Constantine Alexander's Journal

URI scientists: Marine plants can flee to avoid predators

First observation of predator avoidance behavior by phytoplankton

Phtyoplankton sample magnified by 100 times.
Richard Davidson, courtesy of U.K. Fisheries Research Service

Scientists at the University of Rhode Island's Graduate School of Oceanography have made the first observation of a predator avoidance behavior by a species of phytoplankton, a microscopic marine plant. Susanne Menden-Deuer, associate professor of oceanography, and doctoral student Elizabeth Harvey made the unexpected observation while studying the interactions between phytoplankton and zooplankton.

Their discovery will be published in the September 28 issue of the journal PLOS ONE.

"It has been well observed that phytoplankton can control their movements in the water and move toward light and nutrients," Menden-Deuer said. "What hasn't been known is that they respond to predators by swimming away from them. We don't know of any other plants that do this."

While imaging 3-dimensional predator-prey interactions, the researchers noted that the phytoplankton Heterosigma akashiwo swam differently in the presence of predators, and groups of them shifted their distribution away from the predators.

In a series of laboratory experiments, Menden-Deuer and Harvey found that the phytoplankton not only flee when in the presence of the predatory zooplankton, but they also flee when in water that had previously contained the predators. They found only a minimal effect when the phytoplankton were exposed to predators that do not feed on phytoplankton.

"The phytoplankton can clearly sense the predator is there. They flee even from the chemical scent of the predator but are most agitated when sensing a feeding predator," said Menden-Deuer.

When the scientists provided the phytoplankton with a refuge to avoid the predator – an area of low salinity water that the predators cannot tolerate – the phytoplankton moved to the refuge.

The important question these observations raise, according to Menden-Deuer, is how these interactions affect the survival of the prey species.

Measuring survival in the same experiments, the researchers found that fleeing helps the alga survive. Given a chance, the predators will eat all of the phytoplankton in one day if the algae have no safe place in which to escape, but they double every 48 hours if they have a refuge available to flee from predators. Fleeing makes the difference between life and death for this species, said Menden-Deuer.

"One of the puzzling things about some phytoplankton blooms is that they suddenly appear," she said. "Growth and nutrient availability don't always explain the formation of blooms. Our observation of algal fleeing from predators is another mechanism for how blooms could form. Amazingly, looking at individual microscopic behaviors can help to explain a macroscopic phenomenon."

The researchers say there is no way of knowing how common this behavior is or how many other species of phytoplankton also flee from predators, since this is the first observation of such a behavior.

"If it is common among phytoplankton, then it would be a very important process," Menden-Deuer said. "I wouldn't be surprised if other species had that capacity. It would be very beneficial to them."

In future studies, she hopes to observe these behaviors in the ocean and couple it with genetic investigations.

Funding for this research was provided by the National Science Foundation, the National Oceanic and Atmospheric Administration, and the U.S. Department of Agriculture. The study was conducted, in part, at the URI Marine Life Science Facility, which is supported by the Rhode Island Experimental Program to Stimulate Competitive Research.

Contact: Todd McLeish
[email protected]
401-874-7892
University of Rhode Island

 

 

White shark diets vary with age and among individuals

Many white sharks shift from fish to marine mammals as they mature, but individual sharks show surprising variability in dietary preferences

White sharks, the largest predatory sharks in the ocean, are thought of as apex predators that feed primarily on seals and sea lions. But a new study by researchers at the University of California, Santa Cruz, shows surprising variability in the dietary preferences of individual sharks.

The researchers described their findings in a paper published online September 28 in PLoS ONE. They analyzed the composition of growth bands in shark vertebrae to trace variations in diet over a shark's lifetime. Stable isotopes of carbon and nitrogen incorporated into an animal's tissues serve as a natural tracer of dietary inputs.

"We did find that white shark diets changed with age, as expected, but we were surprised that the patterns and extent of change differed among individuals," said Sora Kim, who led the study as a UCSC graduate student and is now at the University of Wyoming.

The researchers analyzed vertebrae of 15 adult white sharks that had been caught along the west coast (14 off California and one off Baja California). Sharks in this population consume a wide range of prey, including seals, sea lions, dolphins, fish, and squid. But not every shark eats the same mix of prey, said coauthor Paul Koch, professor of Earth and planetary sciences at UCSC.

"We confirmed that the diets of many individuals observed at seal and sea lion rookeries shift from fish to marine mammals as the sharks mature," he said. "In addition, we discovered that different individual sharks may specialize on different types of prey. These two types of flexibility in feeding behavior are difficult to document using traditional methods, but may be very important for understanding how the population is supported by the eastern Pacific ecosystem and how it may respond to changes in that ecosystem."

Tagging studies have shown that the white sharks found along the California coast have a regular migratory pattern, cruising coastal sites from late summer to early winter and moving to offshore areas during the rest of the year. While sharks within this population may have predictable movement patterns, the new study shows that there are important dietary and behavioral differences among individual sharks.

The study relied on vertebrae obtained from white shark specimens in various collections. The sharks had been caught at different times and places along the coast from 1957 to 2000. "Interestingly, we do see a small shift in diet as marine mammal populations increased after the passage of the Marine Mammal Protection Act in 1972," Kim said.

In addition to Kim and Koch, the coauthors of the paper include James Estes, professor of ecology and evolutionary biology at UCSC, and Tim Tinker, a biologist with the U.S. Geological Survey and adjunct professor of ecology and evolutionary biology at UCSC. This research was funded by the National Science Foundation.

Contact: Tim Stephens
[email protected]
831-459-2495
University of California - Santa Cruz

 

 

IUCN adopts new 'Green List' to show species on the path to conservation success

Wildlife Conservation Society-sponsored motion would create list of species that are 'fully conserved'

The IUCN World Conservation Congress has adopted a motion sponsored by the Wildlife Conservation Society and partners to create a Green List to assess conservation success. The Green List for Species would include species identified as 'fully conserved,' which are those that exist in ecologically significant numbers, interacting fully with other species in their ecosystems.

The motion was adopted at the World Conservation Congress, which was held this month in Jeju, Republic of Korea.

The aim of the Green List is to highlight species that are thriving parts of a healthy ecosystem and will emphasize that conservation is about more than just preventing extinction.

"Successful species conservation involves the conservation of a species with significant populations, interacting fully with a complete suite of other native species and processes," said WCS President and CEO Dr. Cristián Samper. "The conservation community should be giving to the world a positive and proactive vision of success: ¬species at or near their natural carrying capacity, as integral parts of fully functional ecosystems. The Green List will be a step in that direction."

The Green List will complement the IUCN Red List, which focuses on avoidance of extinction. The Red List has been critical in assessing conservation prioritization and has been a scientifically-rigorous tool highly regarded by governments and other conservation actors. To create the Green List to reach the same level of effectiveness, the motion recommends that IUCN conducts an international scientific consultation process to develop consensus and rigorous criteria.

Dr. Elizabeth Bennett, WCS Vice President of Species Conservation, said: "The Green List represents a positive vision for conservation in the future. It is a roadmap for species to follow on the way to full conservation recovery."

Dr. Simon Stuart, Chair of IUCN's Species Survival Commission, said: "The Green List process is about optimism and success. It will incentivize conservation action and encourage investment in programs and policies that enhance and measure conservation success and management effectiveness."

Contact: John Delaney
[email protected]
718-220-3275
Wildlife Conservation Society

 

 

Songs in the key of sea

Scientists convert oceanic microbe data into music

Soft horns and a tinkling piano form the backbone of "Fifty Degrees North, Four Degrees West," a jazz number with two interesting twists: it has no composer and no actual musicians. Unless you count bacteria and other tiny microbes, that is.

The song is the brainchild of Peter Larsen, a biologist at the U.S. Department of Energy's Argonne National Laboratory. Larsen, it turns out, has no musical training at all; his interests run less towards the blues and more towards blue-green algae.

When faced with an avalanche of microbial data collected from samples taken from the western English Channel, Larsen recognized he needed a way to make sense of it all. "Thinking of interesting ways to highlight interactions within data is part of my daily job," he said. "I am always trying to find new ways to visualize those relationships in ways so that someone can make relevant biological conclusions."

In the case of the western English Channel data, however, Larsen decided that a visual representation of the data would not be as effective as one he could hear.

"There are certain parameters like sunlight, temperature or the concentration of phosphorus in the water that give a kind of structure to the data and determine the microbial populations," he said. "This structure provides us with an intuitive way to use music to describe a wide range of natural phenomena."

A colleague of Larsen's suggested that classical music could effectively represent the data, but Larsen wanted any patterns inherent in the information to emerge naturally and not to be imposed from without.

"For something as structured as classical music, there's an insufficient amount of structure that you can infer without having to tweak the result to fit what you perceive it should sound like," Larsen said. "We didn't want to do that."

While this is not the first attempt to "sonify" data, it is one of the more mellifluous examples of the genre. "We were astounded by just how musical it sounded," Larsen said. "A large majority of attempts to converting linear data into sound succeed, but they really don't obey the dictates of music – meter, tempo, harmony. To see these things in natural phenomena and to describe them was a wonderful surprise."

According to Larsen, the musicality of the data is not limited to the organisms in the English Channel. In another set of analysis, he and his colleagues used a similar methodology to look at the relationship between a plant and a fungus.

"We expect to see the same intuitive patterns recurring in different environments," he said. "Sometimes, it can sound a little avant-garde, but it's not random because it reflects very real phenomena."

• Blues for Elle: This composition highlights seasonal patterns in marine physical parameters at the L4 Station. The chords are generated from seasonal changes in photosynthetically active radiation. The melody of each measure is comprised of eight notes, each mapped to a physical environmental parameter, in the following order: temperature, soluble reactive phosphate, nitrate, nitrite, saline, silicate, and chlorophyll A concentrations.
• Bloom: Some marine microbial taxa are most often present in the L4 Station community at very low abundance, but occasionally become highly dominant community members. To link these microbial blooms to relevant physical parameters, the chords in this composition are derived from changes in chlorophyll A concentrations and salinity. The melody for each measure is derived from the relative abundances of typically rare taxa that were observed to occasionally bloom to higher abundance in the following order: Cyanobacteria, Vibrionales, Opitulates, Pseudomondales, Rhizobiales, Bacillales, Oceanospirallales, and Sphingomonadales.
• Far and Wide: Microbial species of the Order Rickettsiales, such as the highly abundant, free-living planktonic species Pelagibacter ubique, are typically, highly abundant taxa in L4 Station data. Its relative abundance in the microbial community at L4 Station follows a distinctive seasonal pattern. In this composition, there are two chords per measure, generated from photosynthetically active radiation measurements and temperature. The melody of each measure is six notes that describe the relative abundance of the Order Rickettsiales. The first note of each measure is from the relative abundance at a time point. The next five notes of a measure follow one of the following patterns: a continuous rise in pitch, a continuous drop in pitch, a rise then drop in pitch, or a drop then rise in pitch. These patterns are matched to the relative abundance of Rickettsiales at the given time point, relative to the previous and subsequent time points. The pattern of notes in a measure is mapped to the relative abundance of Rickettsiales with fewer rests per measure indicating higher abundance. For time points at which Rickettsiales was the most abundant microbial taxa, the corresponding measure is highlighted with a cymbal crash.
• Fifty Degrees North, Four Degrees West: All of the data in this composition derives from twelve observed time points collected at monthly intervals at the L4 Station during 2007. The composition is composed of seven choruses. Each chorus has the same chord progression of 12 measures each in which chords are derived from monthly measures of temperature and chlorophyll A concentrations. The first and last chorus melodies are environmental parameter data as in ‘Blues for Elle’. The melody in each of the second through sixth chorus is generated from the relative abundances of one of the five most common microbial taxa: Rickettsiales, Rhodobacteriales, Flavobacteriales, Cyanobactera, and Pseudomondales. A different ‘instrument’ is used to represent each microbial taxon. Melodies for microbial taxa were generated as in ‘Far and Wide’.

Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation's first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America's scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy's Office of Science.

Contact: Jared Sagoff
[email protected]
630-252-5549
DOE/Argonne National Laboratory

 

 

Venice Lagoon research indicates rapid climate change in coastal regions

Venice, Italy is featured in this image photographed by an Expedition 14 crewmember on the International Space Station. Credit: NASA

Research undertaken by the University of Southampton and its associates in Venice has revealed that the sea surface temperature (SST) in coastal regions is rising as much as ten times faster than the global average of 0.13 degrees per decade.

Researchers believe that this is partly as a result of a process known as the 'urban heat island effect'; where regions experiencing rapid industrial and urban expansion produce vast amounts of heat, making the area warmer than its surroundings.

Professor Carl Amos of Ocean and Earth Sciences at the University of Southampton, will be making a speech at the Estuarine & Coastal Sciences Association's Research & Management of Transitional Waters international symposium, in Lithuania tomorrow (Thursday 27 September). He explains: "The urban heat island effect is a little considered problem with extreme consequences. Take London for example; the air temperature in the capital and the SST of the Thames is always warmer than it is in the rest of the UK. Similarly, in South Korea, an area which has seen rapid industrial expansion, the SST is rising at a rate of 0.26 degrees per decade – significantly higher than the global average. Two thirds of this rise is explained by local air temperature, which is largely driven by the urban heat island effect."

The world's coastal zone occupies 18 per cent of the world's land mass and it is estimated that 1.6 billion people live in these regions world-wide. The coastal population density is three times the global average and this population is expected to increase 30 per cent by 2025, with trade and infrastructure at the coasts also increasing steadily. Research suggests that in coastal regions of high urban development, human activity is directly warming adjacent coastal waters and that this contribution to global warming at the coastal zones is equal to, or greater than, other factors such as greenhouse gasses.

Professor Amos, who is based at the National Oceanography Centre Southampton (NOCS) says: "The Marine Climate Change Impacts Partnership Report of 2006 stated that the capacity to define and predict long-term coastal changes due to human causes is 'unknown' and confidence in results is 'low'. This is a major barrier to planning for inevitable changes in coastal SST. Most of these changes at coastlines are caused by human activity, but as it is complex to consider these factors accurately, the official International Panel for Climate Change (IPCC) figures do not take these coastal 'anomalies' into account."

In Venice, with 22 million visitors annually and tourism a year-round source of income, the economy remains critically dependent on the city maintaining its status as one of the world's most desirable destinations. Southampton's research in Venice has highlighted the tension between tourism's economic benefits and environmental repercussions. Analyses of seawater temperature trends in the Venice Lagoon have suggested an increase during winter months ten times greater than that predicted globally by the IPCC – a result directly linked to tourism.

Thousands of jobs and the Venetian economy rely on the survival of the fishing industry, which is dependent on the temperature of the coastal seawater in the Venice Lagoon. A rise in SST in the coastal zone reduces oxygen levels and displaces marine fish and associated nursery grounds, causing catastrophic fish kill phenomena. This research has helped predict the viability of clam fisheries and aquaculture habitats that serve the restaurant trade that caters for millions of tourists every year.

Venice, from the Ponte di Rialto in north-eastern direction. Credit: Arian Zweger

Professor Amos says: "The findings in Venice are the result of a 15 year partnership with the city, which are of great importance and have worldwide applications. Massive urbanisation of the coastal zones means urban heat islands represent an acute problem, particularly for the fishing industry and also for the maintenance of coastal infrastructure. The Thames, like the Venice Lagoon, is a major contributor to and casualty of the urban heat island effect. The consequences of the urban heat island effect need addressing urgently to secure the future of our coastal habitats."

Contact: Charlotte Woods
[email protected]
0238-059-2128
University of Southampton

 

 

The Northern Wake by Lou Douros

Humpback Whale. Credit: NOAA

Humpback Whales often become entangled in marine debris and fishing gear. While many reports of courageous rescuers that disentangle whales often makes the evening news, Northern Wake documents the work being done to prevent the problem in the first place.

The full documentary of Northern Wake will begin production Spring of 2013. Lou Douros filmed this sneak preview in August with director of photography, John Northrup. The guerilla funding for the film was provided by the generous backers:

• The National Marine Sanctuary Foundation
• NOAA, National Marine Fisheries Service (Office of Protected Resources, Alaska)
• Future Oceans, Australia
• The Innovation Centre at the University of the Sunshine Coast, Australia

Please consider supporting the production of Northern Wake.

 

 

 

 

New research in Science shows it's not too late for troubled fisheries

Study sheds new light on data-poor fisheries and how recovery can boost seafood supply

A study published in Science magazine contains new population assessments for thousands of fisheries around the globe, providing insight on the health of data-poor fisheries that account for more than 80 percent of the world's catch. The research confirms suspicions that these fisheries are in decline, but it also highlights hope for the future: most of these fisheries have not yet collapsed. If we act quickly to prevent overfishing and allow depleted stocks to recover to sustainable levels, they could provide more seafood over the long-term. This could increase the amount of fish brought to shore by 8-40 percent on average - and more than double it in some areas - compared to yields predicted if we continue current fishing trends.

"Until now, our sense of how fisheries are doing has been based on a minute fraction of the world's fisheries – the large, valuable stocks for which we have lots of data," says UCSB scientist Steve Gaines. "This represents only a few hundred of over 10,000 fish stocks. It's a tiny slice that can give us a skewed view."

"For most fisheries, we simply didn't know how many fish were out there and whether their populations were trending up or down," adds lead author and economist Christopher Costello. "Without good information on fish populations, managing sustainably can be a hard thing to do. It's like trying to decide how far you can drive your car without knowing how much gas is in the tank."

The study provides a new global status report that includes these previously unmeasured fisheries. It brings thousands of what managers call "unassessed" fisheries into focus, using new methods to estimate fish populations. The results show that over half the world's fisheries are in decline. Across the globe, stocks with robust data are doing better than those less-studied, regardless of the country that manages them.

"If we look at assessed stocks we can be pretty satisfied that fishery management systems are generally working to assure long term sustainability," says University of Washington scientist Ray Hilborn, a co-author of the study. "For unassessed stocks, this doesn't appear to be true."

The scientists found that for large-scale fisheries, the stocks that we measure and track are at similar levels as those that we have not formally measured. However, under current fishing pressure their futures look very different: the assessed stocks are starting to show signs of recovery, while large, data-poor populations continue to decline. In small scale fisheries, the data-poor or "unassessed" stocks are in far worse shape than their studied counterparts, and many are plummeting at alarming rates. These fisheries are critical to local food security in many parts of the world.

"Without good population estimates, political pressure tends to dominate decision making, and we end up catching too much," says Costello. "Over time, this can lead a fishery to collapse."

"The impact on food security is most significant for local-level fisheries in poorer countries, but this isn't just a developing world problem," explains UCSB ecologist, Sarah Lester. "Small, unassessed fisheries in the U.S. and Europe are often in as bad a shape as those in the developing world."

The scientists caution that the new method cannot take the place of formal assessment programs for individual fisheries, but their approach provides accurate global and regional information that they hope will inform fisheries management decisions. "At a regional scale, we can gain up to 80 percent of the insights of traditional assessment approaches with just 1 percent of the cost," says Gaines.

The Benefits of Recovery – Environmental and Economic Gains

The closer a fishery is to collapse, the harder and more uncertain its recovery. However, the researchers say that with prompt action the majority of the world's fish populations could still rebound.

"Strong management could increase the number of fish in the ocean by over 50 percent," says Gaines. "When fish populations are healthy they produce more young. It may seem paradoxical, but we can get more fish on our plates by leaving more in the water."

The gains expected from recovery are most pronounced for small scale fisheries, many of which are in countries that face rapid population growth and depend on fish for local food security. Even in North America and Europe, recovery would bring both economic and environmental benefits.

"The good news here is that it's not too late," explains Costello. "These fisheries can rebound. But the longer we wait, the harder and more costly it will be to bring these fisheries back. In another ten years, the window of opportunity may have closed."

Getting to Recovery – Changing the Race for Fish to a Race for Sustainability

The new study in Science is embedded in a larger study, Charting a Course to Sustainable Fisheries, released this week by the consulting firm, California Environmental Associates. This broader study evaluates the successes and gaps in fishery management and conservation programs around the world. It points to the fact that we know how to bring back dwindling fisheries, but political battles often trump putting these concepts into action.

"We know what works. Fishery management policies and practices have been tried, tested, and proven," says report author Matthew Elliott.

In the U.S., for example, many large fisheries are starting to recover. The report's analysis shows that these gains result from a combination of efforts: relying on strong science to set total allowable fishing levels, closing some areas to allow for rebuilding, and using sustainable seafood markets and policies that help fishermen have secure access to a proportion of catch. While there is not a one-size-fits-all solution to eliminate overfishing, the report shows that many of the same principles are applied in successful, local management efforts around the world.

"The key is to use and share these practices more broadly," says Elliott. "In many areas of the world, particularly in the tropics and sub-tropics, we see fisheries expanding quickly with little in the way of management. This research fills an important information gap for these fisheries. We hope it will draw more international attention to fisheries management in the many parts of the world that we have historically ignored."

The scientists and economists involved in the research echo this call for international collaboration. "This isn't something where we need another twenty years of science," says Gaines. "We know what it takes."

"Healthy ocean fisheries hold the potential to feed a growing population without destroying the supporting ecosystems to the point where they no longer produce seafood," adds Elliott. "Within our lifetime, we can make sustainable global fisheries the norm rather than the exception."

This work was supported by the Waitt Foundation, the David and Lucile Packard Foundation, the Gordon and Betty Moore Foundation, the Walton Family Foundation, and the Oak Foundation.

Reference: Charting a Course to Sustainable Fisheries.

Contact: Ashley Simons
[email protected]
415-412-7957
Bren School at UCSB
University of Washington
California Environmental Associates

 

 

'Semi-dwarf' trees may enable a green revolution for some forest crops

Poplar trees in the center of this image are of normal height, but the shorter trees on each side are different types of transgenic trees designed to be shorter. (Photo courtesy of Oregon State University)

The same "green revolution" concepts that have revolutionized crop agriculture and helped to feed billions of people around the world may now offer similar potential in forestry, scientists say, with benefits for wood, biomass production, drought stress and even greenhouse gas mitigation.

Researchers at Oregon State University recently outlined the latest findings on reduced height growth in trees through genetic modification, and concluded that several advantageous growth traits could be achieved for short-rotation forestry, bioenergy, or more efficient water use in a drier, future climate.

This approach runs contrary to conventional wisdom and centuries of tree breeding, which tried to produce forest trees that grow larger and taller, the researchers note. But just as the green revolution in agriculture helped crops such as wheat and rice produce more food on smaller, sturdier plants, the opportunities in forestry could be significant.

"Research now makes it clear that genetic modification of height growth is achievable," said Steven Strauss, an OSU professor of forest genetics. "We understand the genes and hormones that control growth not only in crop plants, but also in trees. They are largely the same."

In a study published in Plant Physiology, researchers inserted a number of genes into poplar trees, a species often used for genetic experiments, and valuable for wood, environmental and energy purposes. They described 29 genetic traits that were affected, including growth rate, biomass production, branching, water-use efficiency, and root structure. All of the changes were from modified gibberellins, plant hormones that influence several aspects of growth and development.

The range and variation in genetic modification can be accurately observed and selected for, based on hormone and gene expression levels, to allow production of trees of almost any height.

For example, for ornamental purposes it would be possible to grow a miniature poplar, or even a Douglas-fir, as a potted plant.

And because height growth, in competition for sunlight, is a primary mechanism that trees use to compete for survival, there would be reduced concern about use of such genetically modified trees in a natural environment. On a long-term basis they would be unable to compete, shaded by larger trees and ultimately they would die out.

Scientists could also produce trees that might have a larger root mass, which should make them more drought-resistant, increase water use efficiency, increase elimination of soil toxins and better sequester carbon. This could be useful for greenhouse gas mitigation, bioremediation or erosion control.

Smaller trees could also be selected that have sturdier trunks for some uses in short-rotation plantation forestry, significantly reducing the number of trees blown down by wind. And shorter, thicker and straighter trunks might create higher-value wood products in many tree species, Strauss said.

Some semi-dwarf trees produced by conventional tree breeding techniques are already an important part of the horticulture industry, allowing easier harvesting of fruit and higher yields. Genetic modification could add new characteristics and more scientific precision to the process, researchers said.

"The main limitation is the onerous regulatory structure for genetically-modified plants in the United States," Strauss said. "Even short, safe and beneficial trees are unlikely to be able to bear the high costs and red tape inherent to obtaining regulatory approval."

This research has been supported by the U.S. Department of Energy, U.S. Department of Agriculture, National Science Foundation, and industry members of the Tree Biosafety and Genomics Research Cooperative at OSU.

Reference: Green revolution trees: Semi-dwarfism transgenes modify gibberellins, promote root growth, enhance morphological diversity, and reduce competitiveness in Populus.  Ani A. Elias, Victor B. Busov, Kevin R. Kosola, Cathleen Ma, Elizabeth R. Etherington, Olga Shevchenko, Harish Gandhi, David Pearce, Stewart Rood and Steven H. Strauss. Plant Physiology August 2012 pp.112.200741

Contact: Steve Strauss
[email protected]
541-737-6578
Oregon State University

 

 

UCSB scientists capture clues to sustainability of fish populations

Black Surfperch (Embiotoca jacksoni). Credit: Clint Nelson

Thanks to studies of a fish that gives birth to live young and is not fished commercially, scientists at UC Santa Barbara have discovered that food availability is a critical limiting factor in the health of fish populations.

The scientists were able to attach numbers to this idea, based on 16 years of data. They discovered that the availability of enough food can drive up to a 10-fold increase in the per capita birthrate of fish. And, with adequate food, the young are up to 10 times more likely to survive than those without it.

This research, published this week in the Proceedings of the Royal Society B, is expected to be useful for managers involved in maintaining sustainable fisheries.

The scientists used a remarkable set of black surfperch population data –– collected from 1993 to 2008 –– to develop these statistics. Divers collected the data by monitoring a fish population off Santa Cruz Island, near Santa Barbara. Russell J. Schmitt and Sally J. Holbrook, both professors in UCSB's Department of Ecology, Evolution, and Marine Biology and UCSB's Marine Science Institute, head the team of scientists.

First author Daniel K. Okamoto, a Ph.D. student in UCSB's Department of Ecology, Evolution, and Marine Biology, explained that there has been a lack of information about how survival and birthrates are influenced by food availability, which is known to fluctuate through time. Black surfperch, found off the Pacific Coast from central Baja California northward to Fort Bragg, feed on small crustaceans and worms.

"If a management procedure has called for a certain harvest rate that is constant through time, that would be like saying we should harvest the same amount of corn through time, even though we know that corn can be influenced by things like drought," said Okamoto.

The scientists consider the black surfperch (Embiotoca jacksoni) to be a model species because it is not fished commercially, making it easier to assess the effects of food availability on fish mortality and reproduction.

A key feature of the black surfperch is the fact that this fish gives birth to live young that remain on the reef, allowing for its population to be counted accurately from year to year.

"The individual fish stay on their natal reef; they have low emigration- immigration rates, so we can actually track cohorts through time," said Okamoto. "An adult gives birth to live, capable young, instead of laying eggs. Those young stay on the reef where the adults were, which is a really nice property. We can go to a reef in a given year, survey it for adults, then go to that reef again the next year and see the young that are there and know, for the most part, that those young came from the adults that were there the year before." By contrast, most fish are dispersed into open water when they are in the larval stage.

Okamoto said that not including food availability in calculating benchmarks for species conservation may leave out a critical element in fisheries management.

Daniel Reed, a research biologist with UCSB's Marine Science Institute and the principal investigator for the Santa Barbara Coastal Long Term Ecological Research Program, is also a co-author of the study. The National Science Foundation provided funding for the research.

Contact: Gail Gallessich
[email protected]
805-893-7220
University of California - Santa Barbara

 

 

Nature's misfits: Reclassifying protists helps us understand how many species remain undiscovered

Since the Victorian era, categorizing the natural world has challenged scientists. No group has presented a challenge as tricky as the protists, the tiny, complex life forms that are neither plants nor animals. A new reclassification of eukaryotic life forms, published in the Journal of Eukaryotic Microbiology, draws together the latest research to clarify the current state of protist diversity and categorization, as well as the many species that remain to be discovered.

"Protists include species traditionally referred to as protozoa and algae, some fungal-like organisms, and many other life forms that do not fit into the old worldview that divided species between plants and animals," said Professor Sina Adl, from the University of Saskatchewan. "By the 1960's it had become clear that these species could no longer fit within such a narrow system, yet the first community-wide attempt to rationally categorize all the protists in the natural evolutionary groups was only made in 2005."

The 2005 classification, led by Professor Adl and published by the Journal of Eukaryotic Microbiology, gave scientists a structure for understanding these species; however, it was limited to the technology available at the time and recent advances have prompted the need for a reclassification.

"With environmental genomics we are experiencing a renaissance of new protist discoveries," said Adl. "These new species allow us to better appreciate how little we know about the biodiversity around us and how they contribute to maintaining the planet's chemical balance."

The most significant changes are the introduction and recognition of new super groups, larger than traditional biological kingdoms. This reflects a greater understanding of the most ancient relationships between protists, their shared ancestry and their connections to animals and plants.

This includes recognition of the Amorphea, a group that links animals, fungi and their protist relatives, including the marine choanoflagellates, to a diverse group of protists largely dominated by various amoeboid cells. This includes macroscopic slime molds, shell-dwelling amoebae, small flagellated amoebae and large voracious amoeboid predators of bacteria, algae and even small crustaceans.

A second new super group, SAR, brings together many of the most common and successful algae, microbial predators, and parasites on earth. Members of this group range from giant kelp and other brown seaweeds, to the forams (living sand grains), and the parasite that causes malaria in humans. Large scale DNA and RNA sequencing studies conducted since 2005 have shown that these profoundly dissimilar forms are all actually related to each other.

"This new classification, that better reflects how species are related, improves our ability to predict the number of species that remain to be discovered," concluded Professor Adl. "There is a huge unknown diversity in the deep sea, but probably even more in the soil we walk on."

Contact: Ben Norman
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Wiley