to some extent, but practically nothing is known about its biology -- partly because it's difficult and expensive, and partly because most researchers had assumed not all that much was going on.

quarta-feira, 17 de novembro de 2010

Heat stress to Caribbean corals in 2005 worst on record; Caribbean reef ecosystems may not survive repeated stress

http://www.sciencedaily.com/releases/2010/11/101116080407.htm

NOAA diver with a one square meter quadrat examining a bleached reef (Montastraea) colony in St. Croix, USVI in Oct., 2005. (Credit: NOAA)
ScienceDaily (Nov. 16, 2010) — Coral reefs suffered record losses as a consequence of high ocean temperatures in the tropical Atlantic and Caribbean in 2005 according to the most comprehensive documentation of basin-scale bleaching to date. Collaborators from 22 countries report that more than 80 percent of surveyed corals bleached and over 40 percent of the total surveyed died, making this the most severe bleaching event ever recorded in the basin.
The study appears in PLoS ONE, an international, peer-reviewed, open-access, online publication.

Satellite-based tools from NOAA's Coral Reef Watch Program guided site selection for field observations conducted across the greater Caribbean region from June to October 2005. Field surveys of bleaching and mortality in this study surpass prior efforts in both detail and extent.
This study also substantially raised the standards for documenting the effects of bleaching and for testing satellite and forecast products. Coral bleaching occurs when stress causes corals to expel their symbiotic algae, or zooxanthellae. If prolonged or particularly severe, it may result in coral death.
"Heat stress during the 2005 event exceeded any observed in the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in at least 150 years," said C. Mark Eakin, Ph.D., coordinator of NOAA's Coral Reef Watch Program. "This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems, and events like this are likely to become more common as the climate warms."
continue at the link above for sciencedaily.com

sábado, 13 de novembro de 2010

New ocean acidification study shows added danger to already struggling coral reefs

Ocean acidification could compromise the successful fertilization, larval settlement and survivorship of Elkhorn corals, new research reveals. (Credit: Evan D'Alessandro, University of Miami)
http://www.sciencedaily.com/releases/2010/11/101108151328.htm
ScienceDaily (Nov. 13, 2010) — Over the next century, recruitment of new corals could drop by 73 percent, as rising carbon dioxide levels turn the oceans more acidic, suggests a new study led by scientists at the University of Miami Rosenstiel School of Marine and Atmospheric Science. The research findings reveal a new danger to the already threatened Caribbean and Florida reef Elkhorn corals.

Oceanography researchers discover toxic algae in open water


Microscopic image of Pseudo-nitzschia. (Credit: Image courtesy of Ross Del Rio)
ScienceDaily (Nov. 13, 2010) — Louisiana State University's Sibel Bargu, along with her former graduate student Ana Garcia, from the Department of Oceanography and Coastal Sciences in LSU's School of the Coast & Environment, has discovered toxic algae in vast, remote regions of the open ocean for the first time.
The findings were published in the Nov. 8 edition of the Proceedings of the National Academy of Sciences(PNAS).
Harmful algal blooms, or HABs, are reported as increasing both geographically and in frequency along populated coastlines. Bargu's research shows that the ubiquitous diatom Pseudo-nitzschia -- an alga that produces the neurotoxin, domoic acid, or DA, in coastal regions -- actually also produces DA at many locations in the open Pacific. The presence of these potent toxins in deep water environments is worrisome, given that in coastal waters, where the phenomenon has been studied, DA can enter the food chain, forcing the closure of some fisheries and poisoning marine mammals and birds that feed on the contaminated fish. The main concern, though, is that the adding of iron to ocean waters -- one of the most commonly proposed strategies to reduce global warming -- appears now to likely result in promoting toxic blooms in the ocean.