By:Jason T. Hoverman(Dept. Of Ecology and also Evolutionary Biology, Uni the Colorado)&Pieter T. J. Johnson(Dept. Of Ecology and also Evolutionary Biology, Uni of Colorado)© Education

Citation:Hoverman,J.T.&Johnson,P.T.J.(2012)Ponds and also Lakes: A Journey through the Life education Knowledge3(6):17




While accounting for just 3% of the Earth"s surface, lakes and ponds are an important habitats, and carry out essential resources for a wide variety of species, including humans. What is the standing of these wealthy ecosystems?

Lakes and also ponds (also known as lentic systems) room a diverse set of inland freshwater habitats that exist across the globe and administer essential resources and also habitats for both terrestrial and aquatic organisms. Return widely spread and an important for countless species, consisting of humans, this habitats account for just over 3% that the Earth"s surface ar (Downing et al. 2006). Importantly, these rare equipment are progressively threatened by the human need for freshwater and also human activity (Dudgeon et al. 2006). Current evidence says that freshwater systems are much more imperiled than marine and terrestrial people (Sala et al. 2000, Dudgeon et al. 2006). Efficient conservation and management of these systems relies on our capacity to fulfill the growing human need for freshwater while preserving system integrity.The examine of lentic equipment is conducted within the ar of limnology. Limnology is the examine of the structural and also functional interrelationships of organisms of inland waters as they are impacted by your dynamic physical, chemical, and biotic environments (Wetzel 2001). Several excellent books published within the previous decade provide in-depth coverage of lakes and also ponds (Wetzel 2001, Brönmark & Hansson 2005, Moss 2010). An additional excellent resource is the Encyclopedia that Inland Waters (2009). In this article, we existing a brief overview the lentic systems and refer the leader to certain literature for an ext detailed information.

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Physical and also Chemical Structure

Lentic solution vary native ephemeral ponds that fill briefly throughout rain events and also then dried out, to permanent water bodies such as lakes (Figure 1). The world"s biggest freshwater lake, based on area, is Lake superior of phibìc America (82,100 km2) if the deepest is Baikal Lake the Asia (max depth = 1741 m; mean depth 730 m). Lakes and also ponds are developed by a diversity that processes. For example, the geologic uplift the mountains have the right to lead to depressions that fill with water to produce lakes. The subsidence the land along faults between tectonic plates has lead to the development of deep rift lakes such as the Rift sink Lakes of eastern Africa. Lakes deserve to also type in the crater of one inactive volcano. The movement of glaciers has actually been crucial force in creating lakes and ponds. For example, the Laurentian an excellent Lakes were produced following the retreat that the Laurentide ice cream sheet during the critical ice age 10,000 year ago. Rivers additionally play a duty in developing lakes. Because that example, a large meander in a river have the right to be reduced off from the main river to kind an oxbow lake. Additionally, the flood plain of a river have the right to inundate surrounding habitats creating small ponds together floodwaters recede.

The Laurentian great Lakes (a) of phibìc America, the three Gorges Dam (b) in China, a small pond (c) offered as a water resource for cattle, a high elevation lake (d) in the Sierra Mountains, California, a short-lived pond (e) installed within a woodland in Michigan, and also a little open-canopy wetland (f) in Pennsylvania.
© 2012 education and learning Photos courtesy of NASA (a, b), Pieter Johnson (c, d), Earl Werner (e), Jason Hoverman (f). All rights reserved.

Humans likewise create lentic habitats. Across the world, people have constructed impoundments and reservoirs to administer water resources for humans and also livestock, create energy, or regulate flooding. While huge water bodies have actually historically received many of the attention, ponds space the numerically leading lentic habitat (Downing et al. 2006). Ponds room generally breakthrough in which the water human body is progressively transformed and also incorporated into the terrestrial landscape. Successional development is propelled by precipitate of inorganic and also organic matter right into the system. Sedimentation prices are influenced by the size and also depth that the system, the surrounding terrestrial landscape, climate, productivity, and decomposition (Wetzel 2001). Shallow ponds provide an excellent example of successional development. Together sedimentation occurs, the depth the the pond is decreased which enables vegetation to progressively encroach into the system. End time, this leader to swamp conditions with was standing water present among the vegetation. Together sedimentation continues, marsh problems are developed with no was standing water however water saturation sediments. The terminal stage of succession can incorporate predominately dried land or bogs depending on such factors as the ar of the water table and climatic conditions.
The structure and role of ponds and lakes are established by determinants such as turbulence, temperature, water clarity, habitat size, and water depth. Wind turbulence and also temperature communicate to affect stratification and water circulation in ~ lakes. In the spring, wind turbulence circulates the water transparent a lake giving oxygen to the entire water column. However, together the temperature increases during the summer and wind subsides, thermal stratification
occurs, creating distinct layers in the water column; the upper warm-water epilimnion is separated indigenous the reduced cold-water hypolimnion through the thermocline. Oxygen concentration in the hypolimnion often tends to decline compared to the epilimnion because of the lack of water circulation. Additionally, without mixing to replenish liquified oxygen, respiration through benthic organisms in ~ the hypolimnion can more reduce oxygen concentrations. As the temperature begins to cool in the autumn, totality lake circulation is restored and the oxygen concentration is equalized. During the winter, thermal stratification can take place again, but the sample is reversed (inverse stratification); cold water rests over warm water because water density is greatest at 4°C. In addition to raising oxygen concentrations, water circulation plays an important role in circulating nutrients. Provided that lentic solution are extensively distributed across different elevations and also latitudes, there are a number of possible stratification patterns (Wetzel 2001). Many tropical lakes, for instance, do not endure seasonal temperatures below 4°C come initiate thermal stratification and also remain well mixed. Similarly, ponds often show small thermal stratification during the summer because of their shallow depth, i beg your pardon facilitates wind-mediated water circulation.
Another vital factor in lakes and also ponds is irradiate transmission, i beg your pardon is forced for photosynthesis in primary producers. Generally, the water pillar is divided into the photic and also aphotic zones. In the photic zone, light penetration is >1% and plants undergo photosynthesis. In contrast, light penetration is primary production. However, a deep lake through low water clarity may have a large aphotic zone since light transmission is blocked by suspended particles in the water column. Importantly, lakes and also ponds can alternate between clear and also turbid says as populations of primary producers respond to changes in light levels and also nutrient accessibility (Scheffer & van Nes 2007).
As in any ecosystem, nutrient inputs and also cycling have essential influences ~ above the structure and role of lentic systems. Nutrients room transported into lentic solution via terrestrial run-off, floor water flow, atmospheric deposition (e.g., rain), absent weathering, and also direct input from terrestrial systems (e.g., sheet litter). The 3 most vital nutrients space nitrogen, carbon, and phosphorus, which are essential aspects to every organisms. If phosphorus has historically been thought about the many limiting in lentic systems due to low input rates and the high propensity to type complexes through iron, leading to mineralization (Schindler 1974), current work says that nitrogen can likewise be minimal in lentic equipment (Elser et al. 2007). The it is provided of nutrients into lentic equipment determines the amount of primary productivity that have the right to be supported. Oligotrophic equipment are identified by short nutrient supply and low primary productivity where as eutrophic solution are identified by high nutrient supply and high major productivity. While organic systems have the right to be eutrophic, human task can boost the entry of nitrogen and also phosphorus into lentic systems bring about anthropogenic eutrophication. Industrial, agricultural, or municipal wastewater deserve to augment nutrient inputs right into lentic systems, i beg your pardon can transition the environmental equilibrium and lead come eutrophication. Anthropogenic eutrophication deserve to dramatically alter the food net structure and reduce water quality. Once eutrophication occurs, it is complicated to reverse owing to interior feedbacks (e.g., hysteresis).Biotic Structure: Lake Zones and Food WebsNearly 6% the described varieties (i.e., 100,000 species) are supported by freshwater systems (Dudgeon et al. 2006). Moreover, several of the world"s earliest lakes (>1 million year old) contain a high diversity that endemic varieties that have evolved through the procedure of adaptive radiation (Cristescu et al. 2010). In lakes and also ponds, much of the types diversity is focused in the littoral zone, near the shore, whereby algae and plants prosper in the numerous light needed for photosynthesis. Living within the plant matter is a cornucopia of pets including snails, amphibians, crustaceans, insects, and also fish. Past the littoral zone is the limnetic zone. This is the zone of open up water where light is still able to penetrate and support photosynthetic birds (i.e., photic zone). Consumer in this zone encompass zooplankton, which feeding on the algae, part insects, and also fish. Finally, the benthic zone is the bottom sediment (e.g., mud, sand, rock) the the habitat, which is overcame by invertebrate species.

Primary producers are generally divided into three groups, periphyton, phytoplankton, and also macrophytes. Periphyton grows on substrates such together mud, sand, rocks, and leaf litter whereby it appears as a green or brown film. This is critical resource for a diversity that herbivores consisting of macroinvertebrates (e.g., snails) and amphibian larvae. Phytoplankton is algae suspended in the water column. Phytoplankton is divided into several groups (e.g., cyanobacteria, diatoms, chrysophytes, dinoflagellates, desmids) that often tend to overcome at various levels of lake productivity. Herbivores such together zooplankton are typical consumers of phytoplankton. Macrophytes are normally the many visible team of primary producers in lakes and also ponds (Figure 2). Macrophyte species possess a diversity of growth forms. Emergent macrophytes experience photosynthesis above the water and also are generally found close come the shoreline. Together depth increases, submerged macrophytes that undergo photosynthesis under the water, dominate. Macrophytes provide resources for numerous herbivores and important refuge from predators.

Emergent macrophytes, which grow near shore, experience photosynthesis above the water. In contrast, submerged macrophytes undergo photosynthesis under water and are discovered farther indigenous shore.

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© 2012 education Photo courtesy that Jeremy Monroe, Freshwaters Illustrated. All rights reserved.
The consumer types found in lentic habitats incorporate worms, snails, amphibians, crustaceans, insects, reptiles, fish, and birds. Herbivorous groups such as snails, amphibian larvae, and also crustaceans play crucial role in regulating primary productivity and algal blooms. Additionally, these teams are a crucial resource because that predators. By integrating main producers, herbivores, and predators together, a food web is formed where species interact both directly and also indirectly v each other. Lakes and ponds have actually proven come be excellent model solution for researching food internet interactions. Food web theory is extremely crucial in ecology due to the fact that it offers a theoretical understanding that how transforms in the variety of types influence other species within the community. Critical characteristic that lentic habitats is their link with terrestrial systems. Indeed, many types depend on both aquatic and terrestrial habitats because of their facility life cycles (e.g., amphibians, insects). As such, power (e.g., nutrients, organisms) moves dynamically between the two systems (i.e., reciprocal subsidies; Nakano & Murakami 2001, Lamberti et al. 2010).Patterns in species RichnessSpecies-area relationships have actually a long history in environmental research and work ~ above lentic systems has actually widely supported rise in species richness with raising habitat area (MacArthur & Wilson 1967, Browne 1981, Wellborn et al. 1996, Dodson et al. 2000). However, there are many other biotic and also abiotic determinants that readjust alongside increases in habitat area, such together permanence, water acidity, and predation pressure. Every one of these may play essential roles in influencing varieties richness and also community framework (Wellborn et al. 1996, Brönmark & Hansson 1998, Wetzel 2000, Williams 2001). Physical environmental determinants such as hydroperiod and water chemistry have the right to limit the breadth of species distributions because of physiological limit (Williams 2001). Because that example, species that are tolerant of pond drying inhabit a diversity that habitat types (i.e., lakes and also ephemeral ponds) whereas types that room intolerant that pond dry are minimal to lakes (Wellborn et al. 1996, Williams 2001). Together a consequence of this physiological constraints, varieties richness often tends to boost as hydroperiod increases. However, biotic interactions likewise can play critical role in structuring communities. Factors such as competition and also predation can duty to limit the diversity of a types (Kerfoot & Sih 1987, Brönmark & Hansson 2002). For example, many types tolerant of pond drying are commonly outcompeted in irreversible waters. For this reason their variety is short or lock mainly occur in marginal habitat of the shores, i m sorry largely features as a temporary habitat. Additionally, the transition to much more permanent water is often associated with boost in the abundance of predators (Wellborn et al. 1996). For example, fish play critical role in reducing the abundance of types and influencing types composition and richness in irreversible lakes. Thus, abiotic and also biotic determinants can interact to influence species richness and community framework in lentic systems. Threats to Lentic Ecosystems

The biodiversity the freshwater habitats is increasingly threatened by person activities. Habitat loss, eutrophication, acidification, chemical contamination, an international warming, and also exotic varieties are just some that the determinants that have straight or indirectly affected lentic systems (Brönmark & Hansson 2002). Considerable progress has actually been do in identifying exactly how some of this threats impact aquatic communities, and also how to develop management methods to reduce or get rid of their impacts. Because that example, the entry of phosphorus, a limiting nutrient in lentic systems, was identified as a significant contributor come lake eutrophication (Schindler 1974). Consequently, laws have been enacted come treat wastewater and reduce sewage input the phosphorus into lentic systems. Although part lentic systems have actually recovered, eutrophication stays a persistent difficulty due to agricultural intensification and other non-point air pollution sources. Another daunting problem is the development of exotic varieties including plants, animals, and also pathogens right into lentic solution (Figure 3). In phibìc America, because that example, exotic wetland tree (e.g., purple loosestrife , Eurasian watermilfoil ) and also animals (e.g., grass carp , zebra mussel ) have the right to outcompete native types for nutrient or space. The arrival of the amphibian chytrid fungus (Batrachochytrium dendrobatidis) into main America is implicated in the die out of plenty of amphibian species (Kilpatrick et al. 2010). When the potential an adverse consequences that exotic types introduction are well recognized, regulating their spread out is complicated and, when established, eliminating castle from areas has been difficult. Lastly, human-mediated habitat loss and change are increasing involves driven through the broadening need for agricultural lands as well as development. These activities not only bring about the ns of habitat for types and an important water sources for a region, but also fragment and alter the landscape in i beg your pardon the continuing to be habitats room embedded. The combination of this threats and the scarcity the freshwater habitats make lentic systems among the most imperiled ~ above the planet (Sala et al. 2000, Dudgeon et al. 2006).