Thursday, July 26, 2012

Fish Kill Reported at Krísuvík Volcano in Iceland

Krísuvík Volcano in Iceland has not erupted for centuries, however the area and its lakes remain rife with fumerolic and hot spring activity. Recently it was reported by Icelandic media and volcano-blogger Jón Frímann that Kleifarvatn lake, a part of the Krísuvík volcanic system, that divers and visitors have been noticing lots of dead fish in the lake. While it is unclear whether or not the fish population in the lake has indeed been hit by unusual activity, fish kills in volcanic lakes are typically a good indicator of volcanic activity.

There are many deadly volcanic lakes in the world, the most notable and famous of which was Lake Nyos in Cameroon which, after a small landslide, caused the liquid CO2 at the bottom of the lake to stir, and escape to the water's surface, eventually escaping the boundaries of the large maar-lake, and inundating lower elevations with deadly amounts of CO2 that killed thousands in a matter of hours.

Kleifarvatn lake lies in parallel with the crater rows of Krísuvík's volcanic system which consists of fissure vents, cinder cone rows, and flood basalts, which last erupted sometime in the late 14th century. The lake itself lies on a low point of the spreading rift, and thus is a great lake to capture gases under water pressure, much like lake Nyos. It could simply be that recent seismicity in the area has stirred up the gases, which mix with the water level the fish typically are at, thus suffocating the fish with volcanic gases and killing them.

It is a trend to watch however. There have not been any studies yet done by local scientists, so right now we don't really know if there have been other changes in the lake such as increased Ph levels, temperatures, or other increases in gas from source vents under the lake.

Fish kill is always a sign to look for if there is anything ominous going on at any volcano. Several episodes of fish kill have occurred near my hometown of San Diego at the Salton Sea, which was related to release of volcanic gases in one instance, but another instance was caused by farm water runoff into the lake that ended up making it one of the most polluted lakes on the planet (a disgusting distinction for an area of the world that is so beautiful). Few people in San Diego or California actually realize that the Salton Sea (who's volcanic counterpart is known as the Salton Buttes) is really a volcano, with fairly recent geological history.

As with the Salton Sea, Krísuvík volcano is also near an actively producing geothermal field. Geothermal drilling can and does cause seismicity which can disturb lake sediments and result in the loss of marine life due to particulates like sediment, and volcanic/organic gases like methane and CO2.

Right now it's all speculation until I can see a study done by scientists that show chemical levels and demonstrate a clear increase in activity. As with much of Iceland, most of the volcanoes there are constantly steaming or releasing some kind of gas, so this may not be unusual for this particular volcano. The lake is lines with steam and hydrothermal vents, hot springs, mud pools, and all sorts of avenues for gases to be released, so it wouldn't surprise me in the least to learn that this has been going on in this lake for a very long time.

In any case, I'll follow up with this volcanic lake if anything new should develop. Stay tuned!

1 comment:

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