Inland lakes are warming, and continued warming will decrease seasonal mixing of stratified lakes and reduce available dissolved oxygen

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Inland lakes are warming on average 0.34°C per decade (O’Reilly 2015, observed 1985-2009) and are projected to warm by as much as 2.9 to 3.02°F in stratified lakes by end of century under three climate models and a high (A2) emissions scenario (Herb 2014). Lake warming is correlated with air temperature trends (Winslow 2017); however, individual lakes are expected to respond differently based upon size, clarity, depth, elevation, sheltering from wind, and adjacent land-uses. Lakes that experience reduced winter ice duration, increased summer air temperatures, less cloud cover, and more shortwave radiation are generally expected to have greater increases in water temperature (O’Reilly 2015). Warming waters increase the duration of lake stratification, creating anoxic conditions and reducing the amount of dissolved oxygen available for plants and aquatic organisms (Snortheim et al. 2017, Hetherington et al 2015). Dissolved oxygen is further reduced when aquatic species increase respiration rates to cope with warming conditions. Cold-water fisheries are expected to be particularly vulnerable and sensitive to anticipated changes in lake dynamics (Hansen 2017, Herb 2014).