It has been a long time since our last entry, and the ocean has been quite busy.
Coastal ocean transitions can often be indicated by temperature trends. To the right is a graph of surface water temperatures at the Newport Pier for this year. The red line is the 2010 data and the black line represent the 5-year average from 2006 to present. The temperature plot is extremely interesting. This past winterthe temperatures were above average through April likely because of the El Nino influence. The winter months saw unseasonably warm waters (about 16C/61F) and a below average occurrence offewer phytoplankton blooms than we expected. The blooms are typically associated with a decrease in temperature that is regularly related to upwelling bringing of cool, and nutrient -rich waters to the surface.
The system transitioned from the warm El Nino conditions throughout last winter and spring to a summer dominated by cold temperatures about 3-5C below average. In fact, most of July, August, and September (about 14.5C/58F) temperatures were cooler than the winter temperature seen from January until April. This year is starkly different than the 5 year average trend which shows that July through September are the warmest months. The unusually cool temperature observations correlated with atypical summer phytoplankton biology. Phytoplankton blooms that are generally expected to occur in spring instead occurred during the cool periods of summer. These blooms included blooms of Pseudo-nitzschia, a harmful toxin-producing algal bloom species.
Currently in mid-November the number of Pseudo-nitzschia is again on the rise. It usually is a rare species making up less that 1% of the phytoplankton in the local community, but now Pseudo-nitzschia is abundant enough to be considered a common species making up 10-24% of the community. The recent increase in Pseudo-nitzschia corresponds to a decrease in temperature in early November. The decreased temperature suggests that nutrient rich waters, which could support Pseudo-nitzschia growth that we are seeing along our coast, are closer to the surface.
The temperature plot was compiled by Stacy Kim, a USC undergrad who volunteers in our lab.
