Susan Allen, University of British Columbia
A bio-physical coupled model of the upper Strait of Georgia
The dominant photosynthetic plants in the ocean are single celled organisms we call phytoplankton. Like all plants they need light and nutrients to grow. However, unlike land plants, the amount of light phytoplankton receive is strongly dependent on the amount of mixing in the ocean. If they are mixed deep in the ocean away from the light, they cannot grow.
As light onto the ocean increases in the spring and winter storms abate, the amount of light phytoplankton receive increases to the point of strong positive growth. This leads to rapid accumulation of biomass until the phytoplankton exhaust the nutrients. We call this biomass accumulation the spring bloom.
In the past there has not always been equipment in place to observe the spring bloom in the Strait of Georgia. Thus we have created a coupled bio- physical model to hindcast the timing of the spring bloom for the last 40 years. In this talk I will discuss the construction and testing of the model, what it tells us and why the timing of the bloom matters.