Biogeochemical Markers

Via PLoS ONE:
Understanding Oceanic Migrations with Intrinsic Biogeochemical Markers

... using tracked pelagic seabirds and some of their own feathers which were known to be grown at different places and times within the annual cycle, we proved the value of biogeochemical analyses of inert tissue as tracers of marine movements and habitat use.

...

Our findings shed new light on the simple and effective assignment of marine organisms to distinct oceanic areas, providing new opportunities to study unknown migration patterns of secretive species, including in relation to human-induced mortality on specific populations in the marine environment.

Read the Open Access article at PLoS ONE.
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UMass Dartmouth to Study Emerging Whelk Fishery

Goal to manage sea snail population before it becomes depleted

UMass Dartmouth School for Marine Science and Technology Professor Bradley Stevens has been awarded $220,000 in Saltonstall-Kennedy funding for a two-year study to improve the conservation of the New England whelk, a large, edible sea snail, locally known as a "conch."

"This is an opportunity to study a fishery before it is significantly depleted," said Dr. Stevens. "Although relatively small now, the whelk fishery has the capacity to expand significantly virtually overnight, and we need to anticipate the effects of such an expansion."

At $3 million in landings per year in Massachusetts (2007 estimates), the whelk fishery is small compared to fisheries such as lobster and scallops, and it operates with few regulations and virtually no biological information, therefore, the population's degree of vulnerability is a question mark. In recent years, the demand for New England whelk has increased, especially in Asian and Italian markets.

Dr. Stevens, who blends expertise in fisheries, whelk biology, and research aquaculture, said, "There are currently 166 conch-pot permits in Massachusetts, but only about 40 of those are actively fished. If the remainder were to be fully utilized, landings could quadruple, which could seriously deplete the whelk population."

Stevens noted that the whelk fishery has been moving northward for decades. Directed fisheries for whelks developed in the 1970s in the Carolinas, the 1980s in Virginia, and the late 1990s in New England.
The Massachusetts whelk fishery was a small bycatch fishery until about a decade ago, just as lobster populations were showing the most dramatic drop. Lobster fishermen have long found whelks in their pots, but as the lobster catch declined, the lobstermen began to target the whelks as an income source. "Wherever such fisheries have sprung up, they started as bycatch fisheries, expanded rapidly as fishermen sought alternative income after sudden declines in other fisheries such as shrimp and lobster, and then just as rapidly began to decline within a few years," Stevens said.

Expanded whelk harvesting could threaten not only the target species, but also the horseshoe crab. The preferred bait for whelk pots, horseshoe crabs are already fully exploited in New England, mostly for medical applications. Stevens will be investigating alternative baits and fishing practices to reduce the pressure on the horseshoe crab population.

Working in cooperation with the Massachusetts Division of Marine Fisheries and the Massachusetts Lobstermen's Association, Stevens will determine life history, growth rates, age distributions, and size/age of sexual maturity in channeled whelks. The information will be provided to managers to improve the conservation of whelks in a sustainable manner.

The Saltonstall-Kennedy Grant Program is a competitive program administered by the National Marine Fisheries Service of the National Oceanic and Atmospheric Administration, Department of Commerce to provide financial assistance for research and development projects to benefit the U.S. fishing industry.
Dr. Stevens lives in Wareham, MA.

Contact Info:
Email: kbeals@umassd.edu Kathy Beals, UMass Dartmouth Office of Public Affairs

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Role for groundwater in Red Tides?

In the new issue of Sound Waves, U.S. Geological Survey (USGS) scientist Christopher Gerald Smith investigates the role of groundwater in initiating blooms of Karenia brevis on the nitrogen-limited west Florida shelf.

Submarine Groundwater Discharge Along the West Florida Shelf: Is Groundwater an Important Nutrient Source for Florida's Red Tides?

Harmful algal blooms have been observed along the west Florida shelf and adjacent water bodies for more than 150 years (some suggest as long ago as 1570), with the first historically documented bloom dating back to 1854. Modern harmful algal blooms, commonly referred to as "red tides," are dominated by the brevetoxin-producing dinoflagellate Karenia brevis. Brevetoxins are neurotoxins that pose a threat to marine and human health. The greatest densities of K. brevis blooms generally occur along the west Florida shelf between Pinellas and Lee Counties, Florida.

Read the entire article at USGS Sound Waves
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Vital marine habitat under threat

Daniel Cressy at NatureNews highlights new research by Michelle Waycott et. al. appearing in PNAS. Michelle was co-author on "A Global Crisis for Seagrass Ecosystems" in 2006.

Destruction of seagrass on a par with loss of rainforests and coral reefs.

While the world has focused on the destruction mankind has brought to coral reefs, the massive loss of an equally important ecosystem has been widely ignored.

Now the first comprehensive assessment of the state of seagrass meadows around the world has revealed the damage that human activities have wrought on these economically and biologically essential areas.

Read Daniel's Summary here.
Read the OpenAccess article at PNAS Accelerating loss of seagrasses across the globe threatens coastal ecosystems.

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Crabs go deep to avoid hot water

Via the National Oceanography Centre, Southampton, UK:

Researchers from the National Oceanography Centre, Southampton, have drawn together 200 years’ worth of oceanographic knowledge to investigate the distribution of a notorious deep-sea giant – the king crab. The results, published this week in the Journal of Biogeography, reveal temperature as a driving force behind the speciation and radiation of a major seafloor predator; globally, and over tens of millions of years of Earth’s history.

In deep seas all over the world, around 100 species of king crabs live largely undiscovered. The fraction that we have found includes some weird and wonderful examples - Paralomis seagrantii has its eight walking legs and claws entirely covered in long fur-like setae; while related group Lithodes megacanthus grows to lengths of 1.5 metres, and has 15-20-cm long defensive spines covering its body. At temperatures of around 1- 4ºC, these crabs thrive in some of the colder waters on Earth; living and growing very slowly, probably to very old ages. Only in the cooler water towards the poles are king crabs found near the water surface – though temperatures found around some parts of the Antarctic (below 1ºC) are too extreme for their survival.

Read the entire release here.
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Surviving mass extinction by bridging the benthic/planktic divide

Via PNAS Early Edition:
Kate F. Darling, et. al. provide evidence for a tychopelagic existence for the planktic foraminifera Streptochilus globigerus citing its relation to the benthic Bolivina variabilis. The evolution from a benthic to planktic existence was generally viewed as a one-time event per clade. This finding shows the possibility that the tychopelagic foraminifera have the capability to quickly recolonize the planktic domain after extinction events.

Evolution of planktic organisms from benthic ancestors is commonly thought to represent unidirectional expansion into new ecological domains, possibly only once per clade. For foraminifera, this evolutionary expansion occurred in the Early–Middle Jurassic, and all living and extinct planktic foraminifera have been placed within 1 clade, the Suborder Globigerinina. The subsequent radiation of planktic foraminifera in the Jurassic and Cretaceous resulted in highly diverse assemblages, which suffered mass extinction at the end of the Cretaceous, leaving an impoverished assemblage dominated by microperforate triserial and biserial forms. The few survivor species radiated to form diverse assemblages once again in the Cenozoic. There have, however, long been doubts regarding the monophyletic origin of planktic foraminifera.

We present surprising but conclusive genetic evidence that the Recent biserial planktic Streptochilus globigerus belongs to the same biological species as the benthic Bolivina variabilis, and geochemical evidence that this ecologically flexible species actively grows within the open-ocean surface waters, thus occupying both planktic and benthic domains. Such a lifestyle (tychopelagic) had not been recognized as adapted by foraminifera. Tychopelagic are endowed with great ecological advantage, enabling rapid recolonization of the extinction-susceptible pelagic domain from the benthos. We argue that the existence of such forms must be considered in resolving foraminiferal phylogeny.

Published online before print July 2, 2009, doi: 10.1073/pnas.0902827106

Read the article at PNAS[subscription required].
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Researchers Survey Mid-Atlantic Ridge

Via AAAS EurekAlert! the NEFSC Announces:
Researchers Survey Mid-Atlantic Ridge Looking For New Forms of Marine Life, Clues to Deep-Sea Communities

An international team of researchers is surveying the Mid-Atlantic Ridge halfway between Iceland and the Azores to determine its biodiversity and perhaps discover new species and clues to deep-sea food webs. The project is part of a 16-nation effort to determine if the underwater mountain chain in the middle of the North Atlantic Ocean has its own distinct animal communities.

Led by NOAA researcher Mike Vecchione of the Northeast Fisheries Science Center (NEFSC), headquartered in Woods Hole, Mass., the research team is working aboard the 208-foot NOAA ship Henry B. Bigelow for six weeks as part of the Mid-Atlantic Ridge Ecosystem Project, or MAR-ECO. The cruise is funded by NOAA Fisheries Service with additional support from the Alfred P. Sloan Foundation.

Read the entire press release from NEFSC
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Expected rate of fisheries-induced evolution is slow

From PNAS:
Expected rate of fisheries-induced evolution is slow

Commercial fisheries exert high mortalities on the stocks they exploit, and the consequent selection pressure leads to fisheries-induced evolution of growth rate, age and size at maturation, and reproductive output. Productivity and yields may decline as a result, but little is known about the rate at which such changes are likely to occur. Fisheries-induced evolution of exploited populations has recently become a subject of concern for policy makers, fisheries managers, and the general public, with prominent calls for mitigating management action.

We make a general evolutionary impact assessment of fisheries by calculating the expected rate of fisheries-induced evolution and the consequent changes in yield. Rates of evolution are expected to be ≈0.1–0.6% per year, and the consequent reductions in fisheries yield are <0.7% These rates are at least a factor of 5 lower than published values based on experiments and analyses of population time series, and we explain why the published rates may be overestimates. Dealing with evolutionary effects of fishing is less urgent than reducing the direct detrimental effects of overfishing on exploited stocks and on their marine ecosystems.

Published online before print June 29, 2009, doi:10.1073/pnas.0901690106

Read the article here. [Subscription Required]

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European scientists investigate the role of Fe-rich Saharan dust in the fertilization of the N-fixing cyanobacteria UCYN-A

European scientists have collaborated with the Leibniz Institute of Marine Sciences (IFM-GEOMAR) to establish the Tenatso Observatory on the Cape Verde island of Sao Vicente. This observatory is the base for research into the role of Fe-rich Saharan dust in the fertilization of the N-fixing cyanobacteria UCYN-A.

Via AlphaGalileo:

The tropical Atlantic waters around Cape Verde are very low in plant nutrients. Nitrogen is in especially short supply and limits the growth of the phytoplankton, the tiny plants that are at the basis of the food chain in the ocean. In this area, the nutrients fall out from the sky: Trade winds carry Saharan dust rich in iron and phosphorus which can fertilize the surface of the ocean. This was one of the reasons for the IFM-GEOMAR and other German and UK institutions to establish an observatory on the Cape Verde island Sao Vicente. The Tenatso Observatory now supports long-term measurements of dust and greenhouse gases as well as an oceanographic mooring and regular sampling expeditions by the small Cape Verdean research vessel Islandia.

“We’re testing whether Saharan dust can promote the growth of a particular type of microbe, a cyanobacteria. These cyanobacteria can fertilize the surface of the ocean by fixing the abundant nitrogen gas that is dissolved in seawater”, says Prof. Julie LaRoche from IFM-GEOMAR, co-leader of the expedition. There is plenty of nitrogen gas in the atmosphere but it needs to be "fixed" so that it turns into a fertilizer which is available to phytoplankton. The enigmatic cyanobacteria UCYN-A seems to be a very special nitrogen fixer. In contrast to other cyanobacteria, it is probably incapable of producing oxygen. This in turns enables it to fix nitrogen during the day while others cannot.

The Trade Winds and frequent dust storms that make this area so important for ocean research also complicate the scientists’ work. Dust samples are collected with filters on top of the atmospheric observatory. The collection of the water samples, however, requires sailing on the Islandia for several hours to the ocean observatory located 130 kilometres offshore in a surrounding water depth of 3600 metres. The samples are returned to laboratories that have been established at Cape Verde’s “National Institute for Fishery Development” where the dust experiments are conducted.

„The working conditions are difficult and some trips on the Islandia are like a roller coaster. But overall it’s a very positive work experience, thanks to our supportive Cape Verdean colleagues, the crew of the Islandia, and the general ambience on the islands “, says Stefanie Sudhaus , Ph.D. student at IFM-GEOMAR and member of the last expedition. Loaded with plenty of data from their experiments and confident that the experiments will deliver new discoveries, the scientists have returned to Kiel. During the expedition they were accompanied by scientists from the Max Planck Institute for Marine Microbiology, the Alfred Wegener Institute for Polar and Marine Research, Leibniz Institute for Baltic Sea Research and the Leibniz Institute for Tropospheric Research.

Research Project at the Cape Verde

Scientists from German and Cape Verdean institutes have started collecting data at Cape Verde Observatory Tenatso in 2008, measurements that they hope to continue in order to follow the effect of global change in the tropical Atlantic Ocean. Their research is part of the SOPRAN project (Surface Ocean Processes in the Anthropocene) that is largely supported by the German Federal Ministry of Education and Research (BMBF).

Nitrogen fixers and UCYN-A

There is plenty of nitrogen gas (N2) in the atmosphere but only few organisms are able to "fix" it so that it turns into a fertilizer with biologically useful molecules. Cyanobacteria or blue-green algae are amongst the most important nitrogen-fixers. Until recently scientists thought that single-cell organisms could only fix the nitrogen during the night because during the day, oxygen is released through photosynthesis and inhibits nitrogen fixation by poisoning the enzyme responsible for it. The cyanobacterium UCYN-A doesn’t seem to work like that. It lacks the genes for photosystem II that are needed for the oxygen release and apparently cannot fix carbon dioxide into sugars. Thus, it may utilize light energy in other ways and forgoes photosynthesis, as is normally carried out by land plants and other algae. Although this organism has never been isolated in pure culture, an initial characterization of its genome was published in 2008 by the group of Jonathan Zehr at University of Santa Cruz (Zehr et al. 2008, Science Vol. 322 no. 5904, pp. 1110-1112). Read more!