BOI 102 Ecology 2024 Lecture 18 PDF

BOI 102 ECOLOGY DR, KHAIRONIZAM MD ZAIN 18 FRESHWATER ECOSYSTEM  Ecosystems are classified into water-based aquatic and land-based terrestrial ecosystem categories. Based on the quality of water involved, the aquatic ecosystems are further classified into fresh water and marine water types...

BOI 102 ECOLOGY DR, KHAIRONIZAM MD ZAIN 18 FRESHWATER ECOSYSTEM  Ecosystems are classified into water-based aquatic and land-based terrestrial ecosystem categories. Based on the quality of water involved, the aquatic ecosystems are further classified into fresh water and marine water types. Freshwater ecosystems are a subset of Earth's aquatic ecosystems. They include lakes and ponds, rivers, streams and springs, and wetlands. They can be contrasted with marine ecosystems, which have a larger salt content. Freshwater habitats can be classified by different factors, including temperature, light penetration, and vegetation  LENTIC Ecosystems The freshwater ecosystems are generally classified into two major groups as, lentic and lotic ecosystems. The term Lentic ecosystems is given to LOTIC Ecosystems standing water bodies or still water bodies. The LENTIC Ecosystems include all standing water bodies like Lakes, ponds, swamps, or bogs. The term Lotic ecosystem is given to the flowing water bodies. The LOTIC Ecosystems include all flowing water bodies like rivers, streams, springs, and creeks.  1. River Ecosystem 2. Ecological factors of Rivers 3. Lake Ecosystem 4. Ecological factors of Lakes  River or Lotic Ecosystems Water is an essential component of life. Surface water resources are the mostly preferred locations for life settlements. Most of the human civilizations were originated near water courses, especially along the major rivers. A river is a large natural course of flowing water obtained from precipitation. The surface water moves down along the slopes due to the action of gravity.  Streams, tributaries, brooks, creeks, and springs are the different types of watercourses classified based on their dimension and distribution. A river water is always on the move. Every river has its own longitudinal profile and different cross-sections. The longitudinal profile indicates the nature of the slope existing at different places and levels. The cross-section of a river varies from the headwater zone to the mouth. These are called river valleys which may be ranging from sharp canyons and gorges to wider flat streams nearer to the delta. The velocity of water flowing in a stream is not uniform along with the longitudinal profile, also within their cross-sections  A river is a powerful geological agent. It can erode, transport, and deposit the sediments. These are called river alluvium. The alluvial deposits, clay, and silt of a river are the materials preferred for different activities.  A river may be called a major, medium, and minor river based on its catchment area, number and length of streams and tributaries, stage of development, and its discharge of water. A river may be called: a perennial river when there is a continuous flow of water throughout the year, an intermittent river when the flow is seasonal, an ephemeral river when the flow is occasional or rare  The following are the terms used to denote the small portions of rivers. Pool is a segment where the water is deeper and moving slowly. Riffle - is a segment where the flow is shallower and more turbulent Headwater, in a river, is the point of origin of the stream. Channel is the river course developed by constant erosion. Floodplain is the flatland existing on either side of the stream that is subject to seasonal flooding. The confluence of a river is called the mouth. This is the point at which the stream discharges all its load into a sea or other static body of water.  A flowing river water carries enormous amounts of salts in solution and sediments in suspension. It also rolls up a lot of bedload along the bottom. The water flowing through a river is called its discharge. The volume and velocity of river discharge depend on several geomorphic factors. The suspended and bedload sediments carried along with other organic matter in the flowing water control the characteristics of the river ecology. ECOLOGICAL FACTORS OF RIVERS The ecology of running waters is unique from that of other aquatic habitats. The following are the unique features of Freshwater Aquatic ecosystems 1. Flow is unidirectional, in lotic ecosystems 2. There is a state of continuous physical change. 3. There is a high degree of spatial and temporal heterogeneity at all scales (microhabitats). 4. Variability between lotic systems is quite high. 5. The biota is specialized to live with flow conditions.  The major abiotic factors controlling the lotic ecosystems are: Slope and geomorphic conditions including the nature of substratum. Physico-chemical properties of water such as temperature, color, alkalinity, pH, and dissolved oxygen. Flow velocity and quantity. Type and amount of suspended and bedload sediments. Turbidity. Thickness of the water column and the depth of light penetration. The climatological factors like atmospheric temperature, humidity, sunshine hours, evapotranspiration, and wind. Characteristics of lotic adaptations: The animals and plants living in lotic environments have certain specific adaptations. They are subjected to varieties of dynamic environmental factors, like water currents, pollutants, and suspended sediments. Lotic habitats are influenced by the effect of continuously moving water, pollution, suspended sediments, floods, and other human activities. The unique characteristics of running water habitat are : The establishment of a firm attachment with the substratum. Most of the diatoms and algae are examples of these. They live on the wooden logs, stones, and rock exposures. The swimmers are expected to have hooks or suckers to maintain grip over the polished surfaces. Some of them build nets around them for food trapping. Some of them, like snails and worms, may have sticky bottoms to move along the base. The life living in rivers, has a streamlined shape of the body. They may have a body rounded anteriorly and tapering posteriorly. This is for a free-swimming habit against the water currents. Some have a flat body to stay within the cracks and crevices of rocks. Rheotaxis is a feature seen in rivers. This is the capacity or mechanism by which fishes and other animals swim against the currents and rapidly flowing water. This is the resistance capacity of many lotic forms. Clinging habitat is another feature of Life in river ecosystems. Some organisms mostly stay closer and nearer to the hard bodies or materials. Some of the life forms in rivers have the characteristic feature of osmoregulation. Especially, the Protozoans eliminate excess water through a contractile vacuole.  Lentic Ecosystems – Need you to find the information about Lake ecosystems.