Deep-sea macrofauna exposed to a simulated sedimentation event in the abyssal NE Atlantic

in situ pulse-chase experiments using C-13-labelled phytodetritus

N Aberle*, U Witte

*Corresponding author for this work

Research output: Contribution to journalArticle

52 Citations (Scopus)

Abstract

Tracer experiments with C-13-labelled diatoms Thalassiosira rotula (Bacillariophycea, 98% 13C-labelled) were conducted at the Porcupine Abyssal Plain (PAP) in the NE Atlantic (BENGAL Station; 48degrees50'N, 16degrees30'W, 4850 m depth) during May/June 2000. In situ enrichment experiments were carried out using deep-sea benthic chamber landers: within the chambers a spring bloom was simulated and the fate of this food-pulse within the abyssal macrobenthic community was followed. In focus was the role of different macrofauna taxa and their vertical distribution within the sediment column in consuming and reworking the freshly deposited material. T rotula is one of the most abundant pelagic diatoms in the NE Atlantic and therefore 0.2 g of freeze dried T rotula, equivalent to 1 g algal C m(-2) yr(-1), was injected into each incubation chamber. Three different incubation times of 2.5, 8 and 23 d were chosen in order to follow the uptake of 13C-labelled phytodetritus by macrofauna. After only 2.5 d, 77% of all macrofauna organisms showed tracer uptake. After 23 d the highest degree of enrichment was measured and 95% of the individuals had taken up C-13 from the introduced algal material. In addition to that a downward transport of organic matter was observed, even though the mixing was not very intense. The initial processing of carbon was dominated by polychaetes that made up a percentage of 52% Of total macrofauna. In general macrofauna organisms that lived close to the sediment surface had higher access to the simulated food-pulse, confirming the hypothesis that individuals close to the sediment surface have the strongest impact on the decomposition of phytodetritus. In our study we observed only modest vertical entrainment of C-13-tracers into the sediment. With regard to contradictory results from former C-13-enrichment experiments in bathyal regions, compared to results from our study site in the abyssal plain, we thus propose pronounced differences in feeding strategies between macrofauna communities from continental margins and abyssal plains.

Original languageEnglish
Pages (from-to)37-47
Number of pages11
JournalMarine Ecology Progress Series
Volume251
Publication statusPublished - 2003

Keywords

  • deep-sea
  • pulse-chase experiment
  • delta C-13 benthic carbon remineralisation
  • macrofauna
  • Porcupine Abyssal Plain
  • BIOGENIC PARTICLE FLUXES
  • FOOD-WEB STRUCTURE
  • NORTHEAST ATLANTIC
  • CONTINENTAL-SLOPE
  • SEASONAL REPRODUCTION
  • VERTICAL-DISTRIBUTION
  • BENTHIC FORAMINIFERA
  • PORCUPINE-SEABIGHT
  • STABLE ISOTOPES
  • STANDING STOCK

Cite this

@article{200efe0286854d038dc944e2efbdfde7,
title = "Deep-sea macrofauna exposed to a simulated sedimentation event in the abyssal NE Atlantic: in situ pulse-chase experiments using C-13-labelled phytodetritus",
abstract = "Tracer experiments with C-13-labelled diatoms Thalassiosira rotula (Bacillariophycea, 98{\%} 13C-labelled) were conducted at the Porcupine Abyssal Plain (PAP) in the NE Atlantic (BENGAL Station; 48degrees50'N, 16degrees30'W, 4850 m depth) during May/June 2000. In situ enrichment experiments were carried out using deep-sea benthic chamber landers: within the chambers a spring bloom was simulated and the fate of this food-pulse within the abyssal macrobenthic community was followed. In focus was the role of different macrofauna taxa and their vertical distribution within the sediment column in consuming and reworking the freshly deposited material. T rotula is one of the most abundant pelagic diatoms in the NE Atlantic and therefore 0.2 g of freeze dried T rotula, equivalent to 1 g algal C m(-2) yr(-1), was injected into each incubation chamber. Three different incubation times of 2.5, 8 and 23 d were chosen in order to follow the uptake of 13C-labelled phytodetritus by macrofauna. After only 2.5 d, 77{\%} of all macrofauna organisms showed tracer uptake. After 23 d the highest degree of enrichment was measured and 95{\%} of the individuals had taken up C-13 from the introduced algal material. In addition to that a downward transport of organic matter was observed, even though the mixing was not very intense. The initial processing of carbon was dominated by polychaetes that made up a percentage of 52{\%} Of total macrofauna. In general macrofauna organisms that lived close to the sediment surface had higher access to the simulated food-pulse, confirming the hypothesis that individuals close to the sediment surface have the strongest impact on the decomposition of phytodetritus. In our study we observed only modest vertical entrainment of C-13-tracers into the sediment. With regard to contradictory results from former C-13-enrichment experiments in bathyal regions, compared to results from our study site in the abyssal plain, we thus propose pronounced differences in feeding strategies between macrofauna communities from continental margins and abyssal plains.",
keywords = "deep-sea, pulse-chase experiment, delta C-13 benthic carbon remineralisation, macrofauna, Porcupine Abyssal Plain, BIOGENIC PARTICLE FLUXES, FOOD-WEB STRUCTURE, NORTHEAST ATLANTIC, CONTINENTAL-SLOPE, SEASONAL REPRODUCTION, VERTICAL-DISTRIBUTION, BENTHIC FORAMINIFERA, PORCUPINE-SEABIGHT, STABLE ISOTOPES, STANDING STOCK",
author = "N Aberle and U Witte",
year = "2003",
language = "English",
volume = "251",
pages = "37--47",
journal = "Marine Ecology Progress Series",
issn = "0171-8630",
publisher = "Inter-Research",

}

TY - JOUR

T1 - Deep-sea macrofauna exposed to a simulated sedimentation event in the abyssal NE Atlantic

T2 - in situ pulse-chase experiments using C-13-labelled phytodetritus

AU - Aberle, N

AU - Witte, U

PY - 2003

Y1 - 2003

N2 - Tracer experiments with C-13-labelled diatoms Thalassiosira rotula (Bacillariophycea, 98% 13C-labelled) were conducted at the Porcupine Abyssal Plain (PAP) in the NE Atlantic (BENGAL Station; 48degrees50'N, 16degrees30'W, 4850 m depth) during May/June 2000. In situ enrichment experiments were carried out using deep-sea benthic chamber landers: within the chambers a spring bloom was simulated and the fate of this food-pulse within the abyssal macrobenthic community was followed. In focus was the role of different macrofauna taxa and their vertical distribution within the sediment column in consuming and reworking the freshly deposited material. T rotula is one of the most abundant pelagic diatoms in the NE Atlantic and therefore 0.2 g of freeze dried T rotula, equivalent to 1 g algal C m(-2) yr(-1), was injected into each incubation chamber. Three different incubation times of 2.5, 8 and 23 d were chosen in order to follow the uptake of 13C-labelled phytodetritus by macrofauna. After only 2.5 d, 77% of all macrofauna organisms showed tracer uptake. After 23 d the highest degree of enrichment was measured and 95% of the individuals had taken up C-13 from the introduced algal material. In addition to that a downward transport of organic matter was observed, even though the mixing was not very intense. The initial processing of carbon was dominated by polychaetes that made up a percentage of 52% Of total macrofauna. In general macrofauna organisms that lived close to the sediment surface had higher access to the simulated food-pulse, confirming the hypothesis that individuals close to the sediment surface have the strongest impact on the decomposition of phytodetritus. In our study we observed only modest vertical entrainment of C-13-tracers into the sediment. With regard to contradictory results from former C-13-enrichment experiments in bathyal regions, compared to results from our study site in the abyssal plain, we thus propose pronounced differences in feeding strategies between macrofauna communities from continental margins and abyssal plains.

AB - Tracer experiments with C-13-labelled diatoms Thalassiosira rotula (Bacillariophycea, 98% 13C-labelled) were conducted at the Porcupine Abyssal Plain (PAP) in the NE Atlantic (BENGAL Station; 48degrees50'N, 16degrees30'W, 4850 m depth) during May/June 2000. In situ enrichment experiments were carried out using deep-sea benthic chamber landers: within the chambers a spring bloom was simulated and the fate of this food-pulse within the abyssal macrobenthic community was followed. In focus was the role of different macrofauna taxa and their vertical distribution within the sediment column in consuming and reworking the freshly deposited material. T rotula is one of the most abundant pelagic diatoms in the NE Atlantic and therefore 0.2 g of freeze dried T rotula, equivalent to 1 g algal C m(-2) yr(-1), was injected into each incubation chamber. Three different incubation times of 2.5, 8 and 23 d were chosen in order to follow the uptake of 13C-labelled phytodetritus by macrofauna. After only 2.5 d, 77% of all macrofauna organisms showed tracer uptake. After 23 d the highest degree of enrichment was measured and 95% of the individuals had taken up C-13 from the introduced algal material. In addition to that a downward transport of organic matter was observed, even though the mixing was not very intense. The initial processing of carbon was dominated by polychaetes that made up a percentage of 52% Of total macrofauna. In general macrofauna organisms that lived close to the sediment surface had higher access to the simulated food-pulse, confirming the hypothesis that individuals close to the sediment surface have the strongest impact on the decomposition of phytodetritus. In our study we observed only modest vertical entrainment of C-13-tracers into the sediment. With regard to contradictory results from former C-13-enrichment experiments in bathyal regions, compared to results from our study site in the abyssal plain, we thus propose pronounced differences in feeding strategies between macrofauna communities from continental margins and abyssal plains.

KW - deep-sea

KW - pulse-chase experiment

KW - delta C-13 benthic carbon remineralisation

KW - macrofauna

KW - Porcupine Abyssal Plain

KW - BIOGENIC PARTICLE FLUXES

KW - FOOD-WEB STRUCTURE

KW - NORTHEAST ATLANTIC

KW - CONTINENTAL-SLOPE

KW - SEASONAL REPRODUCTION

KW - VERTICAL-DISTRIBUTION

KW - BENTHIC FORAMINIFERA

KW - PORCUPINE-SEABIGHT

KW - STABLE ISOTOPES

KW - STANDING STOCK

M3 - Article

VL - 251

SP - 37

EP - 47

JO - Marine Ecology Progress Series

JF - Marine Ecology Progress Series

SN - 0171-8630

ER -