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ScienceDaily (Feb. 5, 2010) — Extensive commercial fishing endangers dolphin populations in the Mediterranean. This has been shown in a new study carried out at the University of Haifa’s Department of Maritime Civilizations. “Unfortunately, we turn our backs to the sea and do not give much consideration to our marine neighbors,” states researcher Dr. Aviad Scheinin.

Above: Dolphin next to trawler. (Credit: Dr. Aviad Scheinin, IMMRAC)

The study, which was supervised by Prof. Ehud Spanier and Dr. Dan Kerem, examined the competition between the two top predators along the Mediterranean coast of Israel: the Common Bottlenose Dolphin (Tursiops truncatus) and bottom trawlers. (Trawling is the principal type of commercial fishing in Israel and involves dragging a large fishing net through the water, close to the sea floor, from the back of a boat.) These two predators off the coast of Israel trap similar types of fish near the sea floor, so the researchers decided to examine the nature of the competition between the two.

Commercial trawling in the Mediterranean off the coast of Israel targets codfish, red mullet and sole, three commercial and sought-after types of fish. The Department of Fisheries in Israel’s Ministry of Agriculture has data showing that over the years the amount of fish from the sea floor looted by Israel’s commercial trawling is larger than the amount of fish that nature provides, indicating that the sea floor fish population dropped between the years 1949 and 2006.

Would this decline in fish supply necessarily cause direct harm to the dolphins, seeing as their diet might also include other types of fish? In order to verify this, the researcher examined the contents of the stomachs of 26 dolphins that died and landed on the beach, or that had been caught by mistake. He also examined the behavior of living dolphins by carrying out 232 marine surveys over more than 3,000 km. along the central coast of Israel. The dolphins’ stomachs contained mainly non-commercialized fish, suggesting that they perhaps do not compete directly with the commercial trawlers, and that the commercial fishing does not directly affect the dolphins’ nutrition.

The living dolphins’ behavior, on the other hand, draws an entirely different picture. According to Dr. Scheinin, most of the dolphins were observed around the trawling boats: the chances of observing a school of dolphins near a trawler is ten times higher than in the open sea. This is because the trawler serves as a “feeding station” for the dolphins: there they are not able to feed from the more expensive loot caught in the nets, but they are able to enjoy schools of other types of fish that swim around the trawler. “The problem is that this type of fishing endangers the dolphins. Eight dolphins die each year off the coast of Israel on average, and of those, four die after having been mistakenly caught in trawling nets. Seeing as many studies have proven the high intelligence of the dolphin, it is clear that these sea mammals are aware of this danger, but are left with little choice due to their need to search for food around the trawlers due to the scarcity of other food sources,” Dr. Scheinin explains.

This conclusion is reinforced by the suckling female dolphins. These dolphins require larger quantities of food than usual, and despite the risk for the younger and much less experienced dolphins that swim by their side, all of the suckling dolphins have been observed significantly more frequently around the trawlers. This indicates that they could not obtain enough food in other places.

The dolphins off the coast of Israel spend most of their time in search of food while their mates in other areas in the world are far busier with social activities. This fact is yet another contributing factor to the assumption that they suffer a deficiency in food resources.

The present study illustrates, for the first time, the characteristics of the dolphins inhabiting the sea region off the Mediterranean coast of Israel. This dolphin population is stable and at any given time can be counted at about 350 dolphins. Of these, the researchers are personally familiar with 150 dolphins — on a first name basis — which can be identified by the dorsal fin, the dolphin’s fingerprint. Forty of these are seen repeatedly and are permanent inhabitants of opposite the coast of Israel. “There is a stable dolphin population off the shores of Israel, and any resolution concerning the sea must also consider the dolphins. So as to preserve this population we must declare extensive marine nature reserves, so as to regulate fishing and bring an end to sea pollution. Regrettably, we are not considerate enough of the dolphins,” concludes Dr. Scheinin.

ScienceDaily (Jan. 26, 2010) — A major increase in maximum ocean wave heights off the Pacific Northwest in recent decades has forced scientists to re-evaluate how high a “100-year event” might be, and the new findings raise special concerns for flooding, coastal erosion and structural damage.

The new assessment concludes that the highest waves may be as much as 46 feet, up from estimates of only 33 feet that were made as recently as 1996, and a 40 percent increase. December and January are the months such waves are most likely to occur, although summer waves are also significantly higher.

In a study just published online in the journal Coastal Engineering, scientists from Oregon State University and the Oregon Department of Geology and Mineral Industries report that the cause of these dramatically higher waves is not completely certain, but “likely due to Earth’s changing climate.”

Using more sophisticated techniques that account for the “non-stationarity” in the wave height record, researchers say the 100-year wave height could actually exceed 55 feet, with impacts that would dwarf those expected from sea level rise in coming decades. Increased coastal erosion, flooding, damage to ocean or coastal structures and changing shorelines are all possible, scientists say.

“The rates of erosion and frequency of coastal flooding have increased over the last couple of decades and will almost certainly increase in the future,” said Peter Ruggiero, an assistant professor in the OSU Department of Geosciences. “The Pacific Northwest has one of the strongest wave climates in the world, and the data clearly show that it’s getting even bigger.

“Possible causes might be changes in storm tracks, higher winds, more intense winter storms, or other factors,” Ruggiero said. “These probably are related to global warming, but could also be involved with periodic climate fluctuations such as the Pacific Decadal Oscillation, and our wave records are sufficiently short that we can’t be certain yet. But what is clear is the waves are getting larger.”

In the early 1990s, Ruggiero said, a fairly typical winter might have an offshore wave maximum of a little more than 25 feet. It was believed then — based primarily on data from two offshore buoys — that 10 meters, or 33 feet, would be about as large as waves would ever get, even in a massive “100-year” storm.

But then a major El Nino — which tends to bring larger waves, higher water levels and increased erosion — happened in 1997-98 and led to a string of “100-year” wave events of around and above 33 feet. Researchers went back to the drawing board, continued to study data and storm events, and now believe that the maximum waves the region may face could approach or even exceed 50 feet.

Increasing wave heights, they said, have had double or triple the impact in terms of erosion, flooding and damage as sea level rise over the last few decades. If wave heights continue to increase, they may continue to dominate over the acceleration in sea level that’s anticipated over the next couple of decades. The prior concern about what sea level rise could do, in other words, is already a reality. If sea levels do increase significantly in future decades and centuries, that will only add to the damage already being done by higher waves.

Exactly what impacts this will have in terms of beach erosion and shifting shorelines is difficult to predict, scientists say, because currents and sand move in complex ways, creating both “winners and losers” in terms of beach stability. But some effects are already visible, Ruggiero said.

“Neskowin is already having problems with high water levels and coastal erosion,” Ruggiero said. “Some commercial structures there occasionally lose the use of their lower levels.

“Going to the future, communities are going to have to plan for heavier wave impacts and erosion, and decide what amounts of risk they are willing to take, how coastal growth should be managed and what criteria to use for structures,” he said.

Hampering the research effort is the fact that two of the major buoys used for these studies, which are some distance off the Pacific Northwest coast and measure waves in deep water, were only installed in the 1970s. Even at that they provide two of the longest high-quality wave height records in the world. OSU researchers are studying historical records through climate data, old newspaper records and other information to try to recreate what wave heights and storm events were like going further back in time.

The largest wave height increases, scientists say, have occurred off the Washington coast and northern Oregon, with less increase in southern Oregon and nothing of significance south of central California. The study also noted that similar increases in wave heights have occurred in the North Atlantic Ocean, as well as the seasonal total power generated by hurricanes.

These issues do not consider the potential drop in land level that is expected to occur in this region with a subduction zone earthquake at some point in the future. Ruggiero noted that he did some research in Sumatra following the huge 2004 earthquake there — an area with geology very similar to that of the Pacific Northwest — and some of the shoreline had dropped from 1.5 to five feet. If and when that occurs, the impacts on shorelines could be enormous.

This research was supported by the Sectoral Application Research Program, a part of the Climate Program Office at the National Oceanic and Atmospheric Administration.

Melting Tundra Creating Vast River of Waste Into Arctic Ocean

ScienceDaily (Jan. 12, 2010) — The increase in temperature in the Arctic has already caused the sea-ice there to melt. According to research conducted by the University of Gothenburg, if the Arctic tundra also melts, vast amounts of organic material will be carried by the rivers straight into the Arctic Ocean, resulting in additional emissions of carbon dioxide.

Sofia Hjalmarsson, PhD, Department of Chemistry, University of Gothenburg. (Credit: Image courtesy of University of Gothenburg)

Several Russian rivers enter the Arctic Ocean particularly in the Laptev Sea north of Siberia. One of the main rivers flowing into the Laptev Sea is the Lena, which in terms of its drainage basin and length is one of the ten largest rivers in the world. The river water carries organic carbon from the tundra, and research from the University of Gothenburg shows that this adds a considerable amount of carbon dioxide to the atmosphere when it is degraded in the coastal waters.

Increased temperatures

The increase in temperature in the Arctic, which has already made an impact in the form of reduced sea-ice cover during the summer, may also cause the permafrost to melt. “Large amounts of organic carbon are currently stored within the permafrost and if this is released and gets carried by the rivers out into the coastal waters, then it will result in an increased release of carbon dioxide to the atmosphere,” says Sofia Hjalmarsson, native of Falkenberg and postgraduate student at the Department of Chemistry.

Study of two areas

In her thesis, Sofia Hjalmarsson has studied the carbon system in two different geographical areas: partly in the Baltic Sea, the Kattegat and the Skagerrak, and partly in the coastal waters north of Siberia (the Laptev Sea, the East Siberian Sea and the Chukchi Sea). The two areas have in common the fact that they receive large volumes of river water containing organic carbon and nutrients, mainly nitrogen.

The thesis Carbon Dynamics in Northern Marginal Seas was publicly defended on 18 December.

Glacial Rebound: 10,000-Year Study of Strata Compaction and Sea-Level Rise on English Coast
ScienceDaily (Dec. 13, 2009) — Environmental scientists at the University of Pennsylvania and Durham University have employed a novel combination of geological and model reconstructions of wetland environments during a 10,000-year period to address spatial variations in sea-level history and provide quantitative estimates of subsidence along the east coast of England.

The findings indicate that glacial rebound — the rise or fall of land masses that were depressed by the huge weight of ice sheets during the last glacial period — explains differences in relative sea levels along the English coast. Current sea levels in Northeast England, the most northerly study area, have been receding to their present level for the past 4,000 years. Unlike Northeast England, however, the Tees Estuary, Humber Estuary, Lincolnshire Marshes, Fenlands and North Norfolk area all reveal sea-level histories trending upward during the past 10,000 years. Using data from sediment cores up to 20 meters deep, researchers found that sediment compaction explained the variations in sea-level observations at every study area, revealing striking correlations to the thickness of overlying sediment.
Coastal subsidence enhances recent sea-level rise, which leads to shoreline erosion and threatens to permanently submerge socio-economically and environmentally valuable wetlands. Yet the causes of subsidence remain controversial, and estimates of subsidence rates vary widely. This collaborative study offers insight into the future behavior of these environmental systems and is an effort to inform policy and management decisions for coastal protection.
“Rising sea levels threaten to permanently submerge wetland environments,” said Benjamin P. Horton, assistant professor in the Department of Earth and Environmental Science at Penn. “Management decisions regarding the best way to intervene to protect these environments depend upon empirically informed, scientific data for each of the processes operating in wetland systems, including sediment compaction. This is a high-profile topic, which is subject to a great deal of controversy, especially concerning the on-going discussions of why deltas around the world are losing wetlands at a particularly alarming rate.”
The study is published in the current issue of the journal Geology and was supported by funding from the National Science Foundation and the Natural Environment Research Council.
It was performed by Horton and by Ian Shennan of the Department of Geography at Durham University in the United Kingdom.

Scientists Find ‘Great Pacific Ocean Garbage Patch 1000 miles offshore’

ScienceDaily (Aug. 28, 2009) — 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.

The expedition was led by a team of Scripps Institution of Oceanography (SIO) graduate students, with support from University of California Ship Funds, the National Science Foundation (NSF) and Project Kaisei.

“SEAPLEX was an important education experience for the graduate students, and contributed to a better understanding of an important problem in the oceans,” said Linda Goad, program director in NSF’s Division of Ocean Sciences. “We hope that SEAPLEX will result in increased awareness of a growing issue.”

After transiting for six days aboard the research vessel, the researchers reached their first intensive sampling site on August 9th.

Team members began 24-hour sampling periods using a variety of tow nets to collect debris at several ocean depths.

“We targeted the highest plastic-containing areas so we could begin to understand the scope of the problem,” said Miriam Goldstein of SIO, chief scientist of the expedition. “We also studied everything from phytoplankton to zooplankton to small midwater fish.”

The scientists found that at numerous areas in the gyre, flecks of plastic were abundant and easily spotted against the deep blue seawater.

Among the assortment of items retrieved were plastic bottles with a variety of biological inhabitants. The scientists also collected jellyfish called by-the-wind sailors (Velella velella).

On August 11th, the researchers encountered a large net entwined with plastic and various marine organisms; they also recovered several plastic bottles covered with ocean animals, including large barnacles.

The next day, Pete Davison, an SIO graduate student studying mid-water fish, collected several species in the gyre, including the pearleye (Benthalbella dentata), a predatory fish with eyes that look upward so it can see prey swimming above, and lanternfish (Tarletonbeania crenularis), which migrate from as deep as 700 meters down to the ocean surface each day.

By the end of the expedition, the researchers were intrigued by the gyre, but had seen their fill of its trash.

“Finding so much plastic there was shocking,” said Goldstein. “How could there be this much plastic floating in a random patch of ocean–a thousand miles from land?”

National Science Foundation. “Scientists Find ‘Great Pacific Ocean Garbage Patch’.” ScienceDaily 28 August 2009. 31 August 2009 http://www.sciencedaily.com/releases/2009/08/090827180747.htm