248
Chapter 9: The Atlantic Ocean
0.36
0.54
0.72
0.90
1.08
0.60
0.75
0.90
1.05
1.20
SeaWiFS (BENG): September 1997 - January 2002
Surface Chl (mg m -3
)
Pt (gC m
-2
d
-1
)
Pt d
-1
Chl m
-3
1998
1999
2000
2001
0
20
40
60
80
100
0
5
10
15
20
Climatology (years)
Depth (m)
Production at DCM (%)
Zm (sigma)
Zeu
Pt (at DCM)
Fig. 9.25 BENG: seasonal cycles of monthly surface chlorophyll and depth-integrated autotrophic production
for the years 1997–2002 from SeaWiFS data together with characteristic seasonal cycles of mixed-layer depths
from Levitus climatological data and photic depths computed from characteristic irradiance and the archive
of chlorophyll profiles discussed in Chapter 1.
Synopsis
Case 6—Intermittent production at coastal divergences—The climatology offered by
archived data does not correspond with any of the individual upwelling cells, but shows
the generally deeper austral winter pycnocline and the effects of austral summer upwelling
on primary production rate (Fig. 9.25). Seasonality of Z m responds both to austral winter
mixing and to coastal upwelling in austral summer. Z eu lies consistently at moderate
depths so thermocline is illuminated in all months except July–October (austral winterspring) and presumably also in strong upwelling cells, the effects of which are concealed
in mean values. Rate of P increases from winter minimum to annual austral summer maximum in May during the maxima of trade wind stress and coastal divergence. Seasonal
dynamic range is strong (05–175 mg chl m
−3 ) but does not closely track seasonality in
rate of P.
Northwest Atlantic Shelves Province (NWCS)
Extent of the Province
The NWCS province comprises the continental shelf and slope water from the Florida
Keys to the Strait of Belle Isle between Newfoundland and Labrador. The offshore
boundary is either, as convenient, the north, inshore wall of the Gulf Stream from Florida
to Newfoundland or the shelf-edge front; arbitrary lines are drawn around the east and
north sides of the Grand Banks. It is traditional to partition the geography of this region
Chapter 9: The Atlantic Ocean
0.36
0.54
0.72
0.90
1.08
0.60
0.75
0.90
1.05
1.20
SeaWiFS (BENG): September 1997 - January 2002
Surface Chl (mg m -3
)
Pt (gC m
-2
d
-1
)
Pt d
-1
Chl m
-3
1998
1999
2000
2001
0
20
40
60
80
100
0
5
10
15
20
Climatology (years)
Depth (m)
Production at DCM (%)
Zm (sigma)
Zeu
Pt (at DCM)
Fig. 9.25 BENG: seasonal cycles of monthly surface chlorophyll and depth-integrated autotrophic production
for the years 1997–2002 from SeaWiFS data together with characteristic seasonal cycles of mixed-layer depths
from Levitus climatological data and photic depths computed from characteristic irradiance and the archive
of chlorophyll profiles discussed in Chapter 1.
Synopsis
Case 6—Intermittent production at coastal divergences—The climatology offered by
archived data does not correspond with any of the individual upwelling cells, but shows
the generally deeper austral winter pycnocline and the effects of austral summer upwelling
on primary production rate (Fig. 9.25). Seasonality of Z m responds both to austral winter
mixing and to coastal upwelling in austral summer. Z eu lies consistently at moderate
depths so thermocline is illuminated in all months except July–October (austral winterspring) and presumably also in strong upwelling cells, the effects of which are concealed
in mean values. Rate of P increases from winter minimum to annual austral summer maximum in May during the maxima of trade wind stress and coastal divergence. Seasonal
dynamic range is strong (05–175 mg chl m
−3 ) but does not closely track seasonality in
rate of P.
Northwest Atlantic Shelves Province (NWCS)
Extent of the Province
The NWCS province comprises the continental shelf and slope water from the Florida
Keys to the Strait of Belle Isle between Newfoundland and Labrador. The offshore
boundary is either, as convenient, the north, inshore wall of the Gulf Stream from Florida
to Newfoundland or the shelf-edge front; arbitrary lines are drawn around the east and
north sides of the Grand Banks. It is traditional to partition the geography of this region