There are Plankton on Hurricane Island?
By Samantha Poratti
It’s a rainy day on Hurricane Island, with fog as far as the eye can see. Many staff may find themselves inside doing computer work. However, you will find one adamant staff member with a microscope in the back corner of the lab, off in their own world exploring fascinating microscopic creatures. These microscopic creatures are called plankton, and they are incredible! Plankton are found in various bodies of water, ranging from fresh to saltwater. They are drifters in the water column, so where they go is dependent on current and tides. Plankton can be classified into two categories, zooplankton and phytoplankton. Zooplankton are animals, while phytoplankton are plants. Zooplankton consume other phytoplankton such as krill, and juvenile forms of scallops or barnacles. While phytoplankton obtain their energy from the sun via photosynthesis. Examples of phytoplankton include Alexandrium spp., Pleurosigma spp., Coscinodiscus spp., etc.
On Hurricane Island, the research staff participates in a Maine Department of Marine Resource Phytoplankton Volunteer Monitoring Program. This program extends across the whole coastal region of Maine and is conducted weekly by volunteers from April to October. The main goal of the program is to consistently monitor phytoplankton species throughout coastal Maine, for the purpose of being able to detect toxic phytoplankton. Toxic phytoplankton species, such as Alexandrium spp., Dinophysis spp., Pseudo-nitschia spp., etc., can be very harmful in certain concentrations to species that interact or consume them. Toxic phytoplankton can result in Paralytic Shellfish Poisoning (PSP) or called “Red Tide”, Diarrhetic, Neurotoxic, and Amnesic Shellfish Poisoning. In the Gulf of Maine, shellfish that constitute a large aquaculture industry, such as Atlantic scallops (Plactopecten magellanicus) and blue mussel (Mytilus edulis), are especially susceptible and are at a high risk to toxic phytoplankton. This is because they have high filtration rates. Meaning, they take in and filter water at faster rates than other species of shellfish. In addition, scallops are very slow to eliminate toxins, unlike other shellfish, because they store these toxins by metabolic processes in other tissues for longer periods of time. So even when there may not be large quantities of toxic phytoplankton currently present in the water column, scallops may be dangerous for humans or other species to consume. This is why it is crucial that there is consistent monitoring of toxic phytoplankton, so that closures and warnings within the shellfish industry can be issued to consumers and harvesters in order to prevent irrevocable damage.
However, for the staff member sitting in the back of the Hurricane Island lab, it is a good day! Not many toxic phytoplankton species are encountered. Instead, Skeletenoma spp., Ceratium longpipes, Navicula spp., and a personal favorite Dictyocha spp. are currently suspended in the water column. By now, hopefully it is apparent that zooplankton and phytoplankton are a unique group of species, but often overlooked. The role they play in the freshwater and marine food webs and within ecosystems, is crucial for the survival of all species. So next time you are in or near a body of water, stop and give a little appreciation to the little guys. They are hard at work!
