The possible role of the cyclopoid copepod Oithona in retarding vertical flux of zooplankton faecal material

González, Humberto E.; Smetacek, Victor

doi:10.3354/meps113233

Cited by 277 publications

(166 citation statements)

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“…To convert volume flux into carbon flux, we adopted carbon contents of 0.057 mg C mm À 3 for faecal pellets (Gonzalez and Smetacek, 1994), and applied the parameterisation for carbon conversion factors used in our previous work (Ebersbach and Trull, 2008). That formulation is based on the fractal decrease of carbon contents with size observed for large coastal marine snow Intact faecal pellet of oval from, dark brown/black 0.06-100 Fig.…”

Section: Particle Properties From the Polyacrylamide Gelsmentioning

confidence: 99%

Controls on mesopelagic particle fluxes in the Sub-Antarctic and Polar Frontal Zones in the Southern Ocean south of Australia in summer—Perspectives from free-drifting sediment traps

Ebersbach

Trull

Davies

et al. 2011

Deep Sea Research Part II: Topical Studies in Oceanography

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a b s t r a c tThe SAZ-Sense project examined ecosystem controls on Southern Ocean carbon export during austral summer (January-February 2007) at three locations: P1 in the low biomass Subantarctic Zone (SAZ) west of Tasmania, P3 in a region of elevated biomass in the SAZ east of Tasmania fuelled by enhanced iron supply, and P2 in High-Nutrient/Low Chlorophyll (HNLC) Polar Frontal Zone (PFZ) waters south of P1 and P3. Sinking particles were collected using (i) a cylindrical time-series (PPS3/3) trap for bulk geochemical fluxes, (ii) indented rotating sphere (IRS) traps operated as in-situ settling columns to determine the flux distribution across sinking-rate fractions, and (iii) cylindrical traps filled with polyacrylamide gels to obtain intact particles for image analysis.Particulate organic carbon (POC) flux at 150 m (PPS3/3 trap) was highest at P1, lower at P2, and lowest at P3 (3.3 71.8, 2.1 7 0.9, and 0.9 70.4 mmol m À 2 d À 1 , respectively). Biogenic silica (BSi) flux was very low in the SAZ (0.2 7 0.2 and 0.02 7 0.005 mmol m À 2 d À 1 at P1 and P3, respectively) and much higher in the PFZ (2.3 7 0.5 mmol m À 2 d À 1 at P2). Hence, the high biomass site P3 did not exhibit a correspondingly high flux of either POC or BSi. Separation of sinking-rate fractions with the IRS traps (at 170 and 320 m depth) was only successful at the PFZ site P2, where a relatively uniform distribution of flux was observed with $ 1/3 of the POC sinking faster than 100 m d À 1 and 1/3 sinking slower than 10 m d À 1 .Analysis of thousands of particles collected with the gel traps (at 140, 190, 240, and 290 m depth) enabled us to identify 5 different categories: fluff-aggregates (low-density porous or amorphous aggregates), faecal-aggregates (denser aggregates composed of different types of particles), cylindrical and ovoid faecal pellets, and isolated phyto-cells (chains and single cells). Faecal-aggregates dominated the flux at all sites, and were larger in size at P1 in comparison to P3. The PFZ site P2 differed strongly from both SAZ sites in having a much higher abundance of diatoms and relatively small-sized faecalaggregates. Overall, the particle images suggest that grazing was an important influence on vertical export at all three sites, with differences in the extents of large aggregate formation and direct diatom export further influencing the differences among the sites.

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Section: Particle Properties From the Polyacrylamide Gelsmentioning

confidence: 99%

Controls on mesopelagic particle fluxes in the Sub-Antarctic and Polar Frontal Zones in the Southern Ocean south of Australia in summer—Perspectives from free-drifting sediment traps

Ebersbach

Trull

Davies

et al. 2011

Deep Sea Research Part II: Topical Studies in Oceanography

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“…It has been hypothesised that removal by metazooplankton is the most likely fate of fecal material in the upper layers of the sea (Paffenhöfer & Knowles 1979, Lampitt et al 1990, González & Smetacek 1994, Viitasalo et al 1999) since bacteria alone can not be responsible for the majority of the remineralisation of freshly egested fecal pellets (Jacobsen & Azam 1984, Lampitt et al 1990. Support for this hypothesis is found in the few existing publications, which show that some copepod species do clear fecal pellets at high rates in the laboratory (Table 5).…”

Section: Ecological Implicationsmentioning

confidence: 97%

“…A high ratio of large calanoid to small cyclopoid copepods is generally related to a high vertical flux of fecal pellets and a low ratio to a low flux of pellets (González & Smetacek 1994, Svensen & Nejstgaard 2003. This coherence could also be caused by the higher sinking rates of large fecal pellets, which may induce a higher vertical flux of pellets when large copepods dominate the copepod community.…”

Section: Ecological Implicationsmentioning

confidence: 99%

“…Numerous field studies (> 500) using sediment traps have revealed that zooplankton fecal pellets often constitute a minor portion of the sedimentary flux, much less than what would be expected from the zooplankton abundances and expected fecal pellet production rates (González & Smetacek 1994, Turner 2002. A reduced vertical flux is often attributed to recycling and repackaging of the fecal pellets by coprophagous (ingestion of pellets) copepods (Smetacek 1980, Bathmann et al 1987, González & Smetacek 1994, González et al 1994a, Lane et al 1994, Urban-Rich et al 1999.…”

Section: Introductionmentioning

confidence: 99%

“…A reduced vertical flux is often attributed to recycling and repackaging of the fecal pellets by coprophagous (ingestion of pellets) copepods (Smetacek 1980, Bathmann et al 1987, González & Smetacek 1994, González et al 1994a, Lane et al 1994, Urban-Rich et al 1999. Also, coprorhexy (fragmentation of pellets) and coprochaly (loosening of pellets) may increase the residence time of fecal material in the water column (Lampitt et al 1990, Noji et al 1991) and make it subject to enhanced microbial degradation (Turner 2002), thus accelerating recycling of fecal pellet material in the water column.…”

Section: Introductionmentioning

confidence: 99%

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Coprophagy and coprorhexy in the copepods Acartia tonsa and Temora longicornis: clearance rates and feeding behaviour

Poulsen¹,

Kiørboe²

2005

Mar. Ecol. Prog. Ser.

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Decades of sediment trap studies have revealed that zooplankton fecal pellets constitute a much smaller fraction of the sedimentary flux than expected from the abundance of copepods and their anticipated production rates of fecal pellets. The explanation for this is thought to be coprophagy (ingestion) of fecal pellets by copepods. We examined fecal pellet clearance rate of Acartia tonsa and Temora longicornis and feeding behaviour of A. tonsa. Pellet clearance rates in A. tonsa and T. longicornis females were similar but low on their own pellets (11 to 22 ml female -1 d -1 ). Our own data together with observations compiled from the literature revealed that copepod fecal pellet clearance rates decrease with increasing relative pellet size and that all species can be described by a common relationship. In A. tonsa, the presence of alternative phytoplankton food increased pellet clearance rate. Direct observations revealed that this was accomplished through the modulating effect of phytoplankton on the feeding behaviour. In the absence of phytoplankton, A. tonsa is nonmotile but perceives sinking fecal pellets at distance. However, only a small fraction of the pellets that came within detection distance elicited an attack. In the presence of phytoplankton food, A. tonsa switched to suspension feeding, and all fecal pellets entrained in the feeding current were encountered. Independent of the feeding mode, fecal pellets were mainly degraded by fragmentation during rejection and only a small fraction was actually ingested (5%). The main impact of A. tonsa on the vertical flux of fecal pellets is therefore through coprorhexy (fragmentation) turning fecal pellets into smaller, slower-sinking particles.

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Variability in under‐ice export fluxes of biogenic matter in the Arctic Ocean

Lalande

Nöthig

Somavilla

et al. 2014

Global Biogeochemical Cycles

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A critical question regarding the organic carbon cycle in the Arctic Ocean is whether the decline in ice extent and thickness and the associated increase in solar irradiance in the upper ocean will result in increased primary production and particulate organic carbon (POC) export. To assess spatial and temporal variability in POC export, under-ice export fluxes were measured with short-term sediment traps in the northern Laptev Sea in July-August-September 1995, north of the Fram Strait in July 1997, and in the Central Arctic in August-September 2012. Sediment traps were deployed at 2-5 m and 20-25 m under ice for periods ranging from 8.5 to 71 h. In addition to POC fluxes, total particulate matter, chlorophyll a, biogenic particulate silica, phytoplankton, and zooplankton fecal pellet fluxes were measured to evaluate the amount and composition of the material exported in the upper Arctic Ocean. Whereas elevated export fluxes observed on and near the Laptev Sea shelf were likely the combined result of high primary production, resuspension, and release of particulate matter from melting ice, low export fluxes above the central basins despite increased light availability during the record minimum ice extent of 2012 suggest that POC export was limited by nutrient supply during summer. These results suggest that the ongoing decline in ice cover affects export fluxes differently on Arctic shelves and over the deep Arctic Ocean and that POC export is likely to remain low above the central basins unless additional nutrients are supplied to surface waters.

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The possible role of the cyclopoid copepod Oithona in retarding vertical flux of zooplankton faecal material

Cited by 277 publications

References 39 publications

Controls on mesopelagic particle fluxes in the Sub-Antarctic and Polar Frontal Zones in the Southern Ocean south of Australia in summer—Perspectives from free-drifting sediment traps

Controls on mesopelagic particle fluxes in the Sub-Antarctic and Polar Frontal Zones in the Southern Ocean south of Australia in summer—Perspectives from free-drifting sediment traps

Coprophagy and coprorhexy in the copepods Acartia tonsa and Temora longicornis: clearance rates and feeding behaviour

Variability in under‐ice export fluxes of biogenic matter in the Arctic Ocean

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