Academic Affiliation: Western Carolina University
Leslie is currently a senior at Western Carolina University and is pursuing a B.S. in Geology. Her love of economic geology stems from spending her childhood helping her family operate their corundum mine in Cowee Valley, NC. Her RESSES 2016 research project involved determining the differences between simulated phytoplankton blooms of the Southern Ocean in coarse and fine resolutions. Understanding these simulations is an important step towards reliably predicting how real world phytoplankton will be affected by future climate change.
Ocean Phytoplankton Biogeography: Earth System Model Estimates at Coarse and Fine Resolution
The base of the oceanic food web is composed of unicellular photosynthetic organisms called phytoplankton. These microscopic autotrophs are present in the photic zone and are crucial to oceanic ecological processes. A considerable amount of research has been conducted on the impact of phytoplankton on the ocean’s biogeochemical cycles. However, less is known about the geographic distribution of the different major groups of phytoplankton. Here we use the Community Earth System Model (CESM) developed by the National Center for Atmospheric Research (NCAR) to analyze the spatial distribution of diatoms and small phytoplankton in the Southern Ocean.
Ocean phytoplankton and circulation were simulated at two horizontal resolutions: 1°x 1° and 0.1°x 0.1°. The coarse model is a forty-nine year run while the fine resolution (due to computational cost) is a five-year run. In order to compare these two models we averaged the diatoms and small phytoplankton across both resolutions for all time slices. We also assessed average sea surface temperature (SST), fractional ice cover, and dissolved inorganic iron (an important nutrient). Stereonet projections of the coarse, fine, and interpolated differences of all factors were created. Our findings suggest that diatoms dominate in the coarse model while small phytoplankton dominate in the fine model. Analysis of total phytoplankton biomass found that the fine resolution simulated 36.4% more small phytoplankton than the coarse resolutions. Therefore, we recommend use of the fine model as it captures more details of phytoplankton community dynamics than the coarse model.