The Malaspina Dragon: A newly-discovered pattern of the early spring bloom in the Strait of Georgia, British Columbia, Canada

•We find a new, repeating pattern in the early spring bloom of the Strait of Georgia.•The pattern suggests seeding of the spring bloom from inlets.•The spring bloom occurs earlier in years in which the pattern occurs.•Satellite images of chlorophyll fluorescence give clearer results than other satellite products.•Since 2009 we have used in situ fluorometers to confirm timing.

MERIS and MODIS ocean colour satellite imagery of the Strait of Georgia, British Columbia, Canada shows a recurring pattern which suggests seeding of the early spring bloom from deep, glacial inlets to the north. We call the pattern the “Malaspina Dragon” after its shape in satellite imagery in 2005, 2008 and 2009 shortly after it enters the Strait. It appears to have been active in five of the nine years, 2003-2011. We use the satellite imagery to determine a start date for the main spring bloom in the Strait of Georgia in each year, and show that in the five “Dragon” years the spring bloom occurred nearly 4 weeks earlier than in the remaining four, suggesting that seeding from inlets may be a significant factor controlling timing. In 2009 and 2010, the presence and evolution of the bloom was confirmed using an ocean glider, and in 2010 and 2011, recording fluorometers provided surface data. Ship samples in 2009 showed that the bloom forming the Dragon pattern consisted of diatoms (Thalassiosira spp.) similar to those that form the main spring bloom in the Strait.