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Giant algal communities harbor great biodiversity and help fight climate change. A study assesses the environmental impact of human activities on these Fuegian ecosystems with the aim of designing strategies to protect them.

The seas of southern Argentina hide extraordinary wonders in their depths. The so/called submerged forests are among them: they are ecosystems dominated by a species of giant brown algae that is associated with the seafloor and forms large columns that can reach the surface. These unique ecosystems are currently in decline due to human activities: in the last 50 years, reductions in 38% of the world’s known kelp forests have been detected. However, each region presents unique patterns that require particular analysis.

A study that analyzes the impact of human actions on the submerged forests of Ushuaia has preliminarily determined that, despite the global trend, these ecosystems generate mechanisms of adaptation to changes in the environment. Julieta Kaminsky, co/author of the study and a doctoral fellow at the Centro Austral de Pesquisa Científica (CADIC/CONICET), presented these observations in the Series of Seminars on the Sea, organized by the Chair of Aquatic Ecology at FAUBA.
Julieta Kaminsky, co/author of the study, highlighted that there are many areas to be investigated in the Argentine Sea and opportunities for students interested in these ecosystems.

According to María Boveri, professor of this chair, “FAUBA graduates in Environmental Sciences who, like Julieta, are capable of working in multiple areas to make concrete contributions to taking care of the environment and improving our quality of life. For work in rivers, lakes and ponds, they have a solid background in continental aquatic ecology, which we complemented with this cycle, which helped to broaden the students’ perspective and put them in contact with professionals who investigate the marine environments of our region. country” .
Marine ecosystems in action

On the coasts of Argentine Patagonia, submerged forests are formed from an alga called cachiyuyo — whose scientific name is Macrocystis pyrifera— which can measure more than 30 meters in length. “We call these ecosystems forests because under the main algae, which form the ecosystem, other smaller species live, as in terrestrial forests”, explains Julieta, a graduate in Environmental Sciences from FAUBA.
Columns of Macrocystis pyrifera, known as cachiyuyo, the giant alga that forms the submerged forests in Ushuaia. Photo: J. Kaminsky

Recently, the importance of macroalgae has been recognized for their ability to “sequester” carbon from the atmosphere and thus prevent further global warming. “Currently, they are part of the so/called blue carbon, which is the name given to emissions absorbed by marine environments. In a context of climate change, ecosystems with high carbon absorption potential fulfill a fundamental ecological function”, said Julieta.

He added: “Macroalgae generate energy and food, provide habitat for other species and can also modify the physical conditions of the environment and reduce coastal erosion caused by waves.”
Glabraser antarctica, one of many starfish species that inhabit Macrocystis forests
Forests at the End of the World

Kaminsky noted that the forests of macrocystis they change throughout the year, as this alga has a high capacity to respond to environmental variations. “The ecosystem adapts to changes in the amount of light, which in this region varies with the time of year, and with glacier discharges, which muddy the waters, in addition to other natural variables. But to this are added human activities, which in Ushuaia are mainly related to the release of wastewater and garbage.
There are many species of molluscs that inhabit submerged forests. Pictured is a red octopus or Enteroctopus megalocyathus, its scientific name

Therefore, Julieta’s research seeks to understand how forests respond to human pressures. “We took samples at two sites, one exposed to industrial waste disposal and the other further away, and we found differences between the two that could give us clues about what strategies macroalgae have to respond to changes in the environment,” she pointed out. Outside.

Julieta highlighted that one difference is that “in the place exposed to the discharges, the algae have other forms, for example, with sheets similar to leaves, which are larger, although less abundant than in the remote place”.

The submerged forests in Argentina are along the coasts from Chubut to Tierra del Fuego. “The communities of macrocystis are seen as continuous and long belts, parallel to the coast, forming very dense forests. But they can also form patches, which are portions of forest separated from each other,” explained Julieta.
Paranotothenia magellanica, one of many fish species associated with these ecosystems
know how to take care

The fellow highlighted that there is a global reduction of macroalgae forests that has not been fully quantified. “This is due to factors such as the increase in nutrients in the water – called eutrophication –, heat waves, rising global temperatures, fishing and the introduction of exotic species, which cause forests to be replaced by less diverse systems. In this study, we want to see to what extent this is happening here and how the algae are responding.”

The results of this research may be relevant to understanding the state of macroalgae in other places with similar environmental conditions, according to Julieta. “The Tierra del Fuego is the southern limit of which there are no more submerged cachiyuyo forests; further away there are other ecosystems that are more like grasslands. And given that rising global temperatures condition their survival, it would be especially worrisome to find that they are retreating in this area,” she explained.

He added: “In Ushuaia there is a strong impulse for the industry, but at the same time, ecological tourism is promoted, which creates a tension between two very different forms of growth. Added to this are factors such as maritime traffic, the fact that it is a border area and also a gateway to Antarctica. All of this can affect marine ecosystems. Therefore, understanding these impacts helps us to prevent them.”
Julieta encouraged the students to delve into Argentina’s marine ecosystems, a fascinating experience that is also necessary for their study and conservation. Photo: J. Kaminsky

Julieta concluded by saying that “there are many areas and species still to be explored in the Argentine Sea. It is a great opportunity, because there are lines of research in several institutes in our country and we need to deepen our knowledge about macroalgae. There are themes, vacancies and ways of studying these ecosystems in Argentina; what we need are divers and divers who dare to dive into them”.

Información clasificada por www.sintesisagraria.com

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