The 500 million years ocean history

Brachiopod Paraspirifer bownockeri from the Middle Devonian of Ohio (USA); Width: 5.6 cm. Picture: U. Jansen, Senckenberg Museum, Frankfurt am Main.

GEOMAR coordinates European research and education project BASE-LiNE Earth
02.03.2015 / Kiel. As the history of the oceans can be reconstructed in the past 500 million based on calcareous shells of fossil marine life, busy to date with the research project BASE-LiNE Earth. At the same time it enables talented young scientists and scientists a doctorate in an international research environment. The European Union supports the at GEOMAR Helmholtz Centre for Ocean Research Kiel coordinated project with a total of 3.8 million euros.

Almost all life on earth would be extinct - and that at least five times in the past 500 million years. The environmental changes that have each led to the mass extinction, the oceans play an important role in almost all cases. How did it happen that was phased so hostile to life as a life-giving force sea? And why have some species still survive? These are fundamental questions that will be examined in the next three years as part of the European research project BASE-LiNE Earth with innovative technologies and methods. In addition to answering the research questions BASE LiNE Earth serves as the training of talented young scholars and scientists who are recruited by means of a demanding selection process from all over the world and doctorate within the scope of the project. 

The EU promotes the GEOMAR Helmholtz Centre for Ocean Research Kiel coordinated project under a Marie Skłodowska-Curie Action in Horizon2020-Pogramm with a total of 3.8 million euros. The challenge for the future BASE-LiNE Earth-doctoral students, is to provide information to gain from distant epochs of earth's history. "When historians want to know about events 100 or 200 years ago, they visit libraries or archives where there is written evidence from these times," says project coordinator Prof. Dr. Anton Eisenhauer from GEOMAR. "We also use archives. 
However, they see something different. It is, for example, the calcareous shells of fossil brachiopods in which the relevant data on the chemical history of ocean water are stored reliably, "explains the Kiel geochemist on. 

The information is in the calcite shells of course not writing before, but encrypted in the chemical and mineralogical composition. "If we precise the ratios of elements such as strontium, magnesium, boron, or measure of the isotopic to each other, we can decrypt the information," says Professor Eisenhauer.

This then the age of the shell, as well as the chemical composition of the previous ocean and prevailing environmental conditions such as water temperature and the acidity of the water can be reconstructed. We know, for example, know that during the greatest mass extinction 251 million years ago, the ocean contained no oxygen and was acidified to a large extent. 

"This is similar to some scenarios that we expect for the future of our ocean," explains Professor Eisenhauer. Model calculations are carried out within the framework of the project should show how far the former changes in the environment are transferable to the present day. The challenge is to gain this information and to make it usable. In collaboration with industry partners modern analytical methods for obtaining information in cooperation with business partners in this area in the context of BASE-LiNE Earth therefore be generated and developed. The project involves a total of 21 scientific institutions from eight European countries and partners from Canada, Israel, Palestine and Australia involved. 15 PhD positions will announce the project this spring, two of them for the GEOMAR in Kiel. 

The Integrated School of Ocean Sciences (ISOS) provides at the University of Kiel for a comprehensive training program in which the scholars not only pursue their academic goals, but also learn more professional qualifications, skills and interact with each other.  In the coming years, the parties want to do their topic also by means of exhibitions and school supplies to a wider audience. "Of course we also bind the doctoral students, which thus also learn to communicate their work understandable," says the project coordinator. For more information on the project website www.baseline-earth.eu.

Source: Geomar

Deep Sea Mining: What are the risks?

During the launch event in Kiel, the project partners plan investigations to ecosystems around the manganese nodules. Photo: J. Steffen, GEOMAR

GEOMAR coordinates European cooperation for the risk assessment
01.29.2015 / Kiel. 50 specialists in deep-sea ecology, marine mining and deep-sea observation of 25 European research institutions meeting this week at the GEOMAR Helmholtz Centre for Ocean Research Kiel. This will free the start of a three-year research project to investigate the risks of potential ore mining on the seabed. The project called "JPI Oceans Ecological aspects of deep-sea mining" is coordinated at GEOMAR.

The world population is growing. This also means that more and more people need a home, want to work with computers and other electronic devices and consume energy. For the construction of houses for the manufacture of electronic goods, but also for the production of wind turbines will require significant amounts of various metals. Currently, all metal ores are promoted on almost a third of the earth's surface - on the continents. 

In some regions of the ocean manganese nodules are recorded in the Atlantic as here, close together on the ocean floors. Photo: Nils Brenke, CeNak

However, in recent decades engaged again, the other two thirds, the oceans, the focus of governments and resource companies. "Many questions about a potential ore mining in the deep sea, however, are still open," says Dr. Matthias Haeckel from GEOMAR Helmholtz Centre for Ocean Research Kiel. He is the scientific coordinator of the "Ecological aspects of deep-sea mining" project to investigate the potential environmental risks in the next three years. A consortium of research ministries in eleven European countries promotes it as part of the Joint Programme Healthy and Productive Seas (JPI Oceans) initiative with a total of 9.5 million euros. 

 In the Clarion-Clipperton Zone are the largest known manganese nodule deposits. Here, the ISA has been awarded 13 research licenses. Image Reproduced from the GEBCO world map 2014

This week, the project starts with a kick-off meeting at GEOMAR. A total of 25 partner institutions from these eleven countries involved in the project. The focus is primarily known as manganese nodules. It is spherical or cauliflower-shaped Erzknollen, which are usually at depths below 4000 meters on the large abyssal plains. They consist not only from the eponymous manganese, but also contain iron and coveted metals such as copper, cobalt or nickel. Already in the 1970s, there were initial plans to reduce manganese nodules from the deep sea, but never came out on trials. The largest reserves are currently known from the Clarion-Clipperton Fracture Zone in the central Pacific. As a result of these activities in international waters on the basis of the International Law of the Sea (UNCLOS), the International Seabed Authority (International Seabed Authority, ISA) was founded in 1994. 

It manages the entire seabed beyond the exclusive economic zone (200 nautical miles) of individual states. To date, the ISA has awarded 13 research licenses for exploration of manganese nodule fields in the Pacific, including in Germany and other European countries. 

                     Sample of the seabed in DISCOL area with top resting manganese nodules. 
                                                    Photo: M. Haeckel, GEOMAR

"But there is no mining licenses, which would only be a next step," said Dr. Haeckel. Since the ISA also aims to ensure effective protection of the marine environment from the potential consequences of ocean mining, relevant research for the licensees are required. "Of course industrial activities on the ocean floor will have an impact, because they disturb the soil and the water column about it," says Dr. Haeckel. Therefore, it is important to know the ecosystems on the sea floor and its local, regional and national connections and interactions accurately. Already this year, several expeditions of the new German research vessel SONNE in the Pacific are planned. 

The first trips in March and April perform the participating scientists to the German, Belgian and French license areas and in a defined by the ISA reserve in the Clarion-Clipperton Zone. Further trips from July to October have the so-called DISCOL area in Peru Basin to the destination. There, in 1989, a very limited area of the seabed was plowed for research purposes. "The goal of this experiment is to recognize the long-term consequences of large-area device used for deep-sea sediments," explains Professor Jens Greinert from GEOMAR, who will lead one of the exits to DISCOL area. Now, a quarter century after the disturbance experiment, the scientists will examine the then machined seabed areas exactly compare with adjacent undisturbed areas to determine, can recover disturbed communities in the deep sea as fast. "We should get to know each other better before we start, a large area to intervene in the deep sea it easy," says project coordinator Dr. Haeckel. 

Source: GEOMAR

NASA Study Finds Earth’s Ocean Abyss Has Not Warmed

While the upper part of the world’s oceans continue to absorb heat from global warming, ocean depths have not warmed measurably in the last decade. This image shows heat radiating from the Pacific Ocean as imaged by the NASA’s Clouds and the Earth's Radiant Energy System instrument on the Terra satellite. (Blue regions indicate thick cloud cover.) Image Credit: NASA

The cold waters of Earth’s deep ocean have not warmed measurably since 2005, according to a new NASA study, leaving unsolved the mystery of why global warming appears to have slowed in recent years.

Scientists at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, analyzed satellite and direct ocean temperature data from 2005 to 2013 and found the ocean abyss below 1.24 miles (1,995 meters) has not warmed measurably. Study coauthor Josh Willis of JPL said these findings do not throw suspicion on climate change itself.

"The sea level is still rising," Willis noted. "We're just trying to understand the nitty-gritty details."

In the 21st century, greenhouse gases have continued to accumulate in the atmosphere, just as they did in the 20th century, but global average surface air temperatures have stopped rising in tandem with the gases. The temperature of the top half of the world's oceans -- above the 1.24-mile mark -- is still climbing, but not fast enough to account for the stalled air temperatures.

Many processes on land, air and sea have been invoked to explain what is happening to the "missing" heat. One of the most prominent ideas is that the bottom half of the ocean is taking up the slack, but supporting evidence is slim. This latest study is the first to test the idea using satellite observations, as well as direct temperature measurements of the upper ocean. Scientists have been taking the temperature of the top half of the ocean directly since 2005, using a network of 3,000 floating temperature probes called the Argo array.

"The deep parts of the ocean are harder to measure," said JPL's William Llovel, lead author of the study published Sunday in the journal Nature Climate Change. "The combination of satellite and direct temperature data gives us a glimpse of how much sea level rise is due to deep warming. The answer is -- not much."

Deep sea creatures, like these anemones at a hydrothermal vent, are not yet feeling the heat from global climate change. Although the top half of the ocean continues to warm, the bottom half has not increased measurably in temperature in the last decade. Image Credit: NERC

The study took advantage of the fact that water expands as it gets warmer. The sea level is rising because of this expansion and the water added by glacier and ice sheet melt.
To arrive at their conclusion, the JPL scientists did a straightforward subtraction calculation, using data for 2005-2013 from the Argo buoys, NASA's Jason-1 and Jason-2 satellites, and the agency’s Gravity Recovery and Climate Experiment (GRACE) satellites. 
From the total amount of sea level rise, they subtracted the amount of rise from the expansion in the upper ocean, and the amount of rise that came from added meltwater. The remainder represented the amount of sea level rise caused by warming in the deep ocean.
The remainder was essentially zero. Deep ocean warming contributed virtually nothing to sea level rise during this period.

Coauthor Felix Landerer of JPL noted that during the same period warming in the top half of the ocean continued unabated, an unequivocal sign that our planet is heating up. Some recent studies reporting deep-ocean warming were, in fact, referring to the warming in the upper half of the ocean but below the topmost layer, which ends about 0.4 mile (700 meters) down.

Landerer also is a coauthor of another paper in the same journal issue on 1970-2005 ocean warming in the Southern Hemisphere. Before Argo floats were deployed, temperature measurements in the Southern Ocean were spotty, at best. Using satellite measurements and climate simulations of sea level changes around the world, the new study found the global ocean absorbed far more heat in those 35 years than previously thought -- a whopping 24 to 58 percent more than early estimates.

Both papers result from the work of the newly formed NASA Sea Level Change Team, an interdisciplinary group tasked with using NASA satellite data to improve the accuracy and scale of current and future estimates of sea level change. The Southern Hemisphere paper was led by three scientists at Lawrence Livermore National Laboratory in Livermore, California.

NASA monitors Earth's vital signs from land, air and space with a fleet of satellites and ambitious airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

Source: Nasa

Stanford scientists use ocean waves to monitor offshore oil and gas fields

A new technique for passively probing the sea floor using weak seismic waves generated by the ocean was tested at the Ekofisk oil field in the North Sea. 

A technology developed by Stanford scientists for passively probing the seafloor using weak seismic waves generated by the ocean could revolutionize offshore oil and natural gas extraction by providing real-time monitoring of the subsurface while lessening the impact on marine life.

"We've shown that we can generate images of the subsurface nearly every day instead of taking snapshots just two or three times a year," said Biondo Biondi, professor of geophysics at Stanford's School of Earth Sciences.

Currently, many energy companies use a technique called time-lapse reflection seismology to monitor offshore oil and gas deposits to optimize production and look for hazards such as hidden gas pockets. Reflection seismology involves ships towing arrays of "air guns" that explode every 10 to 15 seconds to produce loud sound pulses. The pulses bounce off the seafloor and geological formations beneath, then journey back to the surface, where they are recorded by hydrophones. The data are then deciphered to reveal details about subsurface structures.

Each survey can cost tens of millions of dollars, and as a result they are only conducted two to three times a year. Environmental groups and marine biologists have expressed concerns about the use of air guns for contributing to noise pollution in the ocean that can disturb or even injure marine animals, including humpback whales and giant squid.

The new technique developed by Biondi and Sjoerd de Ridder, a student of Biondi's who is now a postdoctoral scientist at the University of Edinburgh, is different. It exploits naturally occurring seismic waves generated by Earth's oceans that are several orders of magnitude weaker than those produced by earthquakes.

Ambient seismicity

As ocean waves collide with one another, they create pressures on the sea floor, where they generate seismic waves that then propagate in every direction. Scientists have known about this "ambient seismic field" for nearly a century, but it was only recently that they understood ways to harness it.

"We knew the ambient seismic energy was there, but we didn't know what we could do with it," De Ridder said. "That understanding has only been developed in recent years. Our technique provides the first large-scale application to harness it for oil and gas production."

The technique that Biondi and De Ridder developed, called ambient seismic field noise-correlation tomography, or ASNT, uses sensors embedded in the seafloor. The sensors, which are typically installed by robotic submersibles, are connected to one another by cables and arranged into parallel rows that can span several kilometers of the seafloor. Another cable connects the sensor array to a platform in order to collect data in real time.

The sensors record ambient seismic waves traveling through Earth's crust. The waves are ubiquitous, continuously generated and traveling in every direction, but using careful signal-processing schemes they developed, Biondi and De Ridder can digitally isolate only those waves that are passing through one sensor and then another one downstream. When this is done repeatedly, and for multiple sensors in the network, what emerges is a "virtual" seismic wave pattern that is remarkably similar to the kind generated by air guns.

Less disruptive

Because the ASNT technique is entirely passive, meaning it does not require a controlled explosion or a loud air gun blast to create a seismic wave signature, it can be performed for a fraction of the cost of an active-reflection-seismology survey and should be far less disruptive to marine life, the scientists say.

Since 2007, Biondi and De Ridder have been testing and refining their technique in a real-world laboratory in Europe. The scientists worked with the energy companies BP and ConocoPhillips to study recordings from existing sensor arrays in the Valhall and Ekofisk oil fields in the North Sea that are capable of recording ambient seismic waves.

The proof-of-concept experiment has been successful, and the scientists have demonstrated that they can image the subsurface at Valhall down to a depth of nearly 1,000 feet. "We've now shown that our technique can very reliably and repeatedly retrieve an image of the near-surface," De Ridder said. "Our hope is that they can also reveal changes in the rocks that could signal an impending problem."

Source: Stanford

Teeth, sex and testosterone reveal secrets of aging in wild mouse lemurs

A brown mouse lemur in the wild. Mouse lemurs, weighing a mere 30 to 80 grams, are the world's smallest primates. Credit: Jukka Jernvall

Mouse lemurs can live at least eight years in the wild -- twice as long as some previous estimates, a long-term longitudinal study finds.

PLOS ONE published the research on brown mouse lemurs (Microcebus rufus) led in Madagascar by biologist Sarah Zohdy, a post-doctoral fellow in Emory's Department of Environmental Sciences and the Rollins School of Public Health. Zohdy conducted the research while she was a doctoral student at the University of Helsinki.

"It's surprising that these tiny, mouse-sized primates, living in a jungle full of predators that probably consider them a bite-sized snack, can live so long," Zohdy says. "And we found individuals up to eight years of age in the wild with no physical symptoms of senescence like some captive mouse lemurs start getting by the age of four."

It is likely that starvation, predation, disease and other environmental stressors reduce the observed rate of senescence in the wild, Zohdy notes, but a growing body of evidence also suggests that captive conditions may affect mental and physical function.

"We focused on wild mouse lemurs because we want to know what happens naturally when a primitive primate is exposed to all of the extrinsic and intrinsic mortality factors that shaped them as a species," Zohdy says. "Comparing longevity data of captive and wild mouse lemurs may help us understand how the physiological and behavioral demands of different environments affect the aging process in other primates, including humans."

The study determined ages of wild mouse lemurs in Madagascar's Ranomafana National Park through a dental mold method that had not previously been used with small mammals. In addition to the high-resolution tooth-wear analysis for aging, fecal samples underwent hormone analysis.

The researchers found no difference between the longevity of male and female mouse lemurs, unlike most vertebrates where males tend to die first.

"And even more interestingly, we found no difference in testosterone levels between males and females," Zohdy says. Mouse lemurs are female dominant, which may explain why their testosterone levels are on a par with males.

"While elevated male testosterone levels have been implicated in shorter lifespans in several species, this is one of the first studies to show equivalent testosterone levels accompanying equivalent lifespans," Zohdy says.

A co-author of the study is primatologist Patricia Wright of the Centre ValBio Research Station in Madagascar and Stony Brook University. Other institutions involved in the study include Colorado State University, Duke University and the University of Arizona, Tucson.
Mouse lemurs, found only on the island of Madagascar, are the world's smallest primates. They are among nearly 100 species of lemurs that arrived in Madagascar some 65 million years ago, perhaps floating over from mainland Africa on mats of vegetation.

Mouse lemurs weigh a mere 30 to 80 grams but in captivity they live six times longer than mammals of similar body size, such as mice or shrews. Captive gray mouse lemurs (Microcebus murinus) can live beyond age 12. By age four, however, they can start exhibiting behavioral and neurologic degeneration. In addition to slowing of motor skills and activity levels, reduced memory capacity and sense of smell, the captive four-year-olds can start developing gray hair and cataracts, Zohdy says.

The wild brown mouse lemurs in the study were trapped, marked and released during the years 2003 to 2010. A total of 420 dental impressions were taken from the lower-right mandibular tooth rows of 189 unique individuals. Over the course of seven years, 270 age estimates were calculated. For 23 individuals captured three or more times during the duration of the study, the regression slopes of wear rates were calculated and the mean slope was used to calculate ages for all individuals.

"We found that wild brown mouse lemurs can live at least eight years," Zohdy says. "In the population that we studied, 16 percent lived beyond four years of age. And we found no physical signs of senescence, such as graying hair or cataracts, in any wild individual."

Limitations of the study include the inability to document gradual physiological symptoms of senescence in the wild. "Our results do not provide information about wild brown mouse lemurs that can be directly compared to senescence in captive gray mouse lemurs," Zohdy says. "Further research, using identical measures of senescence, will help to reveal whether patterns of physiological senescence occur consistently across the genus and in both captive and wild conditions."

Another confounding factor Zohdy cites is "the Sleeping Beauty effect," the fact that wild mouse lemurs hibernate for half the year, possibly boosting their life span.
"We now know that mouse lemurs can live a relatively long time in the wild," she says, "but we don't know the exact mechanisms behind why they live so long."

Source: Emory Health Sciences

Dolphins are attracted to magnets: Add dolphins to the list of magnetosensitive animals, French researchers say

Bottlenose dolphins

Add dolphins to the list of magnetosensitive animals, French researchers say. Dolphins are indeed sensitive to magnetic stimuli, as they behave differently when swimming near magnetized objects. So says Dorothee Kremers and her colleagues at Ethos unit of the Université de Rennes in France, in a study in Springer's journal Naturwissenschaften -- The Science of Nature. Their research, conducted in the delphinarium of Planète Sauvage in France, provides experimental behavioral proof that these marine animals are magnetoreceptive.

Magnetoreception implies the ability to perceive a magnetic field. It is supposed to play an important role in how some land and aquatic species orientate and navigate themselves. Some observations of the migration routes of free-ranging cetaceans, such as whales, dolphins and porpoises, and their stranding sites suggested that they may also be sensitive to geomagnetic fields.

Because experimental evidence in this regard has been lacking, Kremers and her colleagues set out to study the behavior of six bottlenose dolphins in the delphinarium of Planète Sauvage in Port-Saint-Père. This outdoor facility consists of four pools, covering 2,000 m² of water surface. They watched the animals' spontaneous reaction to a barrel containing a strongly magnetized block or a demagnetized one. Except from this characteristic, the blocks were identical in form and density. The barrels were therefore indistinguishable as far as echolocation was concerned, the method by which dolphins locate objects by bouncing sound waves off them.

During the experimental sessions, the animals were free to swim in and out of the pool where the barrel was installed. All six dolphins were studied simultaneously, while all group members were free to interact at any time with the barrel during a given session. The person who was assigned the job to place the barrels in the pools did not know whether it was magnetized or not. This was also true for the person who analyzed the videos showing how the various dolphins reacted to the barrels.

The analyses of Ethos team revealed that the dolphins approached the barrel much faster when it contained a strongly magnetized block than when it contained a similar not magnetized one. However, the dolphins did not interact with both types of barrels differently. They may therefore have been more intrigued than physically drawn to the barrel with the magnetized block.

"Dolphins are able to discriminate between objects based on their magnetic properties, which is a prerequisite for magnetoreception-based navigation," says Kremers. "Our results provide new, experimentally obtained evidence that cetaceans have a magenetic sense, and should therefore be added to the list of magnetosensitive species."

Source: Springer Science+Business Media

Trade winds ventilate the tropical oceans: Explanation for increasing oxygen deficiency

Scheme of the tropical Pacific: Strong growth of plankton (1) leads to a high oxygen consumption and extended oxygen minimum zones (2). Ocean currents (3) at a few hundred meters depth provide an influx of oxygenated water from the subtropics (4). Fluctuations of the trade winds (5) influence the strength of these currents. Credit: Graphics: Claus Böning, Markus Scheinert, GEOMAR

Long-term observations indicate that the oxygen minimum zones in the tropical oceans have expanded in recent decades. The reason is still unknown. Now scientists at the GEOMAR Helmholtz Centre for Ocean Research Kiel and the Collaborative Research Centre 754 "Climate -- Biogeochemical Interactions in the Tropical Ocean" have found an explanation with the help of model simulations: a natural fluctuation of the trade winds. The study has been published in the international journal Geophysical Research Letters.

The changes can be measured, but their reasons were unknown. For several decades, scientists have carefully observed that the oxygen minimum zones (OMZ) in the tropical oceans are expanding. These zones are a paradise for some specially adapted microorganisms, but for all larger marine organisms such as fish and marine mammals they are uninhabitable. Thus, their expansion has already narrowed down the habitat of some fish species.

Marine scientists from the GEOMAR Helmholtz Centre for Ocean Research Kiel and the Kiel Collaborative Research Centre (Sonderforschungsbereich, SFB) 754 "Climate -- Biogeochemical Interactions in the Tropical Ocean" now have found a possible reason for these changes by using a model simulation of climate and biological processes. As their study shows, the trade winds north and south of the Equator play a crucial role in the supply of oxygen to tropical sea water. "So fluctuations in the trade winds could also be responsible for the observed enlargement of the oxygen minimum zones in recent years," explains Dr. Olaf Duteil, lead author of the study, which has now been published in the international journal Geophysical Research Letters.

OMZs exist in different intensities at the eastern edges of all tropical oceans. Because nutrient-rich water from the depths reaches the surface in these areas plankton thrives particularly well. Therefore large amounts of plankton organisms die there, too. After their death they sink down to the ocean floor. On the way down bacteria start to decompose the biomass. In doing so they consume the oxygen. The largest of these OMZs stretches from the coasts of Chile and Peru far into the Pacific ocean.

At the same time currents at a few hundred meters depth transport oxygen-rich water from the subtropics towards the tropics, where the oxygen minimum zones lie. "One can think of the tropical Pacific Ocean as a bathtub. When I open the tap, I fill the bathtub with water or 'oxygen', respectively. When the siphon is open, too, we lose oxygen at the same time. We then have an instable equilibrium between input and output," explains Dr. Duteil, "If I turn off the tap a little, the tub empties slowly."

As the researchers were able to determine in a computer simulation of the oxygen balance now, the strength of the currents and thus the oxygen flow to the tropics is directly related to the strength of the trade winds. "It is well known that they vary on a decadal time scale," says co-author Prof. Dr. Claus Böning from GEOMAR, "but these variations haven never been investigated in relation to the oxygen budget of tropical oceans. "

Since the trade winds have been in a weak phase since the mid-1970s, this could be the explanation for the observed enlargement of the oxygen minimum zones. "The oxygen bathtub of the tropical oceans is emptying," says Dr. Duteil. Once the trade winds come back into a stronger phase, the process will be reversed.

This does not mean that external processes such as the general global warming have no influence on the oxygen concentrations in the tropical oceans. "There is evidence that global change affects the major wind systems of the Earth. That would have a direct impact on the oxygen transport in the subtropical and tropical ocean," explains Prof. Andreas Oschlies, co-author and speaker of the SFB 754. "But it is important that according to this study the trade winds in any case as must be considered as a factor for long-term development of tropical oxygen minimum zones," Oschlies adds.

Source: Helmholtz Centre for Ocean Research Kiel (GEOMAR)

Microplastics in the ocean: Biologists study effects on marine animals

A marine isopod of the genus Idotea with food pellets.
Credit: Photo Alfred Wegener Institute / Julia Hämer

Ingestion of microplastic particles does not mechanically affect marine isopods. This was the result of a study by biologists at the North Sea Office of the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) that was published recently in the journal Environmental Science and Technology. The study marks the launch of a series of investigations aimed at forming a risk matrix on the sensitivity of different marine species to microplastic pollution.

Uptake of large plastic items by birds and fish may cause blockage of the gastrointestinal tract and severe starvation of the animals. "We were wondering whether small plastic particles have a comparable effect on smaller animals," says Dr. Lars Gutow from AWI's North Sea Office. "Only very limited research has been done on the effects of microplastics on living beings. Accordingly, there is great uncertainty about the implications for marine animals," the biologist explains the motivation for the study.

Lars Gutow and his colleagues selected the isopod Idotea emarginata as their model organism for an initial case study. In feeding experiments the researchers offered the isopods artificial algal food supplemented with plastic particles. The food contained three different kinds of microplastics in varying concentrations. They used industrially produced polystyrene particles with a diameter of ten micrometers as well as self-made fragments and fibres made of polyethylene and polyacryl, respectively.

The researchers studied the fate of the different materials under a light microscope, with the help of a fluorescence microscope, and with an electron microscope. They were able to trace the path of the microplastic particles through the isopods and determine the concentrations of the particles in different sections of the digestive system. The study showed that the concentration of microplastics in the faecal material of the isopods was as high as in the food. The scientists found small amounts of microplastics both in the stomach and in the gut of the animals. However, they did not detect any microparticles in the digestive glands. "The isopods ingested and excreted the artificial food with the microplastic particles without absorbing or accumulating the particles," Gutow summarises the results. Thus, plastic particles in the specific size range studied do not represent a direct mechanical risk for isopods and probably not for other crustaceans either. "In the case of Idotea emarginata, the microplastic particles did not enter the digestive gland, which is the principle organ in crustaceans where digestion and resorption of nutrients takes place," states the biologist from AWI's North Sea Office.

In a long-term experiment the scientists could also show that isopods did not display any long-term effects even after feeding on microplastic enriched food for six to seven weeks. 

Fitness parameters such as survival rate and growth did not differ between animals that were fed with and without microplastics, respectively. In an earlier study, however, AWI biologist Prof. Dr. Angela Köhler demonstrated that mussels show inflammatory reactions if they take up and absorb high concentrations of microplastic in an experiment. This clearly shows that different animal species react differently to microplastics. "In contrast to filter feeding mussels, isopods of the genus Idotea probably take up more frequently indigestible particles with their food in their natural habitat and may, thus, have adapted accordingly," elucidates Gutow.

But the biologists are not only interested in the feeding type: "We want to study systematically how the life style, habitat, physiology and anatomy of different marine organisms influence the uptake and utilisation of microplastic particles in order to come up with a risk matrix for diverse types of organisms," says Lars Gutow. "Therefore, it will be necessary to also study the possible chemical (toxic) and biochemical effects in addition to the physical effects that we looked at," he outlines future tasks.

Source: Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research

Atlantic warming turbocharges Pacific trade winds

Tropical beach (stock image). Rapid warming of the Atlantic Ocean, likely caused by global warming, has turbocharged Pacific Equatorial trade winds, according to new research. Credit: © michaelfitz / Fotolia

New research has found rapid warming of the Atlantic Ocean, likely caused by global warming, has turbocharged Pacific Equatorial trade winds. Currently the winds are at a level never before seen on observed records, which extend back to the 1860s.

The increase in these winds has caused eastern tropical Pacific cooling, amplified the Californian drought, accelerated sea level rise three times faster than the global average in the Western Pacific and has slowed the rise of global average surface temperatures since 2001.

It may even be responsible for making El Nino events less common over the past decade due to its cooling impact on ocean surface temperatures in the eastern Pacific.

"We were surprised to find the main cause of the Pacific climate trends of the past 20 years had its origin in the Atlantic Ocean," said co-lead author Dr Shayne McGregor from the ARC Centre of Excellence for Climate System Science (ARCCSS) at the University of New South Wales.

"It highlights how changes in the climate in one part of the world can have extensive impacts around the globe."

The record-breaking increase in Pacific Equatorial trade winds over the past 20 years had, until now, baffled researchers.

Originally, this trade wind intensification was considered to be a response to Pacific decadal variability. However, the strength of the winds was much more powerful than expected due to the changes in Pacific sea surface temperature.

Another riddle was that previous research indicated that under global warming scenarios Pacific Equatorial Trade winds would slow down over the coming century.

The solution was found in the rapid warming of the Atlantic Ocean basin, which has created unexpected pressure differences between the Atlantic and Pacific. This has produced wind anomalies that have given Pacific Equatorial trade winds an additional big push.

"The rapid warming of the Atlantic Ocean created high pressure zones in the upper atmosphere over that basin and low pressure zones close to the surface of the ocean," said Prof Axel Timmermann co-lead and corresponding author from the University of Hawaii.

"The rising air parcels, over the Atlantic eventually sink over the eastern tropical Pacific, thus creating higher surface pressure there. The enormous pressure see-saw with high pressure in the Pacific and low pressure in the Atlantic gave the Pacific trade winds an extra kick, amplifying their strength. It's like giving a playground roundabout an extra push as it spins past."

Many climate models appear to have underestimated the magnitude of the coupling between the two ocean basins, which may explain why they struggled to produce the recent increase in Pacific Equatorial trade wind trends.

While active, the stronger Equatorial trade winds have caused far greater overturning of ocean water in the West Pacific, pushing more atmospheric heat into the ocean, as shown by co-author and ARCCSS Chief Investigator Prof Matthew England earlier this year. This increased overturning appears to explain much of the recent slowdown in the rise of global average surface temperatures.

Importantly, the researchers don't expect the current pressure difference between the two ocean basins to last. When it does end, they expect to see some rapid changes, including a sudden acceleration of global average surface temperatures.

"It will be difficult to predict when the Pacific cooling trend and its contribution to the global hiatus in surface temperatures will come to an end," Prof England said.

"However, a large El Niño event is one candidate that has the potential to drive the system back to a more synchronized Atlantic/Pacific warming situation."

Source: University of New South Wales

Long-running Jason-1 ocean satellite takes final bow

Artist's concept of the joint NASA/CNES Jason-1 ocean altimetry satellite. During its 11-1/2-year life, Jason-1 helped create a 20-plus-year climate record of global ocean surface topography, providing new insights into ocean circulation, tracking our rising seas and enabling more

The curtain has come down on a superstar of the satellite oceanography world that played the "Great Blue Way" of the world's ocean for 11-1/2 years. The successful joint NASA and Centre National d'Etudes Spatiales (CNES) Jason-1 ocean altimetry satellite was decommissioned this week following the loss of its last remaining transmitter.

Launched Dec. 7, 2001, and designed to last three to five years, Jason-1 helped create a revolutionary 20-plus-year climate data record of global ocean surface topography that began in 1992 with the launch of the NASA/CNES Topex/Poseidon satellite. For more than 53,500 orbits of our planet, Jason-1 precisely mapped sea level, wind speed and wave height for more than 95 percent of Earth's ice-free ocean every 10 days. The mission provided new insights into ocean circulation, tracked our rising seas and enabled more accurate weather, ocean and climate forecasts.

"Jason-1 has been a resounding scientific, technical and international success," said John Grunsfeld, associate administrator of NASA's Science Mission Directorate in Washington. 

"The mission met all of its requirements, performed an extended mission and demonstrated how a long-term climate data record should be established from successively launched satellites. Since launch, it has charted nearly 1.6 inches (4 centimeters) of rise in global sea levels, a critical measure of climate change and a direct result of global warming. The Jason satellite series provides the most accurate measure of this impact, which is felt all over the globe."

During parts of its mission, Jason-1 flew in carefully coordinated orbits with both its predecessor Topex/Poseidon and its successor, the Ocean Surface Topography Mission/Jason-2, launched in 2008. These coordinated orbit periods, which lasted about three years each, cross-calibrated the satellites, making possible a 20-plus-year unbroken climate record of sea level change. These coordination periods also doubled data coverage.

Combined with data from the European Space Agency's Envisat mission, which also measured sea level from space, these data allow scientists to study smaller-scale ocean circulation phenomena, such as coastal tides, ocean eddies, currents and fronts. These small-scale features are thought to be responsible for transporting and mixing heat and other properties, such as nutrients and dissolved carbon dioxide, within the ocean.

"Jason-1 was an exemplary and multi-faceted altimeter mission and contributed so much to so many scientific disciplines," said Jean-Yves Le Gall, CNES president in Paris. "Not only did Jason-1 extend the precise climate record established by Topex/Poseidon, it made invaluable observations for mesoscale ocean studies on its second, interleaved orbit. Even from its 'graveyard' orbit, Jason-1 continued to make unprecedented new observations of the Earth's gravity field, with precise measurements right till the end."

The in-orbit Jason-2 mission, operated by the meteorological agencies of the United States and Europe (the National Oceanic and Atmospheric Administration and EUMETSAT, respectively) in collaboration with NASA and CNES, is in good health and continues to collect science and operational data. This same U.S./European team is preparing to launch the next satellite in the series, Jason-3, in March 2015.

Contact was lost with the Jason-1 satellite on June 21 when it was out of visibility of ground stations. At the time of the last contact, Jason-1 and its instruments were healthy, with no indications of any alarms or anomalies. Subsequent attempts to re-establish spacecraft communications from U.S. and French ground stations were unsuccessful. Extensive engineering operations undertaken to recover downlink communications also were unsuccessful.

After consultation with the spacecraft and transmitter manufacturers, it was determined a non-recoverable failure with the last remaining transmitter on Jason-1 was the cause of the loss of contact. The spacecraft's other transmitter experienced a permanent failure in September 2005. There now is no remaining capability to retrieve data from the Jason-1 spacecraft.

On July 1, mission controllers commanded Jason-1 into a safe hold state that reinitialized the satellite. After making several more unsuccessful attempts to locate a signal, mission managers at CNES and NASA decided to proceed with decommissioning Jason-1. The satellite was then commanded to turn off its magnetometer and reaction wheels. Without these attitude control systems, Jason-1 and its solar panels will slowly drift away from pointing at the sun and its batteries will discharge, leaving it totally inert within the next 90 days. The spacecraft will not reenter Earth's atmosphere for at least 1,000 years.

"Like its predecessor Topex/Poseidon, Jason-1 provided one of the most comprehensive pictures of changes in the tropical Pacific Ocean, including the comings and goings of El Nino and La Nina events," said Lee-Lueng Fu, Jason-1 project scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "These Pacific Ocean climate cycles are responsible for major shifts in sea level, ocean temperatures and rainfall every two to five years and can sometimes be so large that worldwide weather patterns are affected. Jason-1 data have been instrumental in monitoring and predicting these ever-changing cycles."

In the spring of 2012, based on concern over the limited redundancy of Jason-1's aging control systems, NASA and CNES moved the satellite into its planned final "graveyard" orbit, depleted its extra fuel and reconfigured the mission to make observations that will improve our knowledge of Earth's gravity field over the ocean, in addition to delivering its oceanographic data products.

The first full 406-day marine gravity mission was completed on June 17. The resulting data have already led to the discovery of numerous small seamounts, which are underwater mountains that rise above the deep-sea floor. The data also have significantly increased the resolution of Earth's gravity field over the ocean, while increasing our knowledge of ocean bathymetry, which is the underwater depth of the ocean floor.

JPL manages the U.S. portion of the Jason-1 mission for NASA's Science Mission Directorate. CNES manages the French portion of the mission.

Source: NASA/Jet Propulsion Laboratory

Intensity of hurricanes: New study helps improve predictions of storm intensity

Rough sea with big waves (stock image). "The air-water interface -- whether it had significant waves or significant spray -- is a big factor in storm intensity," said Alex Soloviev, Ph.D., a professor at Nova Southeastern University's Oceanographic Center. "Hurricanes gain heat energy through the interface and they lose mechanical energy at the interface." Credit: © mimadeo / Fotolia

They are something we take very seriously in Florida -- hurricanes. The names roll off the tongue like a list of villains -- Andrew, Charlie, Frances and Wilma.

In the past 25 years or so, experts have gradually been improving prediction of the course a storm may take. This is thanks to tremendous advancements in computer and satellite technology. While we still have the "cone of uncertainty" we've become familiar with watching television weather reports, today's models are more accurate than they used to be.

The one area, however, where there is still much more to be researched and learned is in predicting just how intense a storm may be. While hurricane hunter aircraft can help determine wind speed, velocity, water temperature and other data, the fact is we often don't know why or how a storm gets stronger or weaker. There has been virtually no progress in hurricane intensity forecasting during the last quarter century.

But, thanks to new research being conducted, all that's about to change.

"The air-water interface -- whether it had significant waves or significant spray -- is a big factor in storm intensity," said Alex Soloviev, Ph.D., a professor at Nova Southeastern University's Oceanographic Center. "Hurricanes gain heat energy through the interface and they lose mechanical energy at the interface."

Soloviev is also an Adjunct Professor at the University of Miami Rosenstiel School of Marine and Atmospheric Science (UM RSMAS) and a Fellow at the Cooperative Institute for Marine and Atmospheric Studies (CIMAS.) He and his fellow researchers used a computational fluid dynamics model to simulate microstructure of the air-sea interface under hurricane force winds. In order to verify these computer-generated results, the group conducted experiments at the UM's Rosenstiel School Air-Sea Interaction Salt Water Tank (ASIST) where they simulated wind speed and ocean surface conditions found during hurricanes.

The study "The Air-Sea Interface and Surface Stress Under Tropical Cyclones" was published in the June 16, 2014 issue of the journal Nature Scientific Reports. Soloviev was the lead author of this study, which was conducted by a multi-institutional team including Roger Lukas (University of Hawaii), Mark Donelan and Brian Haus (UM RSMAS), and Isaac Ginis (University of Rhode Island.)

The researchers were surprised at what they found. Under hurricane force wind, the air-water interface was producing projectiles fragmenting into sub millimeter scale water droplets. This process is known from some engineering applications, including rocket science, as the Kelvin-Helmholtz (KH) instability. This new study then looked at how changes in microphysics of the air-sea interface can make a storm grow or weaken in intensity. With wind speed exceeding a Category 1 threshold, the ocean surface unexpectedly became more "slippery."

When the wind exceeded Category 3 hurricane force, the "slippery" effect started gradually disappearing and was completely gone at Category 5. The conclusion was that some hurricanes might rapidly intensify to Category 3 and then stay in a "comfortable" zone around Category 3 status. This finding is consistent with the global best-track tropical cyclone statistics on maximum intensity for 1982-2009. So far, these early results showed that physical conditions where the air and the ocean interact must be a vital part of any successful hurricane forecasting model and would help explain, and predict, how a storm might intensify as it moves through across the water based on the physical stress at the ocean's surface.

This work has been supported by the NOPP project "Advanced coupled atmosphere-wave-ocean modeling for improving tropical cyclone prediction models" (PIs: Isaac Ginis, URI and Shuyi Chen, UM) and by the Gulf of Mexico Research Initiative (GoMRI) Consortium for Advanced Research on the Transport of Hydrocarbons in the Environment -- CARTHE (PI: Tamay Özgökmen, UM). GoMRI is a 10-year, $500 million independent research program established by an agreement between BP and the Gulf of Mexico Alliance.

The plan is for the team to continue their research and experiments at UM's Alfred C. 

Glassell, Jr. SUSTAIN facility, which has recently been designed by one of the Nature article co-authors, Brian Haus (UM). It's the unique lab facility where they can recreate the conditions found in a Category 5 storm.

"We've got more work to do, but this is a great first step," Soloviev said. "But remember, no matter how good we get in predicting a storm's intensity, people in the path need to prepare accordingly regardless of what Category it is -- that's most important."

Source: Nova Southeastern University

Protect the world's deltas, experts urge

The Atchafalaya River delta meets the Gulf of Mexico. The view is upriver to the northwest. Credit: Photo courtesy A. Belala/U.S. Army Corps of Engineers

Extensive areas of the world's deltas -- which accommodate major cities such as Shanghai, Dhaka and Bangkok -- will be drowned in the next century by rising sea levels, according to a Comment piece in this week's Nature. In the article, Dr. Liviu Giosan, a geologist with the Woods Hole Oceanographic Institution (WHOI), and colleagues call for maintenance efforts to be started now to avert the loss of vast expanses of coastline, and the consequent losses of ecological services, economic and social crises, and large-scale migrations.

The authors state the problems start upstream: deltas are built from sediments deposited at the mouths of rivers, but dams and river engineering have lowered rates of sediment flow. The Nile and the Indus, for example, carry 98 percent and 94 percent less mud respectively than they did 100 years ago. At the coast, rising seas resulting from warmer global temperatures are eroding delta plains, increasing the chance of flooding. Coastal lands lower than a meter in elevation will be inundated within a century.

Lack of quantitative knowledge of basic delta processes is hindering efforts to develop maintenance strategies for deltas, the authors say. At the same time, the role of healthy marshes in coastal processes needs to be more fully understood. Giosan and colleagues call for river sediment flows to be restored, and natural land-building methods to be exploited in delta plains under worldwide monitoring programs coordinated and guided by United Nations committee of experts.

Source: Woods Hole Oceanographic Institution

Emergence of modern sea ice in Arctic Ocean, 2.6 million years ago

Field Work in the Arctic sea ice. Credit: Thomas A. Brown and Simon T. Belt

"We have not seen an ice free period in the Arctic Ocean for 2,6 million years. However, we may see it in our lifetime." says marine geologist Jochen Knies. In an international collaborative project, Knies has studied the historic emergence of the ice in the Arctic Ocean. The results are published in Nature Communications.

The extent of sea ice cover in Arctic was much less than it is today between four and five million years ago. The maximum winter extent did not reaching its current location until around 2.6 million years ago. This new knowledge can now be used to improve future climate models.

"We have not seen an ice free period in the Arctic Ocean for 2,6 million years. However, we may see it in our lifetime. The new IPCC report shows that the expanse of the Arctic ice cover has been quickly shrinking since the 70-ies, with 2012 being the year of the sea ice minimum," Jochen Knies.

He is marine geologist at the Geological Survey of Norway (NGU) and Centre for Arctic Gas Hydrate, Climate and Environment, UiT The Arctic Univeristy of Norway.

In an international collaborative project, Jochen Knies has studied the trend in the sea ice extent in the Arctic Ocean from 5.3 to 2.6 million years ago. That was the last time Earth experienced a long period with a climate that, on average, was warm before cold ice ages began to alternate with mild interglacials.

Fossils reveal past sea ice extent

"When we studied molecules from certain plant fossils preserved in sediments at the bottom of the ocean, we found that large expanses of the Arctic Ocean were free of sea ice until four million years ago," Knies tells us.

"Later, the sea ice gradually expanded from the very high Arctic before reaching, for the first time, what we now see as the boundary of the winter ice around 2.6 million years ago ," says Jochen Knies, who is also attached to CAGE, the Centre for Arctic Gas Hydrate, 

Environment and Climate at the University of Tromsø, the Arctic University of Norway.

Arctic Ocean likely to be completely free of sea ice

The research is of great interest on the international stage because present-day global warming is strongly tied to a shrinking ice cover in the Arctic Ocean. By the end of the present century, the Arctic Ocean seems likely to be completely free of sea ice, especially in summer.

This may have major significance for the entire planet 's climate system. Polar oceans , their temperature and salinity, are important drivers for world ocean circulation that distributes heat in the oceans. It also affects the heat distribution in the atmosphere. Trying to anticipate future changes in this finely tuned system, is a priority for climate researchers. For that they use climate modeling , which relies on good data.

"Our results can be used as a tool in climate modelling to show us what kind of climate we can expect at the turn of the next century. There is no doubt that this will be one of many tools the UN Climate Panel will make use of, too. The extent of the ice in the Arctic has always been very uncertain but, through this work, we show how the sea ice in the Arctic Ocean developed before all the land-based ice masses in the Northern Hemisphere were established," Jochen Knies explains.

Seabed samples from Spitsbergen

A deep well into the ocean floor northwest of Spitsbergen was the basis for this research. It was drilled as part of the International Ocean Drilling Programme, (IODP), to determine the age of the ocean-floor sediments in the area. Then, by analysing the sediments for chemical fossils made by certain microscopic plants that live in sea ice and the surrounding oceans, Knies and his co-workers were able to fingerprint the environmental conditions as they changed through time.

"One thing these layers of sediment enable us to do is to "read" when the sea ice reached that precise point," Jochen Knies tells us.

The scientists believe that the growth of sea ice until 2.6 million years ago was partly due to the considerable exhumation of the land masses in the circum-Arctic that occurred during this period. "Significant changes in altitudes above sea level in several parts of the Arctic, including Svalbard and Greenland, with build-up of ice on land, stimulated the distribution of the sea ice," Jochen Knies says.

"In addition, the opening of the Bering Strait between America and Russia and the closure of the Panama Cannel in central America at the same time resulted in a huge supply of fresh water to the Arctic, which also led to the formation of more sea ice in the Arctic Ocean," Jochen Knies adds.

All the large ice sheets in the Northern Hemisphere existed around 2.6 million years ago.

Scientists at Norwegian Geological Survey (NGU), CAGE, UiT The Arctic University of Norway,University of Plymouth, Universitat Autònoma de Barcelona, Stellenbosch University in South Africa and Institució Catalana de Recerca i Estudis Avançats in Barcelona have collaborated in this work.

Source:  University of Tromso (Universitetet i Tromsø - UiT)