Day 6: Sample, Sample, Sample

Hey everyone! I’m Annika, a 2nd year marine science major! I’m one half of the chlorophyll analysis team. Together with my partner Sophie, the ATP team, and the phosphate and nitrate teams, we left bright and early to collect samples from around the innermost part of ‘Ōpūnohu Bay where a river empties in. We were planning to map out how the influx of terrestrial runoff might be impacting the bay. Most of the waters around Mo’orea and French Polynesia are highly oligotrophic with low levels of nutrients and certain organisms, but the river (and other creeks nearby) could be depositing supplementary nutrients and other good stuff (e.g. chlorophyll) into the bay. 

We ended up sampling six sites with three branching from either side of the river mouth, and got fantastic data! The river mouth is definitely influencing the chemistry of the bay. We’re seeing increased chlorophyll and ATP levels, meaning more organisms active in those waters, and nutrient levels higher than elsewhere on Mo’orea which is likely what is supporting the larger populations. That also matches nicely with our samples from around the Cook’s Bay river and ‘Ōpūnohu Bay earlier this week, with some differences in the dissipation rates moving away from the river and in the exact levels of each parameter, but with relatively consistent increased levels around the rivers and creeks.

After a long day running around one of the most interesting and beautiful places I’ve been, we went for a quick snorkel outside our beach house, helped out the other teams processing samples for our other projects, and slept hard. Such an amazing day!!