Monday, August 15, 2011

MSI: Algae Analysis and Identification

Kaitlin and the MSIs identify their algae samples.

Today, the interns learned about one of the most important living organisms to aquatic, as well as terrestrial, life: algae. Algae is used as both a food source and habitat in the ocean. Algae, especially calcareous species, are extremely important to reef building contributing to both reef accretion and cementing. Algae is also an essential actor in nutrient recycling on reefs.

The interns took algae samples from the dock in front of BIOS back into the lab to identify. They found 15 species including Halimeda monile, Acetabularia crenulata, Bryopsis plumosa, Laurencia obtusa, Cymopolia barbata, Caulerpa taxifolia, Calerpa verticillata, Caulerpa cupressoides, Dictyota divaricata, Padina vikerslae, wrangelia argus, Alathamnion herveyi, Rosenvingea intricata, wurdemannia miniata and Botryocladia shanksii as well as two sea spiders (our best identification guess as Endeis spinosa) and a decorator crab scurrying about amidst an anemone. The interns then classified each species as chlorophyta, phaeophyta or rhodophyta and determined whether they were calcareous, filamentous, coarsely branched, leathery or branched.

One of the sea spiders - note the balloon like structures around the legs - it's pregnant!

In the afternoon, the interns traveled out to Bailey's bay to collect even more algae samples. They laid out five quadrats at random locations along two transect lines and took algae samples from within them. Once back at the lab, they analyzed their five samples to determine the species present and biomass of algae per meter squared in Bailey's bay.

Wednesday morning,
the MSI interns analyzed their algae data collected from Bailey's bay. Using this data, they sought to answer the following questions: what is the diversity of algae at Bailey's bay based on their collected samples, and, what is the biomass per meter squared of algae at Bailey's bay?

The interns found that in Bailey's bay, the average biomass per meter squared is 8.4 +/- 3.37 grams per meter squared. They also found that the species richness of algae at the same location is eleven with the average species richness being three. According to their data, the major contributors to the algae community at Bailey's bay are Laurencia and Caulerpa which are both branching species. This may be due to the environmental conditions at Bailey's bay which include shallow, rather calm and warm waters, a lot of sun exposure, and high sediment density.

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