According to Icelandic news today. Fish has been dying in Kleifarvatn lake. But Kleifarvatn lake is inside Krísuvík volcano system. The exact reason why the fish is dying is not known at this point. But report suggests that large amount of fish has been seen dead already. I do not know how much fish there is in Kleifarvatn lake.
This suggests that hydro-thermal and hot spring activity in increasing in the lake. This also suggest that increased toxic levels (for the fish) are now changing in the lake. What toxins are at work here I do not know. But it can be assumed that it is what comes with magma.
For the past three to four years. Krísuvík volcano has been inflating and deflating at regular time intervals. What this means in unclear at present time. But this is signs of increased activity in the volcano anyway. Hydro-thermal and hot spring activity has also been increasing during this period. This has also been followed by increased earthquake activity in Krísuvík volcano when inflation takes place. What happens next is impossible to know for sure. But it is clear that Krísuvík volcano is still far away from erupting any time soon.
Icelandic news about this
Fiskar í Kleifarvatni sagðir í andarslitrum (Vísir.is)
Fiskar i Kleifarvatni sagðir drepast í stórum stíl (Vísir.is)
Jon, a fish kill like this is the kind of thing that’s likely to get written down in historical accounts. Is there anything in written history you know about, for Kleifarvatn or any other lakes or rivers, where fish kills were recorded preceding an eruption? Might be worth investigating.
Last eruption was in the early 14th century. No documents of what happened before the eruption have been discovered so far.
There might be other reasons for dying fish. One is connected to the summer – which has been unusually warm and dry so far. This depletes lakes of oxygen and promotes growth of algae. When it then starts to rain a lot (which it has in the last few days), this rains brings a lot of small organic material into the lakes which cause further oxygen consumption when its degraded. This can cause so called “dead zones” which are free of oxygen and then fish are dying.
That might be the case. As Kleifarvatn lake is a ground level lake and no river runs into it. How the water level have been in it this summer is not something I know about yet.
I am not sure about the summer, since I haven’t been there for a while. During the spring the water levels rose due to the rain that came down at that time.
it reminds me a lot of the Lake Nyos incident, although with a twist. My theory is that seismicity in the region had stirred up lake bottom sediments and gases suppressed by the weight of lake water to create a deadly soup at a low water level that caught some fish by surprise. At Lake Nyos, this was caused by a landslide, but given the seismicity in the Krisuvik area lately, this would be my guess. It probably has very little to do with new intrusions of magma or anything like that 🙂 Good post Jon!
As far as I know, only lakes that don’t overturn are prone to accumulating and then catastrophically exsolving CO2… I think the conditions that lead to stratification are mostly found in the tropics, where you don’t get much seasonal overturning. I think Icelandic lakes should pretty much should all circulate seasonally, so I think it would take a great deal of gas input to create the situation you envision.
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