Scientists Uncover Global Distribution of Marine Biodiversity
Derek Tittensor (Photo by Nick Pearce)
In an unprecedented effort that will be published online on the 28th of July by the international journal Nature, a team of scientists mapped and analyzed global biodiversity patterns for over 11,000 marine species ranging from tiny zooplankton to sharks and whales. The researchers found striking similarities among the distribution patterns, with temperature strongly linked to biodiversity for all thirteen groups studied. These results imply that future changes in ocean temperature, such as those due to climate change, may greatly affect the distribution of life in the sea. The scientists also found a high overlap between areas of high human impact and hotspots of marine diversity.
Much research has been conducted on diversity patterns on land, but our knowledge of the distribution of marine life has been more limited. This has changed through the decade-long efforts of the Census of Marine Life, upon which the current paper builds. The authors synthesized global diversity patterns for major species groups including corals, fishes, whales, seals, sharks, mangroves, seagrasses, and zooplankton. In the process, the global diversity of all coastal fish species has been mapped for the first time. (more…)
New Study Reveals Decline of Marine Phytoplankton Over the Past Century
Daniel Boyce
A new article published in the 29 July issue of the international journal Nature reveals for the first time that microscopic marine algae known as “phytoplankton” have been declining globally over the 20th century. Phytoplankton forms the basis of the marine food chain and sustains diverse assemblages of species ranging from tiny zooplankton to large marine mammals, seabirds, and fish. Says lead author Daniel Boyce, “Phytoplankton is the fuel on which marine ecosystems run. A decline of phytoplankton affects everything up the food chain, including humans.”
Using an unprecedented collection of historical and recent oceanographic data, a team from Canada’s Dalhousie University documented phytoplankton declines of about 1% of the global average per year. This trend is particularly well documented in the Northern Hemisphere and after 1950, and would translate into a decline of approximately 40% since 1950. The scientists found that long-term phytoplankton declines were negatively correlated with rising sea surface temperatures and changing oceanographic conditions.
The goal of the three-year analysis was to resolve one of the most pressing issues in oceanography, namely to answer the seemingly simple question of whether the ocean is becoming more (or less) „green’ with algae. Previous analyses had been limited to more recent satellite data (consistently available since 1997) and have yielded variable results. (more…)
Changing Chesapeake Bay Acidity Impacting Oyster Shell Growth
New research shows that the shell growth of Crassostrea virginica from Chesapeake Bay could be compromised by current levels of acidity in some Bay waters. (Chris Kelly, UMCES Horn Point Laboratory)
Acidity is increasing in some regions of the Chesapeake Bay even faster than is occurring in the open ocean, where it is now recognized that increased levels of atmospheric carbon dioxide dissolve in the seawater thereby making it more acidic. These more acidic conditions in key parts of Chesapeake Bay reduce rates of juvenile oyster shell formation, according to new research published in the journal Estuaries and Coasts. The study, conducted at the University of Maryland Center for Environmental Science, examined 23 years of water quality data and concluded that significant trends in acidity will have mixed impacts on juvenile oyster growth, with some areas becoming more acidic and others more alkaline.
“The regional changes in acidity revealed in our analysis are greater than what could be caused by increasing atmospheric carbon dioxide alone,” said lead author Dr. George Waldbusser of Oregon State University. “We are seeing a complex pattern of increasing acidity in the more saline regions of the Bay, but the opposite trend of decreasing acidity in the less saline waters of the Bay.” (more…)
Risk of Extinction Increases for Cod
Despite reduced catches in Canada since 1992, cod are now at such historically low levels that they may no longer be able to replace themselves in their ecosystem, increasing the chances the species could face extinction according to Dalhousie University researcher, Jeffrey Hutchings.
When John Cabot arrived on the shores of Newfoundland in 1497, the ship’s crew reported cod fish were so abundant that sailors could scoop them up with buckets. Even years later, English skippers wrote about cod shoals “so thick by the shore that we hardly have been able to row a boat through them.”
Plentiful catches are now the stuff of history books. The Committee on the Status of Endangered Wildlife in Canada (COSEWIC) reports cod populations from the Arctic to the Bay of Fundy declining to perilously low levels—by 97 to 99 per cent since the 1960s.
The committee recommends to federal environment minister Jim Prentice that cod be listed as “endangered” on the legal list of species at risk.
Even with reduced catches since 1992, “cod are at such historically low levels that they have gone beyond their tipping point,” says Jeffrey Hutchings, the Dalhousie University biology professor who just stepped down as the chair of COSEWIC. “They may no longer be able to replace themselves in their ecosystem.”
Cod was designated by COSEWIC as a “special concern” in April 1998 with some populations deemed “threatened” or “endangered” by May 2003. But at that time, the government rejected COSEWIC’s recommendation to list the cod as endangered because of “socio-economic” concerns. (more…)
A Broadband Revolution in the Imaging of the Ocean
Stanton’s low frequency broadband acoustic system is deployed from the deck of a ship. (Woods Hole Oceanographic Institution)
Researchers at Woods Hole Oceanographic Institution (WHOI) have developed two advanced broadband acoustic systems that they believe could represent the acoustic equivalent of the leap from black-and-white television to high-definition color TV. For oceanographers, this could mean a major upgrade in their ability to count and classify fish and to pinpoint tiny zooplankton amid seas of turbulence.
Lead authors Tim Stanton and Andone Lavery in the Department of Applied Ocean Physics and Engineering have already tested the two systems off the east coast of the U.S., with highly promising results. They and their colleagues describe the groundbreaking work in back-to-back papers recently published in the International Council for Exploration of the Sea (ICES) Journal of Marine Science. (Stanton paper; Lavery paper)
The technology is the culmination of efforts spanning two decades. Stanton explains, “Components of these advances separately have been achieved by previous investigators, but this is the first of its kind with all of the technologies in one package.” (more…)
Study Predicts Seabed Response to Climate Change
CSIRO scientists view a 3-D model of Australia's marine territory. Simulations using Sedsim software were performed to predict the potential impact of climate change on the seabed. (CSIRO)
CSIRO scientists have produced the first preliminary predictions of the potential impact of climate change on the Australian seabed.
The results of the five-year study predict potential high-risk areas due to seabed movement, erosion and changes in reef growth.
According to CSIRO Wealth from Oceans Flagship project leader Dr Cedric Griffiths, the interaction between the ocean and the seabed is poorly understood.
“We have more information about the surfaces of the Moon and Mars than we do about the seabed surrounding Australia, let alone the effect that climate change may have on it,” Dr Griffiths said.
“Over 92 per cent of Australia’s identified oil and gas resources lie offshore, and will be produced from facilities that are connected in some way to the seabed. (more…)
Acidic Clouds Nourish World’s Oceans
Scientists at the University of Leeds have proved that acid in the atmosphere breaks down large particles of iron found in dust into small and extremely soluble iron nanoparticles, which are more readily used by plankton.
This is an important finding because lack of iron can be a limiting factor for plankton growth in the ocean - especially in the southern oceans and parts of the eastern Pacific. Addition of such iron nanoparticles would trigger increased absorption of carbon dioxide from the atmosphere.
“This could be a very important discovery because there’s only a very small amount of soluble iron in the ocean and if plankton use the iron nanoparticles formed in clouds then the whole flux of bioavailable iron to the oceans needs to be revised,” says Dr Zongbo Shi, lead author of the research from the School of Earth and Environment at the University of Leeds. (more…)
Scientists Find ‘Great Pacific Ocean Garbage Patch’
SEAPLEX researchers spotted a large net tangled with plastic in the "garbage patch." (Scripps Institution of Oceanography)
Scientists have just completed an unprecedented journey into the vast and little-explored “Great Pacific Ocean Garbage Patch.”
On the Scripps Environmental Accumulation of Plastic Expedition (SEAPLEX), researchers got the first detailed view of plastic debris floating in a remote ocean region.
It wasn’t a pretty sight.
The Scripps research vessel (R/V) New Horizon left its San Diego homeport on August 2, 2009, for the North Pacific Ocean Gyre, located some 1,000 miles off California’s coast, and returned on August 21, 2009.
Scientists surveyed plastic distribution and abundance, taking samples for analysis in the lab and assessing the impacts of debris on marine life.
Before this research, little was known about the size of the “garbage patch” and the threats it poses to marine life and the gyre’s biological environment. (more…)
Humans “Damaging the Oceans”
Dr Andrew Brierley of St Andrews University, Scotland aboard the RRS James Cook on its first ECOMAR cruise to the mid-Atlantic Ridge.
Mounting evidence that human activity is changing the world’s oceans in profound and damaging ways is outlined in a new scientific discussion paper released today.
Man-made carbon emissions “are affecting marine biological processes from genes to ecosystems over scales from rock pools to ocean basins, impacting ecosystem services and threatening human food security,” the study by Professor Mike Kingsford of the ARC Centre of Excellence for Coral Reef Studies and James Cook University and colleague Dr Andrew Brierley of St Andrews University, Scotland, warns.
Their review, published in the latest issue of the journal Current Biology, says that rates of physical change in the oceans are unprecedented in some cases, and change in ocean life is likely to be equally quick.
These include changes in the areas fish and other sea species can inhabit, invasions, extinctions and major shifts in marine ecosystems. (more…)
New Predictions for Sea Level Rise
Fossil coral data and temperature records derived from ice-core measurements have been used to place better constraints on future sea level rise, and to test sea level projections.
The results are published today in Nature Geoscience and predict that the amount of sea level rise by the end of this century will be between 7- 82 cm – depending on the amount of warming that occurs – a figure similar to that projected by the IPCC report of 2007.
Placing limits on the amount of sea level rise over the next century is one of the most pressing challenges for climate scientists. The uncertainties around different methods to achieve accurate predictions are highly contentious because the response of the Greenland and Antarctic ice sheets to warming is not well understood. (more…)
Sea Ice at Lowest Point in 800 Years
There has never been so little sea ice in the area between Svalbard and Greenland in the last 800 years. (NASA/GSFC)
New research, which reconstructs the extent of ice in the sea between Greenland and Svalbard from the 13th century to the present indicates that there has never been so little sea ice as there is now. The research results from the Niels Bohr Institute, among others, are published in the scientific journal, Climate Dynamics.
There are of course neither satellite images nor instrumental records of the climate all the way back to the 13th century, but nature has its own ‘archive’ of the climate in both ice cores and the annual growth rings of trees and we humans have made records of a great many things over the years - such as observations in the log books of ships and in harbour records. Piece all of the information together and you get a picture of how much sea ice there has been throughout time. (more…)
Co-operating Underwater Robots Could Rapidly Identify Threats in Murky Waters
Scientists are developing novel underwater laser networking and imaging to provide significant advantages over existing technologies to rapidly identify and communicate potential threats in murky coastal waters. When fully developed, the technology will be used onboard a group of small, co-operating underwater robots and will have extensive utility for future U.S. military operations including U.S. war fighters. Domestically, it will be used for Maritime security and environmental assessment.
Novel underwater laser networking and imaging technologies being developed by scientists at the Ocean Visibility and Optics Laboratory at Harbor Branch Oceanographic Institute at Florida Atlantic University may provide significant advantages over existing technologies in rapidly identifying and communicating potential threats in murky coastal waters. Harbor Branch has received $2 million from the U.S. Department of Defense, Office of Naval Research, to continue its cutting-edge research and development in the area of underwater laser sensing and robotics in an effort to develop next generation underwater sensing networks to enhance the security of coastal waters and ports, and to expand ecosystem monitoring capabilities.
This project will build on current technologies and capabilities in laser imaging developed at Harbor Branch. When the technology is fully developed, it will be used onboard a group of small, co-operating underwater robots and will have extensive utility for future U.S. military operations including U.S. war fighters (intelligence, surveillance and reconnaissance, and mine countermeasures operations). Domestically, it will be used for Maritime security and environmental assessment to address some of the most critical areas in need of ocean research and technology development over the next ten years. (more…)
Deep-Sea Robotic Vehicle Reaches Deepest Part of the Ocean
Photo of Nereus taken during a test cruise off Hawaii in 2007. On May 31, 2009, Nereus dove to the Challenger Deep in the Mariana Trench. The dive makes Nereus the world’s deepest-diving vehicle and the first vehicle to explore the Mariana Trench since 1998. (Photo by: Christopher Griner, Woods Hole Oceanographic Institution)
A new type of deep-sea robotic vehicle called Nereus has successfully reached the deepest part of the world’s ocean, reports a team of U.S. engineers and scientists aboard the research vessel Kilo Moana. The dive to 10,902 meters (6.8 miles) occurred on May 31, 2009, at the Challenger Deep in the Mariana Trench in the western Pacific Ocean.
The dive makes Nereus the world’s deepest-diving vehicle and the first vehicle to explore the Mariana Trench since 1998.
Nereus’s unique hybrid-vehicle design makes it ideally suited to explore the ocean’s last frontiers. The unmanned vehicle is remotely operated by pilots aboard a surface ship via a lightweight, micro-thin, fiber-optic tether that allows Nereus to dive deep and be highly maneuverable. Nereus can also be switched into a free-swimming, autonomous vehicle. (more…)
Landmark Study Documents Increased Global Mercury Emissions
USGS scientist Dr. David P. Krabbenhoft sampling Ear Spring, Yellowstone National Park, Wyoming, for dissolved mercury species. Old Faithful is erupting in the background
A new landmark study published Friday documents for the first time the process in which increased mercury emissions from human sources across the globe, and in particular from Asia, make their way into the North Pacific Ocean and as a result contaminate tuna and other seafood. Because much of the mercury that enters the North Pacific comes from the atmosphere, scientists have predicted an additional 50 percent increase in mercury in the Pacific by 2050 if mercury emission rates continue as projected.
“This unprecedented USGS study is critically important to the health and safety of the American people and our wildlife because it helps us understand the relationship between atmospheric emissions of mercury and concentrations of mercury in marine fish,” said Secretary of the Interior Ken Salazar. “We have always known that mercury can pose a risk, now we need to reduce the mercury emissions so that we can reduce the ocean mercury levels.” (more…)
Climate Change Leads to Major Decrease in CO2 Storage
Canada Research Chair in Marine Biochemistry Helmuth Thomas, whose work involves understanding the coastal carbon cycle. (Photo: Wayne Glowacki, Winnipeg Free Press courtesy of Dalhousie University).
The North Atlantic Ocean is one of the Earth’s tools to offset natural carbon dioxide emissions. In fact, the ‘carbon sink’ in the North Atlantic is the primary gate for carbon dioxide (CO2) entering the global ocean and stores it for about 1500 years. The oceans have removed nearly 30 per cent of anthropogenic (man-made) emissions over the last 250 years. However, several recent studies show a dramatic decline in the North Atlantic Ocean’s carbon sink.
Concerned by this decline, a group of international scientists, including Helmuth Thomas, professor of oceanography at Dalhousie University, spent the last two years investigating the world’s largest carbon sink. They weren’t sure what was causing the decrease, whether it was man-made or natural reasons. (more…)
Next Gerneration NASA Ocean Tracker Will Enhance Long-Term Weather Predictions
Paul Siqueira is the lead researcher building an interferometric receiver.
For weather forecasters trying to stay ahead of the next tropical cyclone, deadly heat wave or drought, knowing the ocean water temperature, circulation patterns and current shifts can be critical factors to success. Now, scientists at the University of Massachusetts Amherst and the Jet Propulsion Laboratory (JPL), Pasadena, are designing and building the next generation of orbiting tracker for NASA that will supply such data with unparalleled precision.
The 18-inch receiver being built at UMass Amherst, is part of the larger instrument expected to greatly enhance forecasting. It works by reflecting 35-GHz microwaves off the Earth’s surface from an orbit 600 miles above to track factors that long-range meteorologists use to predict climate phenomena. Knowing water temperature and current flow can help to give early warning of an El Niño effect, for example, which periodically triggers drought, floods, and other unusual weather events, costing billions of dollars. (more…)
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