World Oceans Day:
Valdivia & AWI —
Marine and Climate protection

8 June marks ‘World Oceans Day’ – a good oppor­tu­ni­ty to provide an update on the work of the Alfred Wegen­er Insti­tute (AWI), which we support.

We contin­ue our series on the voyages of the flag­ship of German polar and marine research with a report on the Polarstern’s latest Antarc­tic expe­di­tion. There is also news regard­ing the fight against plas­tic pollu­tion in the oceans – and the hope that the inter­na­tion­al commu­ni­ty will come togeth­er to final­ly agree on solu­tions on the neces­sary scale. We had already high­light­ed just how urgent such a deci­sion is in the Valdivia News­room with our arti­cle on the “North­drift”.

Glob­al warm­ing in Antarc­ti­ca too

For a long time, the extent of sea ice in Antarc­ti­ca was consid­ered rela­tive­ly stable – unlike in the Arctic, where ice has been declin­ing by 12 per cent per decade in summer since satel­lite obser­va­tions began in 1979. Since around 2017, howev­er, signif­i­cant changes have also become appar­ent in the Antarc­tic region. During the south­ern hemi­sphere summer, from Decem­ber to Febru­ary, sea ice extent is now also declin­ing sharply here.

On 8 Febru­ary 2026, the Polarstern there­fore weighed anchor in Punta Arenas (Chile) for anoth­er voyage into Antarc­tic waters. On board were 50 scien­tists from eight differ­ent coun­tries, as well as 43 crew members. Under the name “Summer Weddell Sea Outflow Study” (SWOS), the multi­dis­ci­pli­nary research team inves­ti­gat­ed the north-west­ern part of the Weddell Sea – an area of central impor­tance for the glob­al climate and ocean system, which, due to its diffi­cult ice condi­tions, can only be explored by power­ful research icebreak­ers such as the Polarstern.

Track­ing ice melt with SWOS

“The aim of SWOS is to inves­ti­gate why sea ice in Antarc­ti­ca has declined so sharply in recent years and how this is affect­ing the ecosys­tem,” explained Prof. Dr Chris­t­ian Haas of the AWI and leader of the expe­di­tion before the voyage began. To achieve this aim, compre­hen­sive obser­va­tions were carried out for the first time in the north-west­ern Weddell Sea region, rang­ing from the seabed up to the atmosphere.

“Many of our key ques­tions cannot be answered by satel­lites alone,” Chris­t­ian Haas contin­ued. “We need in-situ obser­va­tions to under­stand the state of the sea ice, the currents and the biolog­i­cal commu­ni­ties in the water and on the seabed – and to be able to assess whether the sea ice might disap­pear entire­ly in the future.”

The Weddell Sea – remote yet significant

The expedition’s research area was a region of the South­ern Ocean covered in thick sea ice almost all year round and one of the least explored areas on Earth. From here, water mass­es, nutri­ents and carbon flow into the world’s oceans – there­by influ­enc­ing the glob­al climate system. Ice and ocean inter­act close­ly in this process. They deter­mine the forma­tion and melt­ing of sea ice and, conse­quent­ly, the living condi­tions for organ­isms in the water and on the seabed. The decline in sea ice cover could have far-reach­ing conse­quences – poten­tial­ly also for the stabil­i­ty of the ice shelf.

The research took place at a crit­i­cal junc­ture: the Antarc­tic Ocean is warm­ing and losing sea ice at an increas­ing rate. The data collect­ed should there­fore help to better under­stand these changes and improve climate models. In doing so, SWOS has made an impor­tant contri­bu­tion to under­stand­ing a key zone of the Antarc­tic ice-ocean system – at a time of profound change whose effects extend far beyond Antarctica.

Research from the seabed to the clouds

The main focus of the inves­ti­ga­tions was the inter­ac­tions between sea ice, ice shelves and the ocean, as well as their effects on the ecol­o­gy of the zone. To this end, the scien­tists measured ice and snow thick­ness at inter­vals of a few nauti­cal miles, exam­ined the water mass­es and tracked how nutri­ents and carbon move from the surface to the deep sea. In addi­tion, the expe­di­tion carried out numer­ous other research tasks:

• Zooplank­ton, krill and fish are impor­tant compo­nents of the food web in the South­ern Ocean and contribute to carbon trans­port. Their abun­dance and distri­b­u­tion were record­ed using special nets in vari­ous water layers. The data obtained in this way show how sea ice influ­ences distri­b­u­tion. This enables analy­ses of the role of sea ice and predic­tions regard­ing changes caused by its climate-induced retreat.
• In addi­tion, a CTD probe (for ‘conduc­tiv­i­ty, temper­a­ture, depth’) was deployed. Among other things, it measures light inten­si­ty, salin­i­ty, oxygen, current veloc­i­ty and chloro­phyll concen­tra­tion at vari­ous water depths.
• A submersible drone was also deployed to inves­ti­gate the topog­ra­phy of the seabed and the effects of process­es with­in the ice on the animal and plant commu­ni­ties living there.

Further research activ­i­ties includ­ed obser­va­tions of wildlife, measure­ments of the phys­i­cal and chem­i­cal prop­er­ties of aerosol parti­cles as poten­tial cloud nuclei, and addi­tions to the Inter­na­tion­al Bathy­met­ric Chart of the South­ern Ocean (IBCSO), the precise topog­ra­phy of which is current­ly only partial­ly known.

Follow the Polarstern’s voyages live

The Polarstern is current­ly enjoy­ing a well-deserved rest and over­haul in the dry dock in Bremer­haven. But as early as the begin­ning of July, it will set sail for the Fram Strait between Green­land and Spits­ber­gen. The new expe­di­tion is set to contin­ue long-term ecolog­i­cal research there in the water column and on the seabed. The aim is to observe the effects of signif­i­cant envi­ron­men­tal changes and pollu­tants in the tran­si­tion zone between the north­ern North Atlantic and the central Arctic Ocean. Further research topics include Arctic deep-sea biodi­ver­si­ty and the effects of climate change on deep-sea commu­ni­ties. Remote­ly oper­at­ed under­wa­ter robots and seabed vehi­cles will also be deployed.

By the way, you can follow all Polarstern voyages live: with the new On-Expe­di­tion app! This also gives you access, during our summer months, to reports from the scien­tists over­win­ter­ing at the German Neumey­er II South Pole Station.

A new oppor­tu­ni­ty for a glob­al plas­tics agreement

Since August 2025, an Inter­gov­ern­men­tal Commit­tee (INC) has been nego­ti­at­ing a glob­al plas­tics agree­ment at the Unit­ed Nations in Gene­va – unfor­tu­nate­ly with­out success so far. It has become appar­ent that the INC’s compre­hen­sive mandate – to take into account the entire life cycle of plas­tics – has led to frag­ment­ed and protract­ed debates. Howev­er, with­out bind­ing inter­na­tion­al rules, the entry of plas­tic into the oceans remains a struc­tur­al prob­lem – regard­less of local initiatives.

With the elec­tion of the new chair, Julio Cordano from Chile, on 7 Febru­ary 2026, hopes have arisen that a new mode of nego­ti­a­tion will lead to better results. A propos­al to this effect came from, among others, the German partic­i­pants Melanie Bergmann from the AWI, Paul Einhäu­pl and Linda Del Savio (Research Insti­tute for Sustain­abil­i­ty) and Anni­ka Jahnke (Helmholtz Centre for Envi­ron­men­tal Research): clear prior­i­ties, proce­dur­al rules and major­i­ty deci­sions are to replace the previ­ous approach. This offers hope that marine plas­tic pollu­tion will, after all, be brought under control in the fore­see­able future.

You can find the latest infor­ma­tion on the UNEP Plas­tics Initia­tive on the programme’s website.

Valdivia and the sea – a profound connection

Depth of commit­ment, passion for the sea – that is how we came up with our name Valdivia. For ‘Valdivia’ was the name of the first German research vessel to set sail in 1898 on a system­at­ic explo­ration of the deep sea. This connec­tion moti­vates us to provide prac­ti­cal support for marine research and conser­va­tion: as a member of the Friends of the Alfred Wegen­er Insti­tute, Germany’s lead­ing scien­tif­ic insti­tu­tion for marine and polar research. We warm­ly invite you to join us!

(Image source: AWI – Polarstern)