Dystrophic lake

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Dystrophic lake in Bielawa nature reserve in Poland Dystrophic lake in Bielawa nature reserve in Poland.JPG
Dystrophic lake in Bielawa nature reserve in Poland

Dystrophic lakes, also known as humic lakes, are lakes that contain high amounts of humic substances and organic acids. The presence of these substances causes the water to be brown in colour and have a generally low pH of around 4.0-6.0. Due to these acidic conditions, there is little biodiversity able to survive, consisting mostly of algae, phytoplankton, picoplankton, and bacteria. [1] [2] Ample research has been performed on the many dystrophic lakes located in Eastern Poland, but dystrophic lakes can be found in many areas of the world. [3]

Contents

Classification of dystrophic lakes

Lakes can be categorized according to the increasing productivity as oligotrophic, mesotrophic, eutrophic, and hypereutrophic. Dystrophic lakes used to be classified as oligotrophic due to their low productivity. However, more recent research shows dystrophia can be associated with any of the trophic types. This is due to a wider possible pH range (acidic 4.0 to more neutral 8.0 on occasion) and other fluctuating properties like nutrient availability and chemical composition. Therefore, dystrophia can be categorized as a condition affecting trophic state rather than a trophic state in itself. [4]

Chemical properties

Lake Matheson, a dystrophic lake in New Zealand, has water stained so dark by tannins that its reflection of the nearby Southern Alps has made it a tourist attraction Mount Aoraki (Mt. Cook) & Mount Tasman - Lake Matheson (New Zealand).jpg
Lake Matheson, a dystrophic lake in New Zealand, has water stained so dark by tannins that its reflection of the nearby Southern Alps has made it a tourist attraction

Dystrophic lakes have a high level of dissolved organic carbon. This consists of contains organic carboxylic and phenolic acids, which keep water pH levels relatively stable by acting as a natural buffer [5] . Therefore, the lake’s naturally acidic pH is largely unaffected by industrial emissions. Dissolved organic carbon also reduces the entry of ultraviolet radiation and can reduce the bioavailability of heavy metals by binding them. [6] There is a significantly lowered calcium content in the water and sediment of a dystrophic lake when compared with a regular lake. [1] Essential fatty acids, like EPA[ clarification needed ] and DHA[ clarification needed ], are still present in the organisms in humic lakes, but are downgraded in nutritional quality by this acidic environment, resulting low nutritional quality of dystrophic lake's producers, such as phytoplankton. [7] Hydrochemical Dystrophy Index is a scale used to evaluate the dystrophy level of lakes. In 2016, Gorniak proposed a new set of rules for evaluating this index, using properties such as the surface water pH, electric conductivity, and concentrations of dissolved inorganic carbon, and dissolved organic carbon. [8] Because of different preexisting trophic status, lakes affected by dystrophia may differ strongly in their chemical composition from other dystrophic lakes. [4] Studies of the chemical composition of dystrophic lakes have shown heightened levels of dissolved inorganic nitrogen and higher activities of lipase and glucosidase in polyhumic lakes when compared with oligohumic lakes. In oligohumic lakes, the surface microlayers have higher levels of phosphatase activity than the subsurface microlayers. The opposite is true when the lake is polyhumic. Both oligohumic and polyhumic lakes show higher aminopeptidase activity in the subsurface microlayers than in the surface microlayers. [3]

Life in dystrophic lakes

The catchment area of a dystrophic lake is usually a coniferous forest rich with peat mosses that spread along the water surface. [1] Despite the presence of ample nutrients, dystrophic lakes can be considered nutrient-poor, because their nutrients are trapped in organic matter, and therefore are unavailable to primary producers. [9] The organic matter in dystrophic lakes is mainly allochthonous: it is terrestrially derived: organic matter removed in the catchment area gradually fills this aquatic environment. Due to this organic matter rich environment, it is bacterioplankton that controls for the rate of nutrient flux between the aquatic and terrestrial environments. [10] The bacteria are found in high numbers and have great growth potentials despite dystrophic conditions. These bacteria drive the food web of humic lakes by providing energy and supplying usable forms of organic and inorganic carbon to other organisms, primarily to phagotrophic and mixotrophic flagellates. [11] Decomposition of organic matter by bacteria converts also organic nitrogen and phosphorus into their inorganic forms which are now available for uptake by primary producers which includes both large and small phytoplankton (algae and cyanobacteria). [2] [1] The biological activity of humic lakes is, however, dominated by bacterial metabolism, which dominates the food web. The chemistry of humic lakes makes it difficult for higher trophic levels such as planktivorous fish to establish themselves, leaving a simplified food web consisting mostly of plants, plankton, and bacteria. [10] The dominance of the bacteria means that the dystrophic lakes have a higher respiration rate than primary production rate. [1]

Impacts of dystrophication on a lake ecosystem

The formation of a humic lake via organic runoff has a dramatic effect on the lake ecosystem. Chemical composition changes that increase the lake’s acidity make it difficult for fish and other organisms to proliferate. The quality of the lake for use as drinking water also decreases as the carbon concentration and acidity increase. The fish that do adapt to the increased acidity may also not be fit for human consumption, due to the organic pollutants. Concentrations and mobility of heavy metals may also be altered as a result of changes in chemical composition of a humic lake. [12]

Dystrophic lakes and climate change

Lakes are commonly known to be important sinks in the carbon cycle. Due to their high levels of dissolved organic carbon, dystrophic lakes are significantly larger carbon sinks than clear lakes. [13] The elevated levels of carbon concentrations in humic lakes are affected by vegetation patterns in the catchment area, the runoff from which is the main source of organic material. However, changes in these levels can also be attributed to shifts in precipitation, modifications of soil mineralization rates, reduced sulphate deposition, and changes in temperature. All these factors can be affected by changes in climate. Contemporary climate change is expected to increase the supply of organic carbon to lakes and therefore change the character of some to the dystrophic one. [12]

Examples of dystrophic lakes

Examples of dystrophic lakes that have been studied by scientists include Lake Suchar II in Poland, lakes Allgjuttern, Fiolen, and Brunnsjön in Sweden, and Lake Matheson in New Zealand. [1] [8] [14]

Related Research Articles

<span class="mw-page-title-main">Plankton</span> Organisms living in water or air that are drifters on the current or wind

Plankton are the diverse collection of organisms that drift in water but are unable to actively propel themselves against currents. The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucial source of food to many small and large aquatic organisms, such as bivalves, fish, and baleen whales.

<span class="mw-page-title-main">Phytoplankton</span> Autotrophic members of the plankton ecosystem

Phytoplankton are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater ecosystems. The name comes from the Greek words φυτόν, meaning 'plant', and πλαγκτός, meaning 'wanderer' or 'drifter'.

<span class="mw-page-title-main">Limnology</span> Science of inland aquatic ecosystems

Limnology is the study of inland aquatic ecosystems. The study of limnology includes aspects of the biological, chemical, physical, and geological characteristics of fresh and saline, natural and man-made bodies of water. This includes the study of lakes, reservoirs, ponds, rivers, springs, streams, wetlands, and groundwater. Water systems are often categorized as either running (lotic) or standing (lentic).

<span class="mw-page-title-main">Biological pump</span> Carbon capture process in oceans

The biological pump (or ocean carbon biological pump or marine biological carbon pump) is the ocean's biologically driven sequestration of carbon from the atmosphere and land runoff to the ocean interior and seafloor sediments. In other words, it is a biologically mediated process which results in the sequestering of carbon in the deep ocean away from the atmosphere and the land. The biological pump is the biological component of the "marine carbon pump" which contains both a physical and biological component. It is the part of the broader oceanic carbon cycle responsible for the cycling of organic matter formed mainly by phytoplankton during photosynthesis (soft-tissue pump), as well as the cycling of calcium carbonate (CaCO3) formed into shells by certain organisms such as plankton and mollusks (carbonate pump).

<span class="mw-page-title-main">Redfield ratio</span>

The Redfield ratio or Redfield stoichiometry is the consistent atomic ratio of carbon, nitrogen and phosphorus found in marine phytoplankton and throughout the deep oceans.

<span class="mw-page-title-main">Detritus</span> Dead particulate organic material

In biology, detritus is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts communities of microorganisms that colonize and decompose it. In terrestrial ecosystems it is present as leaf litter and other organic matter that is intermixed with soil, which is denominated "soil organic matter". The detritus of aquatic ecosystems is organic substances that is suspended in the water and accumulates in depositions on the floor of the body of water; when this floor is a seabed, such a deposition is denominated "marine snow".

<span class="mw-page-title-main">Dissolved organic carbon</span> Organic carbon classification

Dissolved organic carbon (DOC) is the fraction of organic carbon operationally defined as that which can pass through a filter with a pore size typically between 0.22 and 0.7 micrometers. The fraction remaining on the filter is called particulate organic carbon (POC).

<span class="mw-page-title-main">Picoplankton</span> Fraction of plankton between 0.2 and 2 μm

Picoplankton is the fraction of plankton composed by cells between 0.2 and 2 μm that can be either prokaryotic and eukaryotic phototrophs and heterotrophs:

Heterotrophic picoplankton is the fraction of plankton composed by cells between 0.2 and 2 μm that do not perform photosynthesis. They form an important component of many biogeochemical cycles.

The microbial food web refers to the combined trophic interactions among microbes in aquatic environments. These microbes include viruses, bacteria, algae, heterotrophic protists. In aquatic ecosystems, microbial food webs are essential because they form the basis for the cycling of nutrients and energy. These webs are vital to the stability and production of ecosystems in a variety of aquatic environments, including lakes, rivers, and oceans. By converting dissolved organic carbon (DOC) and other nutrients into biomass that larger organisms may eat, microbial food webs maintain higher trophic levels. Thus, these webs are crucial for energy flow and nutrient cycling in both freshwater and marine ecosystems.

<span class="mw-page-title-main">Sea surface microlayer</span> Boundary layer where all exchange occurs between the atmosphere and the ocean

The sea surface microlayer (SML) is the boundary interface between the atmosphere and ocean, covering about 70% of Earth's surface. With an operationally defined thickness between 1 and 1,000 μm (1.0 mm), the SML has physicochemical and biological properties that are measurably distinct from underlying waters. Recent studies now indicate that the SML covers the ocean to a significant extent, and evidence shows that it is an aggregate-enriched biofilm environment with distinct microbial communities. Because of its unique position at the air-sea interface, the SML is central to a range of global marine biogeochemical and climate-related processes.

The deep chlorophyll maximum (DCM), also called the subsurface chlorophyll maximum, is the region below the surface of water with the maximum concentration of chlorophyll. The DCM generally exists at the same depth as the nutricline, the region of the ocean where the greatest change in the nutrient concentration occurs with depth.

<span class="mw-page-title-main">Marine snow</span> Shower of organic detritus in the ocean

In the deep ocean, marine snow is a continuous shower of mostly organic detritus falling from the upper layers of the water column. It is a significant means of exporting energy from the light-rich photic zone to the aphotic zone below, which is referred to as the biological pump. Export production is the amount of organic matter produced in the ocean by primary production that is not recycled (remineralised) before it sinks into the aphotic zone. Because of the role of export production in the ocean's biological pump, it is typically measured in units of carbon. The term was coined by explorer William Beebe as observed from his bathysphere. As the origin of marine snow lies in activities within the productive photic zone, the prevalence of marine snow changes with seasonal fluctuations in photosynthetic activity and ocean currents. Marine snow can be an important food source for organisms living in the aphotic zone, particularly for organisms that live very deep in the water column.

<span class="mw-page-title-main">Bacterioplankton</span> Bacterial component of the plankton that drifts in the water column

Bacterioplankton refers to the bacterial component of the plankton that drifts in the water column. The name comes from the Ancient Greek word πλαγκτός (planktós), meaning "wandering" or "drifting", and bacterium, a Latin term coined in the 19th century by Christian Gottfried Ehrenberg. They are found in both seawater and fresh water.

<span class="mw-page-title-main">Sea foam</span> Foam created by the agitation of seawater

Sea foam, ocean foam, beach foam, or spume is a type of foam created by the agitation of seawater, particularly when it contains higher concentrations of dissolved organic matter derived from sources such as the offshore breakdown of algal blooms. These compounds can act as surfactants or foaming agents. As the seawater is churned by breaking waves in the surf zone adjacent to the shore, the surfactants under these turbulent conditions trap air, forming persistent bubbles that stick to each other through surface tension.

<span class="mw-page-title-main">Hypoxia (environmental)</span> Low oxygen conditions or levels

Hypoxia refers to low oxygen conditions. For air-breathing organisms, hypoxia is problematic. But for many anaerobic organisms, hypoxia is essential. Hypoxia applies to many situations, but usually refers to the atmosphere and natural waters.

<span class="mw-page-title-main">Marine biogeochemical cycles</span>

Marine biogeochemical cycles are biogeochemical cycles that occur within marine environments, that is, in the saltwater of seas or oceans or the brackish water of coastal estuaries. These biogeochemical cycles are the pathways chemical substances and elements move through within the marine environment. In addition, substances and elements can be imported into or exported from the marine environment. These imports and exports can occur as exchanges with the atmosphere above, the ocean floor below, or as runoff from the land.

<span class="mw-page-title-main">Viral shunt</span>

The viral shunt is a mechanism that prevents marine microbial particulate organic matter (POM) from migrating up trophic levels by recycling them into dissolved organic matter (DOM), which can be readily taken up by microorganisms. The DOM recycled by the viral shunt pathway is comparable to the amount generated by the other main sources of marine DOM.

<span class="mw-page-title-main">Lake metabolism</span> The balance between production and consumption of organic matter in lakes

Lake metabolism represents a lake's balance between carbon fixation and biological carbon oxidation. Whole-lake metabolism includes the carbon fixation and oxidation from all organism within the lake, from bacteria to fishes, and is typically estimated by measuring changes in dissolved oxygen or carbon dioxide throughout the day.

<span class="mw-page-title-main">Marine food web</span> Marine consumer-resource system

A marine food web is a food web of marine life. At the base of the ocean food web are single-celled algae and other plant-like organisms known as phytoplankton. The second trophic level is occupied by zooplankton which feed off the phytoplankton. Higher order consumers complete the web. There has been increasing recognition in recent years that marine microorganisms.

References

  1. 1 2 3 4 5 6 Drzymulska, D., Fiłoc, M., Kupryjanowicz, M., Szeroczyńska, K., & Zieliński, P. 2015. Postglacial shifts in lake trophic status based on a multiproxy study of a humic lake. Holocene, 25(3), 495-507.
  2. 1 2 Jasser, I. 1997. The dynamics and importance of picoplankton in shallow, dystrophic lake in comparison with surface waters of two deep lakes with contrasting trophic status. Hydrobiologia, 342/343(1), 87-93.
  3. 1 2 Kostrzewska-Szlakowska, I. 2017. Microbial Biomass and Enzymatic Activity of the Surface Microlayer and Subsurface Water in Two Dystrophic Lakes. Polish Journal of Microbiology, 66(1), 75-84.
  4. 1 2 Kostrzewska-Szlakowska, I, Jasser, I. 2011. Black box: what do we know about humic lakes? Polish Journal of Ecology, 59(4), 647-664.
  5. ↑ Kullberg, Anders; Bishop, Kevin H.; Hargeby, Anders; Jansson, Mats; Petersen, Robert C. (1993). "The Ecological Significance of Dissolved Organic Carbon in Acidified Waters". Ambio. 22 (5): 331–337. ISSN   0044-7447.
  6. ↑ Korosi, J. B. and Smol, J. P. 2012. Contrasts between dystrophic and clearwater lakes in the long-term effects of acidification on cladoceran assemblages. Freshwater Biology, 57(1), 2449–2464.
  7. ↑ Taipale, S.J, Vuorio, K, Strandberg, U, et al. 2016. Lake eutrophication and brownification downgrade availability and transfer of essential fatty acids for human consumption. Environment International, 96(1), 156-166.
  8. 1 2 Górniak, A. 2016. A new version of the Hydrochemical Dystrophy Index to evaluate dystrophy in lakes. Ecological Indicators, 78(1), 566-573.
  9. ↑ Drakare, S, Blomqvist, P, Bergstro, A, et al. 2003. Relationships between picophytoplankton and environmental variables in lakes along a gradient of water colour and nutrient content. Freshwater Biology, 48(1), 729-740.
  10. 1 2 Newton, R.J. et al. 2006. Microbial community dynamics in a humic lake: differential persistence of common freshwater phylotypes. Environmental Microbiology, 8(6), 956-970.
  11. ↑ Salonen, K, and Jokinen, S. 1988. Flagellate grazing on bacteria in a small dystrophic lake. Hydrobiologia, 161(1), 203-209.
  12. 1 2 Larsen, S., Andersen, T., and Hessen, D. O. 2010. Global Change Biology, 17(2), 1186-1192.
  13. ↑ Sobek, S. et al. 2006. A Carbon Budget of a Small Humic Lake: An Example of the Importance of Lakes for Organic Matter Cycling in Boreal Catchments. Ambio, 35(8), 469-475.
  14. ↑ Flint, E. A. (1979). "Comments on the phytoplankton and chemistry of three monomictic lakes in Westland National Park, New Zealand". New Zealand Journal of Botany. 17 (2): 127–134. Bibcode:1979NZJB...17..127F. doi:10.1080/0028825X.1979.10426885.
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