{"id":92690,"date":"2023-07-19T08:41:17","date_gmt":"2023-07-19T06:41:17","guid":{"rendered":"https:\/\/www.sonnenseite.com\/?p=92690"},"modified":"2023-07-19T08:41:18","modified_gmt":"2023-07-19T06:41:18","slug":"the-carbon-cycle-is-speeding-up","status":"publish","type":"post","link":"https:\/\/www.sonnenseite.com\/en\/science\/the-carbon-cycle-is-speeding-up\/","title":{"rendered":"The car\u00adbon cycle is speed\u00ading up"},"content":{"rendered":"\n

Soil is the largest natural carbon storage in the world. In Northern ecosystems particularly large amounts of carbon are stored, but they are also particularly strongly affected by global warming. <\/p>\n\n\n\n

A recently published study by an international team led by Michael Bahn of the University of Innsbruck investigated how ongoing warming affects the uptake and release of carbon dioxide in subarctic grassland. The researchers used a geothermally active area in Iceland as a natural \u201eclimate chamber\u201d.<\/p>\n\n\n\n

Subarctic ecosystems store large amounts of carbon. As the climate continues to warm, more and more carbon is being released into the atmosphere. There are large uncertainties concerning the extent to which the loss of carbon from soil can be compensated by the uptake of carbon through plant photosynthesis: \u201cAfter all, if warming increases the decomposition of soil organic matter and thus also the supply of nutrients to plants, then plants should grow better and absorb more carbon dioxide from the atmosphere,\u201d says Michael Bahn of the Department of Ecology<\/a> at the University of Innsbruck. \u201cSurprisingly, this may not be the case, as our recent study shows.\u201d<\/p>\n\n\n\n

Natural climate lab<\/h4>\n\n\n\n

Geothermal rifts in Iceland provide ideal conditions for researchers to explore the longer-term effects of climate warming on ecosystems in the far north. A team led by Michael Bahn used a geothermally active site in Iceland as part of an international project to study the effect of warming and nitrogen supply on the carbon cycle. \u201eThe research plots were located at different distances from the rift line and, accordingly, warmed to a greater or lesser extent,\u201d Michael Bahn explains. \u201eBy fertilizing part of the plots with nitrogen we were able to study the interactive effects of warming and nitrogen supply on the carbon cycle.\u201d<\/p>\n\n\n\n

Warming accelerates the carbon cycle<\/h4>\n\n\n\n

Warming led to a massive loss of carbon in the soil. \u201eIn the area we studied in Iceland, up to 40 percent of the carbon was released into the atmosphere in the first few years after warming,\u201d says Michael Bahn. \u201eIn the subsequent years, the microbial biomass adjusted and the soil carbon balance stabilized again.\u201d To understand the path carbon takes in this cycle from the atmosphere through the plants and soil and back to the atmosphere, the research team added the stable carbon isotope 13<\/sup>C during the experiment. \u201eUsing the isotope, we were able to trace the path of the carbon as it moves through the ecosystem\u201d, explains the ecologist. \u201eWe observed that with increasing warming, the carbon taken up by the plants was transferred more strongly to the microbes and released more rapidly from the soil.<\/p>\n\n\n\n

From the fertilization experiments it can further be concluded that under warming plant productivity became increasingly nitrogen limited. In consequence, the photosynthetic uptake of carbon dioxide by the ecosystem decreased. As warming also accelerated the release of carbon from soil, the ecosystem’s ability to store carbon was thus gradually reduced.\u201d<\/p>\n\n\n\n

The results were recently published in Global Change Biology<\/em>. The research was financially supported by the Austrian Science Fund FWF and the European Union, among others.<\/p>\n\n\n\n