Limnotrons

Infrastructure Description

The Limnotrons are 9 stainless steel indoor mesocosms with a high level of control. The dimensions are: 0.97 m in diameter, depth between 1.32 m (side) and 1.37 m (centre), volume of 922 L. The vessels can be closed with a removable PMMA flange lid. In addition to the possibility to sample vertically with specifically designed integrated water samples, sampling can also be done by using the sampling ports positioned on three depths. Wall growth is prevented by an impeller made of PMMA, with a stainless-steel axis and a silicon rubber strip between the outside and the wall. To create different types of mixing more tailored to growth of cyanobacterial scums, oscillating grids have been designed. The Limnotrons have been adapted to allow for both a pelagic and benthic community as well. Each Limnotron can have a sediment layer of 10-15 cm, and with the recently purchased high intensity lights (that can be manipulated in terms of red/green and blue light), a macrophyte community can be established in these mesocosms. A specific feature of the Limnotrons is its thermostatically regulated microprocessor-controlled temperature regulation system which enables thermal stratification and allows for running complicated temperature scenarios, including episodic events. Volume differences due to temperature settings, evaporation losses and sampling, are compensated by a (refillable) expansion vessel. CO2 levels can be manipulated by providing different CO2/air mixtures with a WITT KM60-2ME gas mixer. Each Limnotron has been equipped with a PTX20 submersible depth transmitter, a LICOR submersible quantum light sensor (Wavelength range 400-700nm, sensitivity 3 µA/1000 µMol s-1 m-2 in water), and an OXYBase WR-RS485M-L5-NAU-YOP-2CS-Set dissolved oxygen sensor. The Limnotrons have recently been provided with with separate control units, with custom-made winch systems and depth gauging systems, allowing for tailor-made sampling control by remote users. Services currently offered by the infrastructure: Individual external users and user groups will have access to the full range of facilities at the NIOO-KNAW. These include: fluorescence microscopes; autoanalyzer for dissolved nutrients, multichannel probes for simultaneous measurements of oxygen, light, pH, conductivity and temperature, PhytoPAM, fluorometer; Coulter particle counter, Flow cytometers for phyto- and bacterioplankton analyses, FlowCAM for analysis of large phyto- and zooplankton, Elemental analyser (particulate C and N contents), Isotope-ratio mass spectrometry (relative abundance of stable isotopes), ICP-MS (quantify trace elements), LC-MS/MS (small organic chemicals, cyanotoxins), modern molecular-biology lab. The facilities are frequently used for experiments by teams of international researchers from different disciplines including ecologists, microbiologists, biogeochemists, and evolutionary biologists assisted by a team of highly skilled researchers and technicians at NIOO- KNAW. Past TA projects included research on emerging pollutants, multiple stressors, and eutrophication control in a changing climate. The laboratory’s broad range of state-of-the-art analytical equipment allows users to tackle innovative, multi-facetted questions, resulting in publications in leading journals. Users will be embedded in an internationally renowned aquatic ecology group providing ample opportunities for networking and large potential for fruitful scientific exchange. The NIOO-KNAW as a whole (250 employees) provides an international working community, hosting several world- leading scientists.

Facility Description

indoor/outdoor – pelagic – freshwater

Limnotrons, outdoor enclosure facility, 36 experimental ponds

Location

Gallery

Contacts

Lisette de Senerpont Domis

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