A snow day and climate change

Today is a "Snow Day" with school canceled due to bad weather. We are all in a positive mood due to the change and unexpected "holiday".  I was reminded that I haven't blogged for a long time and today is a great day to get back on track!

Thinking of freezing rain and poor conditions, negative effects from "climate change" are thought to be greatest and fastest in the polar regions.   (I prefer the term "climate variability" rather than climate change to reflect the uncertainty about the multiple causes in long-term trends and emphasize the variation, not the change itself.)  Summer ice cover in the Chukchi Sea has been consistently very low, marine mammal distributions have changed, and it is reasonable to ask how systems have changed during the period of greatest change in the Arctic?   My recent publications can shed some light on this topic although, unfortunately, the data do not exist to make real inferences (repeated sampling over time of the same locations in representative areas). First, I want to present what we know from Port Valdez, a glacial fjord that does have an appropriate database for demonstrating temporal change.  The Pacific Decadal Oscillation (PDO: http://jisao.washington.edu/pdo/) is the temporal variation of oceanographic conditions in the North Pacific Ocean and the characteristics summarized in the PDO have large ecosystem effects. Among related patterns, the higher water temperatures associated with positive PDO values are related to greater precipitation along the coastline.  A relationship can therefore be expected between benthic fauna and the PDO, as the following plot demonstrates:

The relationship above may occur through increased availability of food through greater inputs of organic carbon, greater survival and recruitment of juveniles, or other pathways.  Curiously, biomass has a negative association with PDO suggesting that the higher abundance is due to greater influxes of juveniles, and not the success of older animals. I need to dig much deeper into this issue.

Can a similar pattern be observed in the Chukchi Sea?  Based on 5-years of data, significant variations in faunal abundance (density) do reflect some oceanographic conditions, although no single variable serves as a primary covariate.  Here is a plot of abundance from our Chukchi Sea study 2008 - 2012 demonstrating significant temporal variability, although the variables driving that are not understood.

It appears that the older animals survive from year-to-year (biomass remains fairly constant) but abundance and the number of different taxa found in each study area vary significantly. Find our reports and other information at http://www.chukchiscience.com/.

Compare the trends marked in blue in the above plot with this plot of the Arctic Oscillation, a climate index for the Arctic:

Not too much relationship between the last two plots.  There really isn't enough data for inferences, but it doesn't look at first glance, like there is a relationship in the Chukchi Sea, like that in Port Valdez. This also needs further attention.