marine science and the coast

Rapid breakup of glaciers raising sea level concerns

CORVALLIS, Ore. - The rapid structural breakdown of some important parts of the ice sheets on Greenland and Antarctica is possible and has happened in the distant past, and some "startling changes" on the margin of these ice masses has been observed in recent years, raising disturbing concerns about sea level rise.

In a new report to be released Friday in the journal Science, researchers from Oregon State University and four other institutions in the U.S. and Europe outline dynamic mechanisms of glacial change that appear to be under way. These changes could significantly speed up the melting of major ice sheets, and have not been considered in current projections for sea level rise.

A possibility, scientists say, is that the melting and collapse of floating ice shelves near the coasts of Greenland and Antarctica will continue and in the process destabilize the ice sheets behind them. This could cause a much more rapid flow of ice to the sea and lead to melting events that transcend those now anticipated due to global warming. Based on this, the researchers say that current projections of sea level rise should be considered an expected minimum; the levels could be much higher and happen more quickly.

"Most of the sea level rise we're now expecting in the next 200 years is due to thermal expansion of water, not the overall loss of ice from Greenland and Antarctica," said Peter Clark, a professor of geosciences at OSU. "But recent events we've studied with improved observational systems and computer modeling suggest there may be much more going on.

"We may be more vulnerable to sea level rise than we thought and it may be more rapid than we have anticipated. This is an issue we should take very seriously." Although they are learning a great deal more about the mechanisms that may lead to more rapid glacial collapse, the scientists cannot yet predict with certainty whether or how fast it might happen, or what the resulting sea level rise may be.

In one event about 14,600 years ago, Earth's sea level rose about 70 feet in less than 500 years - 20 times faster than the current rate of sea level rise. However, climatic conditions then may have been considerably different than today, and that event may not provide an exact analog to what we might expect from current glacial melting events, Clark said. Nevertheless, that event illustrates the potential for existing ice sheets to cause sea level to rise rapidly, he said.

Current projections in climate models suggest that global warming will cause some melting of glacial ice in Greenland in the next century or two, but that may be largely offset by increased precipitation and glacial buildup in Antarctica. During that period, thermal warming of the Earth's oceans is expected to increase sea level by about one-half meter, Clark said. The breakdown of glaciers currently being studied could double the sea level rise to a full meter, he said.

More problems are anticipated later. The Greenland ice sheet may disappear within about 1,000 years, raising Earth's sea level by about 20 feet, and the glacial breakdown mechanisms being studied could speed that up considerably.

What has caught the attention of scientists in recent years is the rapid collapse of some glaciers near the coasts of Greenland and Antarctica.

Jakobshavn glacier in Greenland nearly doubled its flow speed in the past decade. Along the Antarctic Peninsula, warming over the past few decades has caused retreat or near-total loss of several ice shelves, some of which had existed for thousands of years - and surface melting cannot explain most of the losses. In 2002 the Larsen B Ice Shelf in Antarctica collapsed, and major tributary glaciers entering the former ice shelf began to move 2-8 times faster than they had previously. Also in Antarctica, large glaciers feeding the Amundsen Coast thinned and accelerated by up to 26 percent over the last three decades, with repercussions more than 120 miles inland.

It's become clear, Clark said, that the West Antarctic Ice Sheet, much of which sits on land that's actually below sea level, is one of the most vulnerable in the world to these types of rapid breakdowns. If it were to melt, that would add another 20 feet to global sea levels.

In future modeling of potential sea level rise, the researchers said in their report, it's essential that the mechanisms for breakup of major ice sheets in Greenland and Antarctica be more carefully considered in the projections. If these mechanisms continue and prove to be significant, sea level projections will have to be revised upward, the scientists said.

Other collaborators on this study were from Pennsylvania State University, the University of Washington, and institutes or universities in Germany and Belgium.

"The events that have happened so far are pretty small, compared to what we're concerned about," Clark said. "The real problem would occur if these smaller glacial breakups trigger larger ones, and rising sea levels by themselves might cause a feedback mechanism which would further speed up the process."

Media Contact: 

Peter Clark, 541-737-1247

U.S. Artctic Research Commission to meet at OSU

CORVALLIS, Ore. - The United States Arctic Research Commission will hold its annual fall meeting Oct. 25-27 at Oregon State University, where the seven commissioners will hear scientific presentations by more than a dozen OSU researchers.

The commission is an advisory body that recommends Arctic research policy to the president and Congress. It was established in 1984 to develop a federal program for basic and applied research related to the Arctic.

"The visit by the commission brings a lot of attention and prestige to the university," said Mark Abbott, dean of the College of Oceanic and Atmospheric Sciences (COAS). "OSU has a lot of important research focusing on the Arctic by faculty from a number of different colleges and academic backgrounds. Because of global warming concerns and discussions about drilling, the Arctic has been the focus of a lot of interest of late, so the timing for the visit couldn't be better."

The commissioners will spend Tuesday and Wednesday on OSU's main campus in Corvallis, where they will hear a number of presentations from faculty. The meeting will run from 8:30 a.m. to 4:40 p.m. on Tuesday and 9 a.m. to noon on Wednesday at the CH2M-Hill Alumni Center. On Thursday, the commission will move to Newport for sessions at OSU's Hatfield Marine Science Center running from 8:30 a.m. to noon. The sessions are free and open to the public, though space may be limited.

A public discussion on Arctic research will begin at 11 a.m. on Thursday, Oct. 27, at OSU's Hatfield Marine Science Center in Newport.

The agenda for the three-day meeting is available online at http://www.coas.oregonstate.edu/.

Topics covered in the OSU presentations include:

  • "Tracer Hydrography of the Arctic Ocean," by Kelly Falkner, COAS (9:40 a.m., Tuesday);
  • "Submarine-based Observations of the Upper Layers of the Arctic Ocean," Tim Boyd, COAS (10:25 a.m., Tuesday);
  • "The Geomagnetic Field of the Arctic: Understanding Possible Futures from Reconstructing the Past," Joe Stoner, COAS (10:50 a.m., Tuesday);
  • "Contaminants in the Arctic: National Parks as Sentinel Ecosystems," by Kim Hageman, Department of Environmental and Molecular Toxicology (11:15 a.m., Tuesday);
  • "Rain, Fog, Hugs and Tears: Results of the 2005 NSF-funded Field Season on King Island, Alaska," Deanna Kingston, Department of Anthropology (11:40 a.m., Tuesday);
  • "Permafrost Engineering Issues," Ted Vinson, College of Engineering (3:25 p.m., Tuesday);
  • "Arctic Ice Cores and the History of Abrupt Climate Change," Ed Brook, Department of Geosciences (3:50 p.m., Tuesday);
  • "Recent Large Albedo Decreases on a Greenland Outlet Glacier," Anne Nolin, Department of Geosciences (4:15 p.m., Tuesday);
  • "Geochemistry of the Gakkel Ridge: Ultraslow Seafloor Spreading at the Top of the World," David Graham, COAS (9 a.m., Wednesday);
  • "Microbial Ecology in the Arctic Ocean," Ev and Barry Sherr, COAS (9:30 a.m., Wednesday);
  • "Modeling Arctic Ocean Ecosystems," Yvette Spitz, COAS (10:55 a.m., Wednesday);
  • "Fisheries Behavioral Ecology in Alaskan Waters," Cliff Ryer, NOAA Alaska Fisheries Science Center (8:45 a.m., Thursday, Newport);
  • "Free Choice Learning Initiative," Shawn Rowe, Extension Sea Grant (9:10 a.m., Thursday, Newport);
  • "Exploring Submarine Activity off the Antarctic Peninsula Using Passive Underwater Acoustics," Robert Dziak, OSU Hatfield Marine Science Center (10 a.m., Thursday, Newport);
  • "Satellite Tracking Studies of Albatrosses in the Bering Sea and Aleutian Islands," Rob Suryan, OSU Hatfield Marine Science Center (10:25 a.m., Thursday, Newport).

    The U.S. Arctic Research Commission's seven members include four from academic or research institutions, two from private industry undertaking commercial activities in the Arctic, and one from the indigenous residents of the Arctic. The director of the National Science Foundation serves as an ex-officio member.

  • Media Contact: 

    Mark Abbott, 541-737-5195

    Salmonid Hatcheries Cause “Stunning” Loss of Reproductive Ability

    CORVALLIS, Ore. – The rearing of steelhead trout in hatcheries causes a dramatic and unexpectedly fast drop in their ability to reproduce in the wild, a new Oregon State University study shows, and raises serious questions about the wisdom of historic hatchery practices.

    The research, to be published Friday in the journal Science, demonstrates for the first time that the reproductive success of steelhead trout, an important salmonid species, can drop by close to 40 percent per captive-reared generation. The study reflects data from experiments in Oregon’s Hood River.

    “For fish to so quickly lose their ability to reproduce is stunning, it’s just remarkable,” said Michael Blouin, an OSU associate professor of zoology. “We were not surprised at the type of effect but at the speed. We thought it would be more gradual. If it weren’t our own data I would have difficulty believing the results.”

    Fish reared in a hatchery for two generations had around half the reproductive fitness of fish reared for a single generation. The effects appear to be genetic, scientists said, and probably result from evolutionary pressures that quickly select for characteristics that are favored in the safe, placid world of the hatchery, but not in the comparatively hostile natural environment.

    “Among other things, this study proves with no doubt that wild fish and hatchery fish are not the same, despite their appearances,” said Michael Blouin, an OSU associate professor of zoology. “Some have suggested that hatchery and wild fish are equivalent, but these data really put the final nail in the coffin of that argument.”

    Even a few generations of domestication may have significant negative effects, and repeated use of captive-reared parents to supplement wild populations “should be carefully reconsidered,” the scientists said in their report.

    Traditionally, salmon and steelhead hatcheries obtained their brood stock and eggs from fish that were repeatedly bred in hatcheries – they tended to be more docile, adapted well to surface feeding, and they thrived and survived at an 85-95 percent level in the safe hatchery environment.

    More recently, some “supplementation” hatchery operations have moved to the use of wild fish for their brood stock, on the theory that their offspring would retain more ability to survive and reproduce in the wild, and perhaps help rebuild threatened populations.

    “What happens to wild populations when they interbreed with hatchery fish still remains an open question,” Blouin said. “But there is good reason to be worried.”

    Earlier work by researchers from OSU and the Oregon Department of Fish and Wildlife had suggested that first-generation hatchery fish from wild brood stock probably were not a concern, and indeed could provide a short-term boost to a wild population. But the newest findings call even that conclusion into question, he said.

    “The problem is in the second and subsequent generations,” Blouin said. “There is now no question that using fish of hatchery ancestry to produce more hatchery fish quickly results in stocks that perform poorly in nature.”

    Evolution can rapidly select for fish of certain types, experts say, because of the huge numbers of eggs and smolts produced and the relatively few fish that survive to adulthood. About 10,000 eggs can eventually turn into fewer than 100 adults, Blouin said, and these are genetically selected for whatever characteristics favored their survival. Offspring that inherit traits favored in hatchery fish can be at a serious disadvantage in the wild where they face risks such as an uncertain food supply and many predators.

    Because of the intense pressures of natural selection, Blouin said, salmon and steelhead populations would probably quickly revert to their natural state once hatchery fish were removed.

    However, just removing hatchery fish may not ensure the survival of wild populations. Studies such as this consider only the genetic background of fish and the effects of hatchery selection on those genetics, and not other issues that may also affect salmon or steelhead fisheries, such as pollution, stream degradation or climate change.

    Blouin cautioned that these data should not be used as an indictment of all hatchery programs.

    “Hatcheries can have a place in fisheries management,” he said. “The key issue is how to minimize their impacts on wild populations.”

    This research was conducted through use of 15 years of DNA tracking technology of fish breeding in Hood River, a mountain stream that flows northward off Mount Hood into the Columbia River. DNA analysis with scales was done with about 15,000 fish since 1991.

    This research has been supported by the Bonneville Power Administration and the Oregon Department of Fish and Wildlife.

    Media Contact: 

    Michael Blouin,

    OSU video on coastal hazards, building to air on OPAN N

    CORVALLIS, Ore. - A DVD produced at Oregon State University, "Living on the Edge: Building and Buying Property on the Oregon Coast," will receive its broadcast premiere on the Oregon Public Affairs Network (OPAN) Thursday, Oct. 6, at 6 p.m.

    The program will be repeated Thursday, Oct. 13, at the same time. OPAN airs in the greater Portland area, Eugene, Corvallis, Tualatin and the Bend/Sisters area. OPAN broadcasts on channel 27 in Corvallis/Philomath/Lewisburg, and other channels can be located online at www.opan.org or in local listings.

    "Living on the Edge" shows how coastal storms and other natural processes pose particular challenges to those planning to build or buy property along the Oregon coast. While extreme events like earthquakes and tsunamis are not the focus of the DVD, the impact of these catastrophic events as well as the predicted rise in global sea levels are also highlighted.

    The DVD is a co-production of Oregon Sea Grant at OSU and the Oregon Coastal Management Program of the state Department of Land Conservation and Development (DLCD), and can be purchased for $9.95 from Sea Grant Communications, OSU, 322 Kerr Administration, Corvallis, OR 97331. Include $2 shipping and handling for the first DVD and $1 each for additional copies.


    John Greydanus, 541-737-9099

    'Living on the Edge' DVD addresses coastal building issues

    CORVALLIS, Ore. - Coastal storms and other natural processes pose particular challenges to those planning to build or buy property along the Oregon coast, and a new DVD video produced at Oregon State University provides an objective overview of those challenges and how to deal with them.

    "Living on the Edge: Building and Buying Property on the Oregon Coast" is intended for developers, realtors, lenders, and coastal officials as well as builders, buyers, and homeowners. The DVD was co-produced by Oregon Sea Grant at OSU and the Oregon Coastal Management Program of the Department of Land Conservation and Development.

    "Coastal communities are experiencing a surge of growth and renewal, accompanied by an influx of new residents who are attracted by the region's natural beauty and recreational opportunities," said Paul Klarin of the Oregon Coastal Management Program. "We want to provide the public with tools that will allow them to make better decisions about where and how to build along Oregon's beaches."

    The 25-minute video and four additional short features on the DVD provide essential information about the chronic effects of wave, wind, and rain on coastal beaches and bluffs. While extreme events like earthquakes and tsunamis are not the focus of the DVD, the impact of these catastrophic events as well as the predicted rise in global sea levels are also highlighted. Vivid footage reveals the challenges and issues of shoreline development, while knowledgeable Oregon scientists, engineers, planners, and realtors offer their insights and recommendations to address these challenges successfully.

    Jim Good, an Oregon Sea Grant coastal hazards specialist, notes that many visitors and prospective home buyers are lulled by beautiful summer days at the beach. "Beware about how calm and nice it looks in the summertime," said Good in the DVD, "because in the winter we have naturally higher sea levels and big storms that can erode beaches and cliffs. Things are a lot different between summer and winter; and summer is when most people are out looking for property."

    "The overall message we want to convey," said Klarin of DLCD, "is to be diligent and informed about the unique risks that need to be considered when developing along the ocean shore."

    "Living on the Edge" can be purchased for $9.95 from Sea Grant Communications, OSU, 322 Kerr Administration, Corvallis, OR 97331. Include $2 shipping and handling for the first DVD and $1 each for additional copies.


    Paul Klarin, 503-373-0050, ext. 249

    Weber recognized for service to South Slough Reserve

    NEWPORT, Ore. - Lavern Weber, former director of Oregon State University's Hatfield Marine Science Center, has been honored for his service to the state of Oregon as a longstanding member of the South Slough National Estuarine Research Reserve Management Commission.

    The commission, which recently presented a special award to Weber, was created by the Oregon Legislature in 1974 to oversee day-to-day operation of the reserve, located on the southernmost arm of the Coos Estuary near Charleston.

    The 5,000-acre South Slough reserve was created as a natural laboratory to improve human understanding of estuaries and their watersheds. Major program areas at the reserve are focused on research, education, and stewardship.

    Weber was appointed to his first four-year term on the Commission in 1992 by Oregon Gov. Barbara Roberts, and was reappointed in 1996 and again in 2000 by Gov. John Kitzhaber to serve two additional four-year terms.

    "Throughout his term of service, Dr. Weber had an active interest in all aspects of the operation of the South Slough reserve and played a central role in setting the direction for the development of facilities," said Mike Graybill, manager of the reserve.

    As commissioner, Weber brought "great insight and strongly supported furthering the goals of South Slough," said Ann Hanus, director of the Oregon Division of State Lands.

    "He has been an effective advocate for scientific research of our oceans and estuaries and forming educational partnerships with South Slough and the Hatfield Marine Science Center," she said.

    Multimedia Downloads
    Lavern Weber

    Harmful algal blooms increase; researchers seek warning signs

    CORVALLIS, Ore. - Harmful algal blooms that have closed shellfish harvests in the Pacific Northwest and caused "red tides" elsewhere appear to be increasing, scientists say, and the likely suspects are global climate change and increased human impact in coastal zones.

    One recent bloom has significantly elevated levels of a toxin called domoic acid in Oregon razor clams, prompting a statewide harvest closure that has been in effect all summer. This follows several other regional closures over the past 2-3 years. Humans who consume shellfish with high levels of domoic acid may suffer vomiting, diarrhea, disorientation and memory loss; in severe cases, domoic acid can result in comas and even death.

    Two Oregon scientists - one from Oregon State University and the other from the University of Oregon - are trying to identify these toxic blooms as they occur by combining satellite imagery and physical data in a project funded by the National Oceanic and Atmospheric Administration (NOAA).

    They believe that certain areas, including the Heceta Bank off the central Oregon coast, may act as "incubators" for generating the blooms of Pseudonitzschia, a phytoplankton species that can turn toxic, creating domoic acid. When consumed by shellfish, it accumulates in their tissues.

    "Historically, the first warning sign we get for these toxic blooms is when domoic acid shows up during routine testing of razor clams and other shellfish - and by then it's a done deal," said Peter Strutton, an assistant professor in OSU's College of Oceanic and Atmospheric Sciences, and co-principal investigator of the study. "Unlike the phytoplankton species that causes red tides off Florida, the blooms off Oregon don't have characteristic pigment that makes them easily visible.

    "But we think that we can combine satellite data on chlorophyll levels and ocean conditions to eventually detect these blooms as they develop and provide an early warning system for coastal managers, health officials, and commercial and recreational fishers," Strutton added.

    A number of different phytoplankton species bloom regularly off the Pacific Northwest coast and, in fact, are important in feeding the marine food chain. But a breakdown in the metabolic process of Pseudonitzschia - possibly triggered through stress - creates domoic acid, according to Michelle Wood, a professor of biology at the University of Oregon and co-PI on the study.

    Wood said it is possible that a symbiotic interaction between the diatoms and certain species of marine bacteria enable, or enhance, the production of toxins. It may also influence the level of toxicity in a bloom, she added.

    "Clams and other shellfish take in the toxins when they filter water and the toxin level can vary for a number of reasons," Wood said. "The diatoms that produce domoic acid seem to produce less when they are growing rapidly than when they have used up the nutrients in the water and become stressed physiologically. So as each phytoplankton bloom progresses, there is potential for water masses to break off and carry populations of diatoms at different stages of growth onto shore."

    The researchers have combed through data over the last 10 years from the Oregon shellfish monitoring program conducted by the Oregon Department of Agriculture. They are comparing recorded levels of toxicity in razor clams, mussels and other shellfish with archival satellite data showing sea surface temperatures and "ocean color" - chlorophyll levels and rates of fluorescence - in the same regions that the shellfish testing took place.

    Strutton says they hope to find an optical signature for potential blooms, and during the next two years visit those areas at peak times to sample the water and drag nets through the surface ocean to measure phytoplankton abundance and toxicity levels.

    One area of interest is the Heceta Bank, which the researchers believe is similar to the Juan de Fuca eddy off northern Washington - a known "hot spot" for harmful algal blooms. The Heceta Bank bulges out off the Oregon coast, and the shallow water there creates an eddy effect that appears to send a steady flux of nutrients to the surface, triggering the algal blooms.

    "Harmful algal blooms are the negative side of coastal upwelling," Strutton said. "There is growing evidence that these blooms have been increasing over the last 20 years and not only are becoming more frequent, but more intense and with longer duration. We also are starting to record toxic events in places that haven't had them, so there is a concern that they may be spreading.

    "The spreading could be caused by the transport of phytoplankton in the ballast water of ships," he added.

    Strutton said global climate change leading to warmer ocean waters is one theory behind the increasing incidents of harmful algal blooms. Human activity, including the release of nutrients into the oceans from agriculture fertilizers that leech into river systems, may also be a cause.

    "Every spring there is an algal bloom in the Pacific from San Diego, Calif., to Vancouver, B.C., that is a result of warming spring temperatures, upwelling and the general ocean-atmosphere interaction," Strutton said. "Often one species of phytoplankton will dominate, and we need to identify when it is Pseudonitzschia so we can create an early warning system."

    Wood said the lag time from onset of an algal bloom to significant toxicity in shellfish may be a few days depending on how "hot" - or full of toxin-producing cells - the water is. The effects can linger.

    "Mussels lose their toxicity very quickly, in a matter of days," Wood said, "but razor clams incorporate the toxin in their tissue and remain toxic for weeks - even when they are no longer consuming toxin-producing food."

    Media Contact: 

    Pete Strutton, 541-737-2065

    OSU oceanographer heads to Gulf to study hurricane aftermath

    CORVALLIS, Ore. - Hurricane Katrina left a swath of destruction along the Gulf Coast landscape, and now a team of scientists is heading to the Gulf of Mexico to see what effects the storm may have had on the water quality, biology and sediment deposits in the shallow coastal waters.

    Researchers from several institutions will take part in a series of cruises aboard different research vessels as part of a major interagency effort to mobilize the scientific community to study the aftermath of one of the country's most devastating natural disasters. Their projects, which began this week, are federally funded by the National Science Foundation, the National Oceanic and Atmospheric Administration and the Department of Defense.

    Oregon State University chemical oceanographer Miguel Goni leaves for Louisiana this week to study the effects of Katrina on sediment deposits. Goni, who has spent much of the last eight years researching sediment in Gulf waters off the Mississippi delta, says sediment often shifts during storms, but the immense tidal surge of Katrina has the potential to create major changes in "an unnatural system."

    "Human engineering has completely changed the delta and the Mississippi River, in fact, drains into an area of the Gulf that it probably wouldn't, left to its own devices," Goni said. "Since those human activities began, we've annually seen sediments about 2-3 centimeters deep build up in the spring when the river has its highest discharge, and then wash out to deeper water during winter storms."

    "When Hurricane Lili hit the Louisiana coast in 2002, there was a very large shift of sediments into areas not normally affected," Goni added. "We saw deposits of between one and 30 centimeters of very fine sediment in areas that don't really see that kind of activity. And Lili was a category-2 storm that pales compared to Katrina."

    As a result of their cyclonic wind circulation, hurricanes such as Katrina often bring sediments onto shore on the east side of the storm's eye, while they transport them offshore on the west side, said Goni, who is an associate professor in OSU's College of Oceanic and Atmospheric Sciences.

    "The larger, coarser sediments are left on shore, while the smaller, finer material is washed out to sea," he said. "This offshore transport can help the sub-aqueous part of the delta grow."

    The sediment shifts are of concern to the shrimp industry, Goni says, although Gulf Coast shrimp historically have weathered sediment changes because they thrive in the soft, muddy bottom. But the shrimp also depend on algal matter for food, and the region has been struck by several hypoxia events, creating a "dead zone" that virtually snuffs out all marine life.

    "In a complex ecosystem, any change in the environment is a cause for concern," Goni said.

    Shifting sediments may alter currents and contribute to additional algal blooms. When these blooms die off, the organisms sink to the bottom and suck the oxygen out of the water column, suffocating shellfish, fish and other life forms.

    Goni said the sediment also may bury oil pipelines and communication cables - and though they may not damage them, the layers of silt make it difficult to access and repair them.

    "One of the things we're looking at with the sediment, in addition to its volume and location, is its composition," he said. "We can tell if the organic matter in the sediments is natural or if it is petroleum-based, which could indicate that some of the underwater pipes may have been damaged and are leaking."

    Both the oil pipelines and communication cables are in more danger from underwater landslides that may occur as sediment is washed out into the deeper Gulf waters of the Mississippi Canyon.

    Goni said it is sometimes hard for people from other regions to visualize the Gulf of Mexico, which has shallow coastal waters that "really feel the impact of storms." Goni and his colleagues estimated that Hurricane Lili dropped more sediment into those waters than the entire output of the nearby Atchafalaya River did for an entire year.

    "Much of the broad shelf west of the Mississippi delta is very shallow, with water depths of five to 20 meters," Goni said. "I've been out there when there have been two-meter waves and the entire ocean turns chocolate brown. Hurricane Katrina had a six-meter surge and even larger waves. The impact on the seafloor must be immense."

    Goni will join other researchers aboard the Cape Hatteras, which is the research vessel of Duke University, for a series of projects that will examine water quality, pollutants, navigation hazards, and the marine food chain, as well as the area's sediment deposits.

    Media Contact: 

    Miguel Goni, 541-737-0578

    OSU scientists identify, track huge 'internal' waves

    CORVALLIS, Ore. - Waves the height of a 10-story building regularly propagate into the north Pacific from the mouth of the Columbia River, but you won't find big-wave surfers riding them. These waves propagate beneath the ocean surface, carrying near-surface organisms and chemicals halfway to the ocean floor.

    Oregon State University scientists who identified and documented how these waves emerge from the edge of a river plume reported their findings today in the journal Nature.

    For years, scientists, sailors and commercial fishers have known about these waves because they induce currents near the sea surface that cause visible surface slicks and changes in surface roughness and color. However, the prevailing school of thought was that they were caused by currents pushing deep-sea water over rugged topography of the ocean floor. And in many cases around the world, that does happen.

    But on the northern Oregon coast, these waves emerge when fresh water is forced from the mouth of the Columbia River with the outgoing tide, the researchers say. Since the fresh water is also lighter, it spreads over the surface of the coastal waters; its signature can be seen over tens of miles from aircraft or satellite. The interface between the fresher, surface waters and saltier deep waters forms a wave guide upon which large-amplitude waves propagate.

    "The waves form at the edge, or `front' of the freshwater river plume," said Jonathan D. Nash, an assistant professor in OSU's College of Oceanic and Atmospheric Sciences and co-author of the Nature study. "The front is a region of convergence. It accumulates flotsam and plankton, and as it turns out, is also where wave energy can be generated and stored. The waves are released and propagate into the Pacific because they travel faster than the river's advancing freshwater front."

    Some of these internal waves propagate back toward the Oregon coast where they may break as they shoal and mix with near-shore water. Scientists don't yet know all of the impacts of these waves.

    "The internal displacement of water from these waves is huge," said James N. Moum, an oceanography professor at OSU and co-author of the study. "Yet, the surface expression is very subtle. Although a 20-meter internal wave may cause a tiny 2-centimeter 'bulge' on the surface, the surface slicks and whitecaps can be seen easily by pilots, showing up as long lines in the water stretching as much as 100 kilometers.

    "Fishermen have long known about these waves because dolphins and birds hunt along the wave fronts where plankton and fish accumulate," Moum added. "There is tremendous force associated with these waves and the currents can reach 1-2 miles per hour. Fishing trawlers will notice the effects when the surface currents pull their boats in one direction, yet their nets are going in another."

    Satellite imagery clearly shows the plumes of the Columbia River and other large rivers around the world as a major influence on the near-shore waters. But those images are generated only once every two days and fail to show the mechanisms creating these internal waves, Nash pointed out.

    "In hindsight, it seems obvious that river systems like the Columbia can create them," Nash said.

    Recognition of exactly how the waves are generated was made possible by new profiling instruments that measure water temperature, salinity, turbulence, biological fluorescence and sediment concentration every 1-2 minutes. These instruments were developed by a team of OSU engineers, led by Moum. Teamed with ship-mounted acoustics to track the waves' vertical displacement and velocity structure, the scientists can track water within the ocean and identify its characteristics and movement.

    Nash and Moum, together with graduate student Levi Kilcher, will continue their studies by examining the importance of tide strength, river flow rates, and seasonal water temperatures and winds. Their study, funded by the National Science Foundation, is part of a larger project called River Influences in Shelf Ecosystems.

    Media Contact: 

    Jonathan Nash, 541-737-4573

    New system to provide better view of marine biology

    CORVALLIS - Researchers at Oregon State University have created a "benthic terrain modeler," software that can be used with a geographic information system to provide a significant new way of describing the ocean sea floor and the fish and other marine species that probably live there.

    Short of making dives or direct observations in submersibles, this system may allow ocean managers to develop a better understanding of the biology of large ocean areas, scientists say. It is attracting considerable interest from state and federal marine management agencies.

    "This should be a fairly important advance in improving our understanding of marine habitat," said Dawn Wright, an OSU professor of geosciences. "It could be used anywhere in the world, given ocean floor data of sufficient detail, to inform studies of where certain types of fish and other species are likely to be congregating."

    The system might be of value off the Oregon coast to characterize the biology and productivity of different areas, information that could be invaluable in study of the marine "reserves" being considered there. It's already being used in areas ranging from California to Ireland and American Samoa.

    There's a reasonable amount of bathymetric data about ocean depth already available, Wright said. This software system takes that detail to create images of seafloor roughness, peaks, valleys and slopes, and combine that with known information about the area's marine biology obtained through dives, remote cameras or other approaches.

    The result is a reasonably accurate and detailed biological description of the life that should, and usually is, found in a particular area, researchers say.

    "Many nations are getting much more interested in understanding and protecting the biological diversity in their oceans," Wright said. "This is essential to sustaining fisheries, protecting against species extinction, and just understanding the ocean resource. But the oceans are so vast, and often unexplored, that we don't have good information on the biological nature of large areas."

    The new system was tested this summer in studies at American Samoa, examining the marine biology on some coral reefs endangered by invasive species, human pollution and hurricanes. The projected results were tested and proven to be highly accurate by direct undersea monitoring.

    The research has been supported by grants from the National Oceanic and Atmospheric Association. More information and a free copy are available from http://www.csc.noaa.gov/products/btm


    Media Contact: 

    Dawn Wright, 541-737-1229