Particulate inorganic carbon production within E. huxleyi blooms in subpolar and polar seas: a satellite time series study (1998–2013)

Abstract

ABSTRACTMaking use of the OC CCI (Ocean Colour Climate Change Initiative) satellite data, and based on the developed both Emiliania huxleyi bloom contouring methodologies and binary masks, areas of coccolithophore growth were distinguished without supervision from locations of mass developments of other algae. On these grounds, and employing special processing algorithms, multi-year time series of variations in occurrence, surficial extent, and content of particulate inorganic carbon (PIC) within E. huxleyi blooming areas in the North, Norwegian, Greenland, Barents, and Bering Seas were obtained for the time period 1998–2013. Analysis of algorithmic processing of the OC CCI data permitted to reveal the spatio-temporal sequence of E. huxleyi blooming events in the above seas of the North Atlantic and Arctic Oceans. During the intra-annual cycle, E. huxleyi blooms advance from temperate to higher latitudes along the pathways of the Gulf Stream propagation to the north. Annually, the blooms arise in the vicinity of the Great Britain southern extremity, and further on move northward along the western coast of this Island Country, round it to eventually appear first in the North and Norwegian Seas (in early June), then in the Greenland Sea (in late June), and finally in the Barents Sea (in late July–early September). The regularities in dates of bloom outbreak and their duration are revealed. The bloom areas in the North Atlantic–Arctic water are the lowest in the Greenland Sea (10,000–30,000 km2) and by an order of magnitude higher in the Barents Sea. The same pattern holds for the total PIC content within E. huxleyi blooms: 400 t–14 kt in the Greenland Sea and about 0.35 Mt in the Barents Sea. In the Bering Sea, the temporal and spatial dynamics of E. huxleyi development proved to be highly irregular: before and after the 1997–2001 period of high intensity of this phenomenon, the blooms are sporadic, their extent and PIC production are either very low or insignificant. Regarding the range of E. huxleyi bloom areas in the Bering Sea during 1997–2001, it is rather similar to that of the Barents Sea. However, the PIC content in the Bering Sea, as compared to that in the Barents Sea, is higher by a factor of about two with maximum values reaching 0.4 Mt and, on one occasion (in 2001), even about 0.7 Mt.