Abstract
We investigated assemblages of living benthic foraminifera (>63 mu m) from replicate samples at Station M in the abyssal Northeast Pacific. Push cores collected in September 2007 (StatM07) and May 2009 (StatM09) from 3953 m depth were examined for population densities, species composition, and vertical occurrence within the sediment. Analysis of rose Bengal-stained (StaM09) and cytoplasm bearing (StaM07) foraminifera revealed average total abundances in the top 1 cm of 284 ind./10 cm(3) (StaM07) and 365 ind./10 cm(3) (StaM09). At both sites monothalamous saccamminids were numerically abundant, at StM09 they dominated the 1-2 cm interval and at StaM07 they dominated at all depths. Calcareous taxa were numerically least abundant, while agglutinated foraminifera displayed the highest number of species. The occurrence of few abundant and many rare species resulted in diversity measures for StaM09 (H' 3.3, alpha 17.9) and StaM07 (H' 2.6, alpha 15.2). Numbers of individuals peaked at the sediment surface and declined with sediment depth; living specimens present down to 5 cm depth. The majority of species displayed an epifaunal or shallow-infaunal habitat The observed vertical distribution patterns, species diversity, and assemblage composition are similar to other abyssal North Pacific assemblages and reflect the level of organic flux at Station M.
| Original language | English |
|---|---|
| Pages (from-to) | 84-104 |
| Number of pages | 21 |
| Journal | Marine Micropaleontology |
| Volume | 96-97 |
| DOIs | |
| Publication status | Published - Dec 2012 |
| Externally published | Yes |
Funding
The authors would like to thank K.L. Smith Jr., the captain and the crew of the research vessel Western Flyer for their work and ship time. We are also thankful to M.M. Moeseneder and U. Witte for sampling and processing the sediment cores. Many thanks go to H. Schulz and P. Fittkau for their competent help with the SEM. We appreciate the comments by W. Joyce on the article and we also highly acknowledge the work of the three anonymous reviewers and the editor Frans Jorissen to improve this article. This research was supported by the Deutsche Forschungsgemeinschaft (grant HE-2460/5-1 for A. Enge).
Austrian Fields of Science 2012
- 105118 Palaeontology
Keywords
- Benthic foraminifera
- Deep sea
- North Pacific
- Diversity
- Vertical distribution
- Soft-walled foraminifera
- SURFACE OCEAN PRODUCTIVITY
- ORGANIC-CARBON FLUX
- DEEP-SEA SEDIMENTS
- SPECIES-DIVERSITY
- ATLANTIC-OCEAN
- TIME-SERIES
- NE PACIFIC
- PHYTODETRITUS PULSE
- CENTRAL CALIFORNIA
- WEDDELL SEA