Water ecology FAQ frequently asked questions
The question library on water related issues
Ecology is the study of the interactions between organisms and their environment. Various different species living in the same place, interacting amongst themselves and with their environment together form an ecosystem. Within an ecosystem there are several food webs. A food web is an overview of which species in an environment consume which species (plant, animal or both). A healthy ecosystem has a variety of organisms that play different roles in various food chains. If the ecosystem loses one of its members, it can be crippled. For instance, if owls in the forest food web would die out, rodents might start to multiply at an enormous speed, causing them to overrun the area and finish resources that other animals also use.
There are two kinds of aquatic environments, which can sustain life. These are saltwater life zones and freshwater life zones. The major types of organisms found in aquatic environments are determined by the salinity of the water. Salinity means the amounts of salts dissolved in a volume of water. That is why aquatic life zones are divided up between saltwater life zones and freshwater life zones.
The largest saltwater life zones on earth are not very hard to find, as these are in the oceans. Oceans cover about 71% of the earth's surface and are very important for the preservation of all life on earth. Oceans play an important part in the hydrological cycle, because precipitation (rain) consists of evaporated oceanic water and in the regulation of the earth's climate. Oceans also participate in other matter cycles. Oceans are the living environment for about 250,000 species of marine plants and animals. Unfortunately, oceans are also dumps for human waste, because the (polluted) water of all inland water bodies eventually ends up in oceans.
Coastal life zones
The coastal zone makes up only 10% of the oceanic environment, but it contains 90% of all marine species. Coastal zones are the most nutrient-rich life zones of the oceans.
Open ocean life zones
The open sea contains only about 10% of all marine species. The open ocean is divided up into three life zones, the euphotic zone, the bathyal zone and the abyssal zone. The subdivision is based on the penetration of sunlight.
Overview of oceanic life zones:
Freshwater life zones are found in waters with a dissolved salt concentration of less than 1%. Freshwaters are divided up into standing bodies of freshwater, such as lakes, ponds and inland wetlands and flowing bodies of freshwater, such as rivers and streams. Only 1% of the earth's surface is covered with freshwater. However, about 41% of all known fish species live in freshwater. Run-off from land provides the water with nutrients, such as nitrogen and phosphorus, because the freshwater zones are close to terrestrial (land) ecosystems.
Life zones in standing freshwater bodies
Lakes and ponds are large, natural bodies of standing water. They are fed mainly by rainfall and melting snow, and they consist of various different life zones.
Life zones in flowing freshwater bodies
Flowing bodies of freshwater, such as rivers and streams, are watersheds for precipitation water. This water becomes land run-off and flows with the rivers and streams to the sea. The flow of surface water to the sea takes place in three different life zones. These life zones all have their own environmental conditions, which causes species diversity to vary between the three zones.
Overview of freshwater life zones:
Both saltwater and freshwater life zones contain a wide variety of organisms, which all interact with one another in various food webs. A food web is a system in which certain organisms consume other organisms, plant or animal, to form a sustainable system in which species will be in balance and will not experience overpopulation.
To simplify this explanation, we have added a schematic representation here:
Remember that decomposers will not start to decompose consumer material until after the consumers have died.
Aquatic environments have many advantages. Water has many properties and because of that it is a unique kind of environment to live in.
Human's desire to live near the coast has aided to the degradation of aquatic life zones. Today, around two-thirds of the worlds' population lives near coasts. People have been drying wetlands and other coastal areas, in order to gain land for urban development.