Baltic TRANSCOAST Seminar- Dr. Soeren Ahmerkamp (IOW)

In the early 1900s, The Haber-Bosch process revolutionized agriculture
by enabling large-scale synthesis of nitrogen fertilizers, fueling
unprecedented increase in food production and population growth.
However, the widespread use of these fertilizers has also resulted in
substantial nutrient runoff into marine systems, intensifying
eutrophication and altering marine biogeochemical cycles.

Coastal sediments, predominantly composed of permeable sands, play a
crucial role in mitigating nutrient inputs. Long regarded as
biogeochemical deserts, this perception has been overturned over the
past three decades with increasing recognition of the intricate and
challenging to study transport processes occurring in sandy sediments.
In my talk, I will showcase an interdisciplinary approach combining
mathematical modelling, benthic lander deployments and laboratory
experiments to study biogeochemical processes in sandy sediments. The
data obtained reveals that the coastal filter function is driven by a
dynamic interplay between physical transport processes and microbial
activity, across a wide range of spatial scales. Through the mechanistic
understanding obtained, a transfer function is derived that allows for
upscaling benthic biogeochemical processes in sandy sediments using
easily measurable quantities such as grain size, bottom water currents
and microbial activity. This transfer function will pave the way for
improved representation of benthic biogeochemistry in ecosystem-scale
and earth system models.