Marie-Anne Cambon, a microbiologist at Ifremer, is a deep-sea specialist. For 25 years, the oceanographer has been interested in the ecosystems that inhabit the deep sea, particularly those associated with hydrothermal springs.
“Women oceanographers (9/12). They have made the ocean their object of study, sometimes even their main concern.Physicists, chemists, geologists or biologists, they all contribute to improving our knowledge of the marine environment. océans connectés sets out to meet them across France.
By Marion Durand.
Cover photo © Marion Durand
The first time she stepped into the small sphere of the Nautile submarine, Marie-Anne Cambon felt a mixture of apprehension and excitement. In 1999, in the middle of the Pacific Ocean, the oceanographer was about to discover another world: the abysses. I’d been looking forward to this very first dive for so long,’ she recalls. When the door of the submarine closes, there’s a click and then silence. Not a sound. The submarine then begins its descent to the depths and you’re amazed by what you see through the little porthole. Although the researcher is now used to the exercise, after seventeen dives, the journey is still a moment out of time.
“When the submarine reaches the bottom, we turn on the spotlights and it’s an incredible, colourful spectacle. The copper, iron and sulphur released by the hydrothermal springs produce breathtaking colours: blue-green, orange, gold or red,’ describes the researcher. You feel very small and humble in the face of these impressive hydrothermal systems, around which a whole range of ecosystems revolve’.
In the depths of the ocean, between 3,000 and 6,000 metres below the surface, an unsuspected biodiversity has adapted to environments that were thought deserted just a few decades ago. Marie-Anne Cambon is trying to understand how this diverse and abundant fauna lives in absolute darkness, under pressure and despite the toxic gases and heavy metals escaping from the earth’s mantle. “In the deep sea, photosynthesis doesn’t exist because there is no light. The animals live by chemosynthesis: instead of light, it is the chemistry provided by the hydrothermal fluids that feeds the micro-organisms, which in turn enable the animals to settle near these underwater geysers’, explains the microbiologist from the Department of Deep Ecosystem Studies at Ifremer (the French Research Institute for Exploitation of the Sea). To adapt to this extreme environment, this deep-sea fauna has established a close symbiosis with the microbial communities.
Marie-Anne Cambon in the Nautile submarine © Ifremer
The mysteries of the little shrimps of the abyss
Since 2014, the oceanographer has been leading the BICOSE (Biodiversity, Interactions, Connectivity and Symbiosis in Extreme Environments) campaigns conducted along the Mid-Atlantic Ridge to understand the formation of deep-sea ecosystems. The latest sea expedition, BICOSE 3, took place last October on board the Pourquoi pas? vessel, part of the French oceanographic fleet. Around thirty scientists from various French laboratories took part in the expedition. ‘The aim was to gain a better understanding of the continuity between present-day sites of very high-temperature hydrothermal springs and fossil sites that are more than 100,000 years old,” explains the mission leader.
On the abyssal plains, biological diversity is greater but the species are fewer. ‘We come across octopus, crabs, deep-sea fish and sea cucumbers’, says the specialist. Near geological hotspots, anemones, galathea, fish, copepods and gastropods live in a gradient ranging from 3 to 30 degrees depending on the proximity of hydrothermal springs, where the fluid is close to 400 degrees. Marie-Anne Cambon is particularly interested in a species found near hot springs: a small shrimp called Rimicaris exoculata. This small crustacean, found over 8,000 kilometres north-south of the Mid-Atlantic Ridge, harbours microbial communities inside its shell, in its stomach and in its digestive tract. Its high dispersal capacity makes it an ideal model for study. ‘As a researcher, we can’t study many models, so we often concentrate our research on one species in particular. This shrimp has a very interesting microbiological complexity, it is present in large numbers and we can also bring it to the surface to analyse it.
” These biological reservoirs should inspire us “
The deep ocean is the largest ecosystem on the planet, but little is known about it because it is difficult to explore,yet we have so much to learn from it. “Deep-sea ecosystems have adapted to extreme environments, they have incredible biological capacities, and we have no equivalent on the surface or on land. These biological reservoirs should inspire us’,insists the oceanographer. Over the course of evolution, these species have developed different strategies for surviving in difficult conditions, and their resilience opens up many areas of study for medicine, technology and coping with climate change. The deep sea also plays a significant role in the oceanic carbon pump by sequestering part of the CO2.
Scientists may be drawn to the deep sea, but they are not the only ones with an interest. Industrialists dream of exploiting the millions of tonnes of precious metals that lie in the deep sea in the form of gold, copper, silver or cobalt. Yet exploiting them could cause irreversible damage to marine biodiversity. These environments are already under considerable pressure from human activity,” worries the microbial ecology researcher. When the deep sea remained a mystery, we could say we didn’t know. Now that we are beginning to understand these deep-sea ecosystems, it would be criminal to do anything else.
Rimicaris exoculata prawns observed during the BICOSE 2014 campaign at the Snake Pit site at a depth of 3600 metres.© Ifremer, Bicose
” In science, you can’t generalise “
Marie-Anne Cambon is also leading the LIFEDEEPER project, aimed at developing new approaches to better understanding the seabed and protecting it. “Knowledge of the deep sea is a major challenge. Politicians and the general public are starting to become aware of the impact of our activities on the sea and the coastline, because we see waste arriving, animals dying and the water heating up. The deep sea is far away and obscure’. The oceanographer is campaigning to get the deep sea into school textbooks.
In this new project, a major component is devoted to popularising science for politicians. We need to make people understand that the time for science is not the time for politics or industry,” insists the microbiologist. Even after 10 years of studies on an area, we can’t say categorically ‘if we do this, this will happen, if we remove that, this will happen’.Science takes time: experiments are repeated, we go back to sea, we take other samples to be sure of what we have observed on a one-off basis for thirty days over the course of a year. In science, you can’t generalise’.
She believes that oceanographers need to take on the role of mediator and take their research out of the laboratory. ‘ The more we talk about our research, the more it will be understood, and only then will politicians and the general public understand, as we do, why it is so urgent to preserve them’.
In videos posted on social networks, on national radio stations and in front of a class of schoolchildren, Marie-Anne Cambon is keen to share her research into the deep ocean. The oceanographer and mother of a young daughter is focusing on young people: “They’re the adults of tomorrow, and that’s who I want to talk to!”
Marie-Anne Cambon in the laboratory of Ifremer’s Department of Deep Ecosystem Studies© Marion Durand
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