Earth Observation in the frame of EO-MINERS - Earth Observation methods
A wide range of methods exist to assess the state of the 'biosphere'. These methods assess the quantity and quality of faunal, botantical, and fungal constituents of ecosystems. These methods also assess the interaction between those constituents, drawing conclusions on the state of the respective ecosystem. Even an overview over these methods would be beyond the scope of this report. Several indicators (see Ch. 6), e.g. A8 (Recultivation success) and A10 (Soil fertility), refer, however, indirectly to biological properties.
Biological properties can be used to indicate the state of mine-influenced ecosystems.
Bioindicators are organisms, such as plants, lichens, birds, and bacteria that are used to monitor the health of the environment. The organisms are monitored for changes that may indicate a problem within their ecosystem. The changes can be chemical, physiological, or behavioral.
Uses and Types of Bioindicators
Each organism within an ecosystem has the ability to provide information on the health of its environment (http://www.biobasics.gc.ca):
Uses of bioindicators
- Detection of changes in the natural environment.
- Monitoring the presence of pollution and its effect on the ecosystem in which the organism lives.
- Monitoring the progress of environmental cleanup.
- Test substances, like drinking water, for the presence of contaminants.
Types of bioindicators
- Plant Indicators -- The presence or absence of certain plant or other vegetative life in an ecosystem can provide important clues about the health of the environment.
Lichens, often found on rocks and tree trunks, are organisms consisting of both fungi and algae. They respond to environmental changes in forests, including changes in forest structure, air quality, and climate. The disappearance of lichens in a forest may indicate environmental stresses, such as high levels of sulfur dioxide, sulfur-based pollutants, and nitrogen.
- Animal Indicators -- An increase or decrease in an animal population may indicate damage to the ecosystem caused by pollution. For example, if pollution causes the depletion of important food sources, animal species dependent upon these food sources will also be reduced in number. In addition to monitoring the size and number of certain species, other mechanisms of animal indication include monitoring the concentration of toxins in animal tissues, or monitoring the rate at which deformities arise in animal populations.
- Microbial Indicators -- Microorganisms can be used as indicators of aquatic or terrestrial ecosystem health. Found in large quantities, microorganisms are easier to sample than other organisms. Some microorganisms will produce new proteins, called stress proteins, when exposed to contaminants like cadmium and benzene. These stress proteins can be used as an early warning system to detect low levels of pollution.
Diagram of the hierarchical levels of an ecosystem that respond to anthropogenic disturbances or natural stress.
The white ring of environmental variables includes factors that may be directly altered by disturbance or stress. These alterations may subsequently affect individual organisms, populations, or the community as a whole. The outermost colored ring represents individual organisms (cutthroat trout, Pteronarcys Salmonfly, Phaedoactylum diatom), the middle colored ring represents populations of those organisms, and the innermost colored ring represents the community in which all three species coexist. Disturbance and stress may positively or negatively affect energy resources (e.g., food, light), biotic interactions (e.g., competition, predation, herbivory), and the physical (e.g., water velocity, substrate upon which an organism attaches, uses for refugia, lays eggs), or chemical (e.g., nutrients) environment. These environmental changes may increase or decrease growth and reproduction of an organism, consequently impacting the size and productivity of the population and interactions with other species in the community.
An example: Mosses as indicators to air quality
Mosses lack vascular systems and obtain most of their nutrients from precipitation and from dry deposition of airborne particles. Therefore, tissue concentrations are minimally confounded by uptake of mineral elements from soils and subsequent translocation (Hasselbach et al. 2005). As a result, airborne pollutants concentrations can be mapped based on chemical analysis of moss tissue, as presented in the following two figures.
Conditional simulation predictions for moss Lead tissue concentrations in the vicinity of Cape Krusenstern National Monument including 0.05 and 0.95 prediction quantiles. (Hasselbach et al. 2005)
Conditional simulation predictions for moss Cadmium concentrations in the vicinity of Cape Krusenstern National Monument including 0.05 and 0.95 prediction quantiles. (Hasselbach et al. 2005).