Ulrich Schwarz-Schampera, Project Manager „Exploration Polymetallic Sulphides“ and Chief Scientist of the cruise INDEX 2016, here with a sample from 2,400 m depth Source: BGR

Ulrich Schwarz-Schampera, Project Manager „Exploration Polymetallic Sulphides“ and Chief Scientist of the cruise INDEX 2016:

After four years of preliminary work, the BGR has acquired an exploration area in the Indian Ocean for the Federal Republic of Germany. What does this mean?
The cruise INDEX 2016 is already the second exploration cruise after the signature of the license contract in May 2015. Since last May, the 15-year contract with the International Seabed Authority (ISA) in Kingston/Jamaica, has been in force. The contract with this international organization with 166 member states provides for the exploration of the seafloor for ore deposits of so important metals like copper, zinc, lead, gold and silver as well as economically strategic metals like indium, tellurium, selenium, germanium, gallium and antimony. Our activities during the next years will be focused on the prospection of these deposits and the assessment of their size and distribution.

Do environmental aspects play an important part in your search?
Environmental tasks are a substantial part of the exploration license. These tasks are compulsory and account for more than 50 % of the work and financial expenses. Occurrence and distribution of marine creatures, their dependence on vents on the so-called Black Smokers and the general biodiversity on oceanic spreading centers as well as in their surroundings and in the water column are substantial parts of our work. Our work is supported by a number of scientific centers and universities like the German Center for Marine Research on Biodiversity in Wilhelmshaven, the University of Hamburg and Jacobs University in Bremen. The high intensity of this work leads to fundamental progress in marine environmental research, which would not be possible without the license work.

Which tasks are planned for the present cruise INDEX 2016?
During our work, we already found quite a number of new inactive sulfide fields. Such systems have extinguished naturally, the metal accumulation is completed and the place no longer offers a living environment for hydrothermal creatures. These places are in the focus of our interest and during INDEX 2016, further areas with a potential for the occurrence of inactive sulfide accumulations will be tested. At the same time, the marine fauna in these areas will be tested and sampled in order to examine and document the biodiversity from microbes to the megafauna. In this task we get assistance from the French deep sea diving robot VICTOR for a detailed and small-scale sampling. Our research vessel, the N/O POURQUOI PAS? from the French marine research center IFREMER in Brest, France, is very well equipped for our tasks and offers excellent laboratories for scientific work.

Udo Barckhausen und Bernd Schreckenberger hauling in the magnetometer array Source: BGR

Udo Barckhausen, Ingo Heyde, Bernd Schreckenberger:

What can we find out about polymetallic sulfides on the seafloor using magnetic measurements?

The seafloor consists most predominantly of basaltic rock which has a relatively high content of magnetic minerals and therefore also a pronounced magnetic signature. In places where, for a longer time, hot water has been flowing through the rock (the so-called hydrothermalism), the basalt is chemically altered, and especially the magnetic minerals are changed in a way that they lose their ferromagnetic properties. Magnetic measurements can identify the hydrothermally altered rock parts, because they are usually revealed by a weakened magnetic field. As the formation of polymetallic sulfides at the seafloor takes place in direct connection with hydrothermalism, the magnetic anomalies of the altered basalts are an indirect hint to possible deposits.

Which measurements can by carried out especially well with the 'Pourquoi Pas?'?

The 'Pourquoi Pas?' is outstandingly well equipped for the use of the ROV Victor 6000. It can not only be used for the sampling of rocks, fluids etc. but can alternatively be equipped with a so-called bathymetry module. This consists for the main part of a multibeam echo sounding system for high-resolution seafloor mapping. This module, we enhanced with our Fluxgate gradiometer system for a high-resolution magnetic survey of the seafloor. Thus, we obtained data from a surface of 1.5 km x 3.3 km in the extended area of the Kairei hydrothermal field in a constant distance of 50 m above ground. In combination with the bathymetry, this is a unique data set furnishing a high-precision map of the magnetic field in this ridge area. The interpretation of the measured magnetic minima and maxima regarding volcanic structures, but especially active and inactive sulfide occurrences will be extremely exciting. First of all, however, the magnetic field data will have to be processed, in order, for example, to eliminate the magnetic disturbance of the ROV itself.
At a water depth of 2,500 to 3,000 meters, this resolution cannot be achieved with sensors towed close to the ocean surface. It must be noted as well that the magnetic field of a mass anomaly decays, with increasing distance, very quickly at 1/d³. This shows the possibilities of measurements, that are carried out close the magnetic sources.

What kind of magnetometer is used on the cruise INDEX 2016?

Altogether, we use four magnetometer systems, sometimes at the same time. Traditional standard for geophysical measurements is the gradient magnetometer that is towed about 600 m behind the ship. It consists of two high-precision scalar magnetometers that are 150 m apart and measure only the strength of the magnetic field. The difference between the readings allows to eliminate the frequent disturbances of the magnetic field that have their origin in streams caused by the sun in the earth’s higher atmosphere.
Also integrated into the towed system is a magnetometer, that additionally measures the vector components of the field, that means, how strong the field is in driving direction, horizontally to it respectively in the northern and eastern direction and in the Z-direction, i. e. upwards and downwards. Thus, we gain additional information on magnetic bodies under the seafloor, as, for example, their orientation.
Of course there is a reason for the fact that these systems are towed with considerable effort at a distance of some ship’s lengths behind the vessel: it is important to get away from the big iron mass of the ship that disturbs the magnetic measurements significantly.
Quite in contrast to this principle, two identically constructed vector magnetometers are mounted on the compass deck of the ship which perform non-stop recordings throughout the whole cruise. The interpretation is more difficult and not that exact but not impossible and offers also advantages towards the towed system.

Last but not least we still have two vector magnetometers incorporated into a titanium casing which is pressure-resistant down to 6,000 meters water depth. On the cruise INDEX 2016, this system is attached to the ROV Victor and measures the magnetic field about 50 m above ground. So far, this technology has not often been applied, but it offers great possibilities and is the only way to survey small-scale magnetic bodies like, for example, sulfide fields, in greater water depths.

Gravimetry

What can we find out on polymetallic sulfides on the seafloor using gravimetric measurements?

Ship-based gravity data allow, especially by means of density modeling, statements on variations in the structural build-up of the oceanic crust. Thus, areas can be identified where the oceanic crust is especially thick or also especially thin. This allows conclusions on the possible formation of polymetallic sulfides in the respective area. In water-depths of more than 4,000 m, however, the spatial resolution is very limited and statements on single fields is not possible. For that purpose, gravimetric measurements would have to be carried out directly at the seafloor or closely above ground, for example with an AUV (Autonomous Underwater Vehicle).

Which gravimeters were used on the cruise INDEX 2016?

We have installed BGR’s sea gravimeter system KSS32M, built by the firm BGGS in Meersburg, close to the ship’s center on a pedestal especially designed for this purpose. It is a scalar gravimeter, which means, we only measure the vertical component of the gravity acceleration. For that purpose, the gravity sensor is installed on a gyro stabilized platform, which ensures the dynamic levelling. The ship’s own, older KSS31 system is set up very close-by, it includes not only a gyro table and a gravity sensor but also a well-equipped electronic rack for supply and steering of the system. The parallel measurements enlarge the database and allow the comparison of both systems regarding data quality.

Michelle DeWolfe and Harold Gibson, Mount Royal University in Calgary, Canada Source: BGR

Answers with Michelle DeWolfe

Who are you? What do you do?
I am an associate professor in the Earth and Environmental Science Department at Mount Royal University in Calgary, Canada. I have over 15 years of mapping experience in the Canadian Shield where my research has largely focused on ancient submarine volcanic successions hosting massive sulfide deposits. In particular my work focuses on reconstructing the volcanic environment in which massive sulfide deposits formed, including interpreting the volcanic and structural controls on mineralization.

Why are you here, on this cruise?
I was invited on Leg 1 INDEX2013, which was my introduction to research in modern seafloor settings, but there was no ROV on that cruise, and so I was very limited in what I could add to the volcanology of the project. This time around I am well pleased to be a part of a team (with Harold Gibson) that will create a seafloor map based on high definition video observation from the ROV. I am very excited at the opportunity to do this mapping, to transfer my expertise in mapping ancient deposits to the modern seafloor, and then of course, to use what I learn about the modern seafloor and apply that understanding to my research on ancient examples. I think I am in a unique and privileged position in the world to be able to study both modern and ancient volcanic-hosted massive sulfide deposits.

What will you contribute to BGR's INDEX project?
Together with Dr. Gibson we will create a detailed map of the seafloor at each study site showing the various lithologies, lithofacies and structures observed through study of the high definition video recorded by the ROV. We will map by hand on paper maps containing the bathymetry of the area as the ROV dive is in progress. When the cruise is done, our data will be digitized, joined with similar volcanological data obtained on previous cruises (on which Harold Gibson participated), and draped over the bathymetry for each study site. This will result in a detailed geological map of the seafloor for each study site, and a much improved understanding of the volcanological and structural controls on the massive sulfide deposits, which in turn will provide new and useful information that can be used in exploring for more seafloor massive sulfides.

Terue Kihara, Klaas Gerdes and Katharina Kniesz from the institute „Senckenberg at the Sea“ in Wilhelmshaven (DZMB) in the lab, Katharina Kniesz also belongs to Hamburg University Source: BGR

Which animals do occur on the Black Smokers?

Katharina Kniesz:
Amazingly, in this very special environment, there is a considerably high diversity of species. The occurrence of the particular species is clearly divided into individual zones. If we move towards an active hydrothermal field, we find at first the mainly white sea anemones. According to our knowledge, they can also count as indicators for a hydrothermal field. They occur at a distance of up to 100 meters around a hydrothermal field.
Closely below the smoker, the so-called transition zone begins, where we find mussels, snails, bristleworms, flatworms, different crabs and fish associated with hydrothermal fields.
The possibly most important animals on the black smokers are the deepwater shrimps. They are virtually the primary producers in this place, they occur in very high numbers and sit directly on the smokers.
Many of the animals on the Black Smokers show deviations from species known from other areas. So, for example, the “scaly foot snail”, which has developed a hard, scaly foot by embedding iron sulfide as a protection against the harsh environment. Others live in a symbiosis with sulfide oxidizing bacteria and carry them under their mantle, like the mussel Bathymodius and the shrimp Rimicaris. And also not to forget: the very small organisms, the meiofauna, which we will sample too on the INDEX 2016 cruise.

What do the animals on the Black Smokers feed on?

Klaas Gerdes:
All animals we find on the Black Smokers depend on bacteria. These live freely on the surface of the chimneys on the sulfides, but also in symbiosis with the higher organisms. This symbiosis we find, amongst others, between sulfide oxidizing bacteria and hydrothermal shrimps Rimicaris kairei or the mussel Bathymodiolus marisindicus. The shrimps have an especially broad head (Carapax), containing a kind of garden or breeding place for bacteria. The shrimps feed on these bacteria, while the bacteria, in return, get carried by the shrimps close enough to the fluids, where they find hydrogen sulfide which is essential for their reproduction. The mussels carry these symbiotic bacteria on the surface of their gills. Besides these examples, there are other animals that live in symbiosis.
The shrimps are the primary producers in this ecosystem, all other animals living in this area directly or indirectly feed on them.
All other organisms, above all the eye-catching anemones and crabs feed on the shrimps. Many snails and bristleworms, however, eat the exoskeletons of the shrimps and other so-called detritus. Smaller animals also eat directly the bacteria living on the surface of the sulfides.

How do the animals survive at these high temperatures?

Terue Kihara:
Most of the animals within the hydrothermal vent fields are living in a temperature regime of 2°C, which is the ambient temperature in the deep sea in this area. Therefore many hydrothermal animals like anemones, barnacles, polychaetes and many more that do not live close to the active chimney complexes never have to deal with high temperatures at all. Only in areas of diffuse venting or directly at the orifices the temperature is rising. The fluids from the chimneys at hydrothermal vent fields can exceed even 380°C. But the sea water is conducting heat very fast and only a few centimeters apart from the exiting fluids the temperatures are decreasing to less than 100°C.
Therefore the animals do not have to deal with very high temperatures but rather with low oxygen levels and the toxicity of the fluid. The anemones for example are found in up to 20°C. Crabs and mussels have their range between 2°C and 20°C likewise. The hydrothermal shrimps, which occur closest to the chimney exits are found in seawater with temperatures reaching up to 40°C. Occasionally the animals are exposed to higher temperatures. To avoid being cooked alive some animals have modifications in their membranes and enzymes to resist higher fluctuations.

“Plume Hunter” Gary J. Massoth in front of the CTD-sled Source: BGR

Gary J. Massoth:

Why am I out here on the Indian Ocean?
I am here to assist BGR in focusing their exploration for active venting sites. The idea is that active venting sites will be associated with inactive metal sulfide deposits acceptable for marine mining in the future.

What specifically so I do onboard?
I am responsible for towing the CTD sledge over prospective seafloor segments to provide the first detection of active venting in the immediate area. This detection is then used to guide more resolving seafloor tools (such as the HomeSide system, towed cameras, ROVs) for most efficient discovery and characterization of metal sulfide deposits on the seafloor.

Why me?
I have 36 years of experience in plume hunting, starting only one year after the first high-temperature vents were discovered on the East Pacific Rise in 1979. I helped to develop the plume reconnaissance techniques employed world-wide today in the search for venting sites. I selected and help acquire the very newest and best tools for BGR to use for this regard.

More about Hydrothermal Plumes

Source: Gary J. Massoth

Our four ISA-trainees from left to right: Helen Wong, Emmanuel Quayson, Yanina Berbeglia and Mohamed Hassan Source: BGR

The four ISA-trainees introduce themselves:

WONG PEI SAN HELEN
I am a Research Assistant from Tropical Marine Science Institute and Keppel-NUS Corporate Laboratory, National University of Singapore. My project is to study the macrofauna composition within the Ocean Mineral Singapore claim site at Clarion-Clipperton fracture zone.
I am invited by the Federal Institute for Geosciences and Natural Resources (BGR), Hannover for this trainee program to survey the West Indian Ocean. My interest is to learn the survey method and equipment used for the study of the biodiversity in this area.

EMMANUEL QUAYSON
Emmanuel is a Mineral Engineering Graduate from the University of Mines and Technology in Ghana and is currently working on a collaborative research with the Organization of Advanced Science and Technology at Kobe University, Japan. His experience has been with mining on land in Ghana where his role has been at the exploitation stages of mining.
As an ISA trainee in this cruise, I look forward to understanding the mineralogy of the ores by working with geologists on board using ore microscopy procedures. It has been an exciting experience so far and look forward to having the best out it.

MOHAMED HASSAN
I am an Assistant Researcher at Marine Pollution Lab. in the National Institute of Oceanography and Fisheries, Alexandria, Egypt. I am here as one of the International Seabed Authority (ISA) trainees invited by the Federal Institute for Geosciences and Natural Resources (BGR) to participate in INDEX 2016 cruise.
My area of interest is monitoring and assessment of organic and inorganic pollutants in marine and fresh waters and during this cruise I am involved in water sampling and analysis activities using CTD and also KIPS system from hydrothermal vent areas. However, I am very grateful for all BGR staff and my ISA colleagues that give me a great opportunity to be here.

YANINA BERBEGLIA
An Argentine geologist from the Buenos Aires University. She works at the Argentine National Commission of the Outer Limit of the Continental Shelf, where she studies the geomorphological, geological and geophysical aspects of the Argentine continental shelf and the deep sea, in particular the evolution of the passive volcanic margins and the different features identified between the continental and the oceanic crust.
On this cruise, she is here as an ISA trainee and she expects to get a better understanding on how the polymetallic sulfides are formed and the environment in which they develop, and to learn how a survey in this type of area is done and all the different aspects that have to be studied.

Dieter Garbe-Schönberg in front of the ROV – on the left-hand side, the KIPS is fastened to the ROV Source: BGR

Dieter Garbe-Schönberg (Geochemist), Christian Albrechts University Kiel, Germany:

What are my fields of research?

For many years I have been interested in hydrothermal systems in the seafloor where water with temperatures of more than 400°C is circulating. This “fluid” dissolves materials from the oceanic crust, transports them along fissures and other pathways upwards to the seafloor where the dissolved metals and other compounds are subsequently released into the ocean or are deposited as sulfide ores after getting mixed with cold seawater. Most visible indicator for this discharge of fluids are Black Smokers – “chimneys” built of copper-rich sulfide ores. These fluids carrying micronutrients and fuel for chemosynthetic life also provide the basis for real oases of complex life communities consisting of bacteria, mussels, sea anemones, crabs, shrimps and others, as well as innumerable microorganisms with many still unknown species. I determine the chemical composition of these fluids in order to explore the local physico-chemical conditions of the hydrothermal system governing the interaction of hot fluids with host rocks and their capability of dissolving and transporting metals. At the same time we learn which of the dissolved metals are deposited in situ as solid sulfide ores and which are dispersed widely into the marine environment where they also serve as (micro-) nutrients.

What am I doing here on 'N/O Pourquoi Pas?'?

My participation in the cruise INDEX 2016 is within the framework of a contract with the BGR. For sampling seawater and very hot “fluids” directly from Black Smokers in the deep sea I have developed the “KIPS” fluid sampling system for underwater robots (ROV) which is used here during the INDEX expedition. The fluid samples are checked here in the on-board laboratory for acidity (pH) and salinity and then preserved for subsequent analysis in my laboratory at Kiel University. We will determine concentrations of many major, minor and trace elements and other compounds. Our hottest fluid up to now had a temperature of 418°C – world record! – and it showed a much higher salinity than “normal” sea water.

What are for me the highlights of this cruise?

These expeditions are amongst the most beautiful experiences in my professional life because here, in the confined surroundings of a research vessel, scientists from many countries and very different research organizations work on a common topic. This is an extremely creative environment with much intensive exchange between the different disciplines but also between young and old. On this cruise, structural geology, volcanology, geology of mineral deposits, geophysics, geochemistry, oceanography, biology and microbiology are represented and the cruise members come from eight different countries. So we have quite a lot of topics for conversation. For me, the special appeal of this INDEX cruise lies in the fact that we work in the deep sea and discover new things that no one has seen before. The work with underwater robots like VICTOR and its crew has its own special charm because you really witness the discoveries “live”. I will never get tired of watching the bizarre underwater landscapes and the densely populated Black Smokers swarming lively with animals.

The ship’s doctor Torsten Jänisch from Hannover Medical University Source: BGR

The ship’s doctor Torsten Jänisch from Hannover Medical University talks about his job on board:

On a cruise like INDEX 2016, why do we have a doctor on board the research vessel?

To put it simple: for a feeling of safety – but that would be too easy!
The assistance a doctor can render on such a cruise depends very much on the available medical equipment and on the competence of the doctor.

In the case of a serious accident a well-trained and experienced surgeon is the best solution in order to save lives and minimize secondary damages. His possibilities, however, are restricted by limited medical equipment: no anesthesia unit, no monitoring of blood pressure, pulse, respiration, no electrocardiogram, no blood tests and no X-ray examinations.

On the other hand, for the everyday medical problems that might arise on a longer research cruise, a generalist with a practical knowledge of all fields of medicine (ophthalmology, surgery, otolaryngology, gynecology, urology, internal medicine and dentistry) might be more helpful.

Regarding the medical equipment, the cruises at the end of 2015 and at the beginning of 2016 could not have been more different. On the PELAGIA (Dutch research vessel with a length of 66 m), there was no “on board hospital”, only a medical locker and oxygen supply in the first mate’s cabin. On the Pourquoi Pas? (French research vessel with a length of 107 m), there is an on board hospital with op lighting, autoclave and two hospital beds.

But on both ships, the problems are the same. On both cruises, there was one patient who should, on principle, not have been on board because he had already been ill before. In the first case, a patient with an unfinished root canal treatment which incurred a three-weeks’ intensive antibiotic therapy in order to avoid an impending operation of the tooth (the doctor had packed his own dental equipment).

In the second case, a protracted otitis, that could be controlled by repeated ear syringing and the application of several very different medicaments not designed for this purpose.

For the rest, the tasks were limited to the treatment of smaller scratches and bruises, colds, sea sickness and circulatory problems.

Daniela Zoch (BGR) and Nicole Adam (Hamburg University) taking samples from a sediment core in the cold storage room Source: BGR

Daniela Zoch, technical employee at the BGR in the division “Geochemistry of Natural Resources”, working group geomicrobiology. The working group geomicrobiology takes part in the INDEX project with microbiological cell count examinations.

Nicole Adam, Ph. D. student in the working group “Molecular biology of microbial consortia” of Jun. Prof. Dr. Mirjam Perner at the University of Hamburg. Our working group carries out microbial examinations of active and inactive hydrothermal fields on behalf of BGR in the framework of BGR’s INDEX project.

Important questions are:

Can bacteria survive at the seafloor?

Bacteria can be found almost everywhere on earth. They populate very different living environments, so-called habitats, including those, that seem hostile to life. Also in hydrothermal deep sea vents they are to be found. Here, certain species are responsible for the production of biomass. From simple carbon compounds like, for example, carbon dioxide, they can create organic material. Instead of light, they need chemical energy for this process. This ability makes them the basis of complex eco systems in the otherwise sparsely inhabited deep sea. The microorganisms can satisfy their energy demand by gaining electrons from reduced inorganic compounds like, for example, hydrogen or hydrogen sulfide that occur in great quantity and variety in hydrothermal deep sea vents.

With which conditions bacteria have to cope in metal-rich fluids?

A life in a hydrothermally influenced deep sea environment offers very extreme living conditions for the creatures inhabiting this area: They have to cope with very different temperatures (hot fluids with temperatures of up to 400°C, surrounding sea water with a temperature of 2°C), pressure is very high in depths of more than 3,000 meters and zones with and without available oxygen mingle sometimes. It is not surprising, therefore, that the microorganisms living in this environment sometimes show highly specialized ways of metabolism and quite a number of adaptions in their “lifestyle”. Besides the question which microorganisms are to be found in active hydrothermal systems in the Indian Ocean and which functions they have, we, in the framework of the INDEX project, also want to know which microorganisms live in inactive fields and what are the differences between the populations of active and inactive fields.

How is the sampling done, which laboratory work is planned?

In order to examine the different microbiological communities, with the help of the ROV VICTOR samples of fluids, chimneys, rocks and sediments are collected, which afterwards are prepared on board the Pourquoi Pas? for further treatment in Hamburg and Hannover. In order to examine the genome of the microorganisms, samples for DNA extraction are gained. We try, however, already on board, to cultivate resp. enrich the microorganisms in different media of seawater. Additionally, samples are collected that will later on allow an overall cell count of the microorganisms. For this purpose, the samples get “fixed” at first, so that the cells will not be damaged on the long journey, but also to prevent further growth.

Ann Noowong examines a sample of water with an electronic measuring instrument Source: BGR

Ann Noowong (PhD student in geochemistry at Jacobs University Bremen)

What I am working on?
Within the scope of a contract with the BGR, my duty is to investigate the bioavailability of metals in hydrothermal ecosystems in the BGR license area, namely the active Kairei and Pelagia vent fields.

Why is it important to investigate bioavailability of metals and trace elements in hydrothermal environments before any possible future deep sea mining activities?
Hydrothermal vents are one of the major sources of metals and trace elements in the deep ocean. When the water re-emerges and discharges as a hydrothermal fluid, the oxidation of reduced elements provides chemical energy for large communities of sub-surface and benthic microbes, which go on to feed vent-endemic ecosystems. Deep sea hydrothermal vents have high vent-specific biomass despite offering extreme environmental conditions to their inhabitants, such as high temperature, low oxygen, low pH, high pressure, high reducing gas content, absence of light and high concentrations of metals.
Metals and trace elements such as iron, copper, manganese, molybdenum and vanadium are essential for normal growth and development of living organisms but some of these elements can also be toxic when they are found in high concentrations (e.g. copper and manganese). Mobility, toxicity and bioavailability of these metals depend not only on the concentration but also on the form in which metals exist in hydrothermal environments and how much of it can be incorporated in vent organisms.

How does this project enhance our understanding in the hydrothermal environment and the impact of metals on microbes and animals?
The aim of the contract is to deliver a study report which includes the results of metal speciation data (from the hydrothermal source up to the mixing zones) and some potentially toxic metal contents in vent organisms that occur naturally. This data will give us a vivid idea about how hydrothermal vent animals can cope with this stress in natural conditions. This will also lead to a better understanding of whether future deep sea mining activities would have any effects on metal bioavailability or if they would increase metal stress to vent ecosystems. The study will be an important investigation for a better interpretation about the possible consequences of the future mining.

The photo shows from left to right Christian Wöhrl, Simone Sturm and Malte Junge (all BGR) taking samples from a sediment core Source: BGR

My name is Malte Junge.

I work for the BGR in the working group on geology of mineral deposits.
As a geologist, I am occupied with the examination of rocks, ores and sediments. During the exploration cruise INDEX-2016, the underwater robot “VICTOR” systematically samples rocks, ores and sediments from different parts of the German license area. This happens in active as well as in inactive areas of the hydrothermal fields and also in their closer surroundings.
The first treatment is already done on board: for an easier examination, the rock and ore samples are cut and documented by Simone Sturm. The subsequent geological and mineralogical description on board supplies first findings on the ores and rocks and helps directly with the further exploration.
The further detailed geological and mineralogical examination is done after the cruise in the BGR labs. With the help of different analytical methods, information on metal enrichments of copper, zinc and lead and other valuable trace elements is gained.
Among this analytical equipment is the electron probe micro analyzer that allows to gain data on the distribution of trace elements at the micrometer scale.
Since only a few months, BGR owns an ultra-modern electron probe micro analyzer which is unique worldwide in its configuration.
In co-operation with Christian Wöhrl, this work is done at the BGR.
Besides the electron probe micro analyzer, several other analytical methods are applied on the rocks, ores and sediments, supplying information on environmental aspects, but also on the ores’ metal content and the geological formation of the volcanic rocks.
Thus, the systematic sampling of rocks, ores and sediments during the exploration cruise contributes substantially to our understanding of ore formation and the temporal development of hydrothermal systems and allows therefore statements on metal enrichments and an economic usability of the ore deposits.
Furthermore, the acquired knowledge helps to better understand the formation of similar onshore deposit types.

Source: BGR

Hans-Peter Damian

I am working for the Federal Environment Agency, in the section for the protection of the marine environment. In the context of my work in this field, I am also concerned with the environmental impacts of (possible) future marine mining.

The Federal Environment Agency was involved in the procedure for the application for a license for the exploration of the seafloor for ore deposits in the Indian Ocean. This procedure was conducted very transparently by the applying authority, the Federal Institute for Geosciences and Natural Resources (BGR). For the BGR, it is an important concern to maintain this transparency also during the exploration phase. This resulted in the idea, to allow a member of the Federal Environment Agency to take part in one of the exploration cruises into the Indian Ocean.

Here on board, I have the opportunity to get to know the fascinating world of the hydrothermal fields in many different ways. The formation history of the fields is as impressive as the ecology, the great variety of shapes and the beauty of the animals living there.

(from left to right) Wilhelm Weinrebe (GEOMAR), Kai Schumann (BGR) and Ralf Freitag (BGR) Source: BGR

How do you collect information about the seafloor?

The surface structures of the seafloor are presented on bathymetric maps. In order to create these maps, we use multibeam echo sounders. They are integrated into the ship’s hull and emit acoustic signals. In a directional sound fan, the acoustic waves propagate down to the seafloor and are reflected back to the ship. A receiver which is also integrated into the ship’s hull, measures the travel time of the sound waves to the seafloor and back. Depending on the water depth, a swath of several kilometers’ width can be mapped. As only acoustic waves can penetrate the water in these depths, one could say, we hear the depth.

What happens with the depth information?

In order to map a region more precisely, several swaths are combined in a map. This is done with the help of special software that allows us to process the collected echo sounding data. Erroneous data are deleted and as a result, three-dimensional maps of the seafloor are created that form the basis for all further work in the license area.

In a geoinformation system, all obtained data from the different applied methods are collected and the use of equipment is documented in detail. So, a comprehensive database is created, that grows with every cruise and gets more extensive information. In the geoinformation system, the collected data can be arranged, combined and merged as necessary. This knowledge helps us to find possible exploration targets. For the planning of the work on site, detailed maps are indispensable. Contour maps, for example, are needed for the deployments of the ROV. With the help of these maps, pilots know, what structures they fly to. Scientists need these maps for detailed geological mapping during the ROV dives. The geotagged data are added to the database and help with the structural interpretation of the mapped regions, thus leading to a better understanding of the geology and subsequently to an easier detection of hydrothermal fields. This comprehensive database is not only used for cruise planning but also helps BGR with the interpretation of the cruises and of the performed work as well as with the reporting, for example towards the International Seabed Authority.

Who belongs to the bathymetry team?

During the INDEX 2016 cruise, there are three of us. The members of the team are:

Wilhelm Weinrebe, freelance geophysicist from Kiel. With his many years of work in marine research, he contributes a great deal of experience. During this cruise, he is mainly occupied with the interpretation of so-called water column data. Water column data are also recorded by echo sounder systems and show reflections in the water column. These can be caused by plankton or shoals but also by bigger fish. The interpretation of these data helps us to answer questions on environmental aspects.

Ralf Freitag, structural geologist at the BGR. On board, Ralf Freitag is mainly occupied with the processing of the comprehensive bathymetric data. During this four-week cruise, enormous quantities of data are collected that have to be processed. Some erroneous data can be eliminated with the help of filters. During the INDEX project, we are working in an area with a somewhat pronounced relief and as we want to see single Black Smokers for detailed mapping with the ROV, many data have to be corrected manually. This requires a well-trained eye and much experience.

Kai Schumann, geologist at the BGR, is responsible for the maintenance of the geoinformation system on board. All data have to be added to the geoinformation system directly on board, because many operations build up on each other. Information must be presented quickly and be ready for the planning of the next operations. The preparation and post-processing of the operations and the processing inside the geoinformation system requires a very good knowledge about the respective programs.