The Mesocosm Facility

The advanced mesocosm facility at Umeå Marine Sciences Centre are available for researchers from any university world wide.

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The indoor facility consists of 12 cylindrical mesocosms with water columns 4.86 m high and 0.73 m in diameter (volume approximately 2 m³).

The temperature can be controlled and manipulated in 3 different sections in each mesocosm. This allows for experiments which require temperature stratification, controlled convective stirring, or both. The temperature is computer controlled by sensors, which gives an accuracy of at least +/- 0.5º C from the selected temperature. A halocline can be created by addition of salt.

Technical specification

• The water intake to the indoor mesocosms is situated 800 m off-shore at 2 and 8 meter depths. The mesocosms can also be filled with sea, lake or river water transported from elsewhere. Filling can be done through filters of selectable mesh sizes, down to 1 μm. A semi-automatic water renewal system with controllable turnover rate is also available.
  
  
• The light source, Valoya R-258 (Light DNA), is developed to emulate the light spectrum of day light. The light sources can be controlled as for spectrum and intensity, and can be adjusted to latitude and time of day.
  
  

  Spectrum from the mesocosm light source.

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• Four freezers are installed on top of every three mesocosms. This enables control of the air temperature above the water columns down to -20^o C. Ice covering of the mesocosms is thereby possible, and parameters such as freezing or thawing rate can be adjusted. This option allows for systematic seeding experiments.
  
  
• The ventilation of the mesocosm hall is controlled by the CO₂ content in the room, allowing for natural controls in experiments where the CO₂ content in the water is altered. A laboratory is situated directly adjacent to the top floor of the mesocosm hall.
  
  
• The mesocosms as well as all pipes, valves and couplings are made of non toxic polyethylene.
  
  
• Sampling can be done either through a fixed sampling outlets, by gravity or by Ruttner water samplers.
  
  
• It is possible to transfer intact bottom sediment to the mesocosms. Sampling during experiments can be performed by a semiautomatic robot.

Oudoor mesocosms

The outdoor facility is available during summer. It consists of 4 large pools, each carrying 6 cubic mesocosms of 1 m³. The temperature in the pools is kept the same as in the water intake by using high rates of water flow.

Instruments/sensors/equipment

• Two Seaguard CTD equipped with PAR, conductivity, temperature, turbidity, chlorophyll, oxygen, CDOM and pressure sensors.
  
  
• Spectrophotometer
  
  
• Spectrofluorometer
  
  
• Scintillation counter
  
  
• Basic laboratory equipment including salinity and pH meters.

Long time series of data

Through an internet-based database there is access to long time series of ecological variables, which can be used in designing experiments.

Field station surroundings

Through an easy available database on the Internet, there are access to long research time series of ecological variables, which can be used in designing experiments.

Scientific publications