TERRAPUB Journal of Oceanography

Journal of Oceanography, Vol. 57 (No. 6), pp. 723-734, 2001

The Spring Phytoplankton Bloom in the Coastal Temperate Ocean: Growth Criteria and Seeding from Shallow Embayments

Debby Ianson1*, Stephen Pond1 and Timothy Parsons2

1Earth and Ocean Sciences Department, University of British Columbia, BC Canada
2Institute of Ocean Sciences, Sidney, BC Canada

(Received 19 December 2000; in revised form 12 July 2001; accepted 28 August 2001)

Abstract: A method based on time-series of conductivity, temperature and depth (CTD) profiles which successfully determines favourable phytoplankton growth conditions for the spring bloom in nearshore temperate coastal waters was developed. The potential for shallow embayments to influence phytoplankton species composition in larger adjacent waters was also investigated. At temperate latitudes, such embayments should have favourable phytoplankton growth conditions earlier in the spring than open waters as bathymetry limits vertical mixing and thus increases light availability. The study area was Nanoose Bay, which is connected to the Strait of Georgia, British Columbia. Data were collected 2-3 times per week during the winter-spring of 1992 and 1993. A mooring with 5 current meters was placed at the mouth of the bay in 1992. The conservation equation for a scalar was used to estimate the balance between advective transport and biological source and sink terms. Variability in physical conditions and biological response between years was tremendous. Results indicate that seeding from the bay was not possible in 1992 but could have been in 1993. However, to conclusively determine the importance of Nanoose Bay on the spring bloom species composition in the Strait of Georgia, more extensive work is required.


*Corresponding author E-mail: ianson@halodule.tamu.edu


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