Ha­gen Buck-Wiese re­ceives the BRIESE Prize for Mar­ine Re­search 2023

Today's BRIESE award ce­re­mony took place in a spe­cial set­ting this time: Around 100 guests gathered on board the ice edge re­search ves­sel MARIA S. MERIAN, which is cur­rently moored in Warnemünde har­bour for a few days. In ad­di­tion to the hosts from the BRIESE ship­ping com­pany and the IOW, well-wish­ers also in­cluded the Fed­eral Gov­ern­ment's mar­ine com­mis­sioner Se­bastian Un­ger, MV Sci­ence Min­is­ter Bet­tina Mar­tin and the well-known ex­ped­i­tion leader and pub­li­cist Arved Fuchs. "Only very dedicated field and laboratory work, which included four ship expeditions lasting several weeks, has made possible the astonishing discoveries of Hagen Buck-Wiese, who has shown us the unexpected value that brown algae can have for us humans," says Klaus Küper, Head of the Re­search Ship­ping De­part­ment of the Briese ship­ping com­pany, on the oc­ca­sion of this year's present­a­tion of the BRIESE Prize. "The out­stand­ing work of this year's award win­ner shows once again how re­search into ba­sic prin­ciples at sea can de­velop dir­ect so­cial rel­ev­ance," says Küper.

Why brown algae mucus is good for the climate: the prize-winning doctoral topic

"Every year, al­gae fix 50 giga­tonnes (Gt) of car­bon in the ocean, most of it as car­bon hy­drates. Nev­er­the­less, there was a lot of un­cer­tainty about their fate and in­flu­ence on car­bon stor­age in the sea, not least due to a lack of meth­od­o­logy for ex­tract­ing them from sea­wa­ter for fur­ther ana­lyses," says Ha­gen Buck-Wiese, win­ner of the 14th BRIESE Prize, de­scrib­ing the ma­jor know­ledge gap that was the start­ing point for his doc­toral thesis at the Max Planck In­sti­tute for Mar­ine Mi­cro­bi­o­logy in Bre­men. Al­gae, both large and mi­cro­scopic, use pho­to­syn­thesis to con­vert car­bon di­ox­ide dis­solved in sea­wa­ter from the at­mo­sphere into gluc­ose for en­ergy sup­ply and into vari­ous, mostly com­plex mul­tiple sug­ars for bio­mass form­a­tion.
for bio­mass form­a­tion. However, the iden­ti­fic­a­tion and quan­ti­fic­a­tion of com­plex car­bo­hydrates is par­tic­u­larly dif­fi­cult in terms of meth­od­o­logy. "But only if you gen­er­ate de­tailed in­form­a­tion about the type and quant­ity of the dif­fer­ent types of mo­lecules in the mar­ine en­vir­on­ment can you un­cover their ori­gin and thus the path of the car­bon stored in them - from the or­gan­ism via the wa­ter to the sed­i­ment," says Buck-Wiese.
The mar­ine bio­lo­gist from Bre­men has there­fore been work­ing on the de­vel­op­ment of a suit­able method that can ex­tract small poly­sac­char­ide mo­lecules, so-called oli­gosac­char­ides, from sea­wa­ter even at very low con­cen­tra­tions, as is usu­ally the case with field samples. The suc­cess­ful ap­plic­a­tion of the new method, in which samples from sev­eral thou­sand metres of wa­ter depth were also ana­lysed, brought a sur­prise: in ad­di­tion to large quant­it­ies of oli­gosac­char­ides near the sur­face, where they are ex­pec­ted due to the pho­to­syn­thesis that takes place there, the small poly­sac­char­ides were also de­tec­ted in very deep wa­ter. "Their pres­ence in wa­ter masses up to 500 years after sur­face con­tact in­dic­ates that car­bon re­mains bound here for many cen­tur­ies without be­ing re­leased by bac­teria. This oli­gosac­char­ide frac­tion alone stores around 1 Gt of car­bon," em­phas­ises Buck-Wiese.
On the other hand, Ha­gen Buck-Wiese wanted to know what hap­pens to car­bo­hydrates with a par­tic­u­larly com­plex struc­ture. To this end, he car­ried out short and long-term in­cub­a­tion ex­per­i­ments with half a dozen spe­cies of brown al­gae from dif­fer­ent re­gions of the earth, in­clud­ing the blad­der­wrack also known from the North and Baltic Seas and the free-float­ing gulf kelp of the genus Sar­gas­sum, which gives its name to the well-known Sar­gasso Sea in the west­ern At­lantic. Here, too, he made an as­ton­ish­ing dis­cov­ery: with the help of cus­tom­ised ana­lysis meth­ods, which he also de­veloped him­self, he dis­covered for the first time that brown al­gae secrete con­sid­er­able quant­it­ies of a slimy sugar poly­mer into the sea every day. This so-called fu-coidan can make up to 50 per cent of the or­ganic car­bon meas­ured in the sur­round­ing wa­ter and un­der­goes prac­tic­ally no bac­terial de­com­pos­i­tion. "Brown al­gae pro­duce this sub­stance to pro­tect them­selves against harm­ful mi­crobes. It is in the nature of things that brown al­gae mu­cil­age does not taste good to mi­croor­gan­isms and we were there­fore un­able to de­tect any sig­ni­fic­ant de­grad­a­tion in our ex­per­i­ments. The mu­cil­age clumps to­gether with sus­pen­ded mat­ter to form particles that sink to the seabed, so that fuc­oidan enters the sed­i­ment and stores car­bon there for at least cen­tur­ies, if not mil­len­nia," ex­plains Buck-Wiese. Brown al­gae are ex­cep­tion­ally pro­duct­ive. If one ex­tra­pol­ates the res­ults from Buck-Wiese's ex­per­i­ments and the sub­sequent global sampling spe­cific­ally fo­cused on fuc­oidan, it can be as­sumed that they bind up to 150 mil­lion tonnes (t) of car­bon per year in the form of brown al­gae mu­cus, which is dif­fi­cult to de­grade, and thus re­move around 550 mil­lion t of CO2 from the at­mo­sphere. If one also con­siders the stor­age po­ten­tial of the per­sist­ent oli­gosac­char­ides in the deep wa­ter of the oceans, which at the time of sampling was equi­val­ent to around 4 Gt of CO2, the long-term car­bon stor­age in the sea dis­covered by Ha­gen Buck-Wiese is enorm­ous. By com­par­ison, Ger­many's an­nual green­house gas emis­sions amount to 674 mil­lion tonnes of CO2 (es­tim­ate for 2023), ac­cord­ing to the Fed­eral En­vir­on­ment Agency. "Our re­search puts the spot­light on the con­sid­er­able cli­mate pro­tec­tion po­ten­tial of com­plex car­bo­hydrates formed in the sea. In par­tic­u­lar, fuc­oidan se­quest­ra­tion by kelp forests as well as by nat­ural and man­aged al­gae stocks rep­res­ents an im­port­ant eco­sys­tem ser­vice for us hu­mans, which should def­in­itely be taken into ac­count in nature con­ser­va­tion and ren­at­ur­al­isa­tion meas­ures," con­cludes the BRIESE Award win­ner.

The BRIESE Prize jury re­cog­nised Ha­gen Buck-Wiese's doc­toral thesis as fol­lows: "The dis­ser­ta­tion, which was awar­ded 'summa cum laude', fo­cuses on the dif­fer­ent types of car­bo­hydrates formed by al­gae, a group of sub­stances that are among the most fre­quently pro­duced types of mo­lecules in the ocean. Un­til now, however, they have been largely neg­lected when ana­lys­ing the mar­ine car­bon cycle, not least be­cause the com­plex com­pounds were so dif­fi­cult to de­term­ine ana­lyt­ic­ally. Ha­gen Buck-Wiese has mastered the meth­od­o­lo­gical chal­lenges and thus opened a door that had pre­vi­ously been closed. The global sig­ni­fic­ance of the long-lived car­bo­hydrates pro­duced by al­gae can now be sys­tem­at­ic­ally in­vest­ig­ated and meas­ures for util­ising their cli­mate pro­tec­tion po­ten­tial can be de­rived from this."

Information on the 2023 BRIESE prizewinner:
Dr Ha­gen Buck-Wiese (born 1992) stud­ied bio­logy at the Uni­versity of Bre­men and spe­cial­ised in mar­ine bio­logy at the Max Planck In­sti­tute for Mar­ine Mi­cro­bi­o­logy, also in Bre­men, where he also com­pleted his doc­tor­ate. (Ori­ginal title of the doc­toral thesis: En­zymatic diver-si­fic­a­tion and brown al­gae as sources of com­plex glycans in the mar­ine dis­solved or­ganic car­bon reser­voir, de­gree: 6/​2023, grade: "Summa cum laude", su­per­vi­sion: Prof. Dr Jan-Hendrik Hehemann, Uni­versity of Bre­men, and Dr Manuel Liebeke, Max Planck In­sti­tute for Mar­ine Mi­cro­bi­o­logy). Buck-Wiese is cur­rently a postdoc­toral re­searcher at the Uni­versity of South­ern Cali­for­nia, USA, in the field of mar­ine and en­vir­on­mental bio­logy.

The BRIESE Prize for Marine Research
The BRIESE Prize for Mar­ine Re­search is sponsored by the ship­ping com­pany Briese Schiffahrts GmbH & Co. KG, which is re­spons­ible for the man­age­ment of me­dium-sized Ger­man re­search ves­sels such as the ELISA­BETH MANN BORGESE, as well as the lar­ger re­search ves­sels MET­EOR, MARIA S. MERIAN and SONNE. The IOW sci­en­tific­ally su­per­vises the award­ing of the prize. Since 2010, the prize has been awar­ded an­nu­ally to out­stand­ing doc­toral theses in mar­ine re­search whose res­ults are closely re­lated to the use of re­search ves­sels and the use and de­vel­op­ment of tech­no­logy and / or data col­lec­tion at sea.

Original press release of the IOW