التفاصيل البيبلوغرافية
| العنوان: |
Marine productivity leads organic matter preservation in sapropel S1: palynological evidence from a core east of the Nile River outflow |
| المؤلفون: |
van Helmond, Niels A.G.M., Hennekam, Rick, Donders, Timme H., Bunnik, Frans P.M., de Lange, Gert J., Brinkhuis, Henk, Sangiorgi, Francesca |
| المساهمون: |
Marine palynology and palaeoceanography, Marine geochemistry, Palaeo-ecologie, Climate and environment, Coastal dynamics, Fluvial systems and Global change |
| سنة النشر: |
2015 |
| مصطلحات موضوعية: |
Eastern Mediterranean, Holocene, Sapropel S1, Dinocysts, Pollen and spores, Productivity, Preservation, Nile discharge |
| الوصف: |
The formation of Eastern Mediterranean organic matter rich deposits known as sapropels is the results of two mechanisms: (enhanced) marine productivity and preservation of organic material at depth. However, their relative contribution and their leads and lags with respect to each other remain elusive. Here, we address these questions by studying sediments deposited prior to, during, and after the most recent sapropel (S1, ∼10–6 calibrated ka before present, BP) with an integrated marine and terrestrial palynological approach, combined with existing and newly generated geochemical data. The studied core was retrieved from an area under strong influence of the Nile outflow and has high average sediment accumulation rates allowing a high temporal resolution (of several decades to centuries). Marine productivity, as reconstructed with total dinocyst accumulation rates (ARs) and biogenic CaCO3 content, starts to increase ∼1 ka prior to sapropel formation. A shift in the dinocyst taxa contributing to the productivity signal at sapropel onset indicates the rapid development of (seasonal) water column stratification. Pollen and spore ARs also increase prior to sapropel onset, but a few centuries after the increase in marine productivity. Hence, the first shift to a high marine productivity system before sapropel deposition may have been mostly favoured by the injection of nutrients via shoaling of the nutricline with a minor contribution of nutrients from land via river input and flooding of the shelves. Pollen assemblages indicate a gradual change across the sapropel onset from a savanna-like, through coastal marsh expansion, toward an open woodland assemblage, which is consistent with enhanced Nile influence and delta development. At sapropel onset a marked shift in pollen ARs could suggest increased preservation under anoxia. However, major shifts in pollen assemblages and signs of selective- or partial decomposition of terrestrial palynomorphs are absent. We therefore suggest that the high pollen ARs largely result ... |
| نوع الوثيقة: |
article in journal/newspaper |
| وصف الملف: |
application/pdf |
| اللغة: |
English |
| تدمد: |
0277-3791 |
| Relation: |
https://dspace.library.uu.nl/handle/1874/303100 |
| الاتاحة: |
https://dspace.library.uu.nl/handle/1874/303100 |
| Rights: |
info:eu-repo/semantics/EmbargoedAccess |
| رقم الانضمام: |
edsbas.373B9903 |
| قاعدة البيانات: |
BASE |