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Sur­prise in the deep sea: Re­search­ers dis­cover sponge paths on the ocean floor

Apr 26, 2021

Sponges: They are considered to be one of the most primitive forms of animal life, because they have neither locomotion organs nor a nervous system. A team around deep-sea scientist Antje Boetius has now discovered that sponges leave trails on the sea floor in the Arctic deep sea. They conclude that the animals might move actively – even if only a few centimeters per year. They are now publishing these unique findings in the journal Cur­rent Bio­logy.

(Quelle: AWI)
(Quelle: AWI)

The sur­prise was great when re­search­ers looked at high-res­ol­u­tion im­ages of the sea floor of the Arc­tic deep sea in de­tail: Path-like tracks across the sed­i­ments ended where sponges were loc­ated. These trails were ob­served to run in all dir­ec­tions, in­clud­ing up­hill. "We con­clude from this that the sponges might act­ively move across the sea floor and leave these traces as a res­ult of their move­ment," re­ports Dr. Teresa Mor­ganti, sponge ex­pert from the Max Planck In­sti­tute for Mar­ine Mi­cro­bi­o­logy in Bre­men. This is par­tic­u­larly ex­cit­ing be­cause sci­ence had pre­vi­ously as­sumed that most sponges are at­tached to the sea­floor or are pass­ively moved by ocean cur­rents and, usu­ally down slopes.

Sponges leave traces on the seabed of the deep sea. Until now, science assumed that the animals did not move. The traces to living sponges suggest that the animals could be actively moving. The underwater images were taken by researchers from the Alfred Wegener Institute on a Polarstern expedition in the Arctic with the help of the OFOBS (Ocean Floor Observation and Bathymetry System). (Photo: AWI OFOBS team PS101)
Sponges leave traces on the seabed of the deep sea. Until now, science assumed that the animals did not move. The traces to living sponges suggest that the animals could be actively moving. The underwater images were taken by researchers from the Alfred Wegener Institute on a Polarstern expedition in the Arctic with the help of the OFOBS (Ocean Floor Observation and Bathymetry System). (Photo: AWI OFOBS team PS101)

“There are no strong cur­rents in the Arc­tic deep sea that could ex­plain the struc­tures found on the sea floor,” ex­plains ex­ped­i­tion leader Prof. Anthe Boe­t­ius, who works to­gether with deep sea bio­lo­gist Dr. Au­tun Purser from the Al­fred We­gener In­sti­tute, Helm­holtz Cen­ter for Po­lar Mar­ine Re­search (AWI) in the HGF-MPG Joint Re­search Group for Deep-Sea Eco­logy and Tech­no­logy. The re­cently pub­lished re­cord­ings were made dur­ing an ex­ped­i­tion at 87 °North at the Karasik Seamount about 350 kilo­met­ers away from the North Pole with the re­search icebreaker Po­larstern in 2016 with a towed cam­era sys­tem OFOBS (Ocean Floor Ob­ser­va­tion and Ba­thy­metry Sys­tem). “With OFOBS we can cre­ate 3D mod­els from the deep sea. The seamoun­t’s sum­mit was densely pop­u­lated with sponges. 69 per­cent of our im­ages showed trails of sponge spic­ules, many of which led to live an­im­als,” re­ports Au­tun Purser.

Many ques­tions arise from these ob­ser­va­tions: Why do the sponges move? How do they ori­ent them­selves? Pos­sible reas­ons for lo­co­motion could be for­aging, avoid­ing un­fa­vor­able en­vir­on­mental con­di­tions, or to dis­trib­ute off­spring. Search­ing for food in par­tic­u­lar plays a ma­jor role in nu­tri­ent-poor eco­sys­tems such as the Arc­tic deep sea. Sponges have an im­port­ant func­tion there any­way. As fil­ter feed­ers they can util­ize particle and dis­solved or­ganic mat­ter and are in­tens­ively in­volved in nu­tri­ent and mat­ter re­cyc­ling by means of their bac­terial sym­bionts. Sponges also provide arc­tic fish and shrimp use­ful struc­tures to use as a hab­itat. However, the sci­ent­ists still have to in­vest­ig­ate the mech­an­isms of lo­co­motion.

 

(Based on a press release by the Al­fred We­gener In­sti­tute, Helm­holtz Cen­ter for Po­lar Mar­ine Re­search)

Ori­ginal pub­lic­a­tion

Teresa M. Mor­ganti, Au­tun Purser, Hans Tore Rapp, Chris­topher R. Ger­man, Mi­chael V. Jak­uba, Laura Hehem­ann, Jo­nas Blendl, Beate M. Slaby, Antje Boe­t­ius: In situ ob­ser­va­tion of sponge trails sug­gests com­mon sponge lo­co­motion in the deep cent­ral Arc­tic. Cur­rent Bio­logy (2021).

DOI: 10.1016/j.cub.2021.03.014

Please dir­ect your quer­ies to:

Dr. Teresa Maria Morganti

Tel.: +34(0) 622 920 462 or via Skype @teremo83; E-Mail: tmorgant@mpi-bremen.de

Dr. Autun Purser

Tel.: +49(0) 471 4831-1740; E-Mail: autun.purser@awi.de

Folke Mertens, Press Dept. of the Al­fred-We­gener-In­sti­tute, Helm­holtz-Zen­trum für Po­lar- und Meeres­forschung (AWI)

Tel.: +49(0) 471 4831-2007; E-Mail: medien@awi.de

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Dr. Fanni Aspetsberger
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