EU network of mesocosms facilities for research on marine and freshwater ecosystems open for global collaboration.

KOB (Kiel-Outdoor-Benthocosms)

Impact of sporadic upwelling on structure and functioning of benthic communities. Project lead: Martin Wahl. 01 April – 30 October 2018.

The BENTHOCOSMS are open for user approve to AQUACOSM Transnational Access to participate in running experiment from April through October.

KOB project in 2018:

Rationale: Wind and upwelling regimes will shift in the course of Global Change. In addition, in the wake of ongoing warming (intensifying stratification) and eutrophication the difference between surface water and upwelled bottom water will become more extreme with regard to temperature, nutrients, salinity, pH and oxygen.

Research Topic: We will examine the impact of sporadic upwelling on community structure, biotic interactions and ecosystem functioning.

Approach: To this end the 12 KOB are complemented with 12 pelagic mesocosms floating alongside the KOB and having a volume of ca 3 m³ each. Communities included will be a natural inoculum of spring plankton, sediment cores and a macrophyte community composed (initially) of Fucus vesiculosus, Fucus serratus and co-occurring species (snails, gammarids, isopods, mussels etc.) in natural proportions. The experimental unit composed of interconnected sediment community, macroalgal community and plankton community will be replicated six-fold.

The treatment consists of one triggered upwelling of bottom water per month via an existing deep water pipe of 2-3 days duration in half of the tanks. This bottom water will be similar to surface water in spring, have increased nutrients and salinity and lower temperature in summer and, additionally, reduced oxygen and pH in autumn.

Response variables assessed will be, inter alia, individual performance (e.g. growth reproduction), shifts in competitive and trophic interactions, changes in community composition and shifts in community services.

Additionally, own ideas of the visiting researchers may be incorporated.

Any expertise of users is welcome. We specifically encourage experts in stress physiology of algae, sea grass, and invertebrates to join the experiment. We welcome the input of visiting researchers for the customization and optimization of the experimental design.

For additional information contact Martin Wahl (Please login or register to view contact information.)

Application deadline is Oct 6, 2017.

Procedural information at (

A total of 135 person-days is allocated to external users through AQUACOSM Transnational Access provision in 2018. An average of 3 persons for 45 days is envisaged each year. We can accommodate up to 5 external users at a time.

KOB (Kiel-Outdoor-Benthocosms)
Legal name of organisation
GEOMAR-Helmholtz Center for Ocean Research
Organisation address

GEOMAR-Helmholtz Center for Ocean Research

West shore campus
Düsternbrooker Weg 20
D-24105 Kiel

East shore campus
Wischhofstr. 1-3
D-24148 Kiel

Primary contact information (PI)

Professor Martin Wahl (KOB)

Please login or register to view contact information.
Years of Mesocosm Experiments
Description of Facility

off-shore/outdoor/indoor – pelagic/benthic – marine/brackish

Kiel Outdoor Benthocosms – KOB
outdoor – benthic – marine/brackish
Floating infrastructure consisting of sub-dividable 3500 liter tanks, optionally covered by a fully translucent hood. When the system works in a flow-through mode all in situ fluctuations are admitted to the tanks and experimental treatments represent controlled deviations (delta-treatments) from this naturally fluctuating baseline

Controlled Parameters

KOB: CO2, temperature, irradiation, nutrients, oxygen, salinity

Research Topics

KOB: responses of benthic communities to environmental shifts/fluctuations in temperature, pH, pCO2, oxygen, nutrients, salinity

Facility location(s)
Primary interests
Specialist areas
Source of Information
Photos of experiments/installations
KOB – Kiel Outdoor Benthocosms (Photo: Martin Wahl)
KOB – Kiel Outdoor Benthocosms (Photo: Mark Lenz)


Infrastructure (short name)
KOB (Kiel-Outdoor-Benthocosms)
Installation (short name)

Kiel, Germany

Coordinates / (routes, areas if non-static)
Water / environmental conditions
Depths / bottom / surface

The GEOMAR Kiel-Outdoor-Benthocosms (KOB) are designed to simulate future underwater conditions expected under climate change (Fig. 6.7.1). It has been successfully used since 2012. The facility consists of 6 experimental units holding 3000 l each, which can be sub-divided into 12 autonomous units of 1400 l. Covers translucent to all solar wave lengths can be used if headspace conditions need to be controlled. Water movement and turbulence is controlled by water throughflow, internal circulation and wave generators to produce a wide range of hydrodynamic conditions. Natural upwelling events are simulated with a deep water hose supplying water from below the thermocline. Possible simulations include abrupt changes in salinity, O2, pH, pCO2 and nutrients. The entire infrastructure, including a container with master computers, freezers and a workshop, is installed on a floating platform.

A unique feature of KOB is that it can track the short-term fluctuations characterizing natural regimes of environmental factors, such as temperature, pCO2, O2 and nutrient concentrations. It is operated in flow- through mode to create in-situ conditions in real-time by adjusting the climate-change factors of interest to dynamic target values based on the experimentally desired deviation from a continuously recorded baseline in the field. Adjustments to the target values are fully automated by means of a sophisticated instrumentation and control (I&C) system that also records a range of environmental variables continuously. Novel software serves to mimic the exact regimes of temperature, pH, O2 and other environmental factors of a given year in the past or any deviations from those conditions.

Fig. 6.7.1. View of the Kiel Outdoor Benthocosm (KOB) facility (left) and detail of wave generation in a sub-ivided mesocosm (right). Photos: M. Wahl and M. Lenz

Instruments / sensors / equipment

KOB: insulated tanks with 12 experimental units, heaters, coolers, automated, gas mixing unit, wave generators, internal circulation system, flow through system, surface and deep water supply, programmable climate simulation

Modality of access

A total of 405 person-days is allocated to external users through AQUACOSM Transnational Access provision in years 2-4. An average of 3 persons for 45 days is envisaged each year. Users will have access to the mesocosms, laboratories and instrumentation described above. Research activities under AQUACOSM will preferably be integrated into larger multi-disciplinary projects, but could also run in parallel or be intercalated between other KOB experiments. Projects planned for 2017 – 2019 include the combined effects of warming and sporadic hypoxic upwelling, comparative stress ecology in the Baltic and Mediterranean, impact of bioinvasions, emerging marine diseases.

Support offered under AQUACOSM:.

  •  Full operation of the KOB facility during experiments

  •  Logistical and technical coordination

  •  One full time technician

  • Access to lab facilities



    Coordinated data exchange and data archiving as well as data workshops

Unit of access
What is available and when
What service and support facilities are available

Services currently offered by the infrastructure: KOB typically runs relatively long-term experiments on single and interactive global-change effects on benthic marine communities. For example, during the past four years, several experiments were conducted to assess multivariate effects of warming, acidification, eutrophication and hypoxia. More than 30 researcher from Germany, Sweden, The Netherlands, Israel and Portugal were involved. Apart from the mesocosm facility, the following analytical equipment will be available for participants of KOB experiments:

  •  A wide array of microscopic techniques

  •  Access to culture rooms for additional small-scale studies

  •  A flow cytometer for counts and biomass estimates of pico- and nanoplankton

  •  An autoanalyser for dissolved nutrient analyses

  •  A CHN-analyser for elemental analysis of particulate matter

  •  A mass spectrometer to measure stable isotopes (13C, 15N, 34S) as tracers

  •  A SCUBA-diving team and small research vessels


Special rules