Has anyone ever seen hydrologic indicators of lentic or lotic systems? How ca someone classy a water body as lentic or lotic?
When I get back to my computer files, I will send Cowardin et al classification of wetlands and deep water habitats. It may also be searched on the internet.
Dear Paul, the very interesting question!
I never found any quantitative classification. May be it is connected of gradual changing and esp existing of ultra-small reservoirs as artificial objects hardly to be classified.
In Russian-Ukrainian speaking scientific community of hydrobiologists we are using the following approach...
I understand that you know this explanation but may be will be useful for some younger colleagues.
Aquatic ecosystems are divided into two groups, as: stagnant water bodies (lentic environment - from the Latin lentos - calm), it's lakes, ponds, swamps, and flowing water bodies (lotic - from the Latin lotus - washer).
Unlike terrestrial ecosystem, which is easy to delineate by means of phytocenoses, water as environment-forming factor, is characterized by smooth transitions from one complex of conditions to another. Therefore, for both marine and freshwater ecosystems it is difficult to distinguish the boundaries. Often in this case, use the main physical and geochemical characteristics of the water column.
The specificity of water systems isn't determined by the flow or its currency, primarily the thermodynamic properties of water etc. Water of the various ponds are also characterized by transparency, speed of mixing, salinity, content of dissolved gases.
Water pressure increases with depth, the different parts of water bodies in different ways removed from the coast. These and many other circumstances influence the distribution and spread of living water beings.
In lentic ponds there are sub-divided three main zones: littoral (shallow areas where light penetrates to the bottom and usually exist the band of the higher aquatic vegetation), limnetic (the layer of water over which the active light is penetrated, and profundal – zone in which light does not penetrate.
Below limnetic zone the accumulation of biomass is impossible, because here the processes of photosynthesis and respiration are aligned.
The lower bound limnetic zone is called the compensation horizon. To this boundary penetrates about 1% of sunlight. Usually this depth is about 100 m.
Lentic and lotic waters are very diverse in structure. Each of them characterized by complex of specific seasonal dynamics of the temperature that determines the placement of ecological niches. The movement of water, especially in lotic reservoirs associated with its speed, turbulence, determines the movement and localization of the emitted substances, the specificity of their deposition, decomposition, processes of self-purification, patterns of eutrophication.
Lentic and lotic ecosystems are differing in content of species and functional activity of autotrophic organisms (producents), phagotrophic (macroconsumers) and saprotrophic (microconsumers), and especially in the role and proportion of the aerobic and anaerobic decomposers of organic matter.
In rivers and streams mainly two zones are distinguished: shallow shoals and deep stretches. Each of these zones is characterized by its own inhabitants and its own community of organisms (biocenosis).
Andrey
As far as I know there are no quantitative definitions of lentic and lotic systems. As Christopher Taylor suggested that this is more qualitative assessment, related to the water flow conditions of the water body. It is an established fact that these two ecosystems show different ecological characteristics.
Qualitatively flow is present in lotic systems but that flow is by definition always directional (ie always moving in the same direction). This is not so for lentic systems.
Great ecologist E. Odum has for the first time introduced classification of a water body as lentic or lotic ecosystem. See for details:
Eugene Odum // Ecology, 1975
https://archive.org/details/ModernBiologySeriesEugenePleasantsOdumEcologyTheLinkBetweenTheNaturalAndTheSocia
Interesting discussion. And the organisms one finds don't help. In the wave-washed portions of Lake Champlain we find many of the same organisms we find in streams. There are even riffle beetles, sculpins, and Neophylax caddisflies. Lake Champlain is clearly lentic but with stereotypically lotic organisms in the wave-washed zone far removed from tributaries.
- Badges
- Science method
- Similar topics
- Biological Science
- Ecology