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 |
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May 2017
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