MEPS 438:129-142 (2011)  -  DOI: https://doi.org/10.3354/meps09298

ABSTRACT: Foraminifera are an important faunal element of the abyssal ecosystem and largely depend on deposited particulate organic matter from the photic zone to sustain their metabolism for growth and reproduction. However, their role in the carbon cycle in deep-sea sediments is insufficiently studied. We investigated benthic foraminifera at Station M (4000 m depth) in the Northeast Pacific and assessed the response of individual species to a simulated phytodetritus pulse during an in situ feeding experiment. Sediments were incubated for 4 d with ¹³C-labeled diatoms (Thalassiosira weissflogii) applied to the sediment surface. The living foraminiferal community (>0.063 mm) of the upper 3 cm contained >100 species and was strongly dominated by a few taxa of soft-walled saccamminids. Population density of the entire living foraminiferal community was highest at the sediment surface (mean ± SD = 279 ± 72 ind. 10 cm⁻³ in background and ¹³C-incubated cores) and decreased gradually with depth. Large differences were observed in the uptake of the algal material among species and between depth levels. During the experiment, 0.82 mg C m⁻² were ingested, mainly by calcareous (~60%) and agglutinated (~40%) foraminifera. Uptake was highest at the sediment surface and 3 to 5 times less in deeper sediment horizons. Despite clear signs of vitality and a strong representation in the foraminiferal community, none of the soft-walled species showed a noticeable response to the offered algal material. We conclude that soft-walled foraminifera may not be important to the short-term phytodetrital matter cycling at the abyssal sea floor.

KEY WORDS: Deep sea · North Pacific · In situ feeding experiment · δ¹³C · Isotopic labeling · Benthic foraminifera · Carbon remineralization · Soft-walled saccamminid

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Cite this article as: Enge AJ, Nomaki H, Ogawa NO, Witte U and others (2011) Response of the benthic foraminiferal community to a simulated short-term phytodetritus pulse in the abyssal North Pacific. Mar Ecol Prog Ser 438:129-142. https://doi.org/10.3354/meps09298 Export citation Share:    Facebook - - linkedIn