Got Iron? Even the Ocean Recycles!

ScienceDaily — In the vast ocean where an essential nutrient -- iron -- is scarce, a marine bacterium that launches the ocean food web survives by using a remarkable biochemical trick: It recycles iron.

By day, it uses iron in enzymes for photosynthesis to make carbohydrates; then by night, it appears to reuse the same iron in different enzymes to produce organic nitrogen for proteins.

The bacterium, Crocosphaera watsonii, is one of the few marine microbes that can convert nitrogen gas into organic nitrogen, which (just as it does on land) acts as fertilizer to stimulate plant growth in the ocean. So the ocean's productivity is limited by nitrogen, which in turn is limited by scanty supplies of iron for the enzymes needed to make organic nitrogen.

This newfound capacity to conserve precious iron and use it in day-night shifts to satisfy two different metabolic demands reveals a surprising key to life on our planet, say scientists at Woods Hole Oceanographic Institution (WHOI) and Massachusetts Institute of Technology (MIT). They reported their findings Jan. 10 in the Proceedings of the National Academy of Sciences.

The scientists call the strategy "hot bunking," referring to ships that sail with fewer bunks than sailors on board. The bunks are kept continuously hot, as sailors finishing night shifts hop into bunks newly emptied by sailors arising for day shifts.

Crocosphaera uses iron-containing nitrogenase enzymes to convert dissolved nitrogen gas into organic nitrogen (a process called nitrogen "fixing"). As the sun comes up, the bacterium breaks down these enzymes, releasing iron that can be used to make photosynthetic enzymes needed to convert dissolved carbon dioxide into carbohydrates. When the sun goes down, many of the photosynthetic enzymes are broken down, releasing the iron again to be recycled into nitrogenase.

Crocosphaera belongs to a subgroup of bacteria called cyanobacteria. "They have a bit of a Dr. Jekyll and Mr. Hyde lifestyle: photosynthetic by day and nitrogen-fixing by night," said Mak Saito, a WHOI biogeochemist and lead author of the PNAS paper. Scientists previously knew cyanobacteria had this unusual dual-metabolic capacity, but they did not know how they could accomplish it with meager iron supplies.

The bacterium pays a price in energy needed to destroy and rebuild enzymes each day, but it's worth it to maximize the use of scarce iron. The scientists estimate that by using the hot bunking strategy, the organism can survive with about 40 percent less iron than it would otherwise need. It allows Crocosphaera to thrive and produce life-sustaining organic nitrogen in iron-poor waters that would otherwise be less productive.

The surprising abundance of cyanobacteria in the ocean was discovered in the 1970s by WHOI microbiologist Stanley Watson and his colleagues Frederica Valois and John Waterbury and, who later continued their pioneering research to elucidate cyanobacteria's critical ecological roles for the ocean and the planet. Crocosphaera watsonii is named after the late Dr. Watson.

Cyanobacteria have been notoriously difficult to culture in the laboratory. At WHOI, Waterbury, Valois and colleagues established methods to culture cyanobacteria routinely and reliably, and they maintain a collection of cyanobacteria cells in a new building called the Stanley W. Watson Laboratory. The collection is a sort of lending library of cells that provide cultures for scientists all over the world to study, including new generations of WHOI scientists working in the Watson Lab: Saito, graduate student Erin Bertrand, and lab associates Vladimir Bulygin and Dawn Moran.

They applied new biomedical research techniques to the study of the ocean: proteomics. As genomics studies the genes in an organism (its genome), proteomics studies the proteins made from instructions encoded in genes (its proteome).

"We wanted to know not only what could potentially be made from Crocosphaera's genome, but also what proteins Crocosphaera actually did make," Saito said.

A key part of the technique involves using mass spectrometers that distinguish and measure the various proteins in an organism by the infinitesimal differences in their masses. The researchers measured the inventory of iron-containing proteins during periods of dark and light. Nitrogen-fixing enzymes were largely absent during the day and present at night; iron-containing photosynthetic enzymes decreased during dark periods and reappeared during light periods. Thus, at any time of day, Crocsophaera required only about half the iron it would need if it maintained both sets of enzymes throughout the day.

To explore the implications of Crocosphaera's hot bunking ability, scientists at MIT -- Stephanie Dutkiewicz, Fanny Monteiro and Mick Follows -- used a numerical model that simulates global ocean circulation, biochemistry, and ecosystem dynamics. The model showed that Crocosphaera's ability to reduce its iron requirements allowed it to inhabit ocean regions with low levels of iron. It also allowed the same iron supply to support more growth of the cyanobacteria and more nitrogen fixation that supports other marine life higher up on the food chain.

Funding for the research came from the National Science Foundation, an Environmental Protection Agency Star Fellowship, the WHOI Ocean Life Institute, the NSF-funded Center for Microbial Research and Education, and the Center for Environmental Bioinorganic Chemistry at Princeton University. The paper was dedicated to co-author Vladimir Bulygin, who passed away in June 2010.

Source: http://www.sciencedaily.com/releases/2011/01/110110154649.htm

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About Oceanic Defense
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Research: Dolphins' Health Shed Light On Human And Ocean Health; An Important 'Sentinel Species'

(photo by: Jeff Shaw, Oceanic Defense)
WASHINGTON, D.C. -- A panel of governmental, academic and non-profit scientists speaking today at the annual meeting of the American Association for the Advancement of Science (AAAS) unveiled research suggesting that diseases found in dolphins are similar to human diseases and can provide clues into how human health might be affected by exposure to contaminated coastal water or seafood.

“Dolphins and humans are both mammals, and their diet includes much of the same seafood that we consume. Unlike us, however, they are exposed to potential ocean health threats such as toxic algae or poor water quality 24 hours a day,” said Carolyn Sotka of the NOAA Oceans and Human Health Initiative and lead organizer of the session. “Our ecological and physiological similarities make dolphins an important ‘sentinel species’ to not only warn us of health risks, but also provide insight into how our health can benefit from new medical discoveries.”

"Marine animal and ecosystem health are connected to public health and well-being,” said Jane Lubchenco, Ph.D., under secretary of commerce for oceans and atmosphere and NOAA administrator. “NOAA is committed to better understanding these connections and building the partnerships necessary to have healthy oceans, including healthy dolphins.”

NOAA is the principal stewardship agency responsible for protecting dolphins in the wild and supports a network of national and international projects aimed at investigating health concerns. A few of these case studies highlighted today at AAAS illustrate how studying disease processes, or pathologies in dolphins, could lead to future prevention or treatment of some diseases in humans. Equally important is the knowledge gained with regards to overall population health, which can lead to improved management and science-based guidelines to mitigate disease outbreak in both people and animals.

Unprecedented Contaminant Levels in Coastal Dolphins Warn of Potential Health Risks
Researchers from NOAA and its partner institutions recently discovered that bottlenose dolphins inhabiting estuaries along the Georgia coast have the highest levels of polychlorinated biphenyls (PCBs) ever reported in marine wildlife. The term PCB encompasses a suite of persistent contaminants that have been banned in the United States since the late 1970s due to documented adverse health effects. The extraordinarily high levels of PCBs measured in the dolphins, a maximum concentration of 2900 parts per million, may be suppressing their immune function.

The unique signature of the PCB compounds found in these dolphins is consistent with contaminants of concern at a Superfund site near Brunswick, Ga. Scientists are equally concerned about the high PCB levels in dolphins sampled near a marine protected area approximately 30 miles from Brunswick. This suggests that the contaminants are moving along the coast through the marine food web.

“When we received the lab results for the Georgia dolphins, we were alarmed by the contaminant levels and set out to investigate how these heavy chemical burdens were affecting their health,” states Lori Schwacke, Ph.D., with NOAA’s Center for Oceans and Human Health at the Hollings Marine Lab and co-lead investigator on the team.

Last August, the team conducted a dolphin ‘capture-release medical physical’ on this population and found decreased levels of thyroid hormones, elevated liver enzymes and indications of suppressed immune function.

A pilot study is being undertaken by the National Center for Environmental Health, Centers for Disease Control and Prevention (CDC), to examine potential environmental contaminants in residents of nearby coastal communities. The researchers are investigating whether coastal dolphin populations and human communities sharing the same seafood resources experience similar exposures.

Dolphins May Offer Clues to Treating Diabetes in Humans Research conducted in part by the non-profit National Marine Mammal Foundation (NMMF) has uncovered evidence that bottlenose dolphins may be the first natural animal model for type II diabetes. Further study of their genome may elucidate a possible treatment for a disease that accounts for an estimated 5 percent of all human deaths globally, according to the World Health Organization.

These studies have found that healthy dolphins appear to readily turn on and off a diabetes-like state as needed. This “switch” mechanism is likely driven by the dolphins’ very high-protein and very low-carbohydrate fish diet. Analyses have revealed that a fasting mechanism in dolphins may trigger a series of changes in serum chemistries that matches those seen in humans with diabetes.

“While some people may eat a high protein diet to help control diabetes, dolphins appear to have developed a diabetes-like state to support a high protein diet,” according to Stephanie Venn-Watson, Ph.D., director of clinical research for NMMF. “Shared large brains that have high blood glucose demands may explain why two completely different species - humans and dolphins - have developed similar physiological mechanisms to handle sugar.”

Additional evidence collected from this study shows that humans and dolphins may share similar chronic disease outcomes associated with diabetes such as insulin resistance, hemochromatosis (iron overload) and kidney stones.

Model for Epilepsy Discovered from Marine Exposure to Toxic Algae NOAA researchers found that for the first time exposing laboratory animals to a toxin produced by blooms of microscopic ocean algae can induce seizures and eventually lead to epilepsy in almost all of the animals tested. Establishing this novel linkage of oceans and health offers a new perspective to researchers and clinicians studying human epilepsy.

Working with the Marine Mammal Center in Sausalito, Calif., and other partners, scientists initially suspected a marine environmental cause of epilepsy by studying marine mammals and other wildlife with seizures that washed up on California beaches over the past decade.

The seizures were found to be caused by exposure to domoic acid, a neurotoxin produced by the Pseudo-nitzschia australis alga. After realizing thatsome sea lions were stranded with seizures when there were no harmful algal blooms, researchers started to believe that domoic acid poisoning may have progressed to chronic epileptic disease.

Chief of Harmful Algal Blooms & Analytical Response at NOAA's National Centers for Coastal Ocean Science, John Ramsdell, Ph.D., conducted laboratory experiments to validate the field observations seen in sea lions. His research team exposed laboratory rats to domoic acid at levels similar to what a sea lion or dolphin might ingest in the wild by eating contaminated fish.

“Within six months of the initial exposure, 92 percent of laboratory rats tested developed epileptic disease that worsened over their lifetime,” said Ramsdell. “The domoic acid itself is not directly causing the epilepsy, but triggers a brief period of seizures that leads to changes in the brain, resulting in spontaneous and reoccurring seizures, the hallmark of epilepsy.”
The type of epilepsy in the rat model resembles human Temporal Lobe Epilepsy, as confirmed by at least one human case traced back to eating mussels contaminated with the domoic acid toxin.

This research could provide important insight into how dolphins and other species, including humans, respond to domoic acid poisoning. Stranded dolphins with high domoic acid levels do not survive long enough for treatment and study. It is possible that the acute initial poisoning may lead to sudden death; however, these new findings indicate those animals that survive an initial bout of seizures are likely to develop neurological disease with changes in behavior and increasing severity of spontaneous seizures. This new information can help guide future research and emergency response efforts during the next harmful algal bloom event.
Dolphin Viruses May Have Human Health Implications

A team of researchers and veterinarians from the Marine Animal Disease Lab at the University of Florida have discovered at least 50 new viruses in dolphins, the majority of which have yet to be reported in any other marine mammal species.

“We know that the ocean harbors a huge diversity of viruses; but we have very limited knowledge as to which viruses dolphins are susceptible to and how they develop the disease,” said Hendrik H. Nollens, Ph.D., research lead of the UF team. “By studying dolphin viral ecology, we learned more about how viruses infect human and land animals. This research could lead to preventing outbreaks of disease.”

One of these viruses, the human papillomavirus, was found to be common in bottlenose dolphins and likely represents the first natural model of papillomavirus outside the human species. Commonly known as HPV in humans, the virus has historically produced great health risks including cervical tumors or cancer in women, especially women with multiple types of the papillomavirus. This new study shows that while dolphins also host multiple types of papillomaviruses they don’t appear to get cancer, only genital warts. Further research into the genome of this virus in dolphins may help understand, manage and prevent cervical cancer in humans.

Thirteen additional RNA-based viruses that cause intestinal disease and encephalitis in humans have also recently been discovered in dolphins, whales and other marine life. Much like West Nile, Severe Acute Respiratory Syndrome (SARS) and influenza, RNA-based viruses have the ability to quickly adapt, rapidly mutate and jump from animals to people, posing potential threats to public health. Another virus identified in the dolphins had incorporated part of a similar human virus into its DNA make-up, making it a very probable candidate to infect humans.

Source: http://www.underwatertimes.com/news.php?article_id=10564937801

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About Oceanic Defense
We are an international non-profit organization with members in over 60 countries, spanning 6 continents with 1 mission; healthy aquatic ecosystems free from human abuse and neglect. Oceanic Defense teaches people to protect our oceans by acting responsibly as consumers and by making smart decisions in our daily lives. Whether we are buying groceries, commuting to work, planning a vacation or advocating within our own communities; each action we take or decision we make either helps or hurts our oceans. We empower people to be part of the solution rather than part of the problem and work together to protect our blue planet.

Join us on Facebook:
www.facebook.com/OceanicDefense
Visit our official website:
www.oceanicdefense.org
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www.twitter.com/OceanicDefense

Ocean Health Plays Vital Role In Coral Reef Recovery

ScienceDaily — The new research study led by scientists at Scripps Institution of Oceanography at UC San Diego suggests that by improving overall ocean health, corals are better able to recover from bleaching events, which occur when rising sea temperatures force corals to expel their symbiotic algae, known as zooxanthellae. Coral bleaching is a phenomenon that is expected to increase in frequency as global climate change increases ocean temperatures worldwide.

The new findings, published in the July 22 issue of the journal PLoS One, show that following a major bleaching event Mountainous star coral (Montastraea faveolata) on various reefs in Honduras and Belize was able to recover and grow normally within two to three years when the surrounding waters and reef were relatively healthy. In comparison, those corals living with excessive local impacts, such as pollution, were not able to fully recover after eight years.

"You can imagine that when you are recovering from a sickness, it will take a lot longer if you don't eat well or get enough rest," said Jessica Carilli, Scripps graduate student and lead author on the study. "Similarly, a coral organism that must be constantly trying to clean itself from excess sediment particles will have a more difficult time recovering after a stressful condition like bleaching."

Carilli and colleagues analyzed 92 coral cores collected from four reef sites off the coast of Honduras and Belize. The cores were collected from reefs with different degrees of local stress from pollution, overfishing and sediment and nutrient run off from land. By using x-rays, the researchers were able to examine the coral's annual growth rate records since 1950, including the time before and after a major bleaching event in 1998.

"It is clear that Mesoamerican corals really fell off a cliff in 1998 -- nearly everybody suffered mass bleaching," said Dick Norris, Scripps professor of paleooceanography and co-author of the study. "There are no pristine reefs in the region, but the ones in the best shape clearly are more resilient than those that are long-suffering. It shows that a little improvement in growing conditions goes a long way in recovering coral health."

Corals are widely considered to be barometers for global warming and are important for biodiversity in the world's oceans. Coral reefs thrive in warm tropical oceans under just the right conditions that include moderate temperatures and low nutrient and sediment input from land-based sources. Protecting reef health from local sources of stress, such as runoff, can improve resilience to global warming stress.

Coral bleaching occurs when the tiny zooxanthellae, living with the tissues of coral polyps, which are responsible for their vibrant colors, are lost and the coral turns white in color.

The fast-recovering were corals collected from Turneffe Atoll, which is farther offshore than the main Belize Barrier Reef and Cayos Cochinos, a marine biological reserve off the northern coast of Honduras. Those that took longer to recover to pre-1998 conditions were from the Sapodilla Cayes in southern Belize and Utila in Honduras. The Sapodilla Cayes are a marine protected area, but experience significant runoff impacts; meanwhile Utila is quite heavily populated and local impacts probably result from development, sewage and other sources.

Millions Of Pounds Of Trash Found On Ocean Beaches

Trash on a beach. Trash in the ocean kills more than one million seabirds and 100,000 marine mammals and turtles each year through ingestion and entanglement. (Credit: NOAA)

ScienceDaily — Ocean Conservancy released its annual report on trash in the ocean with new data from the 2007 International Coastal Cleanup the most comprehensive snapshot of the harmful impacts of marine debris. The mission of Ocean Conservancy’s International Coastal Cleanup is to engage people to remove trash from the world’s beaches and waterways, to identify the sources of debris and to change the behaviors that cause pollution.

This year, more than 378,000 volunteers participated in cleanups around every major body of water around the globe. Volunteers record the trash found on land and underwater allowing Ocean Conservancy a global snapshot of the problem.

"Our ocean is sick," says Laura Capps, Senior Vice President at Ocean Conservancy. "And the plain truth is that our ocean ecosystem cannot protect us unless it is healthy and resilient. Harmful impacts like trash in the ocean, pollution, climate change, and habitat destruction are taking its toll. But the good news is that hundreds of thousands of people from around the world are starting a sea change by joining together to clean up the ocean. Trash doesn’t’ fall from the sky it falls from people’s hands. With the International Coastal Cleanup, everyone has an opportunity to make a difference, not just on one day but all year long."

Trash in the ocean kills more than one million seabirds and 100,000 marine mammals and turtles each year through ingestion and entanglement. This year, 81 birds, 63 fish, 49 invertebrates, 30 mammals 11 reptiles and one amphibian were found entangled in debris by volunteers. Some of the debris they were entangled or had ingested include plastic bags, fishing line, fishing nets, six-pack holders, string from a balloon or kite, glass bottles and cans.

Entanglement in Ocean Trash

• Wraps around flippers causing circulation loss and amputations
• Creates wounds and cuts leading to bacterial infections
• Slows animals ability to swim making them more vulnerable to predators
• Smothers or traps animals, causing them to drown
• Causes starvation as animals can no-longer eat or feed its young

Ingestion of Ocean Trash

• Leads to starvation by blocking digestive tracks
• Provides false sense of being full once swallowed, which leads to starvation
• Ingests sharp objects like metal or glass that perforate the stomach, causing internal bleeding
• Becomes lodged in animals windpipes, cutting off airflow and causing suffocation

How Long Does It Take for Trash in the Ocean to Decompose?

• A tin can that entered the ocean in 1986 is still decomposing in 2036
• A plastic bottle that entered the ocean in 1986 is decomposing in 2436
• A glass bottle that entered the ocean in 1986 is decomposing in year 1,001,986

Prevention is the real solution to trash in the ocean. The International Coastal Cleanup volunteers make ocean conservation an everyday priority. Since 1986, more than six million volunteers have removed 116,000,000 pounds of debris across 211,460 miles of shoreline in 127 nations. The 23rd annual Flagship International Coastal Cleanup will be held Sept. 20, 2008.

'Jellyfish Joyride' A Threat To The Oceans

ScienceDaily — Early action could be crucial to addressing the problem of major increases in jellyfish numbers, which appears to be the result of human activities.

New research led by CSIRO Climate Adaptation Flagship and University of Queensland scientist, Dr Anthony Richardson, presents convincing evidence that this ’jellyfish joyride’ is associated with over-fishing and excess nutrients from fertilisers and sewage.

“Dense jellyfish aggregations can be a natural feature of healthy ocean ecosystems, but a clear picture is now emerging of more severe and frequent jellyfish outbreaks worldwide,” Dr Richardson says.

“In recent years, jellyfish blooms have been recorded in the Mediterranean, the Gulf of Mexico, the Black and Caspian Seas, the Northeast US coast, and particularly in Far East coastal waters.

“The most dramatic have been the outbreaks in the Sea of Japan involving the gargantuan Nomura jellyfish which can grow up to 2 m in diameter and weigh 200 kg.”

The new research, by Dr Richardson and colleagues at the University of Miami, Swansea University and the University of the Western Cape, has been published in the international journal; Trends in Ecology and Evolution, in time for World Oceans Day on 8 June.

“Fish normally keep jellyfish in check through competition and predation but overfishing can destroy that balance,” Dr Richardson says. “For example, off Namibia intense fishing has decimated sardine stocks and jellyfish have replaced them as the dominant species.”

Climate change may favour some jellyfish species by increasing the availability of flagellates in surface waters – a key jellyfish food source. Warmer oceans could also extend the distribution of many jellyfish species.

“Mounting evidence suggests that open-ocean ecosystems can flip from being dominated by fish, to being dominated by jellyfish,” Dr Richardson says “This would have lasting ecological, economic and social consequences.

“We need to start managing the marine environment in a holistic and precautionary way to prevent more examples of what could be termed a ‘jellyfish joyride’.”

Journal reference:

1. Richardson et al. The jellyfish joyride: causes, consequences and management responses to a more gelatinous future. Trends in Ecology & Evolution, 2009; 24 (6): 312 DOI: 10.1016/j.tree.2009.01.010

Adapted from materials provided by CSIRO Australia.

Good News About Ocean Methane

Methane, a potent greenhouse gas, is emitted in great quantities as bubbles from seeps on the ocean floor near Santa Barbara. About half of these bubbles dissolve into the ocean, but the fate of this dissolved methane remains uncertain. Researchers at the University of California, Santa Barbara have discovered that only one percent of this dissolved methane escapes into the air -- good news for the Earth's atmosphere.

Coal Oil Point, one of the world's largest and best studied seep regions, is located along the northern margin of the Santa Barbara Channel. Thousands of seep fields exist in the ocean bottom around the world, according to David Valentine, associate professor of Earth Science at UC Santa Barbara. Valentine along with other members of UCSB's seeps group studied the plume of methane bubbles that flows from the seeps at COP.

Their results will soon be published as the cover story in Volume 34 of Geophysical Research Letters. This research effort is the first time that the gas that dissolves and moves away from COP, the plume, has been studied.

The amount of methane release from COP seeps is around two million cubic feet per day, according to Valentine. About 100 barrels of oil oozes out of this area as well. Methane warms the Earth 23 times more than carbon dioxide when averaged over a century. Thus the fate of the methane bubbles from the seeps is an important environmental question.

"We found that the ocean has an amazing capacity to take up methane that is released into it -- even when it is released into shallow water," said Valentine. "Huge amounts of gas are coming up here, creating a giant gas plume. Until now, no one had measured the gas that dissolves and moves away, the plume."

Valentine hypothesized that the methane is oxidized by microbial activity in the ocean, thus relieving the ocean of the methane "burden."

To arrive at this hypothesis, Valentine and lead author Susan Mau, a postdoctoral fellow in Valentine's lab, tracked the plume down current from the seeps at 79 surface stations in a 280 square kilometer study area. They found that the methane plume spread over 70 square kilometers.

By boat, the authors sampled the water on a monthly basis. They found variable methane concentrations that corresponded with changes in surface currents. They also found that more wind releases more methane into the atmosphere. Overall, they discovered that about one percent of the dissolved methane escapes into the atmosphere in the area they studied, a long-term average. This lead the authors to hypothesize that most of the methane is transported below the ocean's surface -- away from the seep area. Then it is oxidized by microbial activity.

To back up their findings of their surface sampling of the water, the scientists used a mass spectrometer hauled behind the boat as well. This equipment allowed for very high-resolution chemical information about the methane. This effort showed no significant difference in the numbers.

"We showed that the currents control the fate of the gas and supply it to bacteria in a way that allows them to destroy the methane," said Valentine.

Valentine said that while the seeps at COP are among the largest in the world, they can be found just about anywhere.

Source: http://www.ucop.edu/sciencetoday/article/17087