Novel in situ imaging technology to explore the “ladder of vertical migrations” to the deep-sea

Introduction

The pelagic deep ocean is the largest but least-understood habitat on Earth, harboring enormous fish stocks, a rich (and largely undiscovered) biodiversity, as well as a large carbon sink in the climate system. As almost all life at depth is ultimately nourished by primary production in the surface ocean, pathways of “vertical connectivity” are critical in linking ecological and biogeochemical processes across several thousands of meters.

Vertical Migrations

One of the most enigmatic phenomena is the so far virtually unexplored “ladder of vertical migrations.” This mechanism is hypothesized to link food webs across the entire oceanic water column through a complex interplay of feeding interactions and synchronized migrations of a multitude of species, thereby supporting pelagic life at depths of up to several kilometers.

So far, very little is known about this phenomenon, mainly due to the methodological challenges of studying organisms and their behavior at ecologically relevant spatial and temporal scales, particularly under the extreme pressure in the deep sea.

Project Goals

SEA-THROUGH aims for a breakthrough by providing “a new set of glasses” to study the so far unexplored “ladder of migrations.” To achieve this, we will:

1. Develop novel in situ imaging technology for unparalleled and highly detailed observations of organisms in the deep sea (to 6000m depth): “who is where at which time and what are they doing.”
2. Use this new deep-sea imaging system on ship expeditions for targeted studies of the enigmatic “ladder of migrations.”

Expected Outcomes

Pushing the limits of in situ observation technology will reveal a holistic picture of biodiversity and food-web structure, providing novel insights into the functioning of deep-sea ecosystems and their ecological and biogeochemical connectivity across the water column. This knowledge is urgently needed for evaluating the ecosystem services of the deep ocean (e.g., fisheries, CO2 sequestration), as well as the sustainable management of this vast habitat.