How is the Mediterranean? Here is the study on pollution and biodiversity


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How is the Mediterranean? Not great. But less worse than might be expected. This was revealed in an in-depth study by M.A.R.E., the Mediterranean scientific monitoring project devised by the Caprera Sailing Center Foundation in collaboration with One Ocean Foundation that aims to Promote knowledge and protection of the marine environment. And restarting in 2024.

Why it is important to learn about the Mediterranean

After the analysis of samples collected by the catamaran One (a CVC Bali), the M.A.R.E. sailing platform, which sailed two years in the Mediterranean (in 2022 in the Tyrrhenian Sea, in 2023 in the Adriatic) with five scientific researchers/students on board (and four universities involved: there were eight scientific publications in the two years) we reveal what has been discovered: we are helped by the report of Dr. Ginevra Boldrocchi, scientific coordinator of One Ocean Foundation.

Catamaran One
Catamaran One (a Bali 4.8) is the sailing platform of the M.A.R.E. project.

This is important data to know, because such a “widespread” monitoring campaign has been missing since the 1970s, and the Mediterranean Sea, although it accounts for only 0.82 percent of the world’s total ocean area, contains between 4 and 18 percent of global marine biodiversity. A very important ecosystem.

The samples analyzed by the study

But first we need to ask what samples were examined. In the more than 2,700 miles of sailing between the Tyrrhenian and Adriatic seas (six countries touched by the catamaran: Italy, Slovenia, Croatia, Montenegro, Albania and Greece), scientists collected two types of samples:

  • 55 are water samples collected for analysis of the Environmental DNA (20 in the Tyrrhenian, 35 in the Adriatic) all living things release DNA into the environment in which they live, and the sea is no exception): genetic material is extracted from the samples using specialized laboratory techniques and compared with a database of DNA sequences to identify the organisms in the environmental sample.
  • 100 are those of zooplankton recovered to assess the presence of pollutants (54 in Tyrrhenian, 46 in Adriatic).

Key findings of the Tyrrhenian Sea study.

Zooplankton is an early warning indicator of contamination. However, there are few comprehensive studies in the Mediterranean Sea, mainly dating back to the 1970s, although the basin is considered one of the most polluted seas in the world, partly due to its geographical nature as a “closed” sea. The M.A.R.E. project study, at the ecotoxicology level, provided updated data on the presence and levels of multiple contaminants in zooplanktonic organisms in the Tyrrhenian Sea.

M.A.R.E. Mediterranean Project
Here is where zooplankton samples were collected in the Tyrrhenian Sea in 2022

DDT and PCBs, still present

We start with the detection of concentrations of harmful substances such as the insecticide DDT and PCBs (polychlorinated biphenyls), which, although banned for years, continue to be present in Tyrrhenian Sea. Although to a much lesser extent than in the 1970s, this suggests a decrease over the past 50 years. The highest concentrations, as shown in the tables below, were found near industrial or former industrial areas. In general, however, these are much lower levels than in areas with poor wastewater management, chronic release of pollutants, and where pesticide use is still poorly controlled (such as in India).

The concentration of DDT in Tyrrhenian detected by the study.
The concentration of PCBs in Tyrrhenian detected by the study.

Mercury and Chromium? There are, but.

We now come to the analysis of chemical elements (pollutants and nonpollutants) in Tyrrhenian.

The trace elements in the samples were Arsenic, Cadmium, Copper, Iron, Manganese, Molybdenum, Mercury, Selenium, Strontium, Zinc, Chromium, Vanadium, Cobalt, Nickel and Lead.

mercury concentration
Mercury concentration detected in Tyrrhenian.

The study recorded great spatial variability in the levels measured in zooplankton. This is because the metals have both an anthropogenic and natural source (near volcanic islands, for example). Some concentrations of Zinc, Copper, Lead, and Nickel have concentrations comparable to heavily polluted areas, see the table below.

Chemical elements in Tyrrhenian
Concentration of chemical elements in Tyrrhenian Sea revived from the study of zooplankton samples

But the most polluting and toxic metals (Cadmium, Cobalt, and Mercury) show intermediate levels between heavily impacted and pristine areas.

*Thefull study on the ecotoxicology of the Tyrrhenian Sea is called “Zooplankton as an indicator of the status of contamination of the Mediterranean Sea and temporal trends,” was published in Marine Pollution Bulletin and can be accessed here.

Biodiversity and endangered species in Tyrrhenian Sea

We now come to biodiversity in the Tyrrhenian Sea. The study, which we recall is based on 35 water samples collected for environmental DNA analysis, focused on elusive, data-deficient species (such as the Grampus) and/or endangered species (such as the Stenella or the Common Whale): marine mammals, reptiles and fish.

Mediterranean environmental DNA Tyrrhenian
The study’s environmental DNA sample collection points.

In collaboration with CNR-IRSA, scientists in the M.A.R.E. project have created new genetic markers of the various species. This eliminates the process of method creation and validation for the scientific community, making monitoring faster and easier. The study found positivity for many target species during monitoring in the Tyrrhenian Sea (and environmental DNA turns out to be a reliable and non-invasive method useful for monitoring marine biodiversity).

Where are the species identified through environmental DNA samples.
Where are the species identified through environmental DNA samples. In green are the positives found

Look at the table above: green indicates the positivity of the species’ DNA in the samples tested. The results are surprising. The common dolphin, for example, is not so common. Rather rare also the Manta(mobula) And watch out if you swim in Stagnone, Sicily, Ventotene or Vernazza: you might end up face to face with a cetorino, better known as basking shark! Don’t worry, despite its gigantic size it is a “living filter” and feeds on water!

How is the situation in the Adriatic?

Let us now review another area of the Mediterranean Sea: the Adriatic Sea. We also begin here with ecotoxicological analysis, based on 46 zooplankton samples to assess the presence of pollutants. It should be mentioned that the study (2023) is still in the process of data review by the scientific community

Where zooplankton samples were collected in the Adriatic Sea.
Where zooplankton samples were collected in the Adriatic Sea.

Adriatic, yes PCB, no DDT. And lots of Copper…

PCBs are still present in marine biota today, but the concentration is not uniform and in any case the levels are lower than those published in the 1970s-80′. This suggests a decrease in marine biota over the past 50 years. Compared to the Tyrrhenian Sea, DDT contamination is much lower and is also very low in absolute terms: levels of DDT contamination in the Adriatic are comparable to isolated areas in the tropics and the Arctic!

Adriatic Sea and Metal Pollution Index
Adriatic Sea and Metal Pollution Index

The graphic above, on the other hand, summarizes the result of the analysis aimed at assessing metal pollution. The Venetian lagoon is a “hot” spot: the northern Adriatic is an almost closed sea, and this is where the Po River flows, carrying all the pollutants into the water. But high levels of pollutant metals have also been found in Croatia, Albania and the Tremiti Islands where, however, in the latter case, the high concentration would derive from natural and not anthropogenic sources.

In general, however, the Metal Pollution Index is higher in areas near river deltas, urbanized and industrial areas. Zooplankton, however, show much lower levels of Chromium, Cadmium, Cobalt, Nickel and Lead than areas renowned for their pollution. The study found a very high Copper level: double that of polluted areas (Gulf of Aden, Bengal and Taiwan) and significantly higher than the Tyrrhenian Sea.

*Thecomprehensive study on ecotoxicology in the Adriatic is called “Assessing Chemical Contamination Of The Adriatic Sea (Eastern Mediterranean Sea) Using Zooplankton As Bioindicator Organisms .”The study has just been submitted to the prestigious journal Environmental Pollution for the data review process.

The monk seal in the Adriatic

The biodiversity study in the Adriatic Sea, also based on environmental DNA (20 samples collected) focused exclusively on determining the presence of the extremely rare monk seal.

Mediterranean monk seal
Monk seal

There are two samples that tested positive, in Apulia and they constitute 10 percent of the total samples. In collaboration with the Spot the Monk project, the study will help map the distribution of this species, producing a comprehensive scientific publication.

Where environmental DNA samples were collected in the Adriatic.

The M.A.R.E. project in 2024.

This is not the end of the story. The M.A.R.E. project. (Marine Adventure for Research & Education), created by the foundation Caprera Sailing Center in collaboration with One Ocean Foundation (under the auspices of the Navy) and with Shiseido as main partner, Yamamay as founding partner, Deutsche Bank as institutional partner, and Toio and Workness as technical partners, torna in 2o24.

Mission 2024

Catamaran One will set sail April 27 from La Maddalena and return here July 6 after its mission in the Northwest Mediterranean touching Savona, Nice, Marseille, Port-Argéles, Barcelona, Ibiza, Menorca, Ajaccio, and Santa Teresa di Gallura. There will be “educational” events at various ports of call to raise awareness and narrate the data collected

Objectives of the 2024 mission, in addition to the ecotoxicological and marine biodiversity study, include assessment of marine noise pollution levels .



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