A study proves there is a link between depth and longevity of marine species like corals and gorgonians

The red coral  (<i>Corallium rubrum</i>) is one of the most long-lived anthozoans described so far.
The red coral (Corallium rubrum) is one of the most long-lived anthozoans described so far.
Research
(19/03/2018)

Deep marine ecosystems ─from 100 to 1,000 meters deep─, are dominated by long-lived species that live up to a hundred or a thousand years, while other waters are inhabited by those species that live up to about ten years. This is the main conclusion of a new study on marine ecology and biology, in which the following researchers took part: Cristina Linares and Ignasi Montero Serra, from the Faculty of Biology of the University of Barcelona and the Biodiversity Research Institute (IRBio); Joaquim Garrabou and Jean Baptiste Ledoux, from the Institute of Marine Sciences (ICM-CSIC), and Daniel F. Doak from the University of Colorado (United States).

The red coral  (<i>Corallium rubrum</i>) is one of the most long-lived anthozoans described so far.
The red coral (Corallium rubrum) is one of the most long-lived anthozoans described so far.
Research
19/03/2018

Deep marine ecosystems ─from 100 to 1,000 meters deep─, are dominated by long-lived species that live up to a hundred or a thousand years, while other waters are inhabited by those species that live up to about ten years. This is the main conclusion of a new study on marine ecology and biology, in which the following researchers took part: Cristina Linares and Ignasi Montero Serra, from the Faculty of Biology of the University of Barcelona and the Biodiversity Research Institute (IRBio); Joaquim Garrabou and Jean Baptiste Ledoux, from the Institute of Marine Sciences (ICM-CSIC), and Daniel F. Doak from the University of Colorado (United States).

The study, published in the journal Proceedings of the Royal Society of London B, describes for the first time the impact of the environmental factors ─light, nutrients, temperature, physical disturbances, etc.─ on the longevity patterns of sessile species that live in seabeds (corals, gorgonians, sponges, macroalgae, clams, etc.).

The deeper the water, the most long-lived species

Marine ecosystems are the most abundant in the planet, but less known than the terrestrial ones. Due the difficulties the marine environment gives in scientific research, the most studied biological communities by researchers are mostly those at 30-40 meters deep maximum (tropical reefs, algae infralittoral communities, etc.).

Despite the biological variety of the ocean ecosystems, the new study notes that, the deeper they are, the more longevity these species have. It was known that environmental factors of deep environments -stable and protected from environmental disturbances- favoured long-live in many bodies, but so far, “there was not a single scientific study proving this pattern between depth and longevity quantitatively and systematically”, says Cristina Linares, lecturer from the Department of Evolutionary Biology, Ecology and Environmental Sciences of the University of Barcelona.

The extreme life of red coral in the Mediterranean

The article is centred on several scientific studies on the distribution and longevity of sessile marine species (corals, gorgonians, sponges, macroalgae and clams) and on a long-term study on the red coral, as an emblematic and long-lived species of the Mediterranean.

The new study states that the red coral (Corallium rubrum) can live up to five hundred years, and it is one of the most long-lived anthozoans described so far. Reaching this result was possible thanks to the combination of the analysis of demographical data series with new modelling techniques on population dynamics. In the Mediterranean, the Lophelia pertusa and Madrepora oculata corals, big creators of marine clams in cold waters, show another high longevity profile, just like some marine phanerogamous species, such as Posidonia oceanica.

According to the UB expert Ignasi Montero Serra, predoctoral researcher and first author of the article, “the deepest habitats -more stable than shallower waters- have more long-lived species: these are bodies with stable population dynamics, slow growth rate, a high survival of adult individuals and a lower breeding rate, factors that limit their recovery regarding the effects of environmental disturbances”.

In shallow waters, diversity of life strategy is larger and there is a coexistence of long-lived species with short-lived ones. The populations of these bodies are more dynamic and variant, with a lower survival in adults but a higher sexual reproduction rate. Therefore, these species have faster recovery patterns regarding the impact of disturbances (storms, etc.).  

The most vulnerable communities live in the great depths

Regarding biodiversity preservation, the authors warn about the effects of the human activity on the most vulnerable inhabitants of the seabeds. “Long-lived species in the deepest habitats are usually sensitive to the impact that increase mortality of adult individuals”, says the expert Joaquim Garrabou, scientific researcher at ICM-CSIC.

As a result, the species that live in the deepest seabeds show a low resilience towards the environmental impact created by human activity which can be highly destructive, such as trawling. In case of a natural habitat disturbance, it could take up to dozens or hundreds of years for some species to recover, in case they can even do so.   

Therefore, depth could be a predicting factor for the longevity patterns of benthic organisms in marine ecosystems and it could help assessing the potential vulnerability of deep and unexplored ecosystems regarding potential impacts coming from human activity.

Protecting the ecological state of marine ecosystems

Despite the progress of new studies, there is a lack of knowledge on environmental factors that determine the distribution and composition of communities in marine depths. Therefore, it is necessary to join efforts to get deep in the scientific knowledge of these ecosystems, “prioritize environmental management to protect the known communities, and apply the precautionary principle in areas on which we do not have enough ecological knowledge”, stresses the scientific team.  

The new study was funded by the SMART project (CGL2023-32194), from the Spanish Ministry of Economy, Industry and Competitiveness, and the European project MERCES (Marine Ecosystem Restoration in Changing European Seas), the first to fund Horizon 2020 program to develop tools and solutions that recover the ecological state of degraded marine ecosystems.



 

 

Images: Cristina Linares (UB-IRBio) and Joaquim Garrabou (ICM-CSIC)