Chemocline erosion and its conservation by freshwater introduction to meromictic salt lakes

Abstract Salinity stratification has been documented in two meromictic lakes in detail. We present seven years of field data on the salinity stratification of meromictic lakes Wallendorfer See and Rassnitzer See forming in the pits of the former lignite mine Merseburg-Ost in the Central German Mining District. Mainly from groundwater inflows, salinity stratified meromictic residual lakes had formed before freshwater was introduced intentionally over a period of two years to fill the pits more rapidly close to the final water level. From the observations, changes in the salinity stratification were interpreted in terms of deposited potential energy. Freshwater introduction (capping) was quantified in terms of potential energy. Thus the evolution of the salinity profiles was explained and their residual shapes became understandable as a consequence of the flooding procedure. Based on the quantitative estimates of energy deposited in the stratification during deep recirculation in winter, prospective statements could be made about the further evolution of the monimolimnia.

[1]  Andreas Matzinger,et al.  Similarities and differences in the annual temperature cycles of East German mining lakes , 2000 .

[2]  Martin Schultze,et al.  Numerical prognosis for salinity profiles of future lakes in the opencast mine Merseburg-Ost , 1998 .

[3]  H. Klapper,et al.  Geogenically Acidified Mining Lakes — Living Conditions and Possibilities of Restoration , 1995 .

[4]  A. Wüest,et al.  Double-diffusive convection in Lake Nyos, Cameroon , 2004 .

[5]  R. Wieler,et al.  Accumulation of mantle gases in a permanently stratified volcanic lake (Lac Pavin, France) , 1999 .

[6]  B. Zippel,et al.  Composition and dynamics of autotrophic picoplankton and spectral light distribution in saline lignite mining lakes of Germany , 1999 .

[7]  J. Kjensmo.  The primary production and its influence on the meromictic stability in lake svinsjøen , 1968, Schweizerische Zeitschrift für Hydrologie.

[8]  K. A. Bekiashev,et al.  Intergovernmental Oceanographic Commission (IOC) , 1981 .

[9]  Bertram Boehrer,et al.  Stratification of lakes , 2008 .

[10]  S. Müller,et al.  Ultrasonic in situ measurements of density, adiabatic compressibility, and stability frequency , 2002 .

[11]  Gregory A. Lawrence,et al.  Simulation of Vertical Transport in Mining Pit Lake , 1999 .

[12]  P. Herzsprung,et al.  Limnology of sulfur-acidic lignite mining lakes. I. Physical properties: Influence of dissolved substances on electrical conductivity and density , 2000 .

[13]  M. Kuypers,et al.  Water column anammox and denitrification in a temperate permanently stratified lake (Lake Rassnitzer, Germany). , 2009, Systematic and applied microbiology.

[14]  J. Erez,et al.  Microbial microstratification, inorganic carbon photoassimilation and dark carbon fixation at the chemocline of the meromictic Lake Cadagno (Switzerland) and its relevance to the food web , 2001, Aquatic Sciences.

[15]  C. Kennedy,et al.  Strategies for Remediation of Former Opencast Mining Areas in Eastern Germany , 1999 .

[16]  Bertram Boehrer,et al.  Evidence for double diffusion in temperate meromictic lakes , 2010 .

[17]  J. Melack,et al.  Sensitivity of vertical mixing in a large saline lake to variations in runoff , 1996 .

[18]  H. Klapper,et al.  Water quality management of mining lakes: a new field of applied hydrobiology , 2001 .

[19]  N. P. Fofonoff,et al.  Algorithms for Computation of Fundamental Properties of Seawater. Endorsed by Unesco/SCOR/ICES/IAPSO Joint Panel on Oceanographic Tables and Standards and SCOR Working Group 51. Unesco Technical Papers in Marine Science, No. 44. , 1983 .

[20]  M. Schultze,et al.  Pit lakes of the Central German lignite mining district: Creation, morphometry and water quality aspects , 2010 .

[21]  G. Luther,et al.  An In-lake Reactor to Treat an Acidic Lake: the Effect of Substrate Overdosage , 2002 .

[22]  J. Samper,et al.  Modeling Geochemically Caused Permanent Stratification in Lake Waldsee (Germany) , 2011 .

[23]  S. MacIntyre,et al.  Nutrient fluxes from upwelling and enhanced turbulence at the top of the pycnocline in Mono Lake, California , 2001, Hydrobiologia.

[24]  D. Castendyk,et al.  Sensitivity analyses in pit lake prediction, Martha Mine, New Zealand 1: Relationship between turnover and input water density , 2007 .

[25]  Gregory A. Lawrence,et al.  Stability and meromixis in a water‐filled mine pit , 1998 .

[26]  E. Santofimia,et al.  Changes in stratification and iron redox cycle of an acidic pit lake in relation with climatic factors and physical processes , 2012 .

[27]  Clint D. McCullough,et al.  Approaches to remediation of acid mine drainage water in pit lakes , 2008 .

[28]  P. Kuschk,et al.  Full-scale bioremediation and long-term monitoring of a phenolic wastewater disposal lake , 2010 .

[29]  M. Schmid,et al.  Double‐diffusive convection in Lake Kivu , 2010 .

[30]  I. Lerche,et al.  Flooding of lignite mines: isotope variations and processes in a system influenced by saline groundwater , 2006, Isotopes in environmental and health studies.

[31]  Christoph von Rohden,et al.  Tracer experiment with sulfur hexafluoride to quantify the vertical transport in a meromictic pit lake , 2001, Aquatic Sciences.

[32]  G. C. Miller,et al.  Peer reviewed: understanding the water quality of pit lakes. , 1996, Environmental Science and Technology.

[33]  R. Kipfer,et al.  Impact of lake level change on deep‐water renewal and oxic conditions in deep saline Lake Van, Turkey , 2010 .

[34]  Gregory A. Lawrence,et al.  Treatment of Acid Rock Drainage in a Meromictic Mine Pit Lake , 2006 .

[35]  Jan H. Janse,et al.  Vertical stratification of physical, chemical and biological components in two saline lakes Shira and Shunet (South Siberia, Russia) , 2010, Aquatic Ecology.

[36]  D. Castendyk,et al.  Sensitivity analyses in pit lake prediction, Martha mine, New Zealand 2: Geochemistry, water–rock reactions, and surface adsorption , 2007 .

[37]  C. Blodau,et al.  The Role of Iron Minerals for the Biogeochemistry of Acid Pit Lakes , 2013 .

[38]  Johnnie N. Moore,et al.  Pit lakes: their characteristics and the potential for their remediation , 2000 .

[39]  John M. Melack,et al.  Meromixis in hypersaline Mono Lake, California. 1. Stratification and vertical mixing during the onset, persistence, and breakdown of meromixis , 1993 .

[40]  B. Boehrer,et al.  Assessing groundwater coupling and vertical exchange in a meromictic mining lake with an SF6-tracer experiment , 2009 .

[41]  G. E. Hutchinson,et al.  A treatise on limnology. , 1957 .

[42]  R. Trettin,et al.  Isotopenuntersuchungen zur Wechselwirkung von Grund- und Oberflächenwasser in der Entstehungsphase von Bergbauseen , 1999 .

[43]  Tom Pedersen,et al.  Vertical diffusion in meromictic Powell Lake, British Columbia , 1986 .

[44]  W. Williams.  The largest, highest and lowest lakes of the world: Saline lakes , 1996 .

[45]  G. Lawrence,et al.  The effect of sub-aqueous disposal of mine tailings in standing waters , 1997 .

[46]  E. Santofimia,et al.  Physico-chemical gradients and meromictic stratification in Cueva de la Mora and other acidic pit lakes of the Iberian Pyrite Belt , 2009 .

[47]  John M. Melack,et al.  The onset of meromixis during restoration of Mono Lake, California: Unintended consequences of reducing water diversions , 1998 .

[48]  G. C. Miller,et al.  Understanding the water quality of pit lakes , 1996 .