Carbon
Abstract Size restricted carbon isotopes (d13C) are used to track changes in the onto-genetic life strategies of two species of extinct planktonic foraminifera and demonstrate that the species Morozovelloides crassatus lost their photosymbiotic association prior to their extinction in the latest mid...
| Main Authors: | , , , , , |
|---|---|
| Other Authors: | |
| Format: | Text |
| Language: | English |
| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.600.4393 http://geotest.tamu.edu/userfiles/42/wade2008.pdf |
| Summary: | Abstract Size restricted carbon isotopes (d13C) are used to track changes in the onto-genetic life strategies of two species of extinct planktonic foraminifera and demonstrate that the species Morozovelloides crassatus lost their photosymbiotic association prior to their extinction in the latest middle Eocene. M. crassatus exhibit a strong positive corre-lation between test size and d13C between 39.5 Ma and 38.7 Ma and a Dd13C shift of 1.0%/ 100 mm, this is analogous with modern species that possess an association with algal photosymbionts. Turborotalia cerroazulensis is interpreted as an asymbiotic, thermocline dweller and consistently shows no size related d13C trends and greater d18O values in comparison to Morozovelloides. We show a long-term (1.5 million year) deterioration of Morozovelloides ecology that culminated in their extinction at 38.021 Ma. The Dd13C / 100 mm in M. crassatus is dramatically reduced from 1.0 % at 39.53 to only 0.2 % at 38.026 Ma, 5 kyr before their extinction. The decline in ontogenetic d13C suggests diminished photosymbiotic activity (bleaching) and disruption of foraminiferal ecology in the interval preceding their extinction. We conclude that the demise of Morozovelloides was directly related to the deterioration of photosymbiotic partnerships with algae. |
|---|