Anna Christina Hans‘s talk centered on the Atlantic Meridional Overturning Circulation (AMOC) – a key component of the global climate system. She presented results about the upper branch of the AMOC at 11°S, gathered by the TRACOS observation array (Tropical Atlantic Circulation and Overturning at 11°S). The array combines pressure-equipped inverted echosounders (PIES), moored instruments, and ship data, supplemented by Argo floats and satellite information.

Using a high-resolution ocean model (VIKING20X), the team ran so-called Observing System Simulation Experiments (OSSEs) to investigate how sensitive the transport calculations are to measurement arrangement and methodological assumptions. The results show that despite relatively sparse instrumentation, more than 70% of high-frequency and 60% of low-frequency AMOC variability can be reconstructed. The seasonal cycle dominates the signal with fluctuations of around 20 Sverdrup. At the same time, Anna Christina Hans and her colleagues identified opportunities to improve the array design to capture AMOC variability more robustly.

Florian Schütte’s poster showed a striking example of how physical processes shape biodiversity. Drawing on 20 years of interdisciplinary research around the Cape Verde Archipelago, he and his international team showed how different physical processes influence biological productivity in an otherwise nutrient-poor region of the tropical Atlantic.

The team identified three key processes:

1. Atmospherically generated island wakes: Wind flows over the islands' topography create eddy fields that enhance local mixing and nutrient supply
     
2. Mesoscale eddies from West Africa: Nitrate-rich eddies interact with islands and shallow topography, intensifying submesoscale dynamics and vertical mixing.
     
3. Tides and internal waves: Breaking internal waves lead to mixing rates up to a thousand times higher compared to the open ocean.

These processes increase the nitrate flux into the euphotic zone (the upper ~100 m where photosynthesis occurs) and thus promote primary production. Zooplankton and mesopelagic fish increase three- to tenfold in hotspots. Moreover, fish landings (mackerel, tuna) and the occurrence of humpback whales correlate positively with chlorophyll concentration. The study powerfully illustrates how small‑scale physical processes structure marine biodiversity and food webs.
   

Data-Driven Ocean Emulation

In another poster contribution, Florian Schütte and his colleagues from the Ocean Dynamics Department showed how kilometer-scale ocean simulations can be used to develop cost-efficient data-driven models of the three-dimensional ocean state using deep learning. The researchers aim to generate physically consistent ocean ensembles with significantly reduced computational effort – a promising approach for future ocean forecasting.