Ocean currents shape fluxes of heat and carbon into the ocean with cascading influences on the global climate. Dynamics at small spatial scales (0.1 – 10 km) are important for these fluxes but are difficult to study because the first-order importance of both planetary rotation (geophysical dynamics) and non-linear advection means that the traditional simplifications of the equations of motion are not possible. Recent observations in this small-scale regime challenge classical theories. I will present new theoretical tools to aid dynamical interpretation of velocity and wave observations and to quantify the impact of small-scale currents on biological processes. I will then compare the theoretical results with observations to reveal how eddy dynamics shape the upper ocean distribution of carbon and heat.