1. Role of Bio Markers In Water Monitoring
Biomonitoring Biological monitoring, or biomonitoring is the use of biological responses to
assess changes in the environment generally changes due to anthropogenic causes.
Biomonitoring programs may be qualitative, semi-quantitative, or quantitative.Biomonitoring is
a valuable assessment tool that is receiving increased use in water quality monitoring programs
of all types.
Biomarkers Biomarkers are species, populations or groups of species, which due to their
variability (biochemical physiological, ethological or ecological) allow the description of an
ecosystem status and reveal as early as possible, the natural or anthropogenic modifications
thereof
Types of Biomonitoring Surveillance before and after a project is complete or before and after a
toxic substance enters the water. The other type of biomonitoring is to ensure compliance with
regulations or guidelines or to ensure water quality is maintained.
Biomonitoring involves the use of indicators, indicator species or indicator communities
Benthic macroinvertebrates
Fish
Algae
Aquatic plants
Sentinel organisms:
Sentinel organisms, or indicator species that accumulate pollutants in their tissues from the
surrounding environment or from food, are important biomonitoring devices
Extreme Uptake
Barnacles Zinc (Zn) Bivalve mollusks Copper (Cu), iron (Fe) manganese Gastropod mollusks
Cu, Zn Isopods, amphipods Cu, Fe, Pb, Zn Polychaetes Cu
2. Moderate Uptake
Macroalgae (seaweeds) Most metals Mussels other bivalves Metals, metallothioneins
Polychaetes Cadmium (Cd), Pb Decapods (crayfish) Cd, Pb Finfish Cd, Pb
Assessment Assessment
It involves the monitoring of indicators and behavioral changes of organisms.Indicators must
display a biochemical genetic morphological or physiological change. Behavioral indices are
determined by particular species, populations dynamics or community changes.
Levels and Associated Biomonitoring
Measures Individual Genetic mutations Reproductive success Physiology Metabolism Oxygen
consumption Photosynthesis rate Enzyme/protein activation/inhibition Hormones (growth and
development) Disease resistance Tissue/organ damage Bioaccumulation
Population Survival rate or mortality Sex ratio Abundance/biomass Behavior (migration)
Predation rates Population decline/increase
Community Abundance of an organism or organisms
Biomass Density of an organism or organisms Richness (variety) Number of species size classes,
or other functional groups per unit area or volume or per number of individuals
Common Organisms used for Biomonitoring
Invertebrate indicators Increased ratio of aquatic worms (oligochaetes)
Increased ratio of midges (chironomids)
Increase of herbivorous mayflies (ephemeropterans)
Loss of snails, clams, mussels, daphnids, mayflies, midges
Algae
Algal growth is dependent on sunlight and nutrient concentrations. An abundance of algae is
indicative of nutrient pollution Algae are sensitive to some pollutants at levels which may not
visibly affect other organisms in the short term or may affect other communities at higher
concentrations.
Advantages of Algae
Algae have very short life cycles and rapid reproduction. This can also be a disadvantage. Algae
3. tend to be most directly affected by physical and chemical environmental factors. Sampling is
easy and inexpensive, requires few people and minimally impacts other organisms. Standard
methods exist.
Benthic macroinvertebrates Advantages
Benthic macroinvertebrates are found in most aquatic habitats. There are a large number of
species, and different stresses produce different macroinvertebrate communities Small order
streams often do not support fish but do support extensive macroinvertebrate communities.
Macroinvertebrates generally have limited mobility.Thus they are indicators of localized
environmental conditions. Since benthic macroinvertebrates retain (bioaccumulate) toxic
substances, chemical analysis will allow detection in them where levels are undetectable in the
water resource.
A biologist experienced in macroinvertebrate identification will, be able to determine relatively
quickly whether the environment has been degraded by identifying changes in the benthic
community structure of the water resource. Benthic macroinvertebrates are small enough to be
easily collected and identified. Sampling of macroinvertebrates under a rapid assessment
protocol is easy, requires few people and minimal equipment, and does not adversely affect other
organisms. Macroinvertebrates are the primary food source for recreationally and commercially
important fish.
Disadvantages
Benthic macroinvertebrates do not respond to all impacts. Seasonal variations may prevent
comparisons of samples taken in different seasons. Drifting may bring benthic
macroinvertebrates into waters in which they would not normally occur. Knowledge of drifting
behavior of certain species can alleviate this disadvantage. Certain groups are difficult to
identify to the species level.
Fish
Certain fish species such as salmon, trout, perch and sculpins, are less tolerant of pollution than
others. Bottom dwellers are more tolerant of organic pollution since they are adapted to lower
oxygen levels. Predatory species that use sight to hunt, such as pike, are sensitive to turbid
conditions
4. Fish Advantages
Fish are good indicators of long-term effects (several years) and habitat conditions. Fish
communities represent a variety of trophic levels; toxic substances tend to biomagnify, and thus
fish community structure reflects community health. Fish are consumed by humans. Fish are
relatively easy to collect and identify. Environmental requirements, life history information and
distribution are well known for most species.
Disadvantages
Motility and migration cause difficulty in pinpointing a pollutant as the cause of abnormalities
in individuals or a population. Monitoring only certain fish species will miss changes in the
benthic community or in other species in the community that over time will affect the fish
species. Fish are not as sensitive as their food (macroinvertebrates) to pollution and monitoring
of fish may not reflect severe changes in the invertebrate community. An assessment of fish
alone will not ensure ecosystem health.
Sampling Techniques
Kick seine
Requires 2 or more people.One person places a four by four feet nylon mesh screen seine is
placed along the bottom at an angle that will allow riffle areas to be easily sampled for benthic
macroinvertebrates. Another individual kicks the stream bottom down to 2 inches to loosen
macroinvertebrates for collection upstream of the net.The net is then removed from the water and
organisms are classified
Sweep nets
Used to sample invertebrates from the water column as well as communities attached to wetland
plants. The nets are at the end of a pole which is placed on the bottom of the water body and
swept up vertically through the water column or swept a standard length of vegetation.
Dredges or core samplers
A specified area is enclosed and sediments and the associated organisms are retrieved. Fast
moving organisms can and do escape. Core samplers are particularly useful in wetlands that are
dry.
5. Artificial substrates
Plastic plants or other sterile surfaces allow objective sampling and sample collection in
locations that are difficult to sample.Such artificial substrates should remain in place for at least a
month and the average is 8 weeks.
Emergence traps and funnel traps
Nets or funnels placed at or just above the water surface trap adult aquatic insects emerging from
the water.These will not collect benthic organisms such as aquatic worms and snails
Sampling Techniques Sampling time considerations include migration spawning and dispersal.
Nighttime sampling is suggested particularly for catfish and perch.
Electrofishing
A technique which stuns fish allowing them to be caught identified measured and released
quickly. Permits are required. Water body inlets and outlets can be blocked with nets to prevent
fish from escaping the electrical field
Seines Nets
pulled through the water to capture fish.Seines can allow an estimate of species richness. A
mesh size of 1/8 is recommended for fish
