HARMFUL ALGAL BLOOMS OF PSEUDO-NITZSCHIA

IN THE SANTA BARBARA CHANNEL

 

Natalie McCaffery

mccnat@lbsstudents.org

 

The specific study of the diatom (a single cell alga) known as Pseudo-nitzschia (Shown in target of miscroscope photograph) is conducted here to provide quantitative data of algal blooms and insight on why predictions based purely on environmental factors may not accurately determine the number of Pseudo-nitzschia in a body of water. Some Pseudo-nitzschia are known to produce a neurotoxin known as domoic acid. Domoic acid is responsible for amnesic shellfish poisoning. Bait fish that

feed on phytoplankton such as Pseudo-nitzschia

become carriers of this toxin affecting the neurosystems of

their predators (sea mammals, and birds) often resulting

in death. Harmful Algal Blooms (HABs) are periods of time

when there is a high concentration of harmful phytoplankton

in the water column causing negative impacts on organisms

higher in the food web. A HAB of Pseudo-nitzschia occurs

when there are over 10,000 cells found per liter of seawater.

The objective of my project is to test the California-Harmful

Algal Risk Mapping Model provided by CenCOOS

(Central and Northern California Ocean Observing System)

against the data I collected off the Goleta beach pier.

Predictions and models given by sites similar to CenCOOS

sometimes give over-generalized information to shellfish

farmers who avoid harvesting during predicted HABs.

Farmers want to avoid harvesting shellfish that may be

carriers of amnesic shellfish poisoning. HABs have the

potential to disturb both our coastal ecosystem and

economy through bloom toxicity, so further and

continued research is essential.

 

 

"Harmful Algal Blooms (HABs) are periods of time when there is a high concentration of harmful phytoplankton in the water column causing negative impacts on organisms higher in the food web."

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Partnering with the lab of Dr. Miller at the UCSB Marine Science Institute, I collected water samples for two weeks on Monday, Wednesday, and Friday -- using their pre-existing collection procedure. I counted the Pseudo-nitzschia and extrapolated for the total volume of sample. I concluded that the CenCOOS map is accurate in predicting the probability that a HAB will occur in a location at a specific time. The predictive map was more generalized than the numbers I collected, and the numbers I collected have a large margin of error (that the prediction map is trying to account for) due to the uneven distribution of phytoplankton throughout my sample. I then took my research a step further and looked at the weather forecasts for the days that I collected samples and analyzed the wind, air pressure, and temperature readings in relation to the data I collected and that on the predictive model. Stated in a case study of our West Coast,

 

 

 

“An apparent link between upwelling-related physical signatures, macronutrients, and HABs in the various ‘hotspots’ throughout California has motivated attempts to forecast HABs as a function of select environmental variables."

- Kudela

 

 

 

 

 

Santa Barbara’s fishing industry heavily relies on shellfish, as the rock crab holds one of the longest seasons. Without accurate predictions of when and where these HABs will occur, fishermen are taking risks that could detrimentally affect their crop. As these blooms increase in magnitude and duration, there is a need for a synoptic monitoring network (Kudela). Researchers have created models that identify the weather conditions associated with high-toxicity blooms, and have used these models to predict when the next bloom will occur in proximity to the forecasted conditions. But, there are two problems: we do not have enough temporal analysis to identify the optimal observation frequency necessary to monitor and forecast HABs, and second, we don’t have enough observations to parameterize these models (Kudela). My project is one set of data being added to the books so that we can accumulate the amount of information necessary to parameterize the models. But, the data I have collected is only an attempt to capture the dynamics of HABs. The benefit of my collection is that setting up collection points along the West Coast, specifically in areas that wouldn’t necessarily be detected by the already in-place prediction marks, will help identify trends in hot spots. My project is addressing the clarity of information between the HARM Model and data collected off of the Goleta beach pier. (Graph to Left: the forecast probability map provided by CenCOOS