KIBs: Kiel Indoor Benthocosms

Climate change will not only shift mean environmental conditions, but will also increase frequency and intensity of extreme events, exerting additional stress on organisms and ecosystems. While field observations on extreme events are emerging, experimental evidence of their consequences is rare. We have established a mesocosm system that was solely developed to study the effects of environmental variability of multiple drivers (temperature, salinity, pH, light) at various temporal scales (diurnal – seasonal) in single species and communities: the Kiel Indoor Benthocosms (KIBs):

Kiel Indoor Benthocosms (KIBs) are established to simulate environmental parameters at fluctuating modes over extended periods using automated procedures. The 12 600 L KIB units are equipped with up-to-date controlling units, heaters, coolers, pumps and solenoid valves (not depicted) to control water temperature, salinity and pH. Technical drawings by Dar Golomb.

Real-time offsets from field measurements or dynamic regimes of environmental settings can be accomplished, including sinusoidal curve functions at any chosen amplitude or frequency, stochastic regimes, logged in situdynamics of previous years and modelled extreme events.

Applied temperature test profiles of constant vs. sinusoidal functions run inside KIBs over 4.5 days at amplitudes of 1.5 and 3.0°C (above and below mean) and wavelengths of 1.5 (B) and 4.5 (C) days.
Applied temperature test profiles of the stochastic regimes run in KIBs over 7.5 days as imitations of natural fluctuation patterns recorded in the Kiel Fjord.

With temperature as the driver in focus, we have run several studies demonstrating that environmental fluctuations and importantly, their associated characteristics (such as frequency) mediate the strength of global change impacts on a key marine species.

Overall, systems such as the KIBs can help to overcome major short-comings in marine experimental ecology and can provide robust insights for predicting shifts in ecosystem structure and services, in a changing and fluctuating world.

In addition to temperature, salinity regimes as well as seawater pH can manipulated in fluctuating modes as was already applied in several experiments.

Salinity test manipulations are demonstrated as sinusoidal functions over 7 days at amplitudes of 2.4 salinity units above and below mean, and a wavelength of 36 hours. The pH test manipulations are demonstrated as sinusoidal functions over 2.5 days, at amplitudes of 0.2 pH units above and below mean, and a wavelength of 24 hours.

All 12 fully independent controlled KIB units can be operated independently. Additionally, each of the 12 KIB units can serve as water baths for several experimental (sub-)units, e.g. 1 or 2 L bottles, 4.5 L cell culture bottles or 18 L 600 mm deep PMMA (Plexiglas, acrylic glass) cylinders. Target organisms or simplified communities can, thus, be either placed directly inside the 600 L mesocosms (12 KIB units) at operational water depths of up to 600 mm, or in an almost infinite (depending on size) number of independent units.

Possible applications of the KIB infrastructure from 600 L mesocosms to almost infinitive experimental units (in case of temperature manipulations). Incubation units range from 1 L Kautex bottles over 4.5 L CELLMASTERTM Cell Culture Roller Bottles (with optimized contact area to water volume) to 18 L incubation units equipped with peristaltic pumps and translucent lids, which can be closed for incubations. The incubation units will in the future be equipped with sensor facilities in order to monitor respiration rates as changes in oxygen and pH and possible nutrients online. Technical drawings by Dar Golomb.

 

 


This work is published in:

Christian Pansch and Claas Hiebenthal (2019) A new mesocosm system to study the effects of environmental fluctuations on marine species and communities. Limnology and Oceanography – Methods 17:145-162 (https://doi.org/10.1002/lom3.10306)