A Blooming Threat: Investigating a Linkage Between Phytoplankton Populations, Water Temperature, and the Potential Increase of Harmful Algal Blooms 

Nicholas Reinbold and Dr. Geoffrey Dilly 


Phytoplankton, also known as micro algae, plays a critical role in ocean ecology, being the base of the trophic food web. Algal population growth is influenced by a number of factors including sunlight intensity, nutrient availability, wind conditions, and more. A more recently studied contributing factor is increasing temperature, potentially leading to an increase in algal blooms. As ocean temperatures rise worldwide, the effect this could have on algae proliferation needs to be further clarified. The potential relation of algal growth and temperature is especially important in instances of harmful algal blooms, during which certain neurotoxin-producing genera are consumed by filter feeding bivalves and can cause Paralytic Shellfish Poisoning (PSP). Based on a hypothesis of direct correlation between higher temperatures and increased algal growth, this presentation will discuss the linkage between sea surface temperature and algal populations in Ventura County and the Channel Islands, as well as the implications of rising ocean temperatures and potential mitigation strategies.

To address this linkage, we used both publicly available databases and collected local algal samples and temperature data. Algal sampling occurred at four separate locations, Bechers Bay, Skunk Point, Santa Rosa Island Pier, and Port Hueneme Pier. Concentration was done in two ways; 15-meter vertical tows when conditions allowed or filtering a total of 227 liters through a phytoplankton net when shallow conditions prevented a vertical tow. These concentrated samples were treated with formalin to preserve any collected tissues then quantified using hemocytometer slides. Temperature data were collected at Bechers Bay and Skunk Point, Santa Rosa Island using iButton thermal loggers co-located with algal collection sites. In addition, regional buoy and satellite sea surface temperature data were collected from NOAA public databases – National Data Buoy Center and ERDDAP respectively.


Session 1 – 1:30p.m. – 2:45p.m.

Room A – Sierra 1411