ESA: Midgefest Iceland
Now here’s in mage with an interesting back-story. This is a false-color infrared image, taken from an sensor called ASTER aboard the TERRA satellite, shows some a shallow lake in Iceland called Myvatn, which is well known for “periodic unbelievable eruptions of midges” according to Phil Townsend, of the Forest Remote Sensing Lab at the University of Wisconsin, Madison. The midges leave the lake en mass over a week or so, mate, and keel over on the ground.
This midge pulse delivers a huge amount of biomass to the land around the lake, and as a consequence, it is haloed by vegetation distinctly lush compared to what’s going elsewhere in the area.
In these images, brighter red indicates more vigorous vegetation. Myvatn is the paradigm case: a thin border of hot pink rings the lake, comparable in brightness to the fertilized pastures that show up as blobs further from the lake.
Townsend is using satellites to identify more midge lakes. The signal is less clear on other suspect lakes, but the last two seem to share the pattern. He’s also used the images to estimate exactly how much biomass is being hurled on Myvatn’s shore during these midge pulses. Over eight days in late July and early August, the midges deposited 135 kg of biomass per hectare per day within 150m of the shore.
