The research vessel Polarstern in dense sea ice

PS137 - Expedition to the Gakkel Ridge and Lena Trough with FS Polarstern

Expedition PS137, named ALOIS (Arctic Lithosphere-Ocean Interaction Study), aimed to study the formation of new lithosphere and the associated hydrothermal circulation at the ultra-slow-spreading Gakkel Ridge and Lena Trough in the Arctic Ocean.

The main interest of the petrology team was the collection of rocks and hydrothermal precipitates as well as hydrothermal fluid and plume samples from the "Aurora" and "Lucky B" hydrothermal systems.

Example of a gravity core

M155 - Expedition to Fogo (Cape Verde Islands)

The main objective of the meteor expedition M155 was to study the deposits of a flank collapse of the Fogo volcano (Cape Verde Islands), which triggered a mega-tsunami about 73,000 years ago.

The image shows an example of a gravity core from the southern study area with different background sedimentation (beige to reddish colors) and different layers rich in volcanoclastic sand.

MARUM Quest 4000 on board the research vessel Sonne

SO253 - Cruise to the South Kermadec Island Arc

On R/V Sonne Expedition SO253, four hydrothermally active volcanoes in the southern Kermadec Island Arc (Brothers Caldera, Haungaroa Volcano, Macauley Caldera, Rumble III) were visited and sampled using the remotely operated underwater vehicle MARUM Quest 4000.

The aim was to find out how fast hydrothermal plumes propagate in the ocean and what processes take place when the escaping hot solutions mix with the ocean water masses.

Two-part image with the logo of the meteor expedition M192 on the right and the view from the deck of the research vessel to the sunlit Greek island of Milos on the left.
R/V Meteor off the Greek island of Milos in the Mediterranean Sea (left) and logo of the expedition (right)

Location: Shallow water hydrothermal vents off Milos; Piraeus (Greece) - Limassol (Cyprus)

Date: August 8 — September 5, 2023

Funding: DFG

Participants from our group: Solveig  Bühring, Wolfgang Bach, Charlotte Kleint, Palash Kumawat

Summary: Expedition M192 investigated submarine hydrothermal activity in the transition between shallow and deep water, and the influence of water depth on biological processes off the Greek island of Milos. One objective was to document geochemical changes in fluids and associated microbial diversity with increasing depth and distance from land, and to investigate the relative importance of chemosynthesis and animal dependence on symbiotic associations with microorganisms with increasing depth. To date, shallow-water and deep-sea hydrothermal systems have been treated as independent, seemingly unrelated entities; this expedition is a first attempt to remove this arbitrary boundary and study hydrothermal systems as a continuum.


Further information about Meteor expedition M192

Split image showing a chimera observing the sampling of warm solutions emerging from a mussel-populated site in the deep ocean, and the logo of R/V Meteor cruise M190 on the right.
A chimera observes sampling of warm solutions exiting a site populated by bivalves (left) and logo of R/V Meteor cruise M190 (right)

Location: Hydrothermal vents at the Mid-Atlantic Ridge 29-38°N; Las Palmas (Spain) - Algeciras (Spain)

Date: June 8 — July 10, 2023

Funding: DFG-EXC

Participants from our group:Wolfgang Bach, Patrick Monien, Alexander Diehl

Summary: Cruise M190 of R/V Meteor was carried out in order to be able to take geochemical and biological samples at hydrothermal vents on the Mid-Atlantic Ridge between 29°10''N and 38°20''N. The springs in this area are characterized by very different geological settings, and the fluids are correspondingly very different in nature. The hydrothermal vents were sampled with the ROV MARUM Quest 4000 to determine the material differences between the individual vents and to place them in relation to the geological framework. We also want to investigate how the distribution and composition of the sources affect the genetic and metabolic diversity of symbiotic and free-living microorganisms. Surveying and sampling the water column and subsequent geochemical analyses will reveal how metals are introduced into the ocean and how their binding modes change. Extensive sampling and investigation of diffuse sources will provide insight into the activity of intracrustal microorganisms and their metabolic strategies. A total of 12 dives with the ROV MARUM Quest 4000 and eleven CTD stations, five of them combined with deep-sea pumping, provided sufficient samples to address the scientific questions. In addition, we surveyed unmapped seafloor in several regions with the EM122 multibeam echo sounder and tried to detect bubble trails in the water column to find additional hot springs in volcanic edifices around 38°N.

Aerial view of the research vessel Polarstern in dense sea ice.
R/V Polarstern in dense sea ice
Water sampler on a diving robot arm in the deep sea at a black smoker vent.
Hydrothermal fluid sampling at the Aurora hydrothermal field

Location: Gakkel Ridge & Lena Trough; Tromsø (Norway) – Tromsø (Norway)

Date: June 21, 2023 — July 31, 2023


Funding: ...

Participants from our group: Elmar Albers


Summary: Expedition PS137, named ALOIS (Arctic Lithosphere–Ocean Interaction Study), aimed at investigating the formation of new lithosphere and associated hydrothermal circulation at the ultraslow-spreading Gakkel Ridge and Lena Trough, Arctic Ocean. The main interest of the petrology team was the collection of rocks and hydrothermal precipitates as well as hydrothermal fluid and plume samples from the ‘Aurora’ and ‘Lucky B’ hydrothermal systems.


Further information about expedition PS137

Two-part image with the remotely operated yellow underwater vehicle MARUM SQUID hanging on the hook of the ship's crane next to the ship's side on the left and the logo of the R/V METEOR expedition M183 on the right.
Diving robot MARUM SQUID 2000 during launching (left) and logo of the R/V Meteor expedition M183 (right)

Location: East flank of the Reykjanes Ridge at 58°N; Ponta Delgada (Azores, Portugal) - St. John's (Newfoundland, Canada)

Date: July 13 — August 9, 2023


Funding: DFG-EXC

Participants from our group: Wolfgang Bach, Isabel Lange, Aaron Röhler, Paul Berndt

Summary: Cruise M183 took place to conduct site survey work at the eastern flank of the southernmost Reykjanes Ridge to identify potential targets for MeBo-drilling and ridge flank observatory installation. Survey data to be collected included multibeam echosounding and subbottom profiling, porewater analyses of cored sediment, and temperature measurements in the shallow subseafloor. The survey work began in the area between 58°00'N, 32°W and 58°10'N, 31°W but suitable sediment ponds were not found in that section of the ridge flank. We were successful in identifying the third pond we visited as promising target for MeBo drilling and ridge flank observatory installation. In this sediment pond (named Squid Pond by us) 107 giant heat flow probe deployments yielded a tight data grid that clearly suggests significantly higher heat flow on the northwestern side of the pond and the adjacent ridge than in the respective counterparts on the southeastern side of the sediment pond. After two subbottom profiling dives with ROV MARUM SQUID, the robot was used in and around Squid Pond to collect rocks and push-core sediments. Twelve gravity cores were taken; the most common type of sediment is sandy muds with variable color (dominantly grayish brown to greenish gray) and fluctuating fractions of foraminiferal sand and dropstones. Sediment pore water samples were retrieved and analyzed for oxygen and iron concentrations as well as total alkalinity. The combined data and observations are consistent with an upward-directed flow of basement fluids in the ridge bounding Squid Pond to the northwest.

A new, shiny metallic drill head and a worn, rust-coloured drill head stand next to each.
Drill heads, new and after use in 7 million old ocean crust
Two plastic tubes with fragments of a gray-brown colored drill core of a 49 million year old pillow lava.
Drill core of a 49 million year old pillow lava

Location: South Atlantic Transect II; Cape Town (South Africa) – Cape Town (South Africa)

Date: Juni 7, — August 7, 2022

Funding: IODP

Participants from our group: Elmar Albers


Summary: The South Atlantic Transect is a multidisciplinary ocean drilling project that included two IODP expeditions (Exp. 390 & 393) at which sediments and up to 200 m of the underlying basaltic crust were drilled along a Mid-Atlantic Ridge crustal flow line. Sediments and basement were recovered at 7, 15, 31, 49, and 61 Ma old sites, to investigate the evolution of deep-water masses and past climatic changes, microbiology of sediments and crust, as well as hydrothermal interactions between the aging oceanic crust and the evolving South Atlantic.

Further information about IODP expedition 393

A researcher bends over a table on which lie lots of dark rock samples.
Description of freshly dredged and sawed rock samples.
Close-up of an orange and green macrofauna on a black rock, taken during a dive with the Quest 4000 underwater vehicle.
Macrofauna on altered igneous rocks during a dive with the MARUM Quest 4000 ROV

Location: Marion Rise, Southwest Indian Ridge; Cape Town (South Africa) – Emden (Germany)

Date: March 6, — April 22, 2020

Funding: BMBF

Participants from our group: Elmar Albers, Christian Hansen, Katharina Unger-Moreno


Summary: Departing from Cape Town with a magnificent view of the Table Mountain, expedition SO273 set out to investigate the igneous, tectonic and hydrothermal processes at the Marion Rise along the ultraslow spreading Southwest Indian Ridge (SWIR). The Marion Rise represents an area of anomalously shallow bathymetry and one of the largest rises in the global oceanic ridge system. An interdisciplinary group of geologists, geochemists, and geophysicists from Berlin, Boston, Bremen, Erlangen, Hanover, Helsinki, Laramie, Modena, Münster, and Tallahassee cooperated onboard research vessel Sonne to unravel the origin of this peculiar feature in the Southern Indian Ocean. A detailed view of submarine geological features was acquired with a range of remote sensing methods including bathymetric, gravimetric and magnetometric surveys. A comprehensive set of rock samples was acquired via dredging and during targeted dives using the remotely operated underwater vehicle MARUM QUEST 4000. Samples included pillow basalts, peridotites, alkali basalts, carbonates, and ultramylonitic peridotites from volcanically active to amagmatic ridge segments as well as the first oriented samples from the SWIR. Miniature autonomous plume recorders were deployed with dredges and during ROV dives and complemented with CTD surveys including volatile measurements (hydrogen, methane) in order to explore hydrothermal activity. The recovered samples and the acquired geophysical data will be used to decide whether the Marion Rise rather formed from isostatic upwelling of ancient residual mantle material or from excess melting during plume-ridge interaction. Due to globally increasing travel restrictions in context of the SARS-CoV-2 pandemic SO273 expedition was aborted on the 21st of March with R/V Sonne heading back to Emden (Germany) unfortunately cutting most of the planned research.

Further information about expedition SO273

Frontal view of the research vessel Merian in a fjord on Spitsbergen.
Start of expedition MSM86 in Longyearbyen on Spitsbergen
Four people in neon-colored protective work clothing and helmets use ropes to pull a large, metallic sample grab hanging from the hook of the ship's crane onto the deck of the research vessel Merian. Another person wearing a neon orange jacket and white helmet stands in the foreground of the image and observes the scene.
With the help of the TV grab, rock samples as well as biological samples were taken from the depths

Location:  Vesteris Seamount, Greenland Sea; Longyearbyen (Norway) – Emden (Germany)


Date: August 18, 2019 — September 16, 2019


Funding: DFG

Participants from our group: Wolfgang Bach, Katharina Unger-Moreno


Summary:  Vesteris Seamount is a young and large intraplate volcano located in the Greenland Sea, which erupted many times in the past 500,000 years and is considered presently dormant. Its composition is strange for a volcano this size and rather resembles that of very small volcanic fields. A multidisciplinary and multinational approach in which geologists, geobiologists and geophysics from Bremen, Erlangen, Kiel, Göttingen, Hamburg, Bergen, Helsinki, Stockholm, and Vienna were involved was aimed at improving our understanding of the evolution of this seamount. During cruise MSM86, detailed topographic maps were produced using the modern echosounding systems of our research vessel, the Maria S. Merian. These maps show lava flows, lava fountaining deposits, and landslides that shaped this enigmatic volcano. Moreover, a large number of samples including rocks and biota were collected with a TV-guided grab and during several dives with the ROV (Remotely Operated Vehicle) MARUM-SQUID. Subsequent comprehensive geochemical and (micro)biological analyses will give more insights into mantle melting dynamics and source composition and the geodynamic evolution of the northern North Atlantic, the constructional history of this volcano as well as the diversity of local sponges and the microbiomes they host. Finally, by examining the colonization of volcanic rocks by microorganisms, including fungi and bacteria, we may learn more about the relationship between rock alteration and endolithic life.

Further information about expedition MSM86

The research vessel Meteor with a view of the nearby island of Fogo at sunset.
R/V Meteor near Fogo at sunset
Several plastic half-pipes with gravity cores lie side by side on a table. Different background sedimentations with reddish to beige colors and different layers rich in volcanoclastic sand are visible.
Gravity core with different background sedimentation of reddish to beige colors and different layers rich in volcanoclastic sand.

Location: Fogo, Cape Verde Islands; Pointe-à-Pitre (Guadeloupe) – Mindelo (Cape Verde)

Date: May 26, 2019 — June 30, 2019

Funding: DFG

Participants from our group: Andreas Klügel


Summary: The main objective of Meteor cruise M155 was to investigate the deposits of a giant flank-collapse of Fogo Volcano (Cape Verde Islands) causing a mega-tsunami approximately 73,000 years ago. On nearby Santiago Island tsunami deposits had been found indicating run-up heights of more than 270 m. Hydroacoustic and seismic data were collected to determine and quantify the geometry, extension, volume, sedimentological characteristics and stratigraphy of these deposits. The hydroacoustic data revealed that the mass transport deposits cover an area much larger than previously postulated. Most of the mass transport deposits are related to volcanic flank collapses but additional landslide deposits were identified north and south of Fogo. Moreover, seismic data show several widespread buried mass transport deposits indicating that the most recent collapse was not a unique event. In addition, a total of 32 sediment cores were taken in this area and examined for volcaniclastic turbidites probably related to volcanic eruptions. These turbidites will give us clues on the timing, volume and temporal recurrence of the collapse events.

Further information about expedition M155 in the cruise report

View from the ship of a glacier shining in the sun on the coast of South Georgia.
Glaciers on the coast of South Georgia
Close-up of a brownish rock sample, on the surface of which there are countless solid spheres of different sizes ranging from yellow to orange in color.
Rock sample from Kemp caldera with solidified liquid sulfur

Location: South Sandwich arc, East Scotia ridge; Punta Arenas (Chile) – Port Stanley (Falkland, UK)

Date: April 13, 2019 — May 31, 2019

Funding: BMBF

Participants from our group: Alexander Diehl, Samuel Pereira

Summary: In the mid of April 2019 the research vessel Polarstern has steamed-off to its last expedition prior to the big MOSAIK project. The vessel set out to a seven-week lasting research expedition in the Scotia Sea. Aim of the expedition was to explore the sparsely known plate boundaries, the South Sandwich arc and the East Scotia ridge. The research program was designed manifold and included the registration of whale migration routes, mapping surveys at Saunders volcano, sediment sampling at the continental shelf off South Georgia, and the exploration and investigation of marine hydrothermal vents in intra-oceanic arcs and back-arc spreading centers. Despite a rough sea state during the expedition ROV QUEST 4000 (MARUM) could sample hydrothermal vents from the E2-segment of the East Scotia ridge, as well as the South Sandwich arc volcano Kemp Caldera. The sampled hydrothermal fluids and precipitates could not be more different. High temperature black smoker fluids (> 320 °C), which precipitate large sulfide chimneys when entering the ocean at the E2-segment, are in contrast to lower temperature white smoker vents (<230 °C), which are sometimes accompanied by the discharge of liquid sulfur in Kemp Caldera. Our investigations aim to put our samples into context of the few existing samples from the different working areas and evaluate whether these geologic systems have changed their dynamics or remained stable in terms of energy and chemistry. Furthermore, we examine the differences between these vents from intra-oceanic arc and back arc spreading environments, that represent two extreme types of venting.

Further information about expedition PS119

Two researchers are working on a fluid sampler in the laboratory aboard the research vessel Sonne. This stands behind them on the table, the two researchers squat in front of it and connect a hose to the metal snorkel of the sampler.
Work on an isobaric gas-tight fluid sampler
Close-up of a glass syringe filled with a fluid sample from which gas is bubbling out.
Gas bubbling out in a sampling syringe

Location: Tonga-Rift; Suva (Fiji) – Suva (Fiji)

Date: 1. Juni 2018 — 27. Juni 2018

Funding: BMBF

Participants from our group: Wolfgang Bach, Alexander Diehl, Patrick Monien, Stefan Sopke, Andreas Türke

Summary: Expedition SO263 with research vessel Sonne and ROV MARUM Quest 4000 was carried out from the sun-kissed islands of Fiji to investigate the volcanic, hydrothermal und tectonic history of the Tonga intra-oceanic arc and its back-arc spreading center. During the expedition several hydrothermal vent fields have been investigated at the Niua and Niuatahi arc volcanoes and at the back-arc volcano Maka. Our research agenda comprised of extensive sampling of volcanic rocks and the investigation of hydrothermal fluids, sulfides and chemosynthetic vent communities. The agenda was supplemented by CTD and MAPR investigations of plume dispersal in the water column. The chosen research area provides the opportunity to investigate the evolution of magmatic melts at convergent plate boundaries behind subduction zones. The associated hydrothermal systems are situated in different geologic environments and enable us to study the differences between vent fluids at intra-oceanic arcs and back-arc spreading centers. The implemented research agenda with a coupled investigation of volcanic rocks and hydrothermal processes enables us to profoundly learn about the relationship between magmatic activities and subsequent hydrothermal activities in all its facets.

Further informationen about expedition SO263

Sunrise on board the drilling vessel R/V Joides Resolution.
Sunrise on board the drilling vessel R/V Joides Resolution
The core repository on board the R/V Joides Resolution, on the shelves and on the tables are countless plastic tubes and boxes with a wide variety of rock cores and rock samples.
Sampling in the core laboratory

Location: Brothers volcano, southern Kermadec Arc; Auckland (NZ) – Auckland (NZ)

Date: May 5, 2018 — July 5, 2018

Funding: IODP

Participants from our group: Lucy Schlicht

Summary: Deep-sea drilling of dacitic rocks that were heavily affected by hydrothermal alteration at the NW Caldera and Upper Cone sites of the Brothers volcano, southern Kermadec Arc. Investigations are used for deeper understanding of hydrothermal activity in arc settings, from petrological, geochemical, geophysical, and microbiological point of views.

Further information about IODP expedition 376

Close-up of sediment sample with volcanic ash and shells.
Sediment with volcanic ash and shells from the Vesicomydae family recovered during the M146 cruise by Van Veen grab.
Map showing the recorded ship route of the research vessel Meteor in the area of Henry Seamount southeast of the Canary Island of El Hierro.
Route of Meteor Cruise M146 to Henry Seamount southeast of El Hierro, Canary Islands

Location: Henry Seamount; Recife (Brazil) – Las Pal­mas (Gran Ca­na­ria, Spa­in)

Date: March 17, 2018 — April 16, 2018

Funding: DFG

Participants from our group: Andreas Klügel

Summary: The R/V MET­EOR-cruise M146 was car­ried out at Henry Seamount, an ex­tinct vol­cano loc­ated ca. 40 km south­east of El Hierro, Ca­nary Is­lands. The ob­ject­ive of this cruise was to dis­cover sites of hy­dro­thermal cir­cu­la­tion of sea­wa­ter, which is glob­ally im­port­ant for cool­ing of the litho­sphere, chem­ical ex­change between crust and ocean, and mar­ine eco­sys­tems. This cir­cu­la­tion re­quires base­ment out­crops that form path­ways through im­per­meable sed­i­ment. Data ac­quired dur­ing pre­vi­ous cruise M66/1 showed that Henry Seamount may provide such out­crops. Our meth­ods to find them in­cluded 1) high-res­ol­u­tion map­ping by AUV; 2) high-res­ol­u­tion seis­mic re­flec­tion pro­fil­ing to sur­vey thick­ness and in­ternal struc­ture of sed­i­ment lay­ers on and around the seamount; 3) de­term­in­a­tion of local heat flows to de­tect heat sinks and sources; 4) TV-sled sur­veys; and 5) local sampling.


Further information about expedition M146 on the MARUM website and in the cruise report

A diving robot on the deck of the research vessel R/V Thomas G. Thompson.
ROV Jason II on board the R/V Thomas G. Thompson
Close-up of a hydrothermal vent sawn open lengthwise from Brothers Volcano. The inside of the black vent glitters yellow-gold.
Sample of hydrothermal vent from Brothers volcano

Location: Brothers volcano; Auckland (New Zealand) – Auckland (New Zealand)

Date: March 6, 2018 — March 26, 2018

Funding: BMBF

Participants from our group: Alexander Diehl

Summary: Cruise TN350 was set out in the course of the preparation of IODP expedition 376 “Brothers arc flux”. Aim of the expedition was to investigate active hydrothermal systems at Brothers caldera, to conduct heatflow measurements and to pre-explore potential drill sites for the upcoming IODP drilling at Brothers volcano. ROV Jason II, operated by the Woodshole Oceanographic Institution, was deployed to recover samples of hydrothermal fluids and precipitates. The fluid sampling was done with isobaric gas tight fluid samplers and the focus was set on the analytics of dissolved volatiles in the hydrothermal fluids. During the expedition multiple samples from various vent sites at Brothers Caldera (NW Caldera site, Caldera Rim, Upper Cone, Lower Cone) were successfully sampled. The samples are used to comprehend existing datasets of hydrothermal fluids from Brothers volcano.

Further information about expedition TN350

The research vessel is moored at the pier of the port of Noumea in New Caledonia, it is cloudy, a palm tree can be seen in the foreground.
R/V Sonne in the port of Noumea (New Caledonia)
The Quest 4000 submersible stands on the deck of the research vessel Sonne.
ROV Quest 400 on board the R/V Sonne

Location: South Kermadec arc; Noumea (New Caledonia) – Auckland (New Zealand)

Date: December 22, 2016 — January 21, 2017

Funding: BMBF

Participants from our group: Wolfgang Bach, Alexander Diehl, Christian Hansen, Stefan Sopke, Janis Thal, Andreas Türke

Summary: The research vessel Sonne visited four hydrothermally active volcanoes (Brothers Caldera, Haungaroa Volcano, Macauley Caldera, Rumble III) in the south Kermadec arc, during expedition SO253. The expedition was set out to investigate how fast hydrothermal plumes disperse in the ocean as hydrothermal solutions mix with seawater. A part of the expedition work was to investigate microbial activities and chemosynthetic communities associated with hydrothermal vents. Furthermore, the main objective was to characterize the physical and chemical circumstances under which the hydrothermal fluids and the associated chemosynthetic communities form. With the help of ROV Quest 4000 (MARUM) we sampled various hydrothermal fluids, hydrothermal precipitates formed from these fluids and volcanic rocks that provided the chemical components for these fluids and precipitates. The samples are used to gain a process understanding of which particular processes are responsible for the unique character of some arc hydrothermal fluids. The investigations of rocks and fluids provide a basis to evaluate how volcanic degassing in the subsurface and phase separation of rising fluids influence the chemical composition of arc hydrothermal solutions.

Further information about expedition SO253

The drilling vessel R/V Joides Resolution in the port of Guam (USA) in sunny weather.
The drilling vessel R/V Joides Resolution in the port of Guam (USA)
On a table on board, plastic half-pipes with rock cores are cut open next to each other.
Drill cores

Location: Yinazao, Asùt Tesoru, and Fantangisña mud volcanoes in the Mariana forearc; Guam (USA) – Hong Kong (People’s Republic of China)

Date: December 08, 2016 — Februar 07, 2017

Funding: IODP

Participants from our group: Elmar Albers

Summary: This expedition to the Mariana forearc in the western Pacific Ocean had the aim to investigate the geochemistry, tectonics, and biology in an active subduction zone. We cored the summits and flanks of three serpentinite mud volcanoes - namely the Yinazao, Asùt Tesoru, and Fantangisña seamounts (formerly known as Blue Moon, Big Blue, and Celestial) - and sampled sediments, rocks, and fluids. These will provide insights into shallow subduction zone processes including, e.g., mass transports and geochemical cycling as well as spatio-temporal variability of subduction-related fluids and water–rock interactions.


Further information about IODP expedition 366

The research vessel Polarstern is moored to an ice floe, the gangway is extended, cruise participants are standing on the ice in red full-body suits in the background, poles with red flags can be seen in the foreground, which have been stuck into the ice every few meters.
R/V Polarstern during an ice station in the area of the Langseth Ridge
It is night. Three men in orange protective clothing and helmets stand on the brightly lit deck of the ship around a dredge that has been lifted on board by the ship's crane and is full of rock samples.
Successful rock sampling using a dredge

Location: Karasik seamount in the Arctic Ocean located at 87°N, 61°E; Tromsø (Norway) – Bremerhaven (Germany)

Date: September 9, 2016 — October 23, 2016


Participants from our group: Elmar Albers, Alexander Diehl

Summary: The destination of this expedition was the region of the more than 4000 m high Karasik seamount, which is one of the highest seamounts of the Arctic Ocean. Extensive ocean floor mapping in the course of this cruise revealed Karasik to be part of the Langseth Ridge that meets the ultraslow spreading Gakkel Ridge at about 87°N and 61°E. Our working group is particularly interested in the origin of the Karasik seamount and the Langseth Ridge. Systematic usage of a dredge and gravity corer brought volcanic and plutonic rock samples to deck, as well as rocks that had their origin in or were altered by hydrothermal activity. Together with seafloor image data acquired by OFOS (Ocean Floor Observation System) and NUI (Nereid Under Ice, an hybrid ROV), we could gain valuable insights into the regional geology. A second focus was on studying a nearby active hydrothermal system in the Gakkel Ridge spreading centre. Here, we sampled fresh and hydrothermally altered rocks and sediments from the seafloor, and took water and particle samples from the hydrothermal plume. Images of inactive hydrothermal vents and seepage sites nearby the presumed location of hydrothermal fluid discharge were provided by OFOS.

Further information about Polarstern expedition PS101

Pilot screen of the Quest submersible during a dive to a vertical wall in the southwest of the Azores Platform. Submarine rock formations and the sampling equipment on the submersible can be seen on the cameras pointed in different directions.
Pilot screen during ROV dive to a vertical wall at Princessa Alice Bank in the southwest of the Azores platform.

Location: Azores Plateau in the Atlantic Ocean; Ponta Delgada (Portugal) – Ponta Delgada (Portugal)

Date: July 2, 2016 — July 24, 2016

Funding: DFG

Participants from our group: Wolfgang Bach, Andreas Klügel, Tom Skambraks

Summary: The overarching goal of cruise M128 with research vessel Meteor was to map and sample the oldest and youngest submarine volcanic edifices of the Azores Plateau in order to improve our understanding of the processes involved in the evolution of large oceanic plateaus. Another focus was on the investigation of the young submarine João de Castro seamount located about 100 km northwest of São Miguel island, where hydrothermal activity has been described in the past, and of Serreta volcano off Terceira island where a submarine eruption occurred between 1998 and 2001. By using the MARUM remotely operated underwater vehicle (ROV) QUEST 4000 equipped with high-resolution cameras and sampling devices several rocks, volcanic glasses and biological samples were recovered from these sites. ROV sampling was complemented by a TV grab, a wax corer and hydroacoustic/bathymetric surveys. Miniature autonomous plume recorders were further used to detect potential hydrothermal vents in the young volcanoes of the research area, which, however, could not be confirmed. Subsequent comprehensive petrological and geochemical analyses of rocks and glassy lavas will provide valuable information on the inner structure of the submarine rifts and on the proposed origin of Azores volcanism by a mantle “wetspot”.

Further information about cruise M128 on the website of GeoZentrum Nordbayern and in the cruise report

Water sampler on the arm of a diving robot sampling a black smoker in the deep sea.
Fluid sampling of a black smoker by the ROV Quest
Two scientists stand behind a table in the laboratory aboard the research vessel and present a sample of a vent of a black smoker from the Logatchev hydrothermal field.
Sample of a hydrothermal vent from the Logatchev hydrothermal field

Location: Logatchev hydrothermal vent field at the Mid-Atlantic Ridge; Fortaleza (Brazil) – Bridgetown (Barbados)

Date: April 19, 2016 — May 21, 2016

Funding: DFG

Participants from our group: Wolfgang Bach

Summary: With a total length of about 20,000 km the Mid-Atlantic Ridge is one of the longest mountain chains on Earth. Located in midst of the Atlantic Ocean ranging from the Arctic to close to the Antarctic, this active spreading ridge hosts many hydrothermal vents where hot (up to 400 °C), methane, hydrogen, and sulfide bearing water provides the basis for a unique and biodiverse ecosystem. The goal of this cruise with the research vessel Meteor was to increase our understanding of the links between geochemical reactions within the seafloor and biological processes at hydrothermal vents. We visited four hydrothermal vent fields located between 12°N and 15°N on the Mid-Atlantic Ridge (Logatchev, Semenov, Irinovskoe, and Ashadze), which differ in seafloor tectonics and basement rock compositions. These differences affect the distribution and composition of hot and diffuse hydrothermal fluids as well as the diversity and distribution of the biological communities. During the cruise, comprehensive sampling of rocks, fluids, and biota was done by the remotely operated vehicle QUEST from MARUM, Bremen. Additionally, a CTD/Rosette sampler equipped with Miniaturized Autonomous Plume Recorders was deployed to analyze the dimensions and the geochemistry of the hydrothermal plumes above the vent fields and to sample their microbial communities. The collected data are analyzed in an integrative manner by an interdisciplinary team of national and international researchers to provide information on the interactions between the lithosphere, hydrosphere and biosphere of hydrothermal vents on the Mid-Atlantic Ridge.

Further information about cruise M126

Location: Oman Ophiolite Complex (northern Oman)

Date: February 9, 2015 — Februar 22, 2015

Funding: DFG

Participants from our group: Wolfgang Bach, Bastian Bieseler, Alexander Diehl, Dario Fußmann, Karin Los, Patrick Monien

The cruise participants stand for a group photo in red full body suits on an ice floe in front of the research vessel Polarstern.
Group photo of the participants of the Polarstern expedition PS86
Aerial view of the research vessel Polarstern in the Arctic. The sea is very calm, the ship is reflected in the water, sea ice can be seen in the background.
R/V Polarstern in the Arctic

Location: Aurora sea mount in the Arctic Ocean at 82°N, 6°W; Tromsø (Norway) - Tromsø (Norway)

Date: July 5, 2014 — August 3, 2014


Participants from our group: Andreas Türke, Alexander Diehl

Summary: The cruise to the Aurora mount aimed at studying hydrothermal activity in the deep Arctic. The Aurora mount is located at the western edge of the ultraslow spreading Gakkel Ridge and is a volcanic structure in 3800 m water depth, elevated by 400 m from the surrounding seafloor. Hot fluids venting from the mount produce a hydrothermal plume, which was sampled intensively for geochemical (dissolved trace metals, methane) and microbiological studies. Furthermore, mapping of the seafloor was carried out by several Ocean Floor Observatory System dives, which were able to obtain several high resolution images of hydrothermal vents.

A rusty building with a tall metallic winding tower in the foreground.
The mine Athens
A hand with a chisel points to a stibnite vein on a rock wall in the mine.

Location: Murchison, South Africa

Date: Mai 5, 2013 — Mai 17, 2013

Funding: BGR

Participants from our group: Nikki Blaauwbroek

Summary: The primary goal of the fieldwork was to collect samples to support the PhD research of Nikki Blaauwbroek, which focuses on the geochemical point of view of the antimony mineralization of the Murchison Greenstone Belt (2.97 Ga), South Africa. The antimony enrichment, mainly found as stibnite (Sb2S3), is focused along the so-called “Antimony Line (AL)” in quartz-carbonate veins. The carbonization of the AL represents a structural and geochemical overprint of the metagranodiorite and metakomatite found along the AL. The close spatial correlation of felsic and ultramafic rocks has been explained by a (back-)arc system from the Archaean, where the granodiorite intruded in the komatiite-rich continental crust by arc-volcanism. The antimony has been successfully mined for over 80 years. At the moment, ConsMurch is mining antimony and gold from four mines: Athens, Beta, Monarch and Gravelotte. The samples have been taken from different locations in relative position of the main ore-“reef”, which is where the highest amount of antimony is found. Major and trace element measurements have been performed with these carbonates, quartz and sulfides as well a stable isotope investigation. Geochemical modeling with the use of Geochemical Workbench will be used as an extra tool to explain this remarkable stibnite enrichment through the desired geochemical point of view. For this study, we closely cooperate with colleagues from the BGR and Freiberg University.

Location: Oman Ophiolite Complex (northern Oman)

Date: February 22, 2013 — March 13, 2013

Funding: DFG

Participants from our group: Wolfgang Bach, Bastian Bieseler, Niels Jöns

Summary: During the field trip to the Oman Ophiolite Complex we sampled diopsidite and rodingites dikes in the mantle sections to detect metasomatic reactions and trace water rock interactions and learn about serpentinisation processes. Additional rocks from the exposed crustal cross-section in the Wadi Gideah were sampled to understand the conditions and history of fluid percolation through fast-spreading oceanic crust.

Map section of the study area showing the vessel's route from Freeport to St. John's via North Pond.
Map section of the survey area of the Merian expedition MSM20/5
Schematic and image of a so-called CORK observatory. A lance with sensors and hoses for fluid sampling is cemented into a drill hole in the deep sea. Next to the lance on the seafloor is a metal rack with various measuring instruments.
Schematic and image of a CORK observatory on the seafloor

Location: Western flank of mid-Atlantic Ridge at 23°N, 46°W; Freeport (Bahamas) - St. John's (Canada)

Date: April 11, 2012 — May 10, 2012

Funding: DFG & BMBF

Participants from our group: Wolfgang Bach, Janis Thal

Summary: The research cruise is part of a larger international effort to investigate the origin and nature of microbial communities within basaltic basement below an isolated sediment "pond" located on 7–8 Ma seafloor on the western flank of the Mid-Atlantic Ridge at 23°N. The cornerstone of the program is a transect of borehole “CORKed” microbial observatories being designed to allow long-term (decadal), manipulative, community-based experiments, observations, and sampling. The primary goal of the cruise is the deployment and recovery of seafloor instrument packages on each of the three borehole observatories post drilling and to sample borehole fluids. We also plan to conduct ROV-based sediment sampling and heat flow measurements as well as mapping and rock sampling up the basement outcrops surrounding North Pond. These operations are critical to the success of the larger program aimed at studying the basalt-hosted biosphere. These studies will document and elucidate microbial community composition harbored within a young ridge flank, assess the role of microbes in the weathering of oceanic crust, and quantify relations between crustal hydrogeology and microbial community development. We closely cooperate with colleagues from the US, who have secured complete funding for building all of the borehole and wellhead instruments.

The drilling vessel R/V Joides Resolution in port, the sun is shining, it is slightly cloudy.
The drilling vessel R/V Joides Resolution
On deck, two ship's workers in red work suits, white helmets and safety goggles guide a drill head attached to a steel pipe through the ship's moon pool.
A new drill head is lowered through the moon pool of the ship

Location: Western flank of mid-Atlantic Ridge at 23°N, 46°W

Date: September 15, 2011 — November 16, 2011

Funding: IODP

Participants from our group: Wolfgang Bach

Summary: Installations of subseafloor observatories for monitoring fluid flow, geochemical exchange, and microbial activity were the primary focus of the cruise. Basalt and sediment cores were also retrieved and are currently studied in terms of linked microbial and geochemical processes.

Further information about IODP expedition 336

View from the ship to a green volcano chain.
View of the illuminated working deck of the research vessel Sonne at sunset.

Location: Eastern Manus Basin (Papua New Guinea); Townsville - Madang - Makassar

Date: June 14, 2011 — July 23, 2011

Funding: BMBF

Participants from our group: Wolfgang Bach, Niels Jöns, Eorghan Reeves, Liping Shu, Janis Thal

Summary: The expedition with R/VSONNE to the eastern Manus Basin of Papua New Guinea is aimed at sampling fluids, rocks and biota from hydrothermal systems in a back-arc environment. Furthermore, detailed bathymetric mapping has been undertaken.

Further information about expedition SO216

Example of pillow lava in Oman.
Pillow lava in Oman
View of a valley lined with palm trees and surrounded on the left and right by red-colored, bare mountain slopes.

Location: Oman Ophiolite Complex (northern Oman)

Date: February 14, 2011 — February 25, 2011

Participants from our group: Wolfgang Bach, Bastian Bieseler, Niels Jöns

Summary: During the field trip to the Oman Ophiolite Complex we sampled hydrothermally overprinted rocks from the exposed crustal cross-section to better understand the conditions and history of fluid through fast-spreading oceanic crust.