“Spoke 2,” he explains, “is dedicated to actions aimed at countering biodiversity loss, such as monitoring pollutants, reducing fisheries-related damage, developing technologies that enable aquaculture with less impact on the environment, maritime spatial planning with a view to safeguarding biodiversity, marine genomics, and finally, what I would like to talk about today, ecological restoration of marine benthic ecosystems.”

The importance of a kelp forest

Chiantore recounts the ecological restoration project conducted in the Cinque Terre, focused on restoring forests of a brown seaweed genus Cystoseira which plays a key role in the coastal ecosystem.

“Parliamo di una macroalga: nel Mediterraneo abbiamo alghe che possono raggiungere al massimo il metro di altezza – non come nell’Oceano Pacifico o Atlantico, dove arrivano anche a 15-20 metri. Nonostante l’altezza ridotta, danno tridimensionalità all’habitat.”

“Nell’immaginario collettivo”, aggiunge sorridento, “le alghe sono viste come viscidi substrati su cui camminiamo sulle scogliere. In realtà sono importantissime. Analogamente alle piante, producono ossigeno e immagazzinano anidride carbonica. Inoltre fungono da nursery per diverse specie marine e proteggono le coste dall’erosione causata dal moto ondoso.”

Intertidale: there where the wave beats

Il progetto coordinato da Chiantore si è focalizzato in particolare sull’intertidale, “la zona dove batte l’onda, cioè la zona di marea, che per diverse ore della giornata è fuori dall’acqua.” Questo è un ambiente ostile per gli organismi marini, perché sono esposti a grandi escursioni termiche. “Una foresta che trattiene l’acqua mantiene una temperatura più fresca e protegge dall’impatto delle onde. Può diventare così un ambiente ricco di biodiversità.”

Unfortunately, in the Mediterranean, so-called structuring algae, i.e., those that create habitat, are showing regression due to many factors, includingpollution,water clouding and fishing.

In protected areas, where fishing is banned, “carnivorous fish increase, and this reduces the pressure of herbivores; if there are more carnivores there are slightly fewer herbivores, and the herbivores are the ones who, by grazing, cause a regression of the algal forests. Sea urchins, for example, are grazers that are typically eaten by bream, sea bream — fish that we normally catch.”

In the Cinque Terre, the first half of the twentieth century saw the disappearance of kelp forests due to water clouding: construction work on the mainland had poured much sediment into the sea. Then the situation improved. “Now the water quality is very good,” Chiantore declares, “and aMarine Protected Area has been established.”

A sensitive issue: helping algae to reproduce

The clean water, however, was not enough to regrow the algal forests. “The problem is that this algae, because of the way it reproduces, could not recolonize this area.” The mechanism is supposed to work like this: a zygote, originating from sexual reproduction, falls off the adult alga. Being very adhesive, it sticks to the substrate and grows. If this does not happen, however, the zygote is unable to survive, or be pulled by currents and grow elsewhere.

Help was needed. In the project coordinated by Chiantore, researchers collect the tip of the branches, that is, the fertile portions, from some algae in a healthy population. “Then we place these apexes on terracotta discs, where these portions release zygotes. After 24 hours we remove the apices. What remains are the discs on which our little ones are stuck.”

La fase successiva consiste nel coltivare le alghe in laboratorio per alcune settimane, finché non raggiungono la dimensione di alcuni millimetri. A questo punto, i dischetti di terracotta vengono portati in mare e fissati alla roccia dove le alghe possono crescere nel loro ambiente naturale.

Growth is slow, but already within a couple of years they are sexually mature and able to reproduce.

This restoration project has so far seen 60 percent of the transplanted algae survive and grow back into the sea-a significant percentage.

The exploration of ever-new techniques

And it’s not over. Researchers are working to find other ways to grow seaweed before it is transplanted into the sea. One experiment, currently underway, involves “growing seaweed by hanging it at sea, in baskets that are used to grow oysters, near an aquaculture plant.” The method is cheap and also faster: “the residues from the aquaculture plant,” the scientist explains, “are transformed into nutrients that can be used by the algae. Hanging in the middle of the sea, moreover, they do not suffer from grazing by herbivores and competition with other species.”

Satisfaction with the results achieved can also be measured. “There is an index of ecological quality, called the Carlit index, which gives very important weight to the presence of brown algae. In the stretch of coastline where we worked, this index went up from good to excellent quality. This is really motivating. In the Cinque Terre we will continue with the placement of more pucks again this year, thanks to NBFC funding.”