Lecture 10: Microcosmology BIO410- Ecology and Environmental Engineering FALL 2016 By Jasmin Šutković 12 th Dec. 2016 Lecture 10: Microcosmology

Outline MICROCOSMS FOR DEVELOPING ECOLOGICAL THEORY Book 1: Chapter 4 – follow the subtitles in this presentations while reading the book. Book Chapter Pages 117-166 MICROCOSMS FOR DEVELOPING ECOLOGICAL THEORY MICROCOSMS IN ECOTOXICOLOGY SINGLE vs MULTISPECIES in a MICROCOSMS DESIGN OF MICROCOSMS AND MESOCOSMS THE ENERGY SIGNATURE APPROACH TO DESIGN

Introduction Microecosystems or microcosms are relatively small, closed or semi-closed ecosystems used primarily for experimental purposes. As such, they are living tools used by scientists to understand nature Microcosms literally means “small world,” and it is their small size and isolation which make them useful tools for studying larger systems or issues.

Mesocosm A mesocosm (meso- or 'medium' and -cosm 'world') is any outdoor experimental system that examines the natural environment under controlled conditions. In this way mesocosm studies provide a link between field surveys and highly controlled laboratory experiments

Tomato greenhouse By Goldlocki https://en.wikipedia.org/wiki/Mesocosm#/media/File:TomateJungpflanzenAnzuchtNiederlande.jpg

MICROCOSMS FOR DEVELOPING ECOLOGICAL THEORY Microcosms that are correlated to ecology are : organism, population, community, and ecosystem. Experiments are done in order to checkout the microcosms. Statistical comparasion is undertaken with the parameters of Microcosms

Examples For another line of research, the microcosm provides only a context for studies of population dynamics or species interactions. Energy flow! The early studies outlined the basic processes of energy flow (primary production and community respiration) and biogeochemistry (nutrient cycling), which are the foundations of ecosystem science today.

MICROCOSMS IN ECOTOXICOLOGY Ecotoxicology is the study of the effects of toxic chemicals on biological organisms, especially at the population, community, ecosystem level. Ecotoxicology is a multidisciplinary field, which integrates toxicology and ecology. Microcosms are important as research tools in ecotoxicology for understanding the effect of pollutants on ecosystems.

Goal? Challenges for ecological engineering include the design and operation of microcosms that are effective for both research and risk assessment in ecotoxicology.

All new chemicals must be tested for toxicity by authorized governmental agencies. The industrial and commercial companies produce a lot of new chemicals for their purposes. Many of these chemicals are xenobiotic or man-made, whose potential environmental effects are unknown. Thus, uncertainty arises because natural ecosystems have never been exposed to them and species have not adapted to them.

Most regulatory decisions are made based on the experiments on single species tests in which data from toxicity experiments are compared to estimated environmental exposure data. Thus, test populations of certain species are grown in the laboratory and tested for short-term (acute) vs. long-term (chronic), and lethal (causing mortality) vs. sublethal (causing stress but not mortality) dose experiments.

Dose response

Advantage ? A controversy has arisen about the kinds of tests required in risk assessment of chemicals. A number of ecologists have insisted that single-species tests are inadequate for a full evaluation of ecosystem level impacts and that multispecies toxicity tests should be required.

Argument The main argument against reliance on single-species tests in risk assessment is that they provide no information on indirect and higher order effects in multispecies systems, which many ecologists believe are important.

Single vs multispecies test Only multispecies studies can provide demonstrations of: indirect trophic-level effects, including increased abundances of species via increased food supply through reduced competition or reduced predation; compensatory shifts within a trophic level; responses to chemicals within the context of seasonal patterns that modify water chemistry and birth and death rates of populations; chemical transformations by some organisms having effects on other organisms; and persistence of parent and transformation products

Contra arguments for microcosms in ecology https://oikosjournal.wordpress.com/2011/06/10/objections-to-microcosms-in-ecology-and-their-answers/

DESIGN OF MICROCOSMS AND MESOCOSMS Design of microcosms depends on the nature of the experiment to be conducted and requires a number of straightforward decisions about materials, size and shape of container, energy inputs, and biota.

PHYSICAL SCALE The primary challenge of microcosm design is physical scaling, in terms of both time and space Civil engineering and Scaling of hydraulic models are used as guide to designers of ecological microcosms

THE ENERGY SIGNATURE APPROACH TO DESIGN The concept can be used to design microcosms by matching, as closely as possible, the energy signature of the natural analog system with the energy signature of the microcosm. The most straightforward approach to this matching of energies is to construct the microcosm in the field where it is physically exposed to the same energies as natural ecosystems.

Example Examples are the pond ecosystems commonly used in ecotoxicology and in situ plastic bags floated in pelagic systems (called limnocorrals when used in lakes). A pond is a body of standing water, either natural or artificial, that is usually smaller than a lake