Abstract
Mesocosms are important research tools in aquatic ecology because they close the gap between laboratory studies at the individual or lower organization level and field studies at the population and ecosystem level. However, most mesocosm studies regarding the pelagic environment do not consider the effects of physical factors like water-column stratification, turbulence and mixing. Neglecting such factors might bias the results compared to the natural system. Using a unique indoor mesocosm facility, we present results on how different water-column stratifications can be made and how they act as barriers for exchange between water layers. Turbulent mixing, simulated by vertically rotating incubation vessels, is shown to be of high importance for primary production, generating up to nine times higher production in humus-rich water than incubation vessels at fixed depths. Convective stirring is shown to be an attractive method for generating different turbulence conditions, and different temperature settings can be used to get turnover times from 84 h or more down to 17 min for a 5-m water parcel. We also demonstrate how an anoxic bottom layer can be achieved by stimulating heterotrophic bacteria through addition of bioavailable organic carbon.
Highlights
Mesocosm-based research has become an increasingly important part of aquatic ecology by closing the gap between laboratory studies at the species, individual or lower organisation level and field studies at the population or ecosystem level (Stewart et al 2013)
We describe a unique mesocosm facility where the physical characteristics can be controlled and manipulated and give some examples of biological consequences of different physical conditions
In the second experiment, where we studied oxygen succession in a carbon-enriched environment, primary production was determined using 3-h incubations at mid-day with 100 ml of water in Nunc culture bottles to which 3.2 lCi of Na14CO3 where added
Summary
Mesocosm-based research has become an increasingly important part of aquatic ecology by closing the gap between laboratory studies at the species, individual or lower organisation level and field studies at the population or ecosystem level (Stewart et al 2013). Field studies in the marine environment often require large research ships with daily costs of 10,000€ or more and studies on natural systems, especially pelagic ones, include much short-term variability. High cost of marine field studies combined with the inherent natural spatial and temporal variability heavily constrains the possibility of achieving statistically well-founded results solely based on field studies. Laboratory studies at the individual level can, for example, precisely define physiological responses to both abiotic (light, temperature, salinity, etc.) and biotic variables (food concentration and quality, crowding, gender, age, etc.). Miko et al (2015) compared results from ecotoxity tests on tadpoles in the lab and in outdoor mesocos which showed strikingly different results
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
