Influence of lateral particle advection and organic matter degradation on sediment accumulation and stable nitrogen isotope ratios along a productivity gradient in the Canary Islands region
✍ Scribed by T. Freudenthal; S. Neuer; H. Meggers; R. Davenport; G. Wefer
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 438 KB
- Volume
- 177
- Category
- Article
- ISSN
- 0025-3227
No coin nor oath required. For personal study only.
✦ Synopsis
We compare total and biogenic particle ¯uxes and stable nitrogen isotope ratios (d 15 N) at three mooring sites along a productivity gradient in the Canary Islands region with surface sediment accumulation rates and sedimentary d 15 N. Higher particle ¯uxes and sediment accumulation rates, and lower d 15 N were observed in the upwelling in¯uenced eastern boundary region (EBC) compared to the oligotrophic sites north of Gran Canaria [European Station for Time-Series in the Ocean, Canary Islands (ESTOC]] and north of La Palma (LP). The impact of organic matter degradation and lateral particle advection on sediment accumulation was quanti®ed with respect to the multi-year ¯ux record at the ESTOC. Remineralisation of organic matter in the water column and at the sediment surface resulted in an organic carbon preservation of about 0.8% and total nitrogen preservation of about 0.4% of the estimated export production. Higher total and carbonate ¯uxes and accumulation rates in the lower traps and surface sediment compared to the upper traps indicated that at least 50% of the particulate matter at the ESTOC was derived from allochthonous sources. Low d 15 N values in the lower traps of the ESTOC and LP point to a source region in¯uenced by coastal upwelling. We conclude from this study that the reconstruction of export production or nutrient regimes from sedimentary records in regions with strong productivity gradients might be biased due to the mixture of particles originating from autochthonous and allochthonous sources. This could result in an imprint of high productivity signatures on sedimentation processes in oligotrophic regions.