Water in NatureEssential Knowledge for Naturalists
Water covers over 70 percent of the surface of the Earth. Interestingly, the human body is also made up of over 70 percent water. Plant and animal life on Earth is dependent on water for survival. Water is stored in many ways in Nature. For example, most of the Earth's water is in the oceans, and in the polar ice caps. One fifth of the earths freshwater supplies are found in the Great Lakes. Seas, lakes, ponds, wetlands, rivers, streams, and subsurface aquifers store much of the remaining water.
Living things use water as an indispensable part of their metabolic processes. Plants use the energy of sunlight to break water into its component parts of hydrogen and oxygen. Photosynthesis then combines the hydrogen split from water with carbon dioxide from the air to form simple sugars, which are the energy sources for growth and development.
Certain living creatures, such as fish, are adapted to water, and cannot live in its absence, even for minutes. Such creatures are able to extract the essential gasses of life from water, rather than from the atmosphere. For example, fish use their gills to extract dissolved oxygen from the water around them, while underwater aquatic plants absorb dissolved carbon dioxide from water and release oxygen into the water.
The quality of water is important, not only to humans, but to all of Nature as well. While even three decades after the passage of the Clean Water Act in the United States, we still pollute our waterways with sewage and other pollutants, we are beginning to understand just how critical clean water is to the diversity of life. Certain species need clean water to survive. A little bit of eroded sediment coming into their riverine homes can decimate entire populations. Some of these species act as hosts for other life-forms during certain stages of development.
For example, the salamander mussel, a freshwater mussel, must attach themselves to the gills of the mudpuppy, a large salamander, in their early lives to survive. If mudpuppies decline or are absent, the salamander population cannot survive. There are undoubtedly other species reliant and intertwined with the salamander mussel, which would also decline in the event mudpuppies were removed from an ecosystem. These specific cascading impacts are difficult to determine, because of the complicated, vast nature of, well, Nature.
Stream Dynamics is the study of how streams function in terms of morphology, erosion, energy, and flow. Water flows, evaporates, rains, and pools. It covers just about everything at some time. If harming our water quality can harm life, whether salamanders, mussels, or human, we should not harm our water. Clean water is an asset to human and natural life, and serves many, many important uses. Can you think of ways that your life impacts water? Can you imagine ways that water influences your life?
Humans are physically dependent on water. Perhaps this close attachment is apparent in our psyche as well. Have you ever stood and watched in wonder as thousands of gallons of water flowed over a waterfall? The power of water, and the wonder it creates within us is a constant reminder that we humans are smaller and less powerful than we sometimes imagine. Imagine that.