Specialists from the Centro Austral de Pesquisas Científicas (CADIC, which depends on Conicet) and the Instituto Antártico Argentino (IAA) are studying the impact of the two marine heat waves recorded in Antarctica in the summer of 2020 on plankton, a community of aquatic organisms essential for the marine food web. Although it had negative effects in both cases, in the second wave many species were already adapted to high temperatures, which mitigated the consequences. Research is not only important in the context of climate change, but is also carried out by local scientists.
“That summer was the record temperature at Base Esperanza, with an all-time high of 18.3 degrees. With my team we were there and we were able to analyze how the plankton responded to these high temperaturesthat manifested themselves as waves of marine heat”, describes Irene Schlossresearcher at Conicet and IAA.
The scientist explains that, although in the first heat wave the reaction of the plankton was negative, in the second the scenario changed. “During the first season, productivity and plankton abundance decreased.. In addition, physiological responses to stress were recorded, which had repercussions on the entire marine trophic web in the region”, highlights the researcher. Instead of, during the second wave species that survived or adapted to high temperatures were present of the first wave. Therefore, the effect was less than before.
“We were able to conclude that heat waves will affect marine organisms depending on the time of summer where these events occur. This, which allowed us to calculate the response of plankton to thermal stress, is fundamental because the parameters we record can be used to validate global climate models for the ocean”, underlines the expert, director of the Laboratory of Biological Oceanography at CADIC.
The importance of the ocean
This work is part of a larger research network where investigate how human activities impact marine ecosystems. This is a key area of study, both because of the factors that affect the environment and climate change, and because of the importance of local scientists being able to address these issues.
“We analyzed the effect of global warming on the abundance of phytoplankton, that is, the microalgae that produce food for the rest of the marine food web. Also we study a particular class of microorganisms, which are those that produce toxins and form the so-called Harmful Algae Proliferationsexplains Schloss..
What is more, the research group investigates how the city of Ushuaia affects the cachiyuyo forests –the macroalgae Macrocystis pyrifera–, and the areas of Namuncurá-Banco Burdwood and Yaganes, two Marine Protected Areas.
From the scientist’s perspective, study projects centered on oceanographic issues are fundamental since “the sea is essential to sustain life on Earth. Its functions range from regulating the planet’s temperature, absorbing carbon dioxide and distributing heat globally, until we generate half the oxygen we breathe. It is necessary to take into account that more than 90% of the habitable space on the planet is submerged”, comments the researcher.
Regarding greenhouse gases, the scientist explains that could accelerate global temperature rise if ocean slows down absorption of carbon dioxide from atmosphere. “Likewise, when the upper layers of the water heat up, surface oxygen is rapidly depleted and large fish deaths can be observed,” warns the expert.
emerging research
Schloss and his research group have years of experience in the discipline. For example, in 2022 published an article in the journal Nature Ecology and Evolution together with a consortium of international researchers. There were able to identify 15 priority issues for the next 10 years.
Topics such as the impact of forest fires, the effect of poleward migration on equatorial biodiversity, resource exploitation – including the increased trade in fish swim bladders –, the construction of floating cities due to rising sea levels, new technologies such as light robotics and new biodegradable products.
“These are issues that we call emerging because we need to study them and that there is funding for that. With this work we wanted to shed light on these problems and warn that, if we do not face them, they can increase in severity and become virtually irreversible in the near future”, highlights the researcher.
In addition, the scientist warns of problems already identified such as pollution by hydrocarbons, large and microplastics, acidification of the oceans or the deterioration of habitats not yet resolved.
from south to south
In Schloss’s perspective, that there are scientific and technological projects aimed at studying these problems in Argentina is the key at different levels. “Subantarctic and Antarctic waters are not only of enormous importance due to local and global climate problems, but alsofor our country, also have great geopolitical importance”.
Geographically, the study region is close to the Malvinas Islands, has Chile to the west and south and is close to Antarctica. “Therefore, both in this area and in the waters of the south of the continent, it is essential to invest in science”, comments.