Research Seminar: Meredith Meyer

The UNC-CH’s Department of Earth, Marine, and Environmental Sciences presents a research seminar from graduate student, Meredith Meyer. This event will be held on Monday, September 13th, at 1:25 pm. This event will be hosted in person in G201 Murray Hall and will be streamed via Zoom Meeting 950 4519 5368.

Seminar Title: Size fractionated primary production dynamics at two productivity endmember systems

Abstract: In order to understand the strength and efficiency of the oceanic biological carbon pump, it is critical to quantify the amount of net primary production (NPP), the type of primary production, and the key species engaging in net primary production. This process of NPP makes up the foundation of the biological carbon pump, thus maintaining a healthy, balanced ocean. Using data from the Subarctic North Pacific Ocean and the North Atlantic Ocean, we evaluate NPP from contrasting systems: one low primary production – low export ratio system (Ocean Station Papa) and one high primary production – high export ratio system (the Porcupine Abyssal Plain). To evaluate the drivers and dynamics behind NPP, we collected size-fractionated chlorophyll a and isotopic uptake measurements to assess the balance between NPP from new nitrogen sources and regenerated nitrogen sources as well as biomass and cellular physiology metrics. Our data suggest that Ocean Station Papa is a region of low NPP (23.1 mmol C m-2 d-1) dominantly fueled by regenerated production (72%) occurring in the <5 µm cell size fraction, but brief periods of enhanced new production occurring in both the <5 µm and >5 µm size fractions play an important ecological role as well. Much work remains to be done to further understand the key primary producers at Ocean Station Papa and their physiological strategies as well as comparing these dynamics to those of our high primary production – high export ratio endmember, the Porcupine Abyssal Plain.