The comparative limnology of high arctic, coastal, meromictic lakes

Abstract

Five important features appear in rough order from the surface downwards in physical and chemical profiles from high arctic coastal meromictic lakes. These features are: (1) a supersaturated oxygen maximum, (2) the center of the oxycline, (3) a thermal maximum, (4) a major absorption maximum, and (5) an anoxic stratum. The depth of the absorption maxima and the top of the anoxic strata are both statistically correlated to light penetration and to each other. The depth of the thermal maximum also shows a statistical correlation to light penetration among lakes with a relatively shallow chemocline. The temperature of the thermal maximum appears to be maintained by inputs of light energy while the oxygen maximum is maintained to a large extent by photosynthesis. Thus, these major features are all influenced by light penetration. With the exception of the supersaturated oxygen maximum, all of the above features are dependent for their existence upon the primary chemocline stabilizing the water column. Apparently, in at least some lakes, a near surface secondary chemocline or cool (ca. 4 ~ secondary inverse thermocline will enhance the stability of the water column above the primary chemocline sufficiently to allow a supersaturated oxygen maximum to develop in this region. However, the supersaturated oxygen maximum can extend into the primary chemocline, and in highly transparent Sophia Lake (Cornwallis Island, N.W.T.) this feature extends below the primary chemocline.Where the chemocline is found below depths with adequate illumination, features other than the supersaturated oxygen maximum should be found in deeper water as well, or they should be eliminated from the profiles. Thus, where the chemocline is relatively shallow, the depth of features like the thermal maximum or anoxic strata are related most closely to light penetration, but where chemoclines are deep, as in Lake Tuborg (Ellesmere Island, N.W.T.), the depth of the chemocline determines the depth of the oxycline, thermal maximum, absorption maximum and anoxic stratum.

High Arctic lakes as sentinel ecosystems: Cascading regime shifts in climate, ice cover, and mixing

“…In addition to evidence of long-term lake ice covers from the existence of thermal maxima, these lakes were observed to have a refrozen candled ice cover prior to the onset of melt, which suggests that the ice cover was perennial (Hattersley-Smith et al 1970;Belzile et al 2001). Between 1969 and 1998, these lakes were never reported to have lost their ice cover during the summer beyond melting around the lake shore that created a ''moat'' of variable but limited extent (Bradley et al 1996;Ludlam 1996).…”

“…Lakes A and B have unglacierized catchment areas of 37 km 2 (Van Hove et al 2006) and approximately 5 km 2 , respectively. A perennial ice cover prevents windinduced mixing in all these lakes, while steep salinity gradients (with the exception of Lake C3) prevent convection in their water columns (Ludlam 1996;Vincent et al 2008). Consequently, the lakes have developed deep thermal maxima over many decades of solar heating .…”

“…Briefly, Hattersley-Smith et al (1970) used Knudsen bottles, reversing thermometers, and an automatic temperature-depth-salinity recorder; Jeffries et al (1984), Jeffries and Krouse (1985), and M. O. Jeffries unpubl. data used reversing thermometers and measured aliquots from Knudsen bottles with an Endeco refracting salinometer; Ludlam (1996) used a 2-Hz Seacat SBE 19-03 profiler; and Belzile et al (2001) and Van Hove et al (2006) both used a Hydrolab Surveyor 3 profiler. Unpublished profiles provided by M. Retelle were obtained using a temperature and salinity profiler (YSI) down to a depth of 60 m and from a Kemmerer bottle water for salinity at greater depths.…”

The chemical development of a hypersaline coastal basin in the High Arctic

“…In the Canadian Arctic, chemical and stratigraphic analyses of sediment cores reveal that many coastal lakes were initially marine basins before coastal emergence (Retelle 1986;King 1991). In certain systems, the transition from marine to lacustrine sediments appears to have been quite abrupt ), yet at least 12 lakes have been discovered that have remained saline or become hypersaline (Ludlam 1996;Van Hove et al 2006). What remain unclear are the different evolutionary processes that control the salinity of coastal polar lakes.…”

Mosaic structure of the fungal community in the Kislo-Sladkoe Lake that is detaching from the White Sea

“…As a result, water bodies are detaching from seas and oceans and transforming to meromictic lakes in northern parts of North America and Eurasia (Fig. 1;Dickman 1978;Ludlam 1996;Gibson et al 2002;Hakala 2004;Lutz and Kaulfuß 2006;Van Hove et al 2006;Pouliot et al 2009;Strelkov et al 2014;Gulati et al 2017). The coastal line of the White Sea (Russia) is a prominent example of this natural phenomenon.…”