Zones Found in Freshwater Lakes
- Littoral zone. The topmost zone in a lake is the littoral zone, which is the area near the shore. ...
- Limnetic zone. The limnetic zone is the sunlit part of the lake surrounded by the littoral zone. ...
- Profundal zone. The profundal zone is much colder and denser than the previous zones. ...
- Benthic zone. The benthic zone is the very bottom of a lake. ...
What are the different zones of a lake?
Lakes are divided into three distinct zones which are most commonly determined by depth and distance from the shoreline. Zones found in freshwater lakes include the littoral, limnetic, profundal and benthic zones. The topmost zone in a lake is the littoral zone, which is the area near the shore.
What are freshwater life zones?
Freshwater life zones are found in bodies of water of which the salt concentration is less than 1%. Approximately 1% of the Earth’s surface is covered with fresh water; however, 40% of known fish species inhabit freshwater. Lakes are divided into three distinct zones which are most commonly determined by depth and distance from the shoreline.
What is the zonation system of a lake?
Lakes have a vertical zonation consisting of the water column, underlying lacustrine sediments (lake sediments), and the benthic zone, which occupies a few. Table 1 Summary of the four major zonation systems for lakes. Zonation Temporal Description variability. Horizontal Stable Pelagic zone Littoral zone. Vertical Stable
What are the limiting factors of a freshwater habitat?
However, temperature, light, currents, amount of respiratory gases, and concentration of biogenic salts are important limiting factors influencing the organisms of all freshwater habitats. Lentic waters are generally divided into three zones or sub-habitats: littoral, limnetic, and pro-fundal. A small pond may consist entirely of littoral zone.
What are the 3 zones of a lake?
A typical lake has three distinct zones (limnetic, littoral and the benthic zone; Fig. 11) of biological communities linked to its physical structure. The littoral zone is the near shore area where sunlight penetrates all the way to the sediment and allows aquatic plants (macrophytes) to grow.
How many major zones do lakes have?
Lakes and ponds are divided into three different “zones” which are usually determined by depth and distance from the shoreline. The topmost zone near the shore of a lake or pond is the littoral zone.
What are lake zones based on?
Firstly, there are four different types of lake zones. These zones divide the body of water into different sections, depending on depth. The four lake zones are littoral, limnetic, profundal, and benthic.
What are the three life zones found in aquatic lake habitats?
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. The euphotic zone is the upper oceanic zone, where producer species produce oxygen. Nutrient levels are low and dissolved oxygen levels are high.
What four zones are found in deep lakes?
The source zone, the transition zone, and the floodplain zone. In the narrow source zone, headwater streams are usually shallow, cold, clear, and swiftly flowing. As this turbulent water flows and tumbles downward over obstacles such as rocks, water falls, and rapids, it dissolves large amounts of oxygen from the air.
What is the deepest zone in a lake?
The profundal zone is a deep zone of an inland body of freestanding water, such as a lake or pond, located below the range of effective light penetration. This is typically below the thermocline, the vertical zone in the water through which temperature drops rapidly.
What is the littoral zone of a lake?
The littoral zone is the down-sloping shelf of a pond or lake. This is the area that stretches from the high-water mark to the shore and into the area where sunlight penetrates through to the sediments at the bottom of a waterbody.
What are the aquatic zones?
The basic types of aquatic life zones are the surface, middle, and bottom layers. The life in aquatic life zones is influenced by temperature, access to sunlight for photosynthesis, dissolved oxygen content, and availability of nutrients. 2. The major types of saltwater life zones are the coastal zone and the open sea.
What are the major components of a lake?
Temperature, light, and wind are three of the main factors that affect the physical characteristics of a lake. Temperature and light vary from lake to lake. Depth, plant growth, dissolved materials, time of day, season, and latitude can all affect light's ability to pass through the lake's water.
Do lakes have pelagic zones?
The pelagic zone is the region of a body of water (lake, river, or ocean) that is not associated with the bottom (see benthic zone) or shore (see littoral zone). This habitat zone is truly a three dimensional habitat space.
How many lakes are there in the world?
117 million lakesThere are a lot of lakes in the world. Big lakes, little lakes, red lakes, blue lakes. According to a new survey, there are roughly 117 million lakes on the planet.
How many lakes are in Canada?
Canada has more lake area than any other country in the world, with 563 lakes larger than 100 square kilometres. The Great Lakes, straddling the Canada-U.S. boundary, contain 18% of the world's fresh lake water. The country's largest lakes are depicted in the table below.
What are the aquatic zones?
The basic types of aquatic life zones are the surface, middle, and bottom layers. The life in aquatic life zones is influenced by temperature, access to sunlight for photosynthesis, dissolved oxygen content, and availability of nutrients. 2. The major types of saltwater life zones are the coastal zone and the open sea.
What is the top 10 biggest lakes in the world?
10 Largest Lakes in the WorldCaspian Sea (371,000 km2)[SEE MAP]Lake Superior (82,100 km2)[SEE MAP] ... Lake Victoria (68,870 km2)[SEE MAP] ... Lake Huron (59,600 km2)[SEE MAP] ... Lake Michigan (58,000 km2)[SEE MAP] ... Lake Tanganyika (32,600 km2)[SEE MAP] ... Lake Baikal (31,500 km2)[SEE MAP] ... Great Bear Lake (31,000 km2)[SEE MAP] ... More items...•
What are the three major zones of a freshwater lake?
Freshwater habitats are divided into two major categories, lotic (lotus = washed, or running water), and lentic (lenis = calm, ...
How many zones are there in a lake?
The three major zones of a lake described as follows (Fig. 4.9).
What is the limnetic zone?
The limnetic zone includes all the waters beyond the littoral zone and down to the light compensation level. The limnetic zone derives its oxygen content from the photosynthetic activity of phytoplankton and from the atmosphere immediately over the lake’s surface. The atmospheric source of oxygen becomes significant primarily when there is some surface disturbance of water caused by wind action or human activity. The community of the limnetic zone is composed only of plankton, nekton, and sometimes neuston (organisms resting or swimming on the surface).
What are the major groups of littoral zooplankton?
Important groups of littoral zooplankton are large, weak-swimming species of Daphia and Simocephalus, some species of copepods, many families of ostracods and some rotifers. The nekton of littoral zone is often rich in species and numbers. Adult and larval diving beetles and various adult Hemipetra are conspicuous.
What are the three zones of a lentic lake?
Lentic waters are generally divided into three zones or sub-habitats: littoral, limnetic, and pro-fundal. A small pond may consist entirely of littoral zone. However, a deep lake with an abruptly sloping basin may possess an extremely reduced littoral zone.
What are the two types of freshwater habitats?
Freshwater habitats are divided into two major categories, lotic (lotus = washed, or running water), and lentic (lenis = calm, or standing water) habitats. Lotic habitats are those existing in relatively fast running streams, springs, rivers and brooks. Lentic habitats are represented by the lakes, ponds, and swamps. ...
What are the two conditions that determine the freshwater environment?
The above classification of the freshwater environments is based on two conditions: currents and the ratio of the depth to surface area. Since lakes and ponds often contain currents or at least wave action and since streams often harbour quiet pools or calm backwaters, the difference between lotic and lentic waters is not very precise. However, temperature, light, currents, amount of respiratory gases, and concentration of biogenic salts are important limiting factors influencing the organisms of all freshwater habitats.
Surface water keeps life going
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Usable fresh surface water is relatively scarce
To many people, streams and lakes are the most visible part of the water cycle. Not only do they supply the human population, animals, and plants with the freshwater they need to survive, but they are great places for people to have fun.
How many types of lake zones are there?
Firstly, there are four different types of lake zones. These zones divide the body of water into different sections, depending on depth. The four lake zones are littoral, limnetic, profundal, and benthic.
What is the profundal zone of a lake?
The profundal zone is the section that follows the Limnetic once the sunlight cannot penetrate the lake’s surface any further. The temperature in these waters is also significantly colder, as the warmth from the sun is unable to reach these depths. The water clarity and composition has a significant effect on how deep the sunlight is able to reach, and therefore the size and depth of the profundal layer will vary from lake to lake. There is also a decreased amount of oxygen in this region of the lake, so the amount of fish in this area are also significantly less.
What is the season of dimictic lakes?
Dimictic lakes experience seasons. This means they have both a winter stratification below ice and a summer stratification. Circulation only occurs in these lakes during the fall and spring months.
What is the term used to describe the way lakes separate into layers based on temperature?
Lake stratification is the term used to describe the way lakes separate into layers based on temperature. Though related to the lake zones, this classification is strictly thermal. The change in temperature is due in part to the amount of light which can penetrate that lake’s waters. Because of this, lake density plays a key role in the temperature of the layers, and stratification more generally.
What is the limnetic zone?
The next layer is called the limnetic zone and is the surface or open water section of the lake. The limnetic zone is classified by the amount of light that penetrates the body of water. This upper water layer is also referred to as the euphotic zone, and is the part of the lake that is warmest and receives the most sunlight. Once the sunlight can no longer penetrate the lake, the zone ends. Like the Littoral zone, aquatic plants thrive in this region, due to the presence of sunlight. Oxygen levels are also higher in this section of the lake, meaning the majority of fish also live in this zone.
Why do meromic lakes not mix?
These lakes usually do not mix due to the presence of chemicals which make the waters hold different densities that are always separate.
What is the process of stratification of a lake?
When it comes to lake stratification, there are three different categories or layers. When the surface of a lake is warmed by the sun, water density begins to change, and thus the process of stratification begins. WInd then plays a significant part in mixing the upper layer of water, creating motion for the warm water and cool water to shift. Water that is cooler is denser, and so it circulates to the bottom of the lake, while the warmer water remains closer to the surface.
What is the vertical zone of lakes?
Lakes have a vertical zonation consisting of the water column, underlying lacustrine sediments (lake sediments), and the benthic zone, which occupies a few
Which is more diverse, the littoral zone or the pelagic zone?
In general, the communities of a littoral zone are more diverse than those of the pelagic zone, and the key species of the two zones differ. In the pelagic zone of a lake, the autotroph community is composed of phytoplankton (Figure 1), which are adapted for life in an environment that is free of solid surfaces.
What is the littoral zone?
The littoral zone extends outward from the shoreline to approximately the location at which the solar irradiance at the bottom of the lake corresponds to about 1% of the solar irradiance at the top of the water column. Within the littoral zone, growth of aquatic macrophytes and attached algae (periphyton) is possible.
What is the water column of the pelagic zone?
The water column of the pelagic zone is driven by wind-generated currents into the littoral zone where water is displaced from the littoral zone into the pelagic zone. Thus, water-column constituents such as dissolved gases, dissolved solids, suspended solids, and suspended organisms are constantly exchanged between the pelagic zone and the littoral zone whenever there are currents in the top few meters of a lake. Chemical differences between the top few meters of the pelagic zone and the littoral zone may develop under the influence of biological processes, however, when currents are weak.
What is the outer margin of the littoral zone?
The outer margin of the littoral zone, beyond which is the pelagic zone, is the point at which significant growth of macrophytes and periphyton becomes impossible because of darkness. This boundary corresponds approximately to the location at which the amount of solar irradiance reaching the bottom of the lake is <1% of surface irradiance. At bottom irra-diances <1%, there is little or no net photosynthesis, which prevents growth of the attached autotrophs (macrophytes and periphyton) that are typical of the littoral zone.
What are the autotrophs in the pelagic zone?
The littoral zone also has phytoplankton (which move freely between littoral zone and pelagic zone), but also has two other categories of autotrophs (Figure 1): aquatic vascular plants (aquatic macrophytes), and films of attached algae (periphyton). Periphyton grow on the leaves of macrophytes and on other solid surfaces such as mud, sand, rocks, or wood.
How deep is the littoral zone?
In oligotrophic lakes, which have low nutrient concentrations and therefore develop very small amounts of the phytoplankton biomass that could shade the lower water column of lakes, the littoral zone extends to depths of 4-20 m or even more, depending on transparency of the water. In the eutrophic category, the depth of 1% irradiance ranges between 0.1 and about 2 m, and the mesotrophic category spans ~2-4m. In the most extreme cases of eutrophication (lakes highly enriched with nutrients), where the depth of 1% light corresponds to only a few centimeters, the littoral zone as defined by light is virtually absent, and the littoral zone may be defined instead by the zone of influence for traveling waves and corresponding disturbance of the bottom (0.5-1.5 m). In general, small lakes have a higher percentage of surface area in the littoral zone than do large lakes (Figure 2), although some large, shallow lakes have large littoral zones (e.g., Lake Okeechobee, Florida).
