Comparative oxygen and carbon isotopic records of Miocene and recent lacustrine unionid bivalves from Poland

Abstract

3 As so ci a tion of Pol ish Cli ma tol o gists, Krakowskie Przedmieście 30, 00-927 Warszawa, Po land 4 PHACOPS As so ci a tion of Friends of Geosciences, Łódź, Po land Błażejowski B., Racki G., Gieszcz P., Małkowski K., Kin A. and Krzywiecka K. (2013) Com par a tive ox y gen and car bon iso topic re cords of Mio cene and re cent lac us trine unionid bi valves from Po land. Geo log i cal Quar terly, 57 (1): 113-122, doi: 10.7306/gq.1072The d 13 C and d 18 O iso tope data from both fos sil (Mio cene) and mod ern fresh wa ter bi valve shells of fam ily Unionidae from Poland (spe cies Margaritifera flabellatiformis and Unio tumidus, re spec tively) show a sim i lar, trun cated si nu soi dal pat tern. The iso to pic pro files of the shells are vis i bly marked by three growth stages, linked with a pro gres sive loss of en vi ron men tal record be cause of de clin ing intra-an nual biocarbonate ac cre tion rate. The ju ve nile and gerontic phases ex hibit gen er ally more pos i tive and sta ble (pla teau) iso to pic pat tern than the mid-age stage. An in creas ing d 13 C trend is typ i cal for the fi nal life stage, likely in flu enced by nu tri ent over load ing, re vers ing the ten dency to wards 13 C de ple tion through out the in di vid ual's life induced by met a bolic pro cesses. Due to the pro gres sive loss of en vi ron men tal sig nals through on tog eny, these ini tial and fi nal iso to pic pro file seg ments prob a bly cor re spond to, re spec tively, an in stant sig na ture of the first sea son growth, and a multiyear value set of sum mer max ima dur ing ge ri at ric stage. Vague sea sonal cy clic re cord is the strik ing fea ture of the mid-age d18 O and d 13 C pro file slices. In case of low-am pli tude d 18 O curve, this is prob a bly pro moted by a sen si tiv ity of the lake eco sys tem to many dy namic intra-an nual fac tors af fect ing wa ter bud get bal ance. This con sis tent sig na ture mode seems to be typ i cal for lake-dwell ing unionid shells at least since Mio cene from dif fer ent cli ma tic zones, as con firmed by coeval lac us trine low-lat i tude mus sels from Amazonia. Thus, this iso tope re cord is rel e vant to ob tain in for ma tion on the hab i tat and life cy cle of the fos sil fresh wa ter bi valves, as well as could help to un der stand mod ern en vi ron men tal change.

Bivalve Impacts in Freshwater and Marine Ecosystems

“…Shell geochemistry can also reveal past climatic and other chemical and physical conditions. Isotopic signatures of 18 O and 13 C in freshwater mussels have been used to study climatic conditions as far back as the Miocene (Blazejowski et al 2013), and oxygen isotopes of both fossil and modern clams from the northwestern Atlantic Ocean were used to examine sea water temperature change in the eleventh, fourteenth, and nineteenth centuries relative to global climate patterns (Wanamaker et al 2011). Metal concentrations among shell growth layers can show past exposure to metals and rare earth elements (Merschel & Bau 2015).…”