With the last post concentrated on the direct effects of sea ice loss in the Arctic, this post will look again at tithe phenomena of sea ice, but with a particular focus on the indirect impacts of Arctic sea ice disappearance. Below is a short video which aims to portray ice minimum volume from 1979 to 2013.
Sea ice loss may influence ecological dynamics indirectly through effects on species movements and disease transmission causing species to become more vulnerable. Arctic populations isolated when an ice free season occurs in the Arctic, the declining presence of sea ice could reduce inter-island migration. With the lengthening of the ice free season, genetic isolation among populations is encouraged (Post et al. 2013). For some species, sea ice can act as a barrier to dispersal, due to the lengthening of the sea ice free season will increase population mixing, reducing genetic differentiation. This impending loss of sea ice will increase contact among closely related series for which it currently acts as a mixing barrier. Hybridisation is likely to become increasingly common. Polar bears and grizzly bears may be the result of increasing inland presence of polar bears as a result of prolonged ice free seasons (Hoflinger, 2013). In Canada, the projected decrease in sea ice cover with Arctic warming, will increase contact between Eastern and Western Arctic species.
Image of a 'pizzly' the grizzly-polar bear hybrid.
A second indirect impact is changes that occur in animal behaviour as a result of sea ice loss. In the Canadian Arctic, later ice seasons and increased shipping traffic due to the lengthened ice free seasons could prevent migration of the Dolphin and Caribou (Poole et al. 2010). It is widely understood by ecologists that migration can decrease the likelihood of parasitism. The changes in ice formation within the Arctic could change the amount of parasite loads among the Dolphin migration herds. However, sea ice loss is not always looked on negatively, with the reduction of sea ice promotion migration hence preventing disease epidemics where the sea ice provides a corridor for pathogen transmission (Post et al. 2013).
Sea ice loss also effects terrestrial ecosystems including especially, land adjacent to the sea ice. Arctic warming, delayed freeze season and sea ice loss will promote permafrost warming increasing terrestrial primary productivity. There has been increases in the abundance and cover of shrubs occurring across the Arctic.
A recent report by the Arctic council and the National Oceanic and Atmospheric administration (2013) shows evidence of a shift to a new warmer, greener state. The major findings of this report include:
1) Vegetation in the Arctic is greener with a longer growing season.
2) Wildlife and large land mammal populations continued declining trends with Caribou having unusually low numbers.
3) Sea ice extent in September 2013 was the sixth lowest since observations began in 1979.
4) Northward migration into the Arctic of fish such as Atlantic Mackerel and Atlantic Cod.
This report shows that recently there has been increased concerns over this region of sea ice loss. With the academic community trying to understand how extensive the impacts of sea ice loss are. With conditions changing for many species in the Arctic, it is important to note that sea ice decline is not itself solely responsible for many individual species decline, however it plays a role with a combination of other factors. Declining sea ice is not uniform and therefore individual species responses will remain varied (Mueter and Litzow, 2007).
As we can see from the last two posts, sea ice loss can have both negative and positive effects on the ecological diversity of the Arctic. Keep your eyes peeled for the next post which will offer some insight into a completely different area of global biodiversity, one that is extremely threatened- freshwater biodiversity.
Score Board Update.
As we can see from the last two posts, sea ice loss can have both negative and positive effects on the ecological diversity of the Arctic. Keep your eyes peeled for the next post which will offer some insight into a completely different area of global biodiversity, one that is extremely threatened- freshwater biodiversity.
Score Board Update.
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