Recent ostracods as ecological indicators and its applications: An example from the southern Tibetan Plateau

Abstract

• Environmental significance of ostracods in the Yamdrok-tso basin is disclosed. • Potential of ostracods in inferring natural and anthropogenic influences is assessed. • Ostracod-based transfer functions for Ca, salinity, and alkalinity perform well. • Transfer functions for water quality status are developed for the first time. • Models for water quality status can qualitatively infer anthropogenic influences. Recent ostracods, so-called ‘modern analogues’ of ostracod fossils, are systematically correlated to the ambient environment. The reveal on the ecological response of Recent ostracods to environment variables can contribute to infer the paleolimnology or paleoclimate history based on fossil records. Here we analyzed 49 surface samples collected from the Yamdrok-tso basin in the southern Tibetan Plateau, disclosed the environmental significance of ostracods as ecological indicators, and evaluated the potential of ostracods in inferring natural and potential anthropogenic influences. The results show that ostracods including 12 species within 8 genera are extracted, i.e., one predominant species Leucocytherella sinensis , two abundant species Tonnacypris estonica and Ilyocypris bradyi , and nine less abundant species Leucocythere dorsotuberosa , Fabaeformiscandona gyirongensis , Candona candida , Heterocypris salina , I. echinata , F. caudata , Herpetocypris reptans , C. xizangensis , and Ilyocypris sp. Confronting with calcium content, salinity condition, and alkalinity of the host water, the abundant species have different optima and tolerance ranges. I. bradyi is characterized as mesotitanophilic to polytitanophilic and freshwater to α-oligohaline species adapting to low to moderate alkalinity conditions, while T. estonica is characterized as oligotitanophilic to mesotitanophilic and β-oligohaline species bearing moderate to high alkalinity condition. L. sinensis is an oligotitanophilic to mesotitanophilic and freshwater to polymixohaline species with a wide alkalinity tolerance range. Ostracods show different reaction with respect to heavy metal(loid)s. Most species are sensitive to Pb, Cu, and Ni, and resistant to Ba, As, and U. The developed transfer functions for calcium, salinity, alkalinity, and water quality status imply that it is with considerable potential to infer the natural and anthropogenic influences in the quantitative or qualitative way. Our study provides a new sight of Recent ostracods as ecological indicators and its applications, especially for the indication of water quality status at the first time, and could contribute to develop good ostracod-based proxies for paleoclimate research.