Surfers can help sample phytoplankton near the shore

As autotrophs, that is organisms that create their energy through photosynthesis, microscopic phytoplankton form the basis of the marine ecosystem. These miniscule organisms seem to be most abundant near shore, in the “surf zone.” 

Dr. Bob Brewin, a scientist with the University of Exeter, took to his surfboard to collect phytoplankton. Now, researchers from both Exeter and Plymouth Marine Laboratory are asking kayakers, swimmers and surfers for water samples.

“Nearshore waters often have the highest levels of biodiversity in the ocean,” said Dr. Brewin. “Phytoplankton are a very important component of that, but at present we struggle to monitor seasonal and longer-term changes in nearshore phytoplankton concentrations.””It’s hard to take research vessels or build monitoring stations in places where waves are constantly breaking, and this leaves key gaps in our knowledge.”

A new study is based off 67 samples collected by Dr. Brewin off Bovisand Beach, near Plymouth in the UK over a 12 month period. This is to be a test pilot for a broader citizen science project involving samples collected by recreationists. 

The water samples were tested for chlorophyll-a, which gives an estimate of the phytoplankton biomass. These results are compared to those from water samples collected four miles offshore. 

The results of the comparison showed that the biomass is similar in fall, winter and spring. In summer, however, phytoplankton have a much greater presence nearshore and much less biomass offshore. 

The difference is likely caused by phytoplankton blooming offshore in the spring and the following depletion in nutrients. “The timing and distribution of these blooms is critical for how energy moves up the food web,” explained Dr. Brewin.

“For example, fish larvae need that phytoplankton to feed – if the timing is just a little bit off, that can be devastating for the growth of the larvae.”

The scientists hope that with more citizen science research, they can monitor and keep track of how climate change is affecting the nearshore ecosystem. 

The research is published in the journal Oceans.

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By Zach Fitzner, Earth.com Staff Writer