Overview

The ability of the oceans to regulate the climate system and mitigate its present and future changes depends on the strength and variability of its circulation and the intimate connection between dynamical and biogeochemical processes. By connecting water masses across the full depth of the ocean, the ocean circulation induces a large-scale redistribution of carbon, heat and nutrients that is key to the Earth’s climate and biogeochemical cycles.

My research focuses on:

  • The exchange rate of tracers between the surface and the ocean interior

  • The dynamics of the interior waters, which constitute the largest reservoirs for heat and carbon

(a) Schematic of the global Meridional Overturning Circulation, from Meredith, 2022. (b) Inventory of anthropogenic carbon accumulated in the ocean interior up to 2013 (data from GLODAP gridded dataset). (c) Ocean heat content calculated from GLODAP gridded dataset.

The links between the global-scale ocean circulation and the distribution of tracers such as anthropogenic carbon and heat is shown here. For example, the sinking of dense waters in the North Atlantic provides a pathway for the accumulation of anthropogenic carbon in this region. Similarly, the circumpolar circulation around Antarctica creates a barrier to the transfer of heat south; changes in such circulation have been causing an excessive heat flux to terminating glaciers in West Antarctica, which is causing ice shelf melting, with gloabl implications for sea level rise.

PROJECTs

Below is a brief outline of the main projects/research questions I am currently working on

BRINE: Bellingshausen Region Ice-melt and Nutrient Exchanges(2024-2027)

The team prepares an underwater glider for deployment. Photo credit: Sasha Montelli.

By using state-of-the-art autonomous vehicles, BRINE will explore:

  • The mechanisms driving the intrusion of warm Circumpolar Deep Water onto the continental shelf

  • The production rates and export pathways of freshwater from several ice shelves

  • The impacts of meltwater on biogeochemical cycles

  • The connectivity across West Antarctica, from the Peninsula to the Amundsen Sea

Learn more about BRINE here

Acknowledgments:

Ocean Ventilation

Waters are “ventilated” when they are in contact with the atmosphere, and so they can exchange properties - such as heat, carbon, and oxygen. When water becomes dense and sinks into the ocean interior (for example, in the North Atlantic and around Antarctica), it stops being ventilated and the clock of water “age” starts. Knowing the age of a water mass is important because it tells us how long it can store tracers in the ocean interior, for example, sequestering carbon for centuries or millennia.

In my work, I use transient tracers such as chlorofluorocarbons (CFCs) and sulfur-hexafluoride (SF6) to gain information about the ventilation rates and the age of water masses. CFCs and SF6 concentrations in the ocean interior are monitored thanks to international hydrographic programs, such as GO-SHIP.

The slideshow shows ventilation maps inferred using transient tracers (from Cimoli et al., 2023) and the process of collecting CFCs/SF6 samples from a CTD rosette. Photo credit: Laura Cimoli.

Details to be added soon!

Small-scale Ocean Turbulence