Effects of CO₂ Hydrate on Deep-Sea Foraminiferal Assemblages

Conference · Thu Jun 16 00:00:00 EDT 2005

OSTI ID:1035692

Ricketts, E. R. ^[1]; Kennett, J. P. ^[1]; Hill, T. M. ^[1]; Barry, J. P. ^[2]

---

1. Univ. of California, Santa Barbara, CA (United States). Dept. of Geological Sciences
2. Monterey Bay Aquarium Research Inst., Moss Landing, CA (United States)

This paper, conducted with the Monterey Bay Aquarium Research Institute (MBARI), is the first to investigate potential effects of CO₂ hydrates on benthic microfossils, specifically foraminifera. The experiment was conducted in September 2003 aboard the R/V Western Flier using the ROV Tiburon. Experimental (CO₂ exposed) and control cores were collected at 3600m and stained to distinguish live (stained) from dead (unstained) individuals. Foraminifera are ideal because of differing test composition (calcareous and agglutinated) and thickness, and diverse epifaunal and infaunal depth preferences. The effects of the CO₂ on assemblages have been tracked both vertically (10cm depth) and horizontally, and between live and dead individuals. Increased mortality and dissolution of calcareous forms resulted from exposure to CO₂ hydrate. Preliminary results suggest several major effects on surface sediment assemblages: 1) total number of foraminifera in a sample decreases; 2) foraminiferal diversity decreases in both stained and unstained specimens. The number of planktonic and hyaline calcareous tests declines greatly, with milliolids being more resistant to dissolution when stained; and 3) percentage of stained (live) forms is higher. Down-core trends (up to 10cm) indicate: 1) percent agglutinated forms decline and calcareous forms increasingly dominate; 2) agglutinated diversity decreases with depth; and 3) assemblages become increasingly similar with depth to those in control cores not subjected to CO₂ hydrate. Finally, these results imply almost complete initial mortality and dissolution upon CO₂ hydrate emplacement in the corrals.

• Research Organization: Univ. of California, Santa Barbara, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Biological and Environmental Research (BER)
• DOE Contract Number: FG02-03ER63696
• OSTI ID: 1035692
• Report Number(s): DE-FG02-03ER63696; Project ID 0009590
• Resource Relation: Conference: 5. International Conference on Gas Hydrates, Trondheim (Norway), 13-16 Jun 2005
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
Hydrate
Foraminiferal Assemblages
Rose Bengal
Deep-sea
Carbon Dioxide