The distribution and ecology of <i>Bathysiphon filiformis </i>sars and <i>B. major </i>de folin (Protista, Foraminiferida) on the continental slope off North Carolina

Citation:
Gooday, AJ, Levin LA, Thomas CL, Hecker B.  1992.  The distribution and ecology of Bathysiphon filiformis sars and B. major de folin (Protista, Foraminiferida) on the continental slope off North Carolina. Journal of Foraminiferal Research. 22:129-146.

Date Published:

Apr

Keywords:

abyssal ne atlantic, adamussium-colbecki, benthic foraminifera, community structure, deep-sea, East Pacific Rise, epibenthic meiofauna, manganese nodules, tube-caps, xenophyophores protista

Abstract:

Two large species of the agglutinated foraminifera genus Bathysiphon are common in samples and photographs from bathyal depths on the North Carolina continental slope: B. filiformis off Cape Hatteras (588-930 m bathymetric depth) and B. major off Cape Lookout (850-1950 m depth). The sampling area, and particularly the 850 m station where B. filiformis is abundant (mean densities of 59-154 per m2), is believed to receive large inputs of organic material from various sources. This is consistent with the previously observed occurrence of large Bathysiphon species in regions of high food supply. Ten camera sled transects across the eastern U.S. continental slope between 32-degrees-N and 41-degrees-N emphasize the abundance of B. filiformis in the Cape Hatteras area compared with its rarity or absence elsewhere along the continental slope. Box cores, bottom photographs, and direct submersible observations indicate that B. filiformis tubes project above the sediment in an arcuate curve with only the lower 1 cm or so buried. Bathysiphon major adopts a similar orientation but has a greater proportion (50-80%) of the tube buried. The voluminous, dense, granular protoplasm of both species contains biogenic particles (including diatoms, in B. filiformis only), dinoflagellate cysts, fungal remains, pollen grains, tintinnid loricae, polychaete jaws and setae, benthic foraminiferal tests, and fish tooth fragments), suggesting that they feed mainly on material derived from the sediment surface. Submersible observations indicate that B. filiformis is patchily distributed at 100 m scales. Smaller scale dispersion patterns (analyzed from photographs) are generally random but with a tendency to be aggregated at lower densities and uniform at higher densities. A variety of metazoans and foraminifers live epifaunally on the outer surfaces of B. filiformis tubes. The most frequently occurring metazoans were larvae and juveniles of an unidentified gastropod and a tubiculous terebellid polychaete Nicolea sp. The most common epifaunal foraminifers were Tritaxis conica and Trochammina sp. Tubes of B. major, however, are virtually devoid of epifauna. Our results support the view that large, agglutinated rhizopod tests may influence the structure of deep-water benthic communities. However, in the case of Bathysiphon on the North Carolina continental slope, the effect appears limited to taxa directly associated with the foraminiferal tubes.

Notes:

n/a

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