Fig 1.
A) Climatological seasonal cycles of Mixed Layer Depth (MLD, m), surface chlorophyll concentration (mg m−3) and depth-integrated chlorophyll inventory (mg m−2), averaged over the northern Labrador Sea (60°W-50°W and 60°N-65°N) B) Average percent area of the northern Labrador Sea with satellite chlorophyll observations for each month.
Fig 2.
Climatological April surface chlorophyll concentration (mg m−3) with contours of climatological March MLD (m) overlaid.
The contour interval is 100 m with solid lines used for labelled contours.
Fig 3.
The black dotted-line represents the climatological observed change in chlorophyll inventory between October and February, based on the seasonal cycle shown in Fig 1A.
The three solid curves indicate changes in senescent plankton population with time for various cell sizes (red, blue and magenta for 5, 10 and 15 μm respectively) with sinking as well as re-entrainment considered. The blue dashed-line indicates changes in plankton population with time for a plankton size of 10 μm with sinking only and without re-entrainment.
Fig 4.
A) Maximum March MLD anomalies (m) plotted against maximum April surface chlorophyll concentration anomalies (mg m−3), averaged over the northern Labrador Sea and for the period 1998-2015 (in pink). Purple dots centered on pink dots indicate data points with atleast 600,000 chlorophyll observations in the northern Labrador Sea. B) Number of April satellite chlorophyll observations for each year in the northern Labrador Sea. The dash-dotted horizontal line indicates the cut-off level of 600,000 chlorophyll observations used in A.
Fig 5.
Projected fraction of growing fall phytoplankton population that survives the winter, as a function of plankton cell-diameter in A: RCP 4.5 scenario B: RCP 8.5 scenario. C: and D: As in A and B but for senescent phytoplankton.