The OOI Global Station Papa Array is located in the eastern subtropical North Pacific in the Gulf of Alaska. The Array is co-located with the NOAA Pacific Marine Environmental Laboratory (PMEL) Surface Buoy, an Ocean Climate Station Mooring, and was the location of the historic ocean weather ship Station P from 1949 to 1981 and the current Line P program.
This nugget examines seasonal cycles of water column mixing and production. There is a clear annual cycle of stratification in the summer/fall (May-Oct) and mixing in the winter. Note the shallow mixed layer in the winter that does not reach down to the sensor at 130m. These data reveal a general relationship between stratification and production – when the water column is stratified and phytoplankton have sufficient light for growth, phytoplankton biomass increases. Although there are peaks in chlorophyll during late summer/fall (Aug/Sep), there is no large seasonal bloom. As the area is a high nitrate-low chlorophyll region, the lack of a large bloom is thought to be the result of iron limitation and grazing pressure by zooplankton.
The annual cycle of water column mixing and production in the Gulf of Alaska are often compared and contrasted with the North Atlantic, such as the OOI Global Irminger Sea Array, which has a very deep mixed layer and a large spring bloom. Check out the nuggets on Mixing and Seasonal Production in the Irminger Sea.