Sunday, October 6, 2013

Algae Bloom or Clathrates

There has been some discussion lately as to whether the high levels of methane observed over the Arctic Ocean originated from algae bloom or from clathrates (i.e methane hydrates).

The image below, from, does indeed indicate extensive algae bloom.

[ click on image to enlarge ]
The green color indicates extensive algae bloom, especially in areas where the sea water has been very warm recently, as discussed in earlier posts such as 'Is the North Pole now ice-free?' The image below shows sea surface temperature anomalies as at September 30, 2013.

[ click on image to enlarge ]
Indeed, no surprise to see extensive algae bloom, especially close to Svalbard, where the highest anomalies were recorded. The question is, however, where the methane came from that has showed up so prominently over the Arctic Ocean recently. The animation below shows methane readings over the past week, against a recent sea ice concentration map.

[ click on image to enlarge ]

These high methane levels appear to show up over the sea ice, rather than over open water. This makes it more likely that the methane originates from deep sea clathrates. The color red indicates that the sea ice has maximum concentration, so there will be few holes in the ice where algae can grow. As the top image shows, the green color shows up in areas with open water, rather than over areas covered with ice.

The image below shows sea ice thickness for the same date as the sea ice concentration map.

Even at places where the sea ice has been very thin recently, such as on the North Pole and as discussed in the post North Hole, it is now at least some 30 cm thick, making it unlikely that algae are grow there.

In conclusion, it is likely that the methane originates from deep sea clathrates, and that is a very scary development.


  1. Can methane make it through maximum ice concentration?

    1. One of the few ways to explain these high methane readings over the Arctic Ocean is that the methane must have bubbled up from the depth of the ocean and somehow perforated the ice. Note that this very high ice concentration still means that there can be small open spots, the more so since the ice is very thin in many places, so there may be extensive cracks as well.