By:Jason T. Hoverman(Dept. The Ecology and also Evolutionary Biology, Uni of Colorado)&Pieter T. J. Johnson(Dept. The Ecology and Evolutionary Biology, Uni that Colorado)©2012altoalsimce.org Education

Citation:Hoverman,J.T.&Johnson,P.T.J.(2012)Ponds and also Lakes: A Journey with the Life Aquatic.altoalsimce.org education and learning Knowledge3(6):17
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While audit for just 3% of the Earth"s surface, lakes and also ponds are critical habitats, and carry out essential sources for a wide selection of species, including humans. What is the condition of these affluent ecosystems?

Lakes and ponds (also known as lentic systems) are a diverse set of inland freshwater habitats that exist throughout the world and carry out essential resources and habitats because that both terrestrial and also aquatic organisms. Return widely distributed and vital for countless species, including humans, these habitats account for simply over 3% the the Earth"s surface (Downing et al. 2006). Importantly, this rare systems are increasingly threatened by the human demand for freshwater and human activity (Dudgeon et al. 2006). Recent evidence suggests that freshwater systems are much more imperiled 보다 marine and also terrestrial ones (Sala et al. 2000, Dudgeon et al. 2006). Efficient conservation and management of this systems counts on our ability to satisfy the farming human need for freshwater while preserving system integrity.The examine of lentic equipment is performed within the ar of limnology. Limnology is the research of the structural and functional interrelationships of biology of inland waters together they are impacted by your dynamic physical, chemical, and also biotic atmospheres (Wetzel 2001). Several excellent publications published in ~ the past decade carry out in-depth coverage the lakes and ponds (Wetzel 2001, Brönmark & Hansson 2005, Moss 2010). One more excellent resource is the Encyclopedia the Inland Waters (2009). In this article, we present a short overview the lentic systems and refer the reader to certain literature for more detailed information.

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Physical and also Chemical Structure


Lentic equipment vary native ephemeral ponds that fill briefly during rain events and also then dried out, to irreversible water bodies such as lakes (Figure 1). The world"s largest freshwater lake, based on area, is Lake superior of north America (82,100 km2) when the deepest is Baikal Lake of Asia (max depth = 1741 m; typical depth 730 m). Lakes and ponds are developed by a diversity that processes. For example, the geologic uplift that mountains can lead to depressions the fill with water to create lakes. The subsidence that land along faults between tectonic plates has lead come the development of deep rift lakes such together the Rift valley Lakes of east Africa. Lakes can also form in the crater of one inactive volcano. The movement of glaciers has been vital force in producing lakes and also ponds. For example, the Laurentian an excellent Lakes were created following the retreat of the Laurentide ice sheet during the last ice age 10,000 years ago. Rivers also play a role in producing lakes. For example, a wide meander in a river can be reduced off indigenous the key river to kind an oxbow lake. Additionally, the flood plain of a river deserve to inundate bordering habitats creating tiny ponds as floodwaters recede.


The Laurentian good Lakes (a) of phibìc America, the three Gorges Dam (b) in China, a small pond (c) provided as a water resource for cattle, a high key lake (d) in the Sierra Mountains, California, a short-term pond (e) embedded within a forest in Michigan, and also a little open-canopy marsh (f) in Pennsylvania.
© 2012 altoalsimce.org education and learning Photos courtesy the NASA (a, b), Pieter Johnson (c, d), Earl Werner (e), Jason Hoverman (f). All civil liberties reserved.

Humans likewise create lentic habitats. Across the world, human beings have constructed impoundments and reservoirs to administer water resources for humans and livestock, create energy, or manage flooding. While huge water bodies have historically received many of the attention, ponds room the numerically dominant lentic habitat (Downing et al. 2006). Ponds are generally advancement in i m sorry the water human body is gradually transformed and also incorporated into the terrestrial landscape. Successional development is thrust by sedimentation of inorganic and also organic matter into the system. Sedimentation prices are influenced by the size and also depth of the system, the neighboring 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 reduced which permits vegetation to progressively encroach right into the system. End time, this leads to swamp problems with standing water present amongst the vegetation. Together sedimentation continues, marsh problems are established with no stand water but water saturation sediments. The terminal phase of succession can include predominately dry land or bogs depending on such factors as the ar of the water table and also climatic conditions.
The structure and function of ponds and also lakes are figured out by factors such together turbulence, temperature, water clarity, habitat size, and also water depth. Wind turbulence and also temperature connect to affect stratification and water circulation in ~ lakes. In the spring, wind turbulence circulates the water throughout a lake supplying oxygen come the whole water column. However, as the temperature increases during the summer and also wind subsides, heat stratification
occurs, producing distinct layers in the water column; the upper warm-water epilimnion is separated indigenous the reduced cold-water hypolimnion by the thermocline. Oxygen concentration in the hypolimnion often tends to decline compared to the epilimnion as result of the lack of water circulation. Additionally, without mix to replenish liquified oxygen, respiration by benthic organisms within the hypolimnion can more reduce oxygen concentrations. As the temperature starts to cool in the autumn, totality lake circulation is restored and the oxygen concentration is equalized. During the winter, heat stratification can occur again, but the pattern is reversed (inverse stratification); cold water rests over warm water because water density is highest at 4°C. In enhancement to raising oxygen concentrations, water circulation plays crucial role in turn nutrients. Offered that lentic systems are generally distributed throughout different elevations and also latitudes, there space a variety of possible stratification fads (Wetzel 2001). Many tropical lakes, because that instance, carry out not endure seasonal temperatures listed below 4°C come initiate thermal stratification and remain well mixed. Similarly, ponds regularly show small thermal stratification throughout the summer as result of their shallow depth, i beg your pardon facilitates wind-mediated water circulation.
Another an essential factor in lakes and ponds is light transmission, which is forced for photosynthesis in major producers. Generally, the water column is separated into the photic and also aphotic zones. In the photic zone, irradiate penetration is >1% and also plants undergo photosynthesis. In contrast, light penetration is primary production. However, a deep lake with low water clarity may have actually a large aphotic zone due to the fact that light transmission is blocked by suspended corpuscle in the water column. Importantly, lakes and also ponds can alternate between clear and turbid says as populaces of major producers respond to alters in irradiate levels and nutrient availability (Scheffer & valve Nes 2007).
As in any kind of ecosystem, nutrient inputs and cycling have essential influences top top the structure and duty of lentic systems. Nutrients space transported into lentic equipment via terrestrial run-off, floor water flow, atmospheric deposition (e.g., rain), rock weathering, and also direct input native terrestrial equipment (e.g., leaf litter). The three most vital nutrients room nitrogen, carbon, and also phosphorus, which are essential aspects to every organisms. If phosphorus has historically been thought about the most limiting in lentic systems due to low intake rates and the high propensity to kind complexes v iron, resulting in mineralization (Schindler 1974), current work suggests that nitrogen can additionally be limited in lentic equipment (Elser et al. 2007). The it is provided of nutrients right into lentic systems determines the amount of primary productivity that deserve to be supported. Oligotrophic solution are defined by short nutrient supply and also low major productivity where as eutrophic solution are identified by high nutrient supply and high major productivity. While natural systems can be eutrophic, human task can increase the input of nitrogen and phosphorus right into lentic systems resulting in anthropogenic eutrophication. Industrial, agricultural, or municipal wastewater can augment nutrient inputs into lentic systems, i m sorry can change the ecological equilibrium and lead to eutrophication. Anthropogenic eutrophication have the right to dramatically alter the food internet structure and also reduce water quality. Once eutrophication occurs, it is difficult to turning back owing to interior feedbacks (e.g., hysteresis).Biotic Structure: Lake Zones and Food WebsNearly 6% the described varieties (i.e., 100,000 species) space supported by freshwater systems (Dudgeon et al. 2006). Moreover, few of the world"s earliest lakes (>1 million years old) save a high diversity of endemic varieties that have evolved through the process of adaptive radiation (Cristescu et al. 2010). In lakes and also ponds, lot of the types diversity is focused in the littoral zone, near the shore, whereby algae and also plants thrive in the abundant light necessary for photosynthesis. Living in ~ the plant matter is a cornucopia of animals including snails, amphibians, crustaceans, insects, and fish. Beyond the littoral ar is the limnetic zone. This is the region of open up water where light is still able to penetrate and also support photosynthetic algae (i.e., photic zone). Consumer in this zone incorporate zooplankton, which feed on the algae, part insects, and fish. Finally, the benthic zone is the bottom sediment (e.g., mud, sand, rock) of the habitat, i beg your pardon is conquered by invertebrate species.

Primary producers are extensively divided right into three groups, periphyton, phytoplankton, and also macrophytes. Periphyton grows on substrates such together mud, sand, rocks, and leaf litter wherein it shows up as a green or brown film. This is vital resource for a diversity the herbivores consisting of macroinvertebrates (e.g., snails) and also amphibian larvae. Phytoplankton is birds suspended in the water column. Phytoplankton is split into several groups (e.g., cyanobacteria, diatoms, chrysophytes, dinoflagellates, desmids) that tend to dominate at different levels the lake productivity. Herbivores such together zooplankton are typical consumers that phytoplankton. Macrophytes are generally the most visible team of major producers in lakes and ponds (Figure 2). Macrophyte types possess a diversity of growth forms. Emergent macrophytes experience photosynthesis over the water and also are frequently 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 prosper near shore, undergo photosynthesis above the water. In contrast, submerged macrophytes undergo photosynthesis under water and also are uncovered farther native shore.

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© 2012 altoalsimce.org education and learning Photo courtesy of Jeremy Monroe, Freshwaters Illustrated. All legal rights reserved.
The consumer species found in lentic habitats include worms, snails, amphibians, crustaceans, insects, reptiles, fish, and birds. Herbivorous teams such as snails, amphibian larvae, and crustaceans play vital role in managing primary productivity and algal blooms. Additionally, these teams are a critical resource for predators. By integrating major producers, herbivores, and also predators together, a food web is formed where types interact both directly and also indirectly v each other. Lakes and ponds have actually proven come be excellent model systems for studying food net interactions. Food web theory is extremely important in ecology because it provides a theoretical understanding that how transforms in the variety of types influence other varieties within the community. Vital characteristic the lentic habitats is their connection with terrestrial systems. Indeed, many species depend top top both aquatic and terrestrial habitats because of their complex life cycles (e.g., amphibians, insects). Together such, power (e.g., nutrients, organisms) move dynamically between the two equipment (i.e., reciprocal subsidies; Nakano & Murakami 2001, Lamberti et al. 2010).Patterns in species RichnessSpecies-area relationships have a long background in eco-friendly research and work top top lentic systems has widely supported rise in types richness with boosting habitat area (MacArthur & Wilson 1967, Browne 1981, Wellborn et al. 1996, Dodson et al. 2000). However, over there are numerous other biotic and abiotic components that readjust alongside rises in habitat area, such as permanence, water acidity, and also predation pressure. Every one of these may play important roles in influencing varieties richness and also community structure (Wellborn et al. 1996, Brönmark & Hansson 1998, Wetzel 2000, Williams 2001). Physics environmental components such as hydroperiod and water chemistry have the right to limit the breadth of species distributions due to physiological constraints (Williams 2001). Because that example, varieties that are tolerant the pond drying inhabit a diversity of habitat types (i.e., lakes and ephemeral ponds) whereas types that space intolerant the pond drying are limited to lakes (Wellborn et al. 1996, Williams 2001). As a an effect of this physiological constraints, varieties richness has tendency to rise as hydroperiod increases. However, biotic interactions also can play an essential role in structuring communities. Factors such as competition and predation can duty to limit the diversity of a varieties (Kerfoot & Sih 1987, Brönmark & Hansson 2002). Because that example, many types tolerant the pond dry are commonly outcompeted in permanent waters. For this reason their variety is short or castle mainly occur in marginal habitat of the shores, i beg your pardon largely functions as a momentary habitat. Additionally, the change to more permanent water is often connected with boost in the diversity of predators (Wellborn et al. 1996). For example, fish play critical role in reduce the abundance of types and influencing varieties composition and also richness in irreversible lakes. Thus, abiotic and also biotic components can interact to influence varieties richness and also community structure in lentic systems. Threats to Lentic Ecosystems

The biodiversity that freshwater habitats is progressively threatened by human activities. Habitat loss, eutrophication, acidification, chemical contamination, worldwide warming, and exotic species are just some the the components that have directly or indirectly affected lentic equipment (Brönmark & Hansson 2002). Comprehensive progress has actually been make in identifying just how some of this threats affect aquatic communities, and also how to build management techniques to minimize or get rid of their impacts. Because that example, the input of phosphorus, a limiting nutrient in lentic systems, was established as a major contributor come lake eutrophication (Schindler 1974). Consequently, laws have actually been enacted to treat wastewater and reduce sewer input of phosphorus right into lentic systems. Although some lentic systems have recovered, eutrophication remains a persistent difficulty due to farming intensification and also other non-point air pollution sources. Another an overwhelming problem is the introduction of exotic varieties including plants, animals, and pathogens into lentic equipment (Figure 3). In phibìc America, for example, exotic wetland tree (e.g., violet loosestrife , Eurasian watermilfoil ) and animals (e.g., grass carp , zebra mussel ) can outcompete native species for nutrients or space. The arrival of the amphibian chytrid fungus (Batrachochytrium dendrobatidis) into main America is implicated in the die out of countless amphibian varieties (Kilpatrick et al. 2010). While the potential negative consequences that exotic varieties introduction space well recognized, managing their spread is difficult and, when established, eliminating them from neighborhoods has been difficult. Lastly, human-mediated habitat lose and modification are increasing concerns driven through the expanding need for agricultural lands and also development. These activities not only bring about the ns of habitat for varieties and vital water sources for a region, but likewise fragment and alter the landscape in i beg your pardon the remaining habitats are embedded. The combination of these threats and also the scarcity that freshwater habitats make lentic systems one of the many imperiled ~ above the planet (Sala et al. 2000, Dudgeon et al. 2006).