Tag Archives: USA

2010 El Nino Reduces Marine Life

The ongoing El Niño of 2010 is reducing marine populations according to scientists at NOAA and Scripps Institution of Oceanography.

Researchers are reporting a stronger than normal northward movement of warm water up the Southern California coast, a high sea-level event in January and low abundances of plankton and pelagic fish – all conditions consistent El Niño.

Sea surface temperatures along the entire West Coast of America are 0.5 to 1 degree Celsius (0.9 to 1.8 degrees Fahrenheit) warmer than normal and at points off Southern California are as much as 1.6 degrees Celsius (2.9 degrees Fahrenheit) higher than normal. The most unusually high temperatures were mapped around Catalina and San Clemente islands.

The high coastal sea levels may be caused by strong winter storms, scientists are investigating whether this is the case or whether they are primarily a result of El Niño.

A combination of satellite remote sensing and field measurements is offering scientists a broader view of the evolution of this El Niño that was not available during previous El Niños, which were especially strong in 1982-83 and 1997-98.

The two research centres use data collected by satellites and buoy-mounted instruments to measure sea surface temperature. Researchers embark on quarterly cruises off the California coast to collect vertical temperature profiles in the upper reaches of the water column. They also count eggs of commercially important fishes such as sardines and anchovies as well as measure plankton volumes to estimate the amount of “production” available to marine organisms. NOAA’s Advanced Survey Technologies Group assesses fish populations through acoustic surveys. In contrast with the last major El Niño, Scripps now deploys Spray gliders, diving robots that now gather ocean temperature and other data.

The scientists have observed a drop in biological abundance, or productivity, that appears to be related to the northward movement of warm water from the equator. The flow arrives in pulsing Kelvin waves that are detected by sea level and altimeter monitors and coastal tidal gauges. The layer of warm water often stifles the upwelling of nutrients from lower ocean depths that sustain larger populations of fishes and invertebrates.

A Kelvin wave is a gentle yet massive swell of warm water travelling across the Pacific from West to East. A typical Kelvin wave is 5 or 10 cm high, hundreds of kilometers wide, and a few degrees warmer than surrounding waters.

If El Niño conditions continue, they are likely to be characterized by weaker than normal upwelling and lower biological production. El Niño conditions are forecast to persist into spring. If so, they may result in fewer fish and breeding failure of seabirds.

Further Reading
A Curious Pacific Wave, Science@NASA
Scripps Institution of Oceanography

Red Grouper create home for many animals

Credit: SEFSC Pascagoula Laboratory; Collection of Brandi Noble, NOAA/NMFS/SEFSCResearchers from Florida State University have found that Red Grouper (Epinephelus morio) dig out and maintain complex structures at the bottom of the sea. They remove sand, exposing hard rocks that are crucial to corals and sponges and the animals that rely on them. The work demonstrates that Red Groupers modify their environment, much as beavers do, creating habitat for many other animals including lobster and commercially important fish.

“Watching these fish dig holes was amazing enough,” says Felicia Coleman, lead researcher, “but then we realised that the sites served to attract mates, beneficial species such as cleaner shrimp that pick parasites and food scraps off the resident fish and a variety of prey species for the Red Grouper. So it’s no surprise that the fish are remarkably sedentary. Why move if everything you need comes to you?”

“The research is incredibly valuable because it demonstrates how interconnected species are in the sea,” says Dr. Susan Williams, a professor at the University of California, Davis. “Red Groupers are the ‘Frank Lloyd Wrights’ of the sea floor because they are critical habitat architects. The species that associate with them include commercially valuable species- such as vermilion snapper, black grouper, and lobsters. If the groupers are overfished, the suite of species that depends on them is likely to suffer.”

Working along the West Florida Shelf, the authors observed the excavating behaviour of the Red Grouper during both their juvenile stage in inshore waters as their adult stage at depths of 100 m. The study serves to document this behaviour and its apparent impact on the biological diversity of the ocean. Their article on the study, “Benthic Habitat Modification through Excavation by Red Grouper, Epinephelus morio, in the Northeastern Gulf of Mexico,” is published in the most recent issue of the journal The Open Fish Science Journal.

Red Grouper (Epinephelus morio) is an economically important species in the reef fish community of the southeastern United States, and especially the Gulf of Mexico. It is relatively common in karst regions of the Gulf.

As juveniles, Red Grouper excavate the limestone bottom of Florida Bay and elsewhere, exposing “solution holes” formed thousands of years ago when sea level was lower, and freshwater dissolved holes in the rock surface. When sea level rose to its present state, these solution holes filled with sediment. By removing the sediment from these holes, Red Grouper restructure the flat bottom into a three dimensional matrix.

Spiny lobsters are among the many species that occupy these excavations, especially during the day when they need refuge from roving predators.

“What are the consequence of overfishing these habitat engineers?” asks co-author Koenig. “You can’t remove an animal that can dig a hole five meters across and several meters deep to reveal the rocky substrate and expect there to be no effect on reef communities. The juveniles of a species closely associated with these pits, vermilion snapper, are extremely abundant around the offshore excavations. It is possible that the engineered habitat is significant as a nursery for this species, which other big fish rely on as food. One could anticipate a domino effect in lost diversity resulting from the loss of Red Grouper-engineered habitat.”

Red Grouper clearly remove sufficient sediment to transform an otherwise two-dimensional area into a three-dimensional structure below the seafloor, providing refuge for themselves and for other organisms. In the process, they expose hard substrate, thus creating settlement sites for corals, sponges, and anemones, allowing the creation of three-dimensional structure above the seafloor as well. Addition of these roles to their contribution as resident top predators suggests that they might have a disproportionately large per capita influence on the ecosystem within which they live.

Red Grouper have been harvested in the United States since the 1880s and are currently the most common grouper species landed in both commercial and recreational fisheries of the Gulf of Mexico.

Excessive fishery removals can and often do have cascading effects in marine communities that ultimately result in the loss of many species. This situation arises when the captured species has a disproportionately large influence on the system within which it lives. The Red Grouper has been shown to be one such species.

Further Reading:
Benthic Habitat Modification through Excavation by Red Grouper, Epinephelus morio, in the Northeastern Gulf of Mexico
pp.1-15 (15) Authors: Felicia C. Coleman, Christopher C. Koenig, Kathryn M. Scanlon, Scott Heppell, Selina Heppell, Margaret W. Miller
doi: 10.2174/1874401X01003010001
Florida State University

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USA Creates Three Marine Protected Areas in Pacific

As one of his last acts in office President Bush has designated three areas of the Pacific Ocean, covering nearly 200000 square miles, as new marine “national monuments”.

The first is the Marianas Trench Marine National Monument. At the heart of this protected area will be much of the Marianas Trench — the site of the deepest point on Earth — and the surrounding arc of undersea volcanoes and thermal vents. This unique geological region supports life in some of the harshest conditions imaginable. A fascinating array of species survive amid hydrogen-emitting volcanoes, hydrothermal vents that produce highly acidic and boiling water, and the only known location of liquid sulfur this side of Jupiter.

The other major features of the new monument are the coral reefs off the coast of the upper three islands in the Commonwealth of the Northern Mariana Islands. These islands, some 5,600 miles from California, are home to a striking diversity of marine life — from large predators like sharks and rays, to more than 300 species of stony corals.

The second new monument will be the Pacific Remote Islands Marine National Monument. The monument will span seven areas to the far south and west of Hawaii. One is Wake Island — the site of a pivotal battle in World War II, and a key habitat for nesting seabirds and migratory shorebirds. The monument will also include unique trees and grasses and birds adapted to life at the Equator; the rare sea turtles and whales and Hawaiian monk seals that visit Johnston Atoll; and, according to the White House, some of the most pristine and spectacular coral reefs in the world.

The third new monument will be the Rose Atoll Marine National Monument. Rose is a diamond-shaped island to the east of American Samoa. It includes rare species of nesting petrels, shearwaters, and terns — which account for its native name, “Island of Seabirds.” The waters surrounding the atoll are the home of many rare species, including giant clams and reef sharks — as well as an unusual abundance of rose-colored corals.

These three new protected areas cover nearly 200,000 square miles and will now receive America’s highest level of environmental recognition and conservation.

Further Reading: The White House

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Computers decide when to stop searches at sea

Researchers at Portsmouth University and the US Coast Guard are working together to develop a computer model that will predict how long someone will survive when lost at sea.

The Search and Rescue Survival Model has been designed to take the pressure off rescuers making difficult decisions about when a search and rescue mission should be stopped.

“Using this new computer model will take pressure off humans making very emotional and sensitive decisions about when to end a search,” said Professor Mike Tipton, human and applied physiologist, from the University of Portsmouth.

“When the model predicts that a victim can no longer survive, the search and rescue team can stop or redeploy the search.

“It will ensure that Coast Guard personnel are not exposed to the high risks associated with search and rescue operations any longer than necessary and will also help to save time and resources,” he said.

The US Coast Guard currently uses a software system known as SAROPS (Search and Rescue Optimal Planning System) to calculate how far a person will have drifted and how large the search area should be.

Data such as wind speed, sea state and water temperature is entered into SAROPS along with information about the victim’s sex, height, weight and what they were wearing to determine exactly how the search should be conducted.

“Calculating survival time will add another layer to SAROPS; it will be able to predict not only where a search should be conducted but when it should be stopped,” said Professor Tipton.

“The University of Portsmouth has been able to tap into and analyze data held by the Institute of Naval Medicine and the Royal National Lifeboats Institution, both critical to the development of this survival model. To our knowledge no other similar repository of this information exists – even in the US.

“The development of this technology is very exciting. It will be trialled in American waters in late 2009 and once thoroughly tested, the aim is to roll it out to the whole of the US,” he said.