Editing Limnology (section)

====Thermal stratification====
Similar to light zonation, thermal [[Lake stratification|stratification]] or thermal zonation is a way of grouping parts of the water body within an aquatic system based on the temperature of different lake layers. The less [[Turbidity|turbid]] the water, the more light is able to penetrate, and thus heat is conveyed deeper in the water.<ref name="water quality book">{{cite book|title=Water Quality: An Introduction|date=2015|publisher=Springer|isbn=978-3-319-17445-7|edition= Second|location=Switzerland|last1=Boyd|first1=Claude E.}}{{page needed|date=December 2020}}</ref> Heating declines exponentially with depth in the water column, so the water will be warmest near the surface but progressively cooler as moving downwards. There are three main sections that define thermal stratification in a lake. The [[epilimnion]] is closest to the water surface and absorbs long- and shortwave radiation to warm the water surface. During cooler months, wind shear can contribute to cooling of the water surface. The [[thermocline]] is an area within the water column where water temperatures rapidly decrease.<ref name="water quality book" /> The bottom layer is the [[hypolimnion]], which tends to have the coldest water because its depth restricts sunlight from reaching it.<ref name="water quality book" />  In temperate lakes, fall-season cooling of surface water results in turnover of the water column, where the thermocline is disrupted, and the lake temperature profile becomes more uniform. In cold climates, when water cools below 4<sup>o</sup>C (the temperature of maximum density) many lakes can experience an inverse thermal stratification in winter.<ref>{{Cite journal|last1=Yang|first1=Bernard|last2=Wells|first2=Mathew G.|last3=McMeans|first3=Bailey C.|last4=Dugan|first4=Hilary A.|last5=Rusak|first5=James A.|last6=Weyhenmeyer|first6=Gesa A.|last7=Brentrup|first7=Jennifer A.|last8=Hrycik|first8=Allison R.|last9=Laas|first9=Alo|last10=Pilla|first10=Rachel M.|last11=Austin|first11=Jay A.|date=2021|title=A New Thermal Categorization of Ice-Covered Lakes|url=http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-440176|journal=Geophysical Research Letters|language=en|volume=48|issue=3|pages=e2020GL091374|doi=10.1029/2020GL091374|bibcode=2021GeoRL..4891374Y |s2cid=233921281 |issn=1944-8007}}</ref> These lakes are often [[Dimictic lake|dimictic]], with a brief spring overturn in addition to longer fall overturn. The [[relative thermal resistance]] is the energy needed to mix these strata of different temperatures.<ref name="auto">Wetzel, R. G. (2001). Limnology: Lake and river ecosystems. San Diego: Academic Press.{{page needed|date=December 2020}} p74, 86</ref>