Estimating Water Quality by Aquatic Insects

CHO Yezi

International Linguistic School, 7M1 class, Vladivostok, Russia

Home Country: South Korea

Teacher: T.S. Vshivkova

 

The world is a very comfortable place to live. Our technology is advancing and various developments are being made. Nevertheless, we can also say that human activity is rapidly growing as well. As human activity increases, what can it proceed to?

The greatest issue we can indicate is the deterioration of water quality. Factors affecting water quality include the leaching of chemicals, release of contaminants, and other natural and human influences. The contamination of water is facile, however, once the situation is aggravated, restoration can be strenuous, even impossible.

Multiple organizations and companies are now implementing diverse solutions to ameliorate water quality. But what can we do? How can we determine the quality of water without specialized apparatus?

There is one straightforward answer: Estimating water quality by certain aquatic insects. Water quality differs according to each area, therefore the organisms living there are also different. Aquatic insects are not difficult to find, and they are not exhausting to identify.

There are mainly three kinds of aquatic insects that live in high-quality water: Mayflies, Stoneflies, and Caddisflies (each of them have Order names in Latin: Ephemeroptera, Plecoptera, Trichoptera). If the water is slightly polluted, Dragonfly nymphs can be found. We can find a group of organisms such as Oligochaeta + Chironomidae in substantially polluted water. And certain organisms such as Tubifex worms live in very polluted water. Generally, the quality of the water is rated from 0.00~10.0. As the number gets bigger, the more polluted the water is. 0.00~3.50 is for water with absolutely no pollution found, while 8.51~10.0 rates severely polluted water, in which organisms are scarce.

In this way, we can estimate the quality of water around us by observing which organisms, particularly aquatic insects live in it. Therefore, we can determine if should preserve the water or restore the polluted water. In my opinion, not only the government or huge organizations, but everybody should lend a hand to keep the environment a good place to live in. The water we pollute will also harm us unless we save it ourselves.

Caddisflies, excellent indicators of water quality

Cho Sein

International Linguistic School, 9M1, Vladivostok, Russia

Home Country: South Korea

Teacher: T.S. Vshivkova

Caddisfly (order Trichoptera), are a group of moth like insects that are attracted to lights at night and live near lakes and rivers. They are insects with two pairs of hairy wings that are folded rooflike over the abdomen at rest. There are approximately 14,500 described species. Caddisflies are best known for the portable cases created by their larvae. About thirty families of caddisfly adopt this stratagem. These larvae eat detritus, largely decaying vegetable material, and the dead leaf fragments on which they feed tend to accumulate in hollows. The cases provide protection to the larvae as they make their way between these resources.

Although most larvae feed on aquatic plants, algae, diatoms, or plant debris, a few are predatory on other aquatic insects, crustaceans, and a few are omnivorous. The larvae play an important role in the aquatic community, disposing of animal and plant debris.

The aquatic larvae are found in a wide variety of habitats such as streams, rivers, lakes, ponds, spring seeps and temporary waters. Caddisflies are aquatic insects associated with a wide range of freshwater habitats. Oxygen concentration, associated with water velocity, is important to their larvae, as is the chemical content of the water. In fact, certain species have been used as biotic indicators of pollution. In general, they play a crucial role in determining the water conditions.

Stoneflies – the best indicator for estimation of freshwater quality

Mu Di

International Linguistic School, 9M1, Vladivostok, Russia

Home Country: China

Teacher: T.S. Vshivkova

Stonefly (order Plecoptera), the adults of which have long antennae, weak, chewing mouthparts, and two pairs of membranous wings. The hind wings are generally larger and shorter than the forewings and fold like a fan when not in use. Even though its wings are well developed, the stonefly is a poor flier. Many species are gray, black, or brown and blend into their surroundings.

The life history of the stonefly is not well known. Each female may produce as many as 6,000 eggs, which are dropped in masses into a stream.

Stoneflies, along with mayflies and caddisflies, are important biotic indicators of water quality. Stoneflies are known as sensitive or indicator taxa. What means they are sensitive to change in water quality.

Look for Giant Stoneflies in areas near freshwater streams, creeks, or rivers. They, in general, can be attracted to artificial light after sunset in the late spring and early summer months of the year.

 

Eggs                                               Larva                                              Imago