site.btaScience Is Cooperation and Should Have No Borders, Greek Oceanologists Dionysia Rigatou and Eleni Kytinou Say in Interview with BTA

Science is cooperation and should have no borders, Greek oceanologists Dionysia Rigatou and Eleni Kytinou said in an interview with Bulgarian News Agency (BTA). They are part of the 34th Bulgarian Antarctic Expedition.

"Science is cooperation. It should not have borders. We all need to work together for a common cause, because what happens in Bulgaria happens in Greece, and what happens in Antarctica affects the world. For me, science has no borders, and cooperation, free cooperation, sharing data and expertise, is what can move science forward," Rigatou said, expressing her gratitude to the Bulgarian Antarctic Institute, whose cooperation with Greece has made it possible for her and Kytinou to carry out their project in Antarctica.

Rigatou is an oceanologist at National and Kapodistrian University of Athens, currently working on her doctoral dissertation and part of a research team there. Her team studies how climate change affects marine food webs, with a primary focus on impacts on phytoplankton and zooplankton, which form the base of the marine food chain.

Kytinou is a marine biologist at the Institute of Oceanography at the Hellenic Centre for Marine Research. She is currently a doctoral candidate, with her dissertation focusing on marine trophic regimes. The team she works with relies mainly on scientific diving to assess the environments they study. Her research focuses on rocky reef food webs. Kytinou assesses macroalgae, all invertebrates living on them, and fish, and develops indices of ecological status.

She told BTA that research to date shows overfishing and climate change exert the greatest pressure on coastal ecosystems, along with pollution.

During the current expedition, Rigatou is studying phytoplankton in Antarctic waters by taking measurements and water samples from the ship.

"These will be analysed later to see how phytoplankton structure is distributed and which different phytoplankton communities live here. These communities are influenced by environmental factors as well as climate change," she explained. "We can also use remote sensing to see what phytoplankton was like in the past, going back to the 1990s. That is why we also include environmental variables such as wind, sea-surface temperature and sea-ice cover."

Through the phytoplankton samples, Rigatou and Kytinou aim to understand how the marine environment has changed, whether due to human presence or natural climatic and environmental processes, and how this has affected the entire marine food web.

"At the base of the food web, alongside phytoplankton, are macroalgae, which we will assess through diving. Then come the higher trophic levels: filter feeders, invertebrates living among the macroalgae on the seabed, and fish that occupy higher trophic levels. After that come penguins and seals, which are the apex predators in the area," Kytinou noted.

The two scientists are conducting measurements and sampling aboard the research vessel Sv. Sv. Kiril i Metodii (RSV 421) and near the Bulgarian Antarctic base St. Kliment Ohridski Base. The study relies on animal size measurements, underwater photographs of macroalgae, and video footage of fish.

Alongside phytoplankton expertise, satellite data are used for environmental variables such as temperature, wind and sea-ice cover.

"These are important variables for marine life and are influenced by many factors. For example, sea ice provides nutrients to the ocean, which then feed phytoplankton, followed by zooplankton and macroalgae, and then smaller fish," Rigatou explained. "If one level is affected by climate change, it can affect the higher levels. If you touch something in the ocean, the entire balance changes."

The Greek researchers plan to install stations at several sites to measure human and natural impacts on food webs. So far, they have collected water samples at various depths from multiple locations around Livingston Island, as well as from the Antarctic Sound and Hope Bay near the Antarctic Peninsula. On board the RSV 421, they have equipment to filter the samples and isolate phytoplankton, which will be analysed in laboratories in Greece.

"Recent research in polar regions shows that satellites are not fully accurate there, they underestimate many factors because the communities are different. This relates to chlorophyll levels and other technical elements. Our data can therefore also be used to improve algorithms for polar regions," Rigatou said, adding that this requires consistent, long-term studies.

"I think that because these data are rare, it is very important to have them, even as a baseline. Even if we find that ‘this happens’ only once, it is still very important, because data are scarce, especially in parts of Antarctica. Some areas are relatively well studied because they host bases operating continuously, but other areas - especially biological data around Livingston Island and the Bransfield Strait as a whole - almost do not exist," she added.

Rigatou and Kytinou said that processing the data collected during the expedition will take up to a year. Their research represents only a small part of the broader picture of Antarctic food webs, as samples are taken at specific moments and locations. Building a comprehensive, consistent database, and drawing robust conclusions - will require years of systematic study. They therefore hope that cooperation between the Greek and Bulgarian polar programmes will continue in the future.

The host of the two researchers in the Bulgarian Antarctic Institute, was made possible through the collaboration of BAi with the Hellenic Polar Zones Society whereas the main funding of their expedition was provided by Laskaridis Shipping Co Ltd.