Warmer Future Oceans Could Cause Phytoplankton to Thrive Near Poles, Shrink in Tropics

   Phytoplankton in a dark sea; countless numbers drift through the world's oceans.

 By the end of the 21st century, warmer oceans will cause populations of these marine microorganisms to thrive near the poles and shrink in equatorial waters.

"In the tropical oceans, we are predicting a 40 percent drop in potential diversity, the number of strains of phytoplankton," says Mridul Thomas, a biologist at Michigan State University (MSU) and co-author of the journal paper.

"If the oceans continue to warm as predicted," says Thomas, "there will be a sharp decline in the diversity of phytoplankton in tropical waters and a poleward shift in species' thermal niches--if they don't adapt."

Thomas co-authored the paper with scientists Colin Kremer, Elena Litchman and Christopher Klausmeier, all of MSU.

"The research is an important contribution to predicting plankton productivity and community structure in the oceans of the future," says David Garrison, program director in the National Science Foundation's (NSF) Division of Ocean Sciences, which funded the research along with NSF's Division of Environmental Biology.

"The work addresses how phytoplankton species are affected by a changing environment," says Garrison, "and the really difficult question of whether adaptation to these changes is possible."

The MSU scientists say that since phytoplankton play a key role in regulating atmospheric carbon dioxide levels, and therefore global climate, the shift could in turn cause further climate change.

Phytoplankton and Earth's climate are inextricably intertwined.

"These results will allow scientists to make predictions about how global warming will shift phytoplankton species distribution and diversity in the oceans," says Alan Tessier, program director in NSF's Division of Environmental Biology.

"They illustrate the value of combining ecology and evolution in predicting species' responses."

The microorganisms use light, carbon dioxide and nutrients to grow. Although phytoplankton are small, they flourish in every ocean, consuming about half of the carbon dioxide emitted into the atmosphere.

When they die, some sink to the ocean bottom, depositing their carbon in the sediment, where it can be trapped for long periods of time.

Water temperatures strongly influence their growth rates.

Phytoplankton in warmer equatorial waters grow much faster than their cold-water cousins.

With worldwide temperatures predicted to increase over the next century, it's important to gauge the reactions of phytoplankton species, say the scientists.

They were able to show that phytoplankton have adapted to local temperatures.

Based on projections of ocean temperatures in the future, however, many phytoplankton may not adapt quickly enough.

Since they can't regulate their temperatures or migrate, if they don't adapt, they could be hard hit, Kremer says.

"We've shown that a critical group of the world's organisms has evolved to do well under the temperatures to which they're accustomed," he says.

But warming oceans may significantly limit their growth and diversity, with far-reaching implications for the global carbon cycle.

"Future models that incorporate genetic variability within species will allow us to determine whether particular species can adapt," says Klausmeier, "or whether they will face extinction."

Marine Phytoplankton Declining: Striking Global Changes at the Base of the Marine Food Web Linked to Rising Ocean Temperatures

 

Southern Right whale off the coast of Hermanus; South Africa. Phytoplankton forms the basis of the marine food chain and sustains diverse assemblages of species ranging from tiny zooplankton to large marine mammals, seabirds, fish and certain whales.

  A new article published in the 29 July issue of the journal Nature reveals for the first time that microscopic marine algae known as "phytoplankton" have been declining globally over the 20th century. Phytoplankton forms the basis of the marine food chain and sustains diverse assemblages of species ranging from tiny zooplankton to large marine mammals, seabirds, and fish. Says lead author Daniel Boyce, "Phytoplankton is the fuel on which marine ecosystems run. A decline of phytoplankton affects everything up the food chain, including humans."

Using an unprecedented collection of historical and recent oceanographic data, a team from Canada's Dalhousie University documented phytoplankton declines of about 1% of the global average per year. This trend is particularly well documented in the Northern Hemisphere and after 1950, and would translate into a decline of approximately 40% since 1950. 

The scientists found that long-term phytoplankton declines were negatively correlated with rising sea surface temperatures and changing oceanographic conditions.

The goal of the three-year analysis was to resolve one of the most pressing issues in oceanography, namely to answer the seemingly simple question of whether the ocean is becoming more (or less) „green' with algae. Previous analyses had been limited to more recent satellite data (consistently available since 1997) and have yielded variable results. To extend the record into the past, the authors analysed a unique compilation of historical measurements of ocean transparency going back to the very beginning of quantitative oceanography in the late 1800s, and combined these with additional samples of phytoplankton pigment (chlorophyll) from ocean-going research vessels. The end result was a database of just under half a million observations which enabled the scientists to estimate phytoplankton trends over the entire globe going back to the year 1899.

The scientists report that most phytoplankton declines occurred in polar and tropical regions and in the open oceans where most phytoplankton production occurs. Rising sea surface temperatures were negatively correlated with phytoplankton growth over most of the globe, especially close to the equator. Phytoplankton need both sunlight and nutrients to grow; warm oceans are strongly stratified, which limits the amount of nutrients that are delivered from deeper waters to the surface ocean. Rising temperatures may contribute to making the tropical oceans even more stratified, leading to increasing nutrient limitation and phytoplankton declines.

 The scientists also found that large-scale climate fluctuations, such as the El-Niño Southern Oscillation (ENSO), affect phytoplankton on a year-to-year basis, by changing short-term oceanographic conditions.

The findings contribute to a growing body of scientific evidence indicating that global warming is altering the fundamentals of marine ecosystems. Says co-author Marlon Lewis, "Climate-driven phytoplankton declines are another important dimension of global change in the oceans, which are already stressed by the effects of fishing and pollution. Better observational tools and scientific understanding are needed to enable accurate forecasts of the future health of the ocean." Explains co-author Boris Worm, "Phytoplankton are a critical part of our planetary life support system. They produce half of the oxygen we breathe, draw down surface CO₂, and ultimately support all of our fisheries. An ocean with less phytoplankton will function differently, and this has to be accounted for in our management efforts."

Bio-Crude Turns Cheap Waste Into Valuable Fuel

 

Forest waste can be converted into bio-crude oil. 

CSIRO and Monash University have developed a chemical process that turns green waste into a stable bio-crude oil. The bio-crude oil can be used to produce high value chemicals and biofuels, including both petrol and diesel replacement fuels.

“By making changes to the chemical process, we’ve been able to create a concentrated bio-crude which is much more stable than that achieved elsewhere in the world,” says Dr Steven Loffler of CSIRO Forest Biosciences.

“This makes it practical and economical to produce bio-crude in local areas for transport to a central refinery, overcoming the high costs and greenhouse gas emissions otherwise involved in transporting bulky green wastes over long distances.”

The process uses low value waste such as forest thinnings, crop residues, waste paper and garden waste, significant amounts of which are currently dumped in landfill or burned.

“By using waste, our Furafuel technology overcomes the food versus fuel debate which surrounds biofuels generated from grains, corn and sugar,” says Dr Loffler.

“The project forms part of CSIRO’s commitment to delivering cleaner energy and reducing greenhouse gas emissions by improving technologies for converting waste biomass to transport fuels.”

The plant wastes being targeted for conversion into biofuels contain chemicals known as lignocellulose, which is increasingly favoured around the world as a raw material for the next generation of bio-ethanol.

Lignocellulose is both renewable and potentially greenhouse gas neutral. It is predominantly found in trees and is made up of cellulose; lignin, a natural plastic; and hemicellulose.

CSIRO and Monash University will apply to patent the chemical processes underpinning the conversion of green wastes to bio-crude oil once final laboratory trials are completed.

The research to date is supported by funding from CSIRO’s Energy Transformed Flagship program, Monash University, Circa Group and Forest Wood Products Australia.

National Research Flagships CSIRO initiated the National Research Flagships to provide science-based solutions in response to Australia’s major research challenges and opportunities. The nine Flagships form multidisciplinary teams with industry and the research community to deliver impact and benefits for Australia.

Neuroscientists Find the Molecular 'When' and 'Where' of Memory Formation

 

Neuroscientists have isolated the “when” and “where” of molecular activity that occurs in the formation of short-, intermediate-, and long-term memories

Neuroscientists from New York University and the University of California, Irvine have isolated the "when" and "where" of molecular activity that occurs in the formation of short-, intermediate-, and long-term memories. Their findings, which appear in the journal the Proceedings of the National Academy of Sciences, offer new insights into the molecular architecture of memory formation and, with it, a better roadmap for developing therapeutic interventions for related afflictions.

"Our findings provide a deeper understanding of how memories are created," explained the research team leader Thomas Carew, a professor in NYU's Center for Neural Science and dean of NYU's Faculty of Arts and Science. "Memory formation is not simply a matter of turning molecules on and off; rather, it results from a complex temporal and spatial relationship of molecular interaction and movement."

Neuroscientists have previously uncovered different aspects of molecular signaling relevant to the formation of memories. But less understood is the spatial relationship between molecules and when they are active during this process.

To address this question, the researchers studied the neurons in Aplysia californica, the California sea slug. Aplysia is a model organism that is quite powerful for this type of research because its neurons are 10 to 50 times larger than those of higher organisms, such as vertebrates, and it possesses a relatively small network of neurons -- characteristics that readily allow for the examination of molecular signaling during memory formation. Moreover, its coding mechanism for memories is highly conserved in evolution, and thus is similar to that of mammals, making it an appropriate model for understanding how this process works in humans.

The scientists focused their study on two molecules, MAPK and PKA, which earlier research has shown to be involved in many forms of memory and synaptic plasticity -- that is, changes in the brain that occur after neuronal interaction. But less understood was how and where these molecules interacted.

To explore this, the researchers subjected the sea slugs to sensitization training, which induces increased behavioral reflex responsiveness following mild tail shock, or in this study, mild activation of the nerve form the tail. They then examined the subsequent molecular activity of both MAPK and PKA. Both molecules have been shown to be involved in the formation of memory for sensitization, but the nature of their interaction is less clear.

What they found was MAPK and PKA coordinate their activity both spatially and temporally in the formation of memories. Specifically, in the formation of intermediate-term (i.e., hours) and long-term (i.e., days) memories, both MAPK and PKA activity occur, with MAPK spurring PKA action. By contrast, for short-term memories (i.e., less than 30 minutes), only PKA is active, with no involvement of MAPK.

The study's other co-authors were Xiaojing Ye, a postdoctoral fellow in NYU's Center for Neural Science, Andreea Marina, an undergraduate at UC Irvine at the time of the study. The research was conducted at NYU's Center for Neural Science and UC Irvine's Center for Neurobiology of Learning and Memory.

This work was supported by grants RO1 MH 041083 and RO1 MH 081151 from the National Institute of Mental Health, part of the National Institutes of Health, and a grant IOB-0444762 from the National Science Foundation.

Glaciers Cracking in the Presence of Carbon Dioxide

 

Ice. Researchers have shown that the material strength and fracture toughness of ice are decreased significantly under increasing concentrations of CO₂ molecules, making ice caps and glaciers more vulnerable to cracking and splitting into pieces.

(Oct. 10, 2012) — The well-documented presence of excessive levels of carbon dioxide (CO₂) in our atmosphere is causing global temperatures to rise and glaciers and ice caps to melt.

New research, published October 11, in IOP Publishing's Journal of Physics D: Applied Physics, has shown that CO₂ molecules may be having a more direct impact on the ice that covers our planet.

Researchers from the Massachusetts Institute for Technology have shown that the material strength and fracture toughness of ice are decreased significantly under increasing concentrations of CO₂ molecules, making ice caps and glaciers more vulnerable to cracking and splitting into pieces, as was seen recently when a huge crack in the Pine Island Glacier in Antarctica spawned a glacier the size of Berlin.

Ice caps and glaciers cover seven per cent of Earth -- more than Europe and North America combined -- and are responsible for reflecting 80-90 per cent of the Sun's light rays that enter our atmosphere and maintain Earth's temperature. They are also a natural carbon sink, capturing a large amount of CO₂.

"If ice caps and glaciers were to continue to crack and break into pieces, their surface area that is exposed to air would be significantly increased, which could lead to accelerated melting and much reduced coverage area on the Earth. The consequences of these changes remain to be explored by the experts, but they might contribute to changes of the global climate," said lead author of the study Professor Markus Buehler.

Buehler, along with his student and co-author of the paper, Zhao Qin, used a series of atomistic-level computer simulations to analyse the dynamics of molecules to investigate the role of CO₂ molecules in ice fracturing, and found that CO₂ exposure causes ice to break more easily.

Notably, the decreased ice strength is not merely caused by material defects induced by CO₂ bubbles, but rather by the fact that the strength of hydrogen bonds -- the chemical bonds between water molecules in an ice crystal -- is decreased under increasing concentrations of CO₂. This is because the added CO₂ competes with the water molecules connected in the ice crystal.

It was shown that CO₂ molecules first adhere to the crack boundary of ice by forming a bond with the hydrogen atoms and then migrate through the ice in a flipping motion along the crack boundary towards the crack tip.

The CO₂ molecules accumulate at the crack tip and constantly attack the water molecules by trying to bond to them. This leaves broken bonds behind and increases the brittleness of the ice on a macroscopic scale.