Arctic Ocean Microbial Community Structure before and after the 2007 Record Sea Ice Minimum
Figure 2
Physicochemical trends in the Arctic Ocean.
(A–D) Salinity and nutrient concentrations in the central Amundsen Gulf. Values are from within the salinity layer bounded by 31 and 33 psu, approximating the Pacific water mass defined by the Tmax of the summer water and the Tmin of the winter water [15]. Values are averaged over all stations in waters deeper than 300 m; station variability is indicated by standard deviation. Time series trend is indicated by linear regression of year average, n = 9. (E–F) September minimum sea ice extent in the Arctic Ocean from the IARC-JAXA. Values for each year (E) are the averages of the 30 daily values of September and variability is indicated by standard deviation. The boxplot (F) indicates the medians, 1st and 3rd quartiles, and ranges (whiskers) of the data in (E) for the 4 years before the major melt of 2007 and the four subsequent years (n = 120 for each case). The statistical result indicated is the two-sample t-test (unequal variance).