We characterise seasonal patterns in phytoplankton community composition on the Scotian Shelf, northwest Atlantic Ocean, through a study of the numerical abundance of different cell sizes — pico-, nano- and microphytoplankton. Cell abundances of each size class were converted to cellular carbon and their seasonal patterns compared with the partial pressure of carbon dioxide (pCO₂) also measured at the study site. We observed a persistent drawdown of CO₂ throughout the summer months, despite nutrient depleted conditions and apparent low biomass suggested by the chlorophyll record. This drawdown was associated with a summertime phytoplankton assemblage numerically dominated by small phytoplankton that reach their peak abundance during this period. It was found that phytoplankton carbon during this period accounted for approximately 10% of spring bloom phytoplankton carbon and pointed to the importance role that small cells play in annual CO₂ uptake.

Item Type:	Refereed Article
Keywords:	CO2 drawdown, small phytoplankton, cell abundance
Research Division:	Biological Sciences
Research Group:	Ecology
Research Field:	Community ecology (excl. invasive species ecology)
Objective Division:	Environmental Management
Objective Group:	Marine systems and management
Objective Field:	Marine biodiversity
UTAS Author:	Shadwick, EH (Dr Elizabeth Shadwick)
ID Code:	106876
Year Published:	2015
Web of Science® Times Cited:	5
Deposited By:	CRC-Antarctic Climate & Ecosystems
Deposited On:	2016-02-24
Last Modified:	2017-11-06
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