Cascading effects of permafrost melting
EurekAlert reports today the latest findings of Michael Gooseff presented in the annual meeting of the Ecological Society of America. It’s a suggested reading if you are into the impacts of climate change on polar areas. I’ll only highlight some of the links between drivers of regime shifts that potentially cause cascading effects among them.
The increasing melting of polar ice is driven by climate change. Ice is melting faster and it’s expected to “change flow patterns, expand the stream networks, and change both the location of habitats and timing of life cycles” . For example, Gooseff reports “temperatures and snow and rain across the tundra shifts annually and seasonally. We know that fall is beginning later than it once did”.
One of the most common link reported in the literature is that as polar areas warm up, permafrost begins to melt and liberate huge amounts of carbon dioxide and methane that has been stored for centuries. As carbon is released to the atmosphere, climate change is reinforced by the permafrost melting feedback loop.
However, something I haven’t seen is the link between permafrost melting and nutrients runoff. The latest is an important driver of regime shifts like eutrophication, hypoxia and transitions in food webs. Here are some notes:
Extended frost-free time causes soils that do thaw annually to have longer active periods when microbes can mineralize nutrients. While the soils remain frost free longer, plants continue their normal cycle dictated by the length and intensity of daylight, which has not changed. Microbes may continue to create nutrients, but the plants no longer use them, so that when rain or meltwater comes the nutrients leach into the rivers and streams.
“That is exactly what we are seeing,” said Gooseff. “In September and October, we see a substantial increase in nutrients in the water. Concentrations increase many times for nutrients such as nitrate and ammonium.”
I wonder how such linkages will change the map of dead zones, or areas under hypoxia regime around the world. Do you think it will be strong enough to create new dots in polar coasts?
The Dead Zones map was created by EarthObservatory | NASA based on the following paper:
Diaz, R. J., & Rosenberg, R. (2008). Spreading Dead Zones and Consequences for Marine Ecosystems. Science, 321(5891), 926-929.
via: Polar climate change may lead to ecological change. | EurekAlert