The cold-water coral Lophelia pertusa is able to counteract negative effects of ocean acidification under controlled laboratory conditions when water temperature rises by a few degrees at the same time. Whether this will also be possible in the natural habitat depends on the degree of change in environmental conditions, researchers argue.
The PhD student from the department of Biological Oceanography at GEOMAR conducted the experiments and is lead author of a publication on the effects and impact of ocean acidification and warming on the growth and fitness of Lophelia pertusa in the research journal Frontiers in Marine Science. Monthly measurements and final analyses showed: Under more acidified conditions and unchanged temperatures, the corals grew slower, regardless of the food supply. But when acidification was combined with elevated temperature, they developed at about the same rates as under today's CO2 concentrations and water temperatures. "The elaborate experimental setup shows that when applied in combination, different climate change drivers can interact in their effects on the corals. Depending on the extent at which the ocean acidifies in the course of climate change and which water temperatures the corals experience, their overall reaction could be less neutral than observed in the experiment, the GEOMAR team assumes. If temperatures continue to rise, the compensatory effect observed in this study could turn negative, amplifying the effect of ocean acidification. Because they build their skeletons from calcium carbonate, cold-water corals such as the globally distributed species Lophelia pertusa are considered particularly threatened by ocean acidification. This change in seawater chemistry, caused by the absorption of carbon dioxide (CO2) from the atmosphere, reduces the concentration of carbonate ions. With fewer carbonate ions, calcification becomes more difficult. However, laboratory studies at GEOMAR Helmholtz Centre for Ocean Research Kiel reveal, that a simultaneous increase in water temperatures could help Lophelia pertusa to counteract negative effects of ocean acidification. The experiments that were conducted as part of the German research programmer on ocean acidification BIOACID (Biological Impacts of Ocean Acidification) demonstrate how important it is to investigate Lophelia's response to single drivers of climate change as well as their combined effects. https://www.sciencedaily.com/releases/2017/04/170427100646.htm
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Sonja Knapp were able to demonstrate that the number of plant species in Halle has risen considerably between the end of the 17th century and the beginning of the 21st -- from 711 to 860 species. At the same time, however, the evolutionary diversity of plants has declined: native species from a wide range of plant families have died out regionally and been replaced by more closely related species. The team calculated how the current evolutionary diversity of Halle's flora would change if, firstly, the plants found in Halle listed on the Red List of endangered species disappeared and, secondly, the most common introduced species in Germany which are not yet found in Halle were to migrate there. As the loss of evolutionary diversity in Halle is primarily being driven by the loss of native species -- including many species which depend on cool, nutrient-poor environments, Sonja Knapp and her colleagues are calling for more protection for these species and their habitats.
All over the globe, the urbanization of landscapes is increasing. 60% of the land surface which is expected to be urban by 2030 is currently not built on at all. How this will impact on biological diversity will only be apparent in retrospect. However, for most cities there have been systematic surveys of biological diversity, although only since the second half of the 20th century. Researchers have now revealed, on the basis of historical data, how plant diversity in the region of Halle an der Saale has changed in over 300 years of urbanization, and have also made predictions about the future. Urbanization is one of the most important issue and topics to be discussed today. https://www.sciencedaily.com/releases/2017/04/170426093154.htm About a year ago, a group of researchers discovered Palmer is resistant to the herbicide class known as PPO-inhibitors, due to a mutation -- known as the glycine 210 deletion -- on the PPX2 gene. "We were using a quick test that we originally developed for waterhemp to determine PPO-resistance based on that mutation.Tranel and his colleagues decided to sequence the PPX2 gene in plants from Tennessee and Arkansas to see if they could find additional mutations. Sure enough, they found not one, but two, located on the R98 region of the gene. "Almost all of the PPO-resistant plants we tested had either the glycine 210 deletion or one of the two new R98 mutations. None of the mutations were found in the sensitive plants we tested," Tranel says. Furthermore, some of the resistant plants had both the glycine 210 deletion and one of the new R98 mutations. Tranel says it is too early to say what that could mean for those plants. In fact, there is a lot left to learn about this resistance mechanism. Tranel hopes they will be able to determine how common the three mutations are in any given population. "That way," he says, "when a farmer sends us a resistant plant and it doesn't come back with the glycine 210 deletion, we will be able to tell him how likely it is that he's dealing with another one of these mutations." In the meantime, other research groups or plant testing facilities could use the new genetic assay to detect the mutations in Palmer samples. Tranel hopes they will. "The more labs testing for this, the more we learn about how widespread the mutation is," he says.
Palmer amaranth is a nightmare of a weed, causing yield losses up to 80 percent in severely infested soybean fields. It scoffs at farmers’ attempts at control, having evolved resistance to six classes of herbicides since its discovery in the United States 100 years ago. And now, scientists have discovered it has two new tricks up its sleeve. If this weed continues to resit the herbicides, then we can not control the growth nor the spread of it. https://www.sciencedaily.com/releases/2017/04/170404124409.htm The team around the former GFZ PhD student of the GFZ section Climate Dynamics and Landscape Evolution, Gordon Schlolaut (now Japan Agency for Marine-Earth Science and Technology), investigated sediments from Lake Suigetsu in Japan, to reconstruct East Asian climate change during the Younger Dryas. Achim Brauer, Head of the GFZ section Climate Dynamics and Landscape Evolution and Director of the Department Geoarchives says: "Little by little we come to understand the interplay between regional climate changes at the end of the last glacial phase. The scientists assume that this warming was related to changes in atmospheric pressure that pushed cold polar air masses and with them the westerlies that are determinant for the European climate further north, which before, during the glacial phase, reached down to Southern Europe. The algae of the investigated lake, and the spores and pollen from plants that were surrounding the lake, that were deposited throughout the centuries of the cold period, as well as changes in the chemical composition of the sediments, provide the scientists with important information on regional changes in temperature and rainfall. Like parts of a puzzle, these different regional archives provide an overall picture of the climatic changes during that time and show how regional climate changes were influencing each other.
The climate of the Earth follows a complex interplay of cause-and-effect chains. A change in precipitation at one location may be caused by changes on the other side of the planet. A better understanding of these "teleconnections" -- the linkages between remote places -- may help to better understand local impacts of future climate change. A look into the climate of the past helps to investigate the teleconnections. https://www.sciencedaily.com/releases/2017/03/170331120340.htm "We've determined that most of the gas ever present in the Mars atmosphere has been lost to space," said Bruce Jakosky, principal investigator for MAVEN and a professor at the Laboratory for Atmospheric and Space Physics (LASP). MAVEN team members had previously announced measurements showing that atmospheric gas was being lost to space and that described the processes by which atmosphere was being stripped away. Young stars have far more intense ultraviolet radiation and winds, so atmospheric loss by these processes was likely much greater early in Mars' history, and these processes may have been the dominant ones controlling the planet's climate and habitability, according to the team. The team used this enrichment together with how it varied with altitude in the atmosphere to estimate what fraction of the atmospheric gas has been lost to space. In sputtering, ions picked up by the solar wind impact Mars at high speeds and physically knock atmospheric gas into space. The team made its estimate using data on the Martian upper atmosphere from MAVEN's Neutral Gas and Ion Mass Spectrometer (NGIMS) instrument supported by measurements from the Martian surface made by NASA's Sample Analysis at Mars (SAM) instrument on board the Curiosity rover.
Solar wind and radiation are responsible for stripping the Martian atmosphere, transforming Mars from a planet that could have supported life billions of years ago into a frigid desert world, according to new results from NASA's MAVEN (Mars Atmosphere and Volatile Evolution Mission) spacecraft led by the University of Colorado Boulder. This is important to know because this could be the same fate for Earth. We should look into ways to prevent this potential issue. https://www.sciencedaily.com/releases/2017/03/170330142211.htm UC Davis postdoctoral researcher Julie Cridland is working with Santiago Ramirez, assistant professor of evolution and ecology at UC Davis, and Neil Tsutsui, professor of environmental science, policy and management at UC Berkeley, to understand the population structure of honey bees (Apis mellifera) in California. To understand California bees, the researchers realized that they first needed to better understand honey bee populations in their native range in the Old World. There are two major lineages of honey bees in Europe -- C, "Central European," including Italy and Austria and M, including Western European populations from Spain to Norway -- which give rise to most of the honey bees used in agriculture worldwide. The more docile C lineage bees came later, and today many California bees are from the C lineage, but there is still a huge amount of genetic diversity, Ramirez said. "You can't understand the relationships among bee populations in California without understanding the populations they come from," Cridland said.
Where do honey bees come from? A new study clears some of the fog around honey bee origins. The work could be useful in breeding bees resistant to disease or pesticides. Honeybees are essentially to our world and agriculture. In order to have plants grow and prosper we need pollination which the bees help do. https://www.sciencedaily.com/releases/2017/02/170217012456.htm In a new study published in Scientific Reports this week, a team led by researchers from Michigan Technological University created the first, truly global inventory for volcanic sulfur dioxide emissions, using data from the Dutch-Finnish Ozone Monitoring Instrument on NASA's Earth Observing System Aura satellite launched in 2004. While this number is higher than the previous estimate made in the late 1990s based on ground measurements, the new research includes data on more volcanoes, including some that scientists have never visited, and it is still lower than human emissions of sulfur dioxide pollution levels. He led the effort to catalog sulfur dioxide emissions sources from human activities and volcanoes and to trace emissions derived from the satellite observations back to their source by using wind data. But the satellite data could allow us to target new ground-based measurements at unmonitored volcanoes more effectively, leading to better estimates of volcanic carbon dioxide emissions." Ground-based data are more detailed, and in areas like Central America where large sulfur dioxide-emitting volcanoes are close together, they better distinguish which specific volcano gas plumes come from. The work highlights the necessity of consistent long-term data, according to co-author Nick Krotkov, an atmospheric scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, which produces the sulfur dioxide data from the Aura satellite.
Volcanoes erupt, they spew ash, their scarred flanks sometimes run with both lava and landslides. But only occasionally. A less dramatic but important process is continuous gas emissions from volcanoes; in other words, as they exhale. A number of volcanoes around the world continuously exhale water vapor laced with heavy metals, carbon dioxide, hydrogen sulfide and sulfur dioxide, among many other gases. Of these, sulfur dioxide is the easiest to detect from space. https://www.sciencedaily.com/releases/2017/03/170309150624.htm Using a library of more than 10,000 deep-sea corals collected by Caltech's Jess Adkins, an international team of scientists has shown that periods of colder climates are associated with higher phytoplankton efficiency and a reduction in nutrients in the surface of the Southern Ocean (the ocean surrounding the Antarctic), which is related to an increase in carbon sequestration in the deep ocean. There is 60 times more carbon in the ocean than in the atmosphere -- partly because the ocean is so big. As such, the ocean is the greatest regulator of carbon in the atmosphere, acting as both a sink and a source for atmospheric CO2. As the sea creatures who consume those sugars -- and the carbon they contain -- die, they sink to the deep ocean, where the carbon is locked away from the atmosphere for a long time. In most parts of the modern ocean, phytoplankton deplete all of the available nutrients in the surface ocean, and the biological pump operates at maximum efficiency. However, in the modern Southern Ocean, there is a limited amount of iron -- which means that there are not enough phytoplankton to fully consume the nitrogen and phosphorus in the surface waters. Because the Southern Ocean flows around Antarctica, all of its waters funnel through that gap -- making the samples Adkins collected a robust record of the water throughout the Southern Ocean. As a result, there is a correlation between the ratio of nitrogen isotopes in sinking organic matter (which the corals then eat as it falls to the seafloor) and how much nitrogen is being consumed in the surface ocean -- and, by extension, the efficiency of the biological pump. As such, the evidence suggests that colder climates allow more biomass to grow in the surface Southern Ocean -- likely because colder climates experience stronger winds, which can blow more iron into the Southern Ocean from the continents.
We know a lot about how carbon dioxide (CO2) levels can drive climate change, but how about the way that climate change can cause fluctuations in CO2 levels? New research from an international team of scientists reveals one of the mechanisms by which a colder climate was accompanied by depleted atmospheric CO2 during past ice ages. Efficient nutrient consumption by plankton in the Southern Ocean drove carbon sequestration in the deep ocean during the ice ages, a new study suggests. https://www.sciencedaily.com/releases/2017/03/170314150916.htm Each year from early May to late June, researchers looked daily for the first signs of growth in plots enclosing individual plant species. "When we started studying this, I never would have imagined we'd be talking about a 26-day per decade rate of advance," said lead author Eric Post, a polar ecologist in the UC Davis Department of Wildlife, Fish and Conservation Biology who has been studying the Arctic for 27 years. While how early a plant emerges from its winter slumber depends on the species, the study demonstrates that the Arctic landscape is changing rapidly. Caribou come to the study site each year during calving season to take advantage of the nutritious plants needed to recover from winter and provide for their newborns. But as the emergence of plant species in spring has shifted, the caribou internal clock, driven by seasonal changes in day length, has not kept up. "That's one example of the consequences of this for consumer species like caribou, who have a limited window to build up resources before going into the next winter," Post said. "With the most recent study, we're taking a step toward understanding how extensive and cryptic the effects of sea ice loss might be in the Arctic." As a result, fewer calves are born and more die early in years when spring plant growth outpaces the caribou calving season.
This article identified the changes happening in nature and how it could affect our ecosystems. Spring is coming sooner to some plant species in the low Arctic of Greenland, while other species are delaying their emergence amid warming winters. The changes are associated with diminishing sea ice cover, according to a study. https://www.sciencedaily.com/releases/2017/02/170223134408.htm In a new study, recently recovered Russian observations show an increase in sea ice from 1950 to 1975 as large as the subsequent decrease in sea ice observed from 1975 to 2005. This cooling effect may have disguised the influence of global warming on Arctic sea ice and may have resulted in sea ice growth recorded by Russian aerial surveys in the region from 1950 through 1975, according to the new research. The new study helps sort out the swings in Arctic sea ice cover that have been observed over the last 75 years, which is important for a better understanding of sea ice behavior and for predicting its behavior in the future, according to Fyfe. "The cooling impact from increasing aerosols more than masked the warming impact from increasing greenhouse gases," said John Fyfe, a senior scientist at Environment and Climate Change Canada in Victoria and a co-author of the new study accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union.The new study's use of both observations and modeling is a good way to attribute the Arctic sea ice growth to sulfate aerosols, said Cecilia Bitz, a sea ice researcher at the University of Washington in Seattle who has also looked into the effects of aerosols on Arctic ice.
The importance of this article shows humans may have been altering Arctic sea ice longer than previously thought, according to researchers studying the effects of air pollution on sea ice growth in the mid-20th Century. The new results challenge the perception that Arctic sea ice extent was unperturbed by human-caused climate change until the 1970s. https://www.sciencedaily.com/releases/2017/02/170223124327.htm |
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