Papers that I selected this week will demonstrate that salt lake research is not always about aquatic ecology. Lake is a habitat for many species and one of favorite study sites for ornithologists. Lake also can be considered as a geochemical factory. It is not surprising that geologists and chemists likes to study saline lakes.
1. Small and nice Snowy Plovers are nesting on shorelines of saline lakes within the Southern High Plains of Texas. If one checks the Google Earth he/she easily finds that this area is intensively used for agriculture. Resulted reduced artesian spring flow makes saline lakes unsuitable for nesting and migrating shorebirds. Sarah Saalfeld with colleagues monitored 215 nests from three saline lakes to evaluate factors influencing nest success of Charadrius nivosus. Predation and weather were the leading causes of nest failures. Nest success was negatively influenced by number of plants near the nest and positively influenced by percent surface water availability. When scientists compared results of nests monitoring in 2008-2009 and 1998-1999 they find that mean nest success has declined by 31%. The tendency is obvious – increased predation rates, decreased hydrological integrity, and habitat alterations lead to the decline of the Snowy Plovers in the region.
2. I never heard about Monohydrocalcite (MHC). Most probably you are also not aware on this mineral. While Japanese scientists leaded by Keisuke Fukushi demonstrate that monohydrocalcite is a promising remediation material for hazardous anions. MHC is a rare mineral that occurs in recent sediments in saline lakes.
The formation conditions is the pH of lake water should be higher than 8 and the Mg/Ca ratio should exceed 4. MHC is unstable and readily transforms to calcite or aragonite. In spite of instability it occurs in some lakes. Most probably certain additives, particularly phosphate and magnesium, stabilize MHC. Paper also discusses hazardous oxyanion sorption properties of MHS. For example the maximum arsenic sorption capacity per initial unit mass of MHC is more than four times higher than the simple adsorption capacity of calcite. I am not sure why monohydrocalcite is so rare. May be just nobody is interested in it. At least conditions described in the paper are nicely suit to our salt lakes. Probably I should go to our chemical department with the idea to check the availability of rare mineral in our lakes:)