Blue Whale-Sized Mouthfuls Make Foraging Super Efficient December 09, 2010 11:54 AM
ScienceDaily (Dec. 9, 2010) How much can a blue whale eat in a single mouthful and how much energy do they burn while foraging? These are the questions that Bob Shadwick from the University of British Columbia, Canada, and his colleagues have asked. They discovered that blue whales can swallow almost 2,000,000kJ (almost 480,000kcalories) in a single mouthful of krill, and eat 90 times as much energy as they burn during a dive.
Diving blue whales can dive for anything up to 15 minutes. However, Bob Shadwick from the University of British Columbia, Canada, explains that blue whales may be able to dive for longer, because of the colossal oxygen supplies they could carry in their blood and muscles, so why don't they?
'The theory was that what they are doing under water must use a lot of energy,' says Shadwick. Explaining that the whales feed by lunging repeatedly through deep shoals of krill, engulfing their own body weight in water before filtering out the nutritious crustaceans, Shadwick says, 'It was thought that the huge drag effect when they feed and reaccelerate this gigantic body must be the cost'. However, measuring the energetics of blue whale lunges at depth seemed almost impossible until Shadwick and his student Jeremy Goldbogen got chatting to John Hildebrand, John Calambokidis, Erin Oleson and Greg Schorr who were skilfully attaching hydrophones, pressure sensors and two-axis accelerometers to the elusive animals. Shadwick and Goldbogen realised that they could use Calambokidis's measurements to calculate the energetic cost of blue whale lunges. They publish their discovery that blue whales swallow almost 2,000,000kJ (almost 480,000kcalories) in a mouthful of krill, and take in 90 times as much energy as they burn during a single dive in The Journal of Experimental Biology.
Analysing the behaviour of each whale, Goldbogen saw that dives lasted between 3.1 and 15.2 minutes and a whale could lunge as many as 6 times during a single dive. Having found previously that he could correlate the acoustic noise of the water swishing past the hydrophone with the speed at which a whale was moving, Goldbogen calculated the blue whales' speeds as they lunged repeatedly during each dive. Next the team had to calculate the forces exerted on the whales as they accelerated their colossal mouthful of water. Noticing that the whales' mouths inflated almost like a parachute as they engulfed the krill, Goldbogen tracked down parachute aerodynamics expert Jean Potvin to help them build a mathematical model to calculate the forces acting on the whales as they lunged. With Potvin on the team, they were able to calculate that the whales used between 3226 kJ of energy during each lunge. But how did this compare with the amount of energy that the whales could extract from each gigantic mouthful of krill?
Goldbogen estimated the volume of the whales' mouths by searching the whaling literature for morphological data and teamed up with paleontologist Nick Pyenson to measure the size of blue whale jaw bones in several natural history museums. He also obtained krill density values from the literature -- which are probably on the low side. Then he calculated the volume of water and amount of krill that a whale could engulf and found that the whales could consume anything from 34,776kJ up to an unprecedented 1,912,680kJ from a single mouthful of krill, providing as much as 240 times as much energy as the animals used in a single lunge. And when the team calculated the amount of energy that a whale could take on board during a dive, they found that each foraging dive could provide 90 times as much energy as they used.
Shadwick admits that he was initially surprised that the whales' foraging dives were so efficient. 'We went over the numbers a lot,' he remembers, but then he and Goldbogen realised that the whales' immense efficiency makes sense. 'The key to this is the size factor because they can engulf such a large volume with so much food in it that it really pays off,' says Shadwick
Coast Guard Studies Whale Safety In San Francisco Bay December 02, 2010 11:39 AM
SAN FRANCISCO (KCBS ) The Coast Guard is looking at ways to avoid contact between large shipping vessels in and around the San Francisco Bay and whales.
Since July, five whales have been killed after being hit by ships. There were no such reported incidents last year.
The coasts along Northern California have seen a larger than normal amount of whales this year due to a high abundance of krill in the waters. Krill is the main source of food for whales.
Jackie Dragon, the Marine Sanctuaries Program Director for the nonprofit Pacific Environment, said that this has become a serious issue.
Whales have a much better outcome and opportunity to avoid serious injury or death by ships drag when ships are traveling slower in the waters, say ten knots, said Dragon. This is something thats been implemented on the East Coast to protect the endangered right whale.
Shipping companies said a change in shipping lanes could present a navigation hazard, but havent ruled it out.
Understanding the Vulnerable Northern Bottlenose Whale November 29, 2010 2:52 PM
ScienceDaily (Nov. 21, 2010) The northern bottlenose whale -- Hyperoodon ampullatus -- is a strange creature. They have a long, stout body with a bulbous forehead -- called a "melon" -- and a short, tube-like snout.
Hunted for centuries for their oil (and until the 1970s for dog food), there may be only 160 of these gentle giants in the population found off Nova Scotia. In 2006, this population (known as the Scotian Shelf population) was designated as endangered by the Canadian Species At Risk Act.
They can be hard animals to study. For one thing, it's tough to get out to their prime habitat (in deep submarine canyons along the edge of the Scotian Shelf, about 200 kilometres offshore of Nova Scotia), especially in the winter when the weather is rough. Secondly, they're a deep-diving species which spends most of their time underwater. They make long, deep dives sometimes for 70 minutes, reaching depths of more than 1,400 metres. They surface to breathe for about 10 minutes, before diving down again in search of their primary prey, the armhook squid.
Not that the difficulty in conducting research has discouraged Hilary Moors. The PhD candidate with Hal Whitehead's Cetacean Research Lab of Dalhousie University in Halifax, Nova Scotia, just calls them on the "hydrophone."
Well, sort of. The hydrophone is a scientific instrument that's been positioned on the ocean floor to record sounds.
She's been able to make recordings of the northern bottlenose whale's underwater vocalizations. The whale's echo-location signals, used to help them navigate and locate food in dark murky waters, sound like high-pitched clicks as captured by the hydrophone.
One of the questions Ms. Moors has answered is whether the population that frequents The Gully, a Marine Protected Area on the edge of the Scotian Shelf, is year-round or migrating. It's an important question, particularly as scientists attempt to determine if oil and gas development activities in the vicinity have impacted at all on the population.
"We knew they were around in the summer, but the winter? That's what I wanted to find out," says Ms. Moors, who works part-time for the Department of Fisheries and Oceans as a marine mammal observer. "What we've been able to determine is that they're generally out there in the winter as much as they are in the summer."
Last summer, Ms. Moors observed the whales as part of the crew aboard Dr. Whitehead's 12-metre sailboat and floating research station, Balaena.
"Pretty much anytime you go out, you can see them. They're very curious and they love to check us out," she says.
Joining the expedition this summer was Kristin O'Brien, a master's student originally from Surrey, B.C. Her job was to photograph the whales at the surface; the nicks and gouges in the dorsal fin can help researchers identify individual animals.
"When you're out there, you don't see land for weeks, but we do see lots of marine life -- northern bottlenose whales, blue whales, which are also endangered, pilot whales and Sowerby's beaked whales"
"It's almost like living in a camper," adds Ms. Moors. "You'll either love it or hate it, but I think for me, it's made me very enthusiastic about the research."
King Crab Distributions Limited by Temperature in the Southern Ocean November 09, 2010 10:31 AM
ScienceDaily (Nov. 8, 2010) Invasions of voracious predatory crabs due to global warming could threaten the unique continental-shelf ecosystems of Antarctica, according to newly published findings.
"King crabs are ecologically important predators and form the basis of economically significant commercial fisheries," said Dr Sven Thatje, an evolutionary ecologist at the University of Southampton's School of Ocean and Earth Science (SOES ), which is based at the National Oceanography Centre in Southampton.
Thatje and graduate student Sally Hall studied how water temperature influences the distributions of king crab species in the Southern Ocean, which has some of the coldest waters on Earth. The results appear in the journal Polar Biology.
King crabs are cold blooded, their body temperature being determined largely by that of the surrounding environment. Although many of them live in cold, deep-sea habitats, experiments have shown that their larvae fail to mature in water temperatures below around half a degree Celsius, even after only brief exposure.
"We tested the hypothesis that the king crab species of the Southern Ocean only thrive above a critical minimum temperature and that it is this thermal barrier that determines their biogeographical distributions in the Southern Ocean," said Thatje.
To do this, Thatje and Hall carefully studied the distribution of seventeen species of king crab living at depths between around 500 and 1600 metres in the Southern Ocean. They collated data frompublished records, museum collections, commercial fishing records, and reports from scientific research cruises. They then compared these records to water temperatures measured at a range of relevant depths and geographical latitudes.
Consistent with their hypothesis, they found that king crabs occur mostly at locations where the polar water temperature is relatively warm. The coldest waters in which king crabshave been found are between 0.4 and 0.5°C in the Ross Sea, suggesting that this indeed represents a thermal barrier limiting king crab distributions.
In addition, the records showed that only two species are endemic to waters south of 60 degrees South, suggesting that particular physiological and reproductive adaptations are required for life in the most extreme environments.
The researchers found that gaps in king crab distributions largely coincide with regions of low water temperature, although there are some anomalous absences yet to be explained.
Their findings imply that even relatively small increases in water temperature due to global warming could lead to king crabs moving into new areas.
"Rapidly increasing water temperatures observed along the West Antarctic Peninsula could allow king crabs to spread from the slope of the peninsula to the continental shelf itself," explained Hall.
This could have considerable ecological consequences. King crabs are voracious predators that crush and then feed on their prey, but they and potentially competing predators such as sharks and rays and other predatory crustaceans are largely absent on the high-Antarctic continental shelves.
"The worry is that the sudden appearance of a new predator with few competitors could threaten isolated shelf communities such as those of the Bellingshausen Sea on the west side of the Antarctic Peninsula," said Hall.
The researchers believe that their study provides a baseline against which future changes in the distribution of king crabs expected under global warming can be compared.
The study was supported by the Total Foundation (Abyss2100), the European Union's Sixth Framework Programme (FP6 ) Marine Biodiversity and Ecosystem Functioning (MarBEF ) project, and by the Natural Environment Research Council.
New Species of Sea Slug Discovered September 23, 2010 9:19 AM
ScienceDaily (Sep. 22, 2010) Sometimes, treasures can be found in your own backyard -- especially if you know what to look for. This is what happened to Jeff Goddard, project scientist with the Marine Science Institute at UC Santa Barbara.
Goddard was working in the tide pools at Carpinteria Reef, in Carpinteria State Park, Calif., when he found a new species of nudibranch -- a group of sea slugs noted for their bright colors and delicate forms. Recognizing it as new, Goddard carefully documented the living specimen before preserving it and sending it off to Terrence M. Gosliner, an authority on the taxonomy of sea slugs at the California Academy of Sciences in San Francisco. Goddard kept the slug in his lab for a few days, until it laid an egg mass, and was also able to observe its early development and hatching larvae.
Gosliner named the new sea slug after Goddard when he described it -- and one other newly discovered species of California nudibranch -- in the Sept. 15 online edition of the Proceedings of the California Academy of Sciences.
"The shallow-water nudibranch fauna of Southern California especially is well known, so it was pretty exciting to find a new species right under our noses here in Santa Barbara County," said Goddard. "Only one specimen was found, so now we need to find out where more are hiding, what they feed on, and whom they interact with."
Goddard said that he was honored that Gosliner chose to name the new species after him. The scientific name is Flabellina goddardi, and it measures about 30 millimeters long when stretched out and crawling. The genus Flabellina also includes the well-known "Spanish shawl" nudibranch, Flabellina iodinea. Goddardi is now the fifth species of Flabellina known from California.
In the scientific article, Goslinger writes: "Flabellina goddardi is named for friend and colleague Jeff Goddard who found the only specimen of this distinctive species. Jeff is the consummate naturalist with superb powers of observation."
For the scientific record, Goddard describes the new species as "characterized externally by its smooth rhinophores; long tail and cephalic tentacles; pointed foot corners; red and orange tipped cerata; and lack of pigmentation on the head, body and head tentacles."
Goddard discovered the sea slug in 2008. As with many taxonomic discoveries,
the finding often takes a couple of years for documentation, comparison with known species, and publication. Meanwhile Goddard and his colleagues will continue searching for more specimens of the newly described species.
Deep, Open Ocean Is Vastly Under-Explored, Study Finds August 03, 2010 11:08 AM
ScienceDaily (Aug. 2, 2010) New research from the University of Sheffield has discovered that the deep open ocean, by far the largest habitat for life on Earth, is currently the most under-explored area of the sea, and the one we know least about.
The research, published in the journal PLoS ONE, has mapped the distribution of marine species records and found that most of our knowledge of marine biodiversity comes from the shallow waters or the ocean floor, rather than the deep pelagic ocean- the water column deeper than the sunlit surface waters but above the sea bed.
This area is home to uncounted animals which never experience a hard surface, including megamouth sharks, giant squid, and a myriad of smaller species of gelatinous animals and other planktonic organisms.
The research was led by Dr Tom Webb, a Royal Society Research Fellow and marine ecologist from the University's Department of Animal and Plant Sciences, in conjunction with the Ocean Biogeographic Information System (OBIS ) secretariat at Rutgers University, and the Consortium for Ocean Leadership in the USA.
The team used data from OBIS, which collates all available information on geographical distributions of marine life, to plot the position in the water of seven million records of marine species. They combined this data with a separate dataset of the bottom surface of the ocean, and then attributed each separate record to a position in the ocean, to enable them to provide a global analysis of the depth distribution of recorded marine biodiversity.
The almost limitless deep waters of the sea have been largely under explored due to a long-held belief, first expressed by Charles Wyville Thomson, leader of the challenger Expedition in the 1870s, which effectively launched the discipline of deep sea biology. He believed that life in the deep water was confined primarily to a belt at the surface and one near the sea bed, and believed the area in the middle to be almost completely without larger animals.
More recent sampling, employing new techniques, has revealed that this is not the case, and the deep pelagic is actually teeming with life. The global picture provided by this new study has led to calls for increased exploration of the Earth's last frontier of biodiversity research.
Dr Tom Webb said: "It's shocking that in 2010, the International Year of Biodiversity, the largest habitat on Earth remains virtually unexplored. On a more positive note, being able to highlight gaps in our knowledge is an important step towards filling them, and our analysis -- the first at a global scale -- was possible because of the commitment in the marine biodiversity research community to sharing data through initiatives like OBIS."
Dr Ron O'Dor, Senior Scientist with the Census of Marine Life, said: "The Census of Marine Life has invested more than $650M in exploring all of the global ocean realms in the last decade, but we have barely made a dent in this one. One project has provided a look at everything that lives in the water column in the Charlie-Gibbs Fracture Zone in the northern Mid-Atlantic Ridge -- just a single piece of a giant puzzle.
"Another project collected plankton with a giant net and doubled the amount of sampling in a single cruise in the North Atlantic. Now we know how to do this, but just need commitment to continue our exploration for the rest of the planet."
Rising Carbon Dioxide and 'Acidified' Waters Found in Puget Sound, Off Seattle US July 19, 2010 7:36 AM
ScienceDaily (July 18, 2010) Scientists have discovered that the water chemistry in the Hood Canal and the Puget Sound main basin is becoming more "acidified," or corrosive, as the ocean absorbs more carbon dioxide from the atmosphere. These changes could have considerable impacts on the region's shellfish industry over the next several decades.
The study, co-sponsored by NOAA, the University of Washington Applied Physics Laboratory and School of Oceanography (UW), the Washington State Department of Ecology and the U.S. Environmental Protection Agency, was conducted in the winter and summer of 2008 to determine the combined effects of ocean acidification and other natural and human-contributed processes on Puget Sound waters. Annual survey support is typically provided by UW's Puget Sound Regional Synthesis Model Program (PRISM), while EPA provided the ocean survey vessel Bold for the summer survey.
"We observed unusually low pH values in the deep waters of southern Hood Canal," said Richard Feely, Ph.D., director of the Ocean Acidification Program at NOAA's Pacific Marine Environmental Laboratory. "Our calculations suggest that ocean acidification can account for a significant part of the pH decrease in this region."
"This is the first time that the combined impacts of ocean acidification and other natural and human-induced processes have been studied in a large estuary like Puget Sound," says Jan Newton, Ph.D., University of Washington co-author on the study and chief scientist for the winter cruise. "We are concerned that ocean acidification may be contributing to the recent loss of oyster larvae reported by oyster hatcheries in the Pacific Northwest including within Puget Sound."
The research team estimated that ocean acidification accounts for 24-49 percent of the pH decrease in the deep waters of the Hood Canal sub-basin of Puget Sound relative to estimated pre-industrial (before 1850) values. The remaining change in pH between when seawater enters the Sound and when it reaches this deep basin results from the decomposition of organic matter.
Over time, the relative impact of ocean acidification could increase significantly, accounting for 49-82 percent of the pH decrease in Puget Sound subsurface waters (depths greater than 40 meters) for a doubling of atmospheric carbon dioxide, according to the study.
To better understand the effects of ocean acidification on shellfish within Puget Sound, the Puget Sound Partnership, with funds from EPA, has partnered with the Puget Sound Restoration Fund to support UW, NOAA, Pacific Shellfish Institute, Washington Department of Ecology, Taylor Shellfish and Baywater, Inc., to conduct collaborative studies investigating whether or not corrosive seawater is affecting shellfish populations.
The work monitors both water conditions and shellfish larvae, providing high-resolution oceanographic data along with measurements on ocean acidification and larval settlement from two locations where shellfish are growing, Dabob Bay and Totten Inlet.
As part of this study, UW moved one of the existing Oceanic Remote Chemical-optical Analyzer (ORCA) marine monitoring buoys from Hood Canal to Dabob Bay and added surface water carbon dioxide measurements with a NOAA sensor to the existing suite of measurements.
"We simply need more data near the shellfish growing sites in order to evaluate causal relationships," said Allan Devol, Ph.D., UW, an oceanographer and the designer of the ORCA buoy.
The findings are scheduled to appear in the August issue of Estuarine, Coastal, and Shelf Science.
New Leviathan Whale Was Prehistoric "Jaws"? July 13, 2010 10:00 AM
Dubbed Leviathan melvilleian homage to Moby-Dick author Herman Melvillethe recently unearthed fossil sea monster lived about 13 million years ago in waters atop what's now a Peruvian desert, according to a study published by the journal Nature on Wednesday.
Noted - Adios El Niño, Hello La Niña? June 24, 2010 1:45 PM
ScienceDaily (June 24, 2010) The latest image of Pacific Ocean sea surface heights from the NASA/European Ocean Surface Topography Mission/Jason-2 oceanography satellite, dated June 11, 2010, shows that the tropical Pacific has switched from warm (red) to cold (blue) during the last few months.
The blue area in the center of the image depicts the recent appearance of cold water hugging the equator, which the satellite measures as a region of lower-than-normal sea level. Remnants of the El Niño warm water pool, shown here in red and yellow, still linger north and south of the equator in the center of the image.
The image shows sea surface height relative to normal ocean conditions. Red (warmer) areas are about 10 centimeters (4 inches) above normal. Green areas indicate near-normal conditions. Purple (cooler) areas are 14 to 18 centimeters (6 to 7 inches) below normal. Blue areas are 5 to 13 centimeters (2 to 5 inches) below normal.
"The central equatorial Pacific Ocean could stay colder than normal into summer and beyond. That's because sea level is already about 10 centimeters [4 inches] below normal, creating a significant deficit of the heat stored in the upper ocean," said JPL oceanographer and climatologist Bill Patzert. "The next few months will reveal if the current cooling trend will eventually evolve into a long-lasting La Niña situation."
A La Niña is essentially the opposite of an El Niño. During a La Niña, trade winds in the western equatorial Pacific are stronger than normal, and the cold water that normally exists along the coast of South America extends to the central equatorial Pacific. La Niñas change global weather patterns and are associated with less moisture in the air, resulting in less rain along the coasts of North and South America. They also tend to increase the formation of tropical storms in the Atlantic.
"For the American Southwest, La Niñas usually bring a dry winter, not good news for a region that has experienced normal rain and snowpack only once in the past five winters," said Patzert.
Ocean Changes May Have Dire Impact on People June 19, 2010 5:12 PM
ScienceDaily (June 19, 2010) The first comprehensive synthesis on the effects of climate change on the world's oceans has found they are now changing at a rate not seen for several million years.
In an article published June 18 in Science magazine, scientists reveal the growing atmospheric concentrations of man-made greenhouse gases are driving irreversible and dramatic changes to the way the ocean functions, with potentially dire impacts for hundreds of millions of people across the planet.
The findings of the report emerged from a synthesis of recent research on the world's oceans, carried out by two of the world's leading marine scientists, one from The University of Queensland in Australia, and one from The University of North Carolina at Chapel Hill, in the USA.
Professor Ove Hoegh-Guldberg, lead author of the report and Director of The University of Queensland's Global Change Institute, says the findings have enormous implications for mankind, particularly if the trend continues.
He said that the Earth's ocean, which produces half of the oxygen we breathe and absorbs 30% of human-generated CO2, is equivalent to its heart and lungs. "Quite plainly, the Earth cannot do without its ocean. This study, however, shows worrying signs of ill health.
"It's as if the Earth has been smoking two packs of cigarettes a day!"
He went on to say, "We are entering a period in which the very ocean services upon which humanity depends are undergoing massive change and in some cases beginning to fail," says Prof. Hoegh-Guldberg. "Further degradation will continue to create enormous challenges and costs for societies worldwide."
He warned that we may soon see "sudden, unexpected changes that have serious ramifications for the overall well-being of humans," including the capacity of the planet to support people. "This is further evidence that we are well on the way to the next great extinction event."
The "fundamental and comprehensive" changes to marine life identified in the report include rapidly warming and acidifying oceans, changes in water circulation and expansion of dead zones within the ocean depths.
These are driving major changes in marine ecosystems: less abundant coral reefs, sea grasses and mangroves (important fish nurseries); fewer, smaller fish; a breakdown in food chains; changes in the distribution of marine life; and more frequent diseases and pests among marine organisms.
Report co-author, Dr John F. Bruno, an Associate Professor at The University of North Carolina, says greenhouse gas emissions are modifying many physical and geochemical aspects of the planet's oceans, in ways "unprecedented in nearly a million years." "This is causing fundamental and comprehensive changes to the way marine ecosystems function," Dr Bruno said.
"We are becoming increasingly certain that the world's marine ecosystems are approaching tipping points. These tipping points are where change accelerates and causes unrelated impacts on other systems, the results of which we really have no power or model to foresee."
The authors conclude: "These challenges underscore the urgency with which world leaders must act to limit further growth of greenhouse gases and thereby reduce the risk of these events occurring. Ignoring the science is not an option."
In their study, the researchers sought to address a gap in previous studies that have often overlooked the affects of climate change on marine ecosystems, due to the fact that they are complex and can be logistically difficult to study.
According to leading US marine scientist, the University of Maine's School of Marine Services Professor Robert S. Steneck, the study provides a valuable indicator of the ecological risk posed by climate change, particularly to coastal regions.
"While past studies have largely focused on single global threats such as 'global warming', Hoegh-Guldberg and Bruno make a compelling case for the cumulative impacts of multiple planet-scale threats," Prof. Steneck said.
Earlier this month the National Oceanic and Atmospheric Administration (NOAA) announced its selection of UM to continue to lead its CIMAS partnership, which has been in place since 1977 to improve our understanding of climate, hurricanes, and marine ecosystems along the southeastern U.S. coast. The renewed partnership allows investigators from UM and partner institutions to receive NOAA, as well as other federal agency support for research projects, and facilitates collaboration with NOAA scientists at NOAA/AOML, National Hurricane Center, Southeast Fisheries Science Center, as well as other NOAA facilities and 18 Cooperative Institutes nationwide.
Scientists Locate 23-Mile Long Oil Plume Off Florida's Treasure Coast June 14, 2010 1:16 PM
ScienceDaily (June 12, 2010) A team of dedicated South Florida researchers from the University of Miami's Cooperative Institute for Marine and Atmospheric Studies (CIMAS) and the National Oceanic and Atmospheric Administration's Atlantic Oceanographic and Meteorological Laboratory (NOAA/AOML) were determined to check on whether oil was, as predicted, being pulled into the Loop Current and carried toward the Dry Tortugas.
The University of Miami's 96-foot catamaran the RV/F.G. Walton Smith had just completed a two-week National Science Foundation (NSF) sponsored cruise sampling the deep submerged plumes near the Deepwater Horizon well site. NOAA/AOML offered to pay for a few additional days, but the ship which is part of the University National Laboratory System, had to return to Miami on its tight schedule. The best they could do was extend the trip home by 18 hours.
Using funding provided through CIMAS, a team was rapidly assembled that included UM and CIMAS oceanographers Tom Lee and Nelson Melo, as well as a group of scientists led by Michelle Wood, director of the NOAA/AOML's Ocean Chemistry Division. A sampling plan was pulled together using particle trajectories calculated by the UM Rosenstiel School of Marine & Atmospheric Science's Coastal Shelf Modeling Group, in combination with information provided by Roffer's Ocean Fishing Forecast Service (ROFFS) and remotely sensed images from UM's Center for Southeastern Tropical Advanced Remote Sensing (CSTARS). Using these sophisticated tools, the team decided that the most likely pathway for oil to reach the Florida Keys was for it to be pulled into a counterclockwise rotating frontal eddy in the northeast corner of the Loop Current, and then south along the eastern frontal zone of the Loop Current to the Dry Tortugas.
They set out, borrowing surveying equipment from NSF scientists who were leaving the ship, including geological oceanographer Vernon Asper of the University of Southern Mississippi and Samantha Joye from the University of Georgia. As they traveled into the eddy field they saw areas of sheen, but no tar balls.
Changing course to the south, however they found an area of strong flow convergence within a southward flowing jet that resulted from flow being pulled into the eddy. Knowing that this was just the type of oceanographic feature that would concentrate any floating material, including oil, they followed it. At about the same time a U.S. Coast Guard flight that had been sent to visually survey the area spotted what they thought could be an oil slick in the area and contacted the scientists aboard the Walton Smith to have the ship get a closer look at the slick.
"As we approached, we found an extensive oil slick that stretched about 20 nm (20 miles) along the southward flowing jet which merged with the northern front of the Loop Current. The slick was made up of tar balls shaped like pancakes that went from the size of a dime to about 6 inches in diameter," said Tom Lee, UM Research Professor Emeritus and CIMAS scientist. "The combination of models and satellite images, along with our shipboard observations and ROFFS daily analysis had helped us to identify and study this previously unidentified oil plume located off Florida's southwest coast and heading toward the Tortugas."
Scientists quickly set up net tows and lowered a CTD (Conductivity, Temperature and Depth) instrument equipped with oil sampling devices into the water, collecting samples of both the oil and saltwater in the area. As they headed further south they kept looking for other tendrils oil, but increased winds made spotting tell-tale sheens more difficult. As a result they could not confirm the exact length of this southern arm of the oil slick, which they had previously inferred from their data. Samples have been provided to federally sanctioned laboratories to confirm the source of materials gathered.
"The good news is that the various approaches we are using to project its pathway seem to be yielding similar answers and guiding us properly. We need to maintain our vigilance and expand our efforts to determine the degree of risk to unique downstream resources like the Dry Tortugas and Florida Keys National Marine Sanctuary, which are vital natural environments that we need to protect," said Peter Ortner, UM Marine Biology and Fisheries professor and director of CIMAS. "NOAA Cooperative Institutes, like CIMAS, continue to stand ready to assist their federal partners with the best available science to ensure that response and restoration resources are deployed as proactively and responsibly as possible during this national emergency."