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Movement using a pseudopod is accomplished through increases in pressure at one point on the cell membrane. This pressure increase is the result of actin polymerization between the cortex and the membrane. As the pressure increases the cell membrane is pushed outward creating the pseudopod. When the pseudopod moves outward, the rest of the body ...
These organisms can be used to indicate the presence, concentration, and effect of water pollutants in the aquatic environment. Some water contaminants—such as nutrients, chemicals from surface runoff, and metals [20] —settle in the sediment of river beds, where many benthos reside. Benthos are highly sensitive to contamination, so their ...
Water flow can be described as laminar or turbulent. [2] Laminar flow is characterized by smooth motion: neighboring particles advected by such a flow will follow similar paths. Turbulent flow is dominated by re-circulation, whorls, eddies and apparent randomness. In such a flow particles which are neighbors at one moment can find themselves ...
Thermodynamically the flow of substances from one compartment to another can occur in the direction of a concentration or electrochemical gradient or against it. If the exchange of substances occurs in the direction of the gradient, that is, in the direction of decreasing potential, there is no requirement for an input of energy from outside the system; if, however, the transport is against ...
The BBL is generated by the friction of the water moving over the surface of the substrate, which decrease the water current significantly in this layer. [2] The thickness of this zone is determined by many factors, including the Coriolis force. The benthic organisms and processes in this boundary layer echo the water column above them. [2]
Benthos are the organisms that live in the benthic zone, and are different from those elsewhere in the water column; even within the benthic zone variations in such factors as light penetration, temperature and salinity give rise to distinct differences, delineated vertically, in the groups of organisms supported. [10]
One cycle takes several seconds, depending on the species and the osmolarity of the environment. The stage in which water flows into the CV is called diastole. The contraction of the contractile vacuole and the expulsion of water out of the cell is called systole. Water always flows first from outside the cell into the cytoplasm, and is only ...
Other physical and chemical conditions that also determine phytobenthos distributions include flow, acidity, nutrient, temperature, and the community's composition. [1] Water flow can determine the types and distributions of phytobenthos, especially in the stream communities where the water is constantly moving. [ 1 ]