October 2024
Water is the medium of life. My teacher taught me that when I was studying biology at school many years ago. This is also why astronomers are so preoccupied by looking for water on the Moon or Mars. In fact, they think they have discovered that Mars has water but it is 10 or 20 kilometres below the planet surface! So, then the questions are how do astronauts get it out? Why try?
We live on a beautiful blue planet where water makes up over 70% of the surface and can be as much as 11,000 metres deep. We (humans) are 55 – 60% water. If we cannot find any on a very hot day, we are not likely to survive. Space is a very unhealthy place with no available water or food. Moreover, there is not much oxygen there either, so I for one would not be interested to go there. We must look after this planet as there is no plan(et) B as someone has said. We must simply solve the problems we have on our home planet.
Rivers are the vascular system of our natural world. They provide us with the water for our taps in our houses, and ultimately take away wastewater when we flush the toilet and pull out the sink plug. What happens in between keeps us clean, from being thirsty, and removes our bodily waste. It is a miracle that we all take for granted every day. We have faith that the supply company maintains the reservoirs, filters, pipes and chlorinators that provide our potable tap water. Also, the sewage workers (and I have been one in the past) that ensure that the water returning to rivers does not kill the animals (and plants) that live in it. These are some of them, first the invertebrates: Stonefly (Plecoptera) larvae, these are the best sign of good quality water; caddisfly (Trichoptera) larvae, many make little jackets out of fibres or sand; various dragonfly (Odonata) larvae, including demoiselles (Calopteryx spp.) larvae which take up to 2 years to develop before emerging as the most beautiful flying insect I know. Dragonflies are beautiful primitive voracious predators of other invertebrates; freshwater shrimps (Gammarus pulex) are miniatures of their marine cousins. There are also whirligig beetles (Gyrinidae) that dance on the surface of water; also, water skaters (Gerridae) true bugs also with the ability to walk and run on water; leaches (Hirudinea) which are parasitic or predatory worms, some have a traditional use in medicine. Additionally, the vertebrates (like us), including fish such as bullheads, sticklebacks, eels and trout that feed on the invertebrates; also, water voles, otters and kingfishers make rivers their homes if they can.
Scientists collect samples of invertebrates from rivers using a technique called kick netting. They identify them under microscopes and attribute a score (1. poor to 10. good) dependent on what is there, some are more pollution tolerant than others. This determines the quality of the river water and is called the River Invertebrate Prediction and Classification System (RIVPACS) method.