Join us for the next BPE Seminar
Lipids and carbohydrates as labile elemental and chemical energy currencies in the upper ocean
with Dan Lowenstein, MIT-WHOI joint program student, Woods Hole Oceanographic Institution.
Abstract: Marine microbes and particulate organic matter (POM) are central to global elemental cycles but their macromolecular (e.g. carbohydrates, lipids, proteins) and elemental compositions are poorly constrained in both space and time. First, using publicly available datasets of lipid abundances, nutrient concentrations, and POM stoichiometry, we conduct the first basin-scale survey of lipid stoichiometry along a north-south transect spanning the western Atlantic Ocean from ~40°S to ~55°N, and demonstrate that surface ocean lipid stoichiometry is highly variable, is primarily linked to phosphate (P) availability, and is strongly correlated with POM stoichiometry. Second, though it is well established that the abundance of surface ocean POM changes throughout the day due to photosynthesis and respiration, the magnitude of this cycle and the chemical pools through which microbes store and consume this biomass are not well studied. To this end, we quantified the contributions of triacylglycerol lipid (TAG, i.e. fat) and total glucose to particulate organic matter over multiple daily cycles at two oligotrophic and two coastal locations: the North Pacific Subtropical Gyre and Sargasso Sea, and the coastal Pacific near Oregon and the Gulf of Maine. In all locations, we observe a clear diel cycle in both lipids and carbohydrates, with production in these pools accounting for up to 75% of daily primary production, and differences in carbon allocation between TAG and glucose systematically influenced by microbial community composition. These processes have broad implications for POM lability, trophic transfer, export, and stoichiometry at the global scale.
Zoom info:
https://columbiauniversity.zoom.us/j/95332400100?
Meeting ID: 953 3240 0100
Passcode: 504872
