DK: 18O on gastropods. Another time series is published for another gastropod and an ostracode speices. All three are very similar, although ostracodes are less complete.

cleaned of organic material using 15% H2O2, then washed with deionized water, rinsed in methanol, and dried. Gastropods were cleaned in the same manner, except that specimens were additionally cleaned by sonication...Multiple (5) gastropod shells were ground to a fine powder with a mortar and pestle and a portion of the pulverized aragonite was loaded into stainless steel carrying boats for isotopic analysis.Multiple individuals, each living approximately one year, were used to average shortterm (i.e. yearly) changes in lake conditions.

Mean lake water was enriched in 18O by evaporation and was 3.6? greater than mean rainwater.

Calculated 18O values for aragonite and calcite, precipitated in equilibrium with modern lake water (18Owater = + 2.6‰) at a mean annual temperature of 25 C, yield values of 0.92‰ and 0.78‰, respectively (Craig, 1965; Grossman & Ku, 1981). These theoretical values are close to mean values (0.85‰, 0.47‰, and 0.39‰) for recent samples of Cochliopina sp., Pyrgophorus sp., and C. ilosvayi, respectively. This suggests that all three taxa precipitate carbonate near equilibrium with the water in which they live.

Interpretation of early Holocene (9000 until 7300 14C yrBP) oxygen isotopic results in terms of E/P is at odds with the strong evidence for moist conditions based on the presence of extensive lowland forest. The discrepancy between early Holocene pollen and 18Oresults in the PetenItza core can be reconciled if lakewater 18O is assumed to have been controlled by both regional climate and the changing surface area/volume ratio of the filling lake

One gastropod species data used here, also another gastropod species and ostracod records which show the same trends.

year (MAT67aecea202): interpretation5_scope: '' has been replaced by 'climate'
depth (MAT9c7c006553): interpretation5_scope: '' has been replaced by 'climate'