¥Hypothesis: The occurrence of
large populations of Calanus finmarchicus in the coupled GB/GoM system REQUIRES (1)
high seed stocks (supply) of diapausing C.finmarchicus in the deeper ocean regions nearby
(GOM basins and the Slope Sea), (2) that the deep C. finmarchicus
stocks terminate diapause
at the appropriate time to be synchronous with continental shelf spring blooms, and (3) a nutrient
enriched, highly productive ecosystem in the GB/GoM to sustain high growth and survival rates
of Calanus that will provide seed for the subsequent year.
¥Prediction A: Overwintering Calanus finmarchicus seed stocks are LOW and GB/GoM productivity is HIGH when
the water masses of the Slope Sea have little influence (input) from Labrador-Irminger Gyre
(Labrador Slope Water) water masses (due to the relatively nutrient replete bottom waters and
low Calanus supply in Warm Slope Waters), but C. finmarchicus
recruitment is good because
of a near-perfect match between the time of diapause awakening and the time of the spring
bloom, the latter of which is large because of the higher concentration of nutrients in deep warm
slope waters.
¥Prediction B: Overwintering C.
finmarchicus seed stocks are HIGH
and GB/GoM productivity is LOW when the water masses
of the Slope Sea have a large proportion of Labrador Sea water (due to the relatively
nutrient-depleted bottom waters and high C.
finmarchicus supply in cold Labrador Slope Water),
but recruitment and productivity
are poor because of the generally low springtime productivity
(low nutrients) and a timing mismatch between diapause awakening, ascent and reproduction and
the NW Atlantic spring bloom.