Response of the benthic foraminiferal community to a simulated short-term phytodetritus pulse in the abyssal North Pacific

Annekatrin J. Enge*, Hidetaka Nomaki, Nanako O. Ogawa, Ursula Witte, Markus M. Moeseneder, Gaute Lavik, Naohiko Ohkouchi, Hiroshi Kitazato, Michal Kucera, Petra Heinz

*Corresponding author for this work

Research output: Contribution to journalArticle

24 Citations (Scopus)

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 C-13-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 C-13-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 (similar to 60%) and agglutinated (similar to 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.

Original languageEnglish
Pages (from-to)129-142
Number of pages14
JournalMarine Ecology Progress Series
Volume438
Early online date5 Oct 2011
DOIs
Publication statusPublished - 2011

Keywords

  • Deep sea
  • North Pacific
  • In situ feeding experiment
  • delta C-13
  • Isotopic labeling
  • Benthic foraminifera
  • Carbon remineralization
  • Soft-walled saccamminid
  • DEEP-SEA FORAMINIFERA
  • SEASONALLY DEPOSITED PHYTODETRITUS
  • MARINE ORGANIC-MATTER
  • TIME-SERIES
  • NE ATLANTIC
  • ARABIAN SEA
  • MICROHABITAT PREFERENCES
  • SEDIMENTATION EVENT
  • MELONIS-BARLEEANUM
  • NORWEGIAN FJORD

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