A tugboat maneuvering the RV Sonne into the harbor of Cape Town after four weeks of transit from Emden. Due to COVID-19, we were not allowed to leave the ship, not even for a jog in the harbor.
Germany’s largest research vessel – the RV Sonne – recently returned to harbor in the port town of Emden after 73 days, the longest-ever research cruise in the history of the ship. I was lucky enough to participate in the journey, which took us to through Cape Town, Walvis Bay and Las Palmas. As part of a team of 30 scientists, 22 women and 8 men, we set out to study one of the most productive ecosystems in the world: the Benguela Upwelling System off the coast of South Africa and Namibia.
Spending this long at sea is a truly special experience and here’s my personal account of what it’s like day-to-day on one of the largest research ships in the world.
The “Candelabra” black smoker at a water depth of 3,300 meters in the Logatchev Hydrothermal Field on the Mid-Atlantic Ridge (Image Credit: MARUM − Zentrum für Marine Umweltwissenschaften, Universität Bremen, CC BY 4.0, Image Cropped)
The deep sea is an unimaginably large and dark environment, and humanity’s attempt to learn about it is comically clumsy. Sampling the animals in the deep sea is often done “blindly”, by dragging nets along the ocean floor or through the water column, or bringing up cores of deep-sea sediment. The most sophisticated, precise and least destructive method is using underwater robots that have arms that can be controlled remotely to sample specific animals in real time, though naturally, this is also the most expensive.
These sampling efforts are comparable to sampling a rainforest with a helicopter. At night. With a map that a kindergartener drew. How long would it take to get a reliable record of all the different species of bird, beetle, monkey and flower found in the rainforest? How long to find a male and female of every species?
A young octopus (Graneledone verrucosa) moves across the seafloor. Observed during the Okeanos Explorer Northeast U.S. Canyons 2013 expedition. (Image Credit: NOAA Ocean Exploration & Research, CC BY-SA 2.0, Image cropped)
In nature every death brings new life. A fascinating example are whale-falls: when a whale dies, its carcass will sink down to the ocean floor where it creates a unique ecosystem for bottom-dwelling organisms. Whales’ bodies can weigh up to 200 tons and contain massive amounts of fat and proteins. When a dead whale reaches the ocean floor it brings a lot of resources to an environment which is usually limited by food availability. The fortunate creatures experiencing the whale-fall welcome such a great source of nutrition, and use up everything they can, until the last vertebra is decomposed.
Image Credit: Andrei Savitsky (left and right), CC BY-SA 4.0 ; Uwe Kils (centre), CC BY-SA 3.0
The deep sea is a wondrous world of biodiversity, darkness, and mysteries we still know very little about. Despite the fact that we rely on the deep sea as a sink for carbon dioxide – and increasingly as a source of natural gases and minerals – we have very little understanding of how our actions will affect its intricate food web.
Near the base of the food web sits an incredibly diverse group of animals called copepods. They are so abundant and have such sweeping variety that we are still struggling to come up with a way to classify them. Dr. Nancy Mercado-Salas has worked with these tiny creatures since her bachelor’s thesis, both in freshwater and in marine ecosystems, and her message is clear: We need to increase our knowledge on this group of animals before it is too late.
Drawing of deep-sea fishes by ‘Résultats des Campagnes Scientifiques’ (1889) by Albert I, Prince of Monaco (1848–1922). (Image Credit: Rawpixel Ltd., CC BY 4.0, Image Cropped)
If you were asked what the largest and most common habitat on Earth is, you may intuitively think of forests, grasslands or deserts. When you think of the least explored regions, pictures of some far-off rainforest may come to mind.
Introducing: the deep sea, covering over 70% of our planet, and arguably the most unexplored environment on Earth, which is simultaneously highly vulnerable and currently threatened by human activities.