500 rivers across the globe used to establish the effect of climatic factors on river-based ecosystems

The work of 153 researchers from 40 countries, including scientists from the Marine Institute, Newport, in Co Mayo has led to new findings on the effect of climatic factors on river-based ecosystems.

Quantifying decomposition rates in over 500 rivers across the globe, including every continent, the study found that climatic factors, such as temperature and moisture, influenced carbon-cycling rates of river-based ecosystems.

"Staff based in the Institute's Newport research facility conducted the fieldwork in the Burrishoole catchment, where long term ecological research has been carried out since 1955. We carried out the work in the Srahrevagh, Fiddaunnahoilean, Fiddaunveela and  and are important spawning streams for salmon and trout," explained Elvira de Eyto, Marine Institute.

Carbon cycling is critical for the functioning of systems across a range of spatial scales, from local food webs to the global climate.

Scott Tiegs, biology professor at Oakland University in Michigan, who led the study, explains that "river ecosystems play significant roles in the global carbon cycle by regulating rates of decomposition and transporting organic matter to the oceans. However, we have only a rudimentary understanding of how decomposition rates vary from river to river."

Unlike most previous studies on carbon cycling in streams and rivers, the methodology in this study was identical across all field sites. The study made use of a standardized, easy-to-use bioassay, which enabled a large number of researchers to participate in the study.

The paper noted that the climatic factors that govern decomposition rates are increasingly impacted by human activities. These findings will help researchers establish baselines to quantify environmental impacts to the functioning of ecosystems on a global scale.

"In addition to providing fundamental information on how river ecosystems function, our results provide baseline data that will enable future researchers to evaluate large-scale ecological responses to warming and other dimensions of global climate change," Dr Tiegs added.

The findings are published in the latest issue of the journal Science Advances where the paper can be read in full at: http://advances.sciencemag.org/content/5/1/eaav0486