Biodiversity and Maritime Traffic
With the grant of
Ministry of the University and Scientific and Technological Research Ministero dell'Università e della Ricerca
Stowaways in ballast water and in fouling The introduction into new environments of invasive marine species through the involuntary transport of organisms in ballast waters, or attached to the keels of ships or by means of other vectors, is recognised as one of the gravest threats to marine biodiversity.
Akashiwo sanguinea sanguinea is a toxic marine dinoflagellate (planktonic microalga) discovered in the ballast water tanks of certain merchant ships.
Planktoniella sol is a marine diatom (planktonic microalga) native of the North Atlantic Ocean, which has been discovered in ballast waters of some merchant ships.
Several animal species can be found in ballast waters, most in a larval stage, as well as vegetal material, especially in spore form. Port areas, which are rich in nutrients, are the ideal habitat for these organisms that take hold and develop aided by the particular physico-chemical conditions of the waters. They eventually out-compete and eliminate the autochthonous species.
Cargo of the holds
On the bottoms of ships and on all the submerged surfaces, “sessile” animal and plant species take hold, apart from other “epibionts” that grow on top of the organisms that would have already taken hold on the ship’s surface. Eve in these cases, the port areas are the ideal habitat for the development of these organisms. This phenomenon is more acute when ships are docked, even for a few days.
Ballast waters Gyrodinium instriatum Resting stage produced by the dinoflagellate (planktonic microalga) and discovered in the sediments of ballast water tanks in certain cargo ships.
Fouling
Bicarinellum tricarinelloides Resting stage produced by the dinoflagellate (planktonic microalga) and discovered in the sediments of ballast water tanks in certain cargo ships.
There are several thousands of marine species that can be transported in ballast waters and as fouling on ships: bacteria and other microbes, small invertebrates, and eggs, cysts and larvae of various species. Virtually all the marine species have life cycles that include a planktonic stage; hence even those species that as adults would find it difficult to enter ballast waters because of their large size, can be transported in these waters during their planktonic phase. Some organisms, like the amphipods, can travel as larvae in the ballast waters and as adults in the fouling communities
Amphipod
Realized by
Maritime Admiral Michelagnoli Foundation NGO non-profit Fondazione Marittima Ammiraglio Michelagnoli Onlus - Taranto - Italy
Balanus
Zoea (larva of a crab)
The presence of fouling organisms on the hulls of ships drastically reduces the velocity of the ships leading to a higher consumption of fuel (a 5% coverage on the hull results in a 40% increase in fuel consumption). To counteract these encrustations, the use of certain biocidal paints that include chemical substances (synthetic organic pesticides and heavy metals) that partially reduce the growth of these organisms are allowed. At an international level, the use of paints that include arsenic, DDT, and other highly toxic products that can enter the food chain have been banned. Today, the research on anti-fouling products studies methods used by marine organisms to prevent the settlement of other organisms on their own body surfaces (epibiosis). The aim is to have ships that do not leave a stream of poison in their wake, but instead emit specific negative signals to spores and larvae in search of a substrate to settle on. Photo archive "Mare Nostrum" , property of Fondazione Michelagnoli & Giuseppe Pignataro (international champion) www.fondazionemichelagnoli.it English version translated by Dr Adrian Mallia - Adi Associates Environmental Consultants Ltd - Malta
Detail of the encrusting organisms (serpulids) and epiphytes (tunicates and algae).
What is “fouling”?
Marine organisms tend to occupy all the spaces available, even those artificial, that is, the various items and infrastructure produced by man and submerged in the sea. These can be maritime constructions, such as quays and piers, hulls, platforms, buoys, submarine cables: on contact with sea water their surfaces become a substrate for the growth of organisms. The name given to this very complex ensemble of organisms is “fouling”.
The picture shows very clearly the cover by colonies of invertebrates and algae on the ropes used in mussel culture. In order to eliminate Zooids, these fouling colonial ascidian organisms it is tunicate necessary to expose them to the air. In several cases, “alien” species that have settled on the mussels have completely suffocated them, impeding their growth and causing their death.
Jellyfish
Research on anti-fouling
Ships hull covered by fouling.
Fouling on a pole submerged in water in Mar Piccolo in Taranto. One can distinguish spirographs, ascidians, botrillids, mussels, oysters, and algae. In agreement with
National Interuniversity Consortium For Marine Sciences - Italy Co.N.I.S.Ma. - Consorzio Nazionale Interuniversitario di Scienze del Mare