The biological (soft tissue) pump (BP) sustains a marine surface-to-deep DIC gradient, which is known to significantly lower atmospheric pCO2 and modulate Earth climate. In today’s ocean the balance between export of organic matter, its degradation in the interior and the circulation-driven return flux of inorganic carbon towards the surface supports the storage of ‘respired carbon’ (carbon from the BP), in the ocean interior equivalent to about 1800 Gt C. Understanding what controls rates of gain (i.e. production, export, flux divergence) and loss (return flux) of respired carbon in the ocean, and its feedback to atmospheric pCO₂, is critical for reliable predictions of the oceans role in the global carbon cycle under conditions of a changing climate. We invite presentations from observationalists, experimentalists, and modellers that help to better understand how the biological pump will change in the future and to reduce the related uncertainties in ocean carbon cycle projections. We particularly invite presentations that explore the respective potential role of processes that are so far understudied in the current climate models, e.g. non-Redfield stoichiometry, more mechanistic ecosystem models, or alternative temperature dependence of biological processes. We also look forward to studies of past climate change that can guide our understanding of the role of the biological pump in a changing future climate.