Kim, H.-J., A. J. Miller, J. McGowan and M. Carter, 2008:
Climate and coastal algal blooms in the Southern California Bight.
Progress in Oceanography, sub judice.
Abstract.
Surface chlorophyll measured at the Scripps Pier in the Southern California Bight
(SCB) for eighteen years (1983 - 2000) reveals that the spring bloom occurs with
irregular timing and intensity each year, unlike sea-surface temperature (SST), which is
dominated by a regular seasonal cycle. In the 1990's, the spring bloom occurred earlier in
the year and with larger amplitudes compared to those of the 1980's. Seasonal anomalies
of the chlorophyll have no significant correlation with local winds, offshore winds, or
upwelling index anomalies. Consequently, classical coastal upwelling may not be the
process that drives chlorophyll variations in the nearshore SCB.
The annual mean Pier chlorophyll concentration exhibits a clear increasing trend with
no concomitant trend evident in the Pier SST over these two decades. The interannual
variations of the Pier SST and chlorophyll is not correlated with tropical El Nino or La
Nina conditions over the entire observing period, but a few strong El Nino and La Nina
events have significant impacts on the Pier data. The Pier chlorophyll is highly coherent
at low frequencies (3-7 years) with nearby offshore in situ surface chlorophyll
observations at the CalCOFI (California Cooperative Fisheries Investigations) station
93.27. Both the Pier and CalCOFI station 93.27 (12.5 km offshore) are on the continental
shelf (water depth < 200m), but the Pier chlorophyll observations have magnitudes that are
roughly one to two orders greater than the offshore surface chlorophyll observed by
CalCOFI.
Preprint (pdf)