The forests of gorgonians, a Mediterranean coral, has suffered in the last 15 years a massive mortality due to the rise in sea temperature. However, research has discovered that at a certain depth this species resists these changes, as explained by the researcher at the French National Center for Scientific Research (CNRS), Lorenzo Bramanti.
The CNRS researcher pointed out that “gorgonians, cousins of corals, have a flexible skeleton that it is not made of calcium carbonate like reef corals, but of a protein”. They are shaped like trees and are so important that when they reach a “high enough density” form “animal forests” that are very similar to the tree masses, Bramanti indicates to Efe Verde.
From an ecological point of view, he says, this metaphor of animal forests leads to a “better understanding of what a forest is under the sea,” because gives shelter to different types of species that find a favorable environment inside that forest, which allows an increase in biodiversity.
For this reason, his study has defined these animal forests as “Noah’s Ark of the depths, a future for biodiversity.”
In addition, he adds, the gorgonians, of which there are 20 different specieshave a role in the “biogeochemical cycle of matter”, because it transforms organic matter.
Bramanti emphasizes that his study focuses on the red gorgonian (“Paramuricea clavata”)), the “most common, the one that suffers the most mortality and it has the peculiarity of being found from 20 to 200 meters deep or more”.
It is a species found in the northwestern Mediterranean in Spain, France, Italy, but also in Greece and Turkey.
The project is endorsed by the ONE Ocean Foundation and the United Nations Educational, Scientific and Cultural Organization (Unesco) -which has invited Bramanti to present it at its headquarters in Paris- and in collaboration with the CNRS and the LECOB research unit of the Oceanological Observatory of Banyuls-sur-Mer in France will last two years.
Mortality of gorgonians by temperature
The CNRS researcher explains that in the last fifteen years there has been a “massive mortality of gorgonians” due to the increase in seawater temperaturesa in summer thanks to heat waves, with records of “losses of up to 70 or 80% in some populations.”
According to Bramanti, the experts intend to “understand the mechanisms” of this mortality, which “is lower below 30-40 meters deep in the sea, the distance up to which a person normally dives.”
Points out that, for some years now, it has been observed that gorgonian populations “below 40-50-60 meters deep have no signs of mortality or very low signs”a finding made by the researcher together with experts from ONE Ocean at depths of between 50 and 150 meters.
The hypothesis is that “heat waves do not reach these lower depths”, which is why “refuges or safes” are formed in which the gorgonians are protected from the increase in temperature.
However, the researcher draws attention because, although on the one hand it may be “good news to have populations of gorgonians still pristine”, It is not known how long this situation can persist, because heat waves are becoming stronger and more frequent.
For this reason, he explains, the project has three different phases: sample collection, analysis and genetic research. For the first, it also has research and data from other scientific studies.
larvae for reproduction
The second phase, he points out, studies that These populations are a refuge, because they are capable of subsisting “without depending on surface populations for demography”, which increases because once a year the gorgonians, which are fixed to the marine substrate and do not move, release some larvae that do until they find a place to settle, “something that becomes a formula” .
Genetic research determines the lifespan of a gorgonian forest, because, if “new individuals” do not arrive, the refuge is temporary and endsand, on the other hand, it is also trying to find out if the deep-sea populations are self-sufficient -from a demographic point of view-.
The third phase includes a study of the gorgonian forests existing in sunken wreckswhose sinking date will allow you to know the time of existence of these specimens.
Promote marine protected areas
He adds that for these studies the monitoring data on the temperature of the sea water that it collects is very valuable. the Institute of Marine Sciences of Barcelona dependent on the Higher Center for Scientific Research (ICM-CSIC) in the Mediterranean between 0 and 40 meters deep, although it intends that this margin covers up to 80-90 meters.
These data “are very valuable information that is missing from my puzzle,” he maintains, because in research everything is done in a group.
It stresses that “We must create and promote the formation of marine protected areas (AMP) for the conservation of gorgoniansand in which these species can also be observed.
However, he advocates the reduction of greenhouse gas (GHG) emissions in any sector, including tourism, which is a political decision to benefit the fact that the deep sea can become “climate refuges for marine forests”.
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