Sinking velocities of fecal pellets of doliolids and calanoid copepods

Patonai, Katalin; El-Shaffey, Hisham; Paffenhöfer, Gustav‐Adolf

doi:10.1093/plankt/fbr011

Cited by 24 publications

(16 citation statements)

References 15 publications

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“…Also, measured sinking velocities on ellipsoid pellets can be higher than those calculated from Stoke's law, which assumes a spherical shape (Ploug et al 2008). For ellipsoid FP produced by Eucalanus pileatus (volume 2.5 ± 0.2 × 10 6 µm 3 , mean ± SD) fed with Thalassiosira weissflogii, the sinking velocity is 36.4 ± 3.8 m d −1 (Patonai et al 2011). Small et al (1979) ) (Ploug et al 2008).…”

Section: In Situ Downward Flux and Degradation Of Copepod Fpmentioning

confidence: 81%

Degradation of copepod faecal pellets in the upper layer: role of microbial community and Calanus finmarchicus

Svensen¹,

Riser²,

Reigstad³

et al. 2012

Mar. Ecol. Prog. Ser.

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Copepod faecal pellets (FP) are considered important contributors to vertical carbon flux, but investigations comparing FP production with FP export using sediment traps conclude that vertical export is not their only fate. FP are degraded to a large extent in the upper 60 m, and even among large, fast-sinking FP, only a fraction reaches sediment traps deeper than 200 m. Retention mechanisms for copepod FP are still not well understood. In order to investigate the relative importance of the small (<180 µm) compartment of the plankton community versus larger filter-feeding copepods for degradation of large, fast-sinking FP, we incubated FP produced by Calanus finmarchicus (Gunnerus) in 180 µm-filtered water from the chlorophyll a maximum. From a series of experiments, we found that the degradation of large FP is time-dependent, as no degradation was apparent after 20 or 48 h of incubation, but after 72 h FP volume was reduced by 32%. We also found that large filter-feeding copepods may facilitate the degradation process, since FP degradation increased from 0 to 75% after 48 h of incubation in the presence of 5 C. finmarchicus. We conclude that ciliates and dinoflagellates are able to degrade large copepod FP, but that this process is too slow to explain observed retention of large FP in the upper 200 m of the water column due to fast sinking of large particles. Rather than looking for single-factor explanations for flux-regulating processes, we stress the importance of investigating combined effects in relevant time frames to understand the complexity of carbon flux regulation in natural systems. KEY WORDS: Faecal pellet · Faecal pellet retention · Microbial degradation · Faecal pellet fragmentation · Calanus finmarchicus · Carbon cycling Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 462: [39][40][41][42][43][44][45][46][47][48][49] 2012 by copepods. Gon zález & Smetacek (1994) hypothesised that the abundant cyclopoid copepods Oithona spp. play a key role in the retention of copepod FP, but evidence is conflicting, indicating that Oithona spp. may be indi cators for a retention community rather than the retaining organisms (Reigstad et al. 2005, Poulsen & Kiør boe 2006. This shows that organisms other than Oithona spp. could play a major role in FP retention. In an experiment investigating the effect of various size-fractions of grazers, Poulsen & Iversen (2008) concluded that heterotrophic ciliates and dinoflagellates are the main degraders of small FP from the calanoid copepod Acartia tonsa and that the effect of copepods on degradation rates is comparatively minor. At high latitudes, the copepod community is dominated by larger copepod species producing larger FP. It is therefore relevant to ask if the same groups of organisms and mechanisms are important for degradation of larger FP at high latitudes.Sediment trap investigations revealed considerable attenuation of particulate organic carbon (POC) over a limited depth range (30−60 m) in areas whe...

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Section: In Situ Downward Flux and Degradation Of Copepod Fpmentioning

confidence: 81%

Degradation of copepod faecal pellets in the upper layer: role of microbial community and Calanus finmarchicus

Svensen¹,

Riser²,

Reigstad³

et al. 2012

Mar. Ecol. Prog. Ser.

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“…While it is not clear whether this variation could be attributed to genotypic or phenotypic differences, detailed information on the physiological characteristics of the nurse stages is required to better understand the development of doliolid blooms and the effect they have on the pelagic ecosystems in the study site. As doliolid blooms generally persist for more than a week (Deibel ; Paffenhöfer ), it is likely that the doliolids in the study site eventually cleared almost all food particles in their immediate environment, as has been suggested in the SAB, while most of fecal pellet would be mineralized before export to depth as their fecal pellet sink very slowly (Patonai et al ).…”

Section: Discussionmentioning

confidence: 92%

In situ observations of a doliolid bloom in a warm water filament using a video plankton recorder: Bloom development, fate, and effect on biogeochemical cycles and planktonic food webs

Takahashi

Ichikawa

Fukugama

et al. 2015

Limnology & Oceanography

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We investigated distribution patterns of a doliolid (Dolioletta gegenbauri) bloom in relation to the physical environment using a video plankton recorder in the Oyashio-Kuroshio mixed water region. Using 12 km transects, doliolid blooms were encountered at a horizontal scale of about 2-3 km, which corresponds to submesoscale physical events. Doliolids were also consistently encountered in the subsurface layer above the pycnocline in warmer (> 14 C) and higher-salinity (> 34) water masses, and seawater density was the most critical factor affecting distribution depth. Compared to previous studies, the density and biomass of the blooms observed in this study (77 mgC m 23 and 4600 inds m 23) were highest in the open ocean. Bloom formation consisted of two phases; first, the seeding population of a nurse stage increased rapidly to 2000 inds m 23 by asexual reproduction, followed by asexual production of phorozooids. Estimated population clearance rates revealed that these dense patches could potentially sweep the surrounding water within 2-3 d. The incidence of exhausted and shrunken zooids was significantly correlated with patch density, suggesting that mortality was due to overgrazing. Shrunken doliolids appeared to sink below the pycnocline, corresponding to 8-17% of the particulate organic carbon flux at 150 m. Hydromedusae, pelagic polycheates, and sapphirinid copepods preyed on the doliolids. These results indicate that doliolids, which were seeded by populations originating from the Kuroshio, formed dense blooms in response to submesoscale physical events and would alter the sinking particle properties (i.e., biological pump) and the epipelagic food web structure through their grazing and mortality.

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“…They have round or pointed ends and are encased in a peritrophic membrane that makes the pellets more resistant to bacterial degradation and breakage (Gauld 1957, Yoon et al 2001, Köster et al 2011. Copepod fecal pellet sinking rates range from 5 to 220 m d −1 (Turner 2002, Møller et al 2011, Patonai et al 2011. Salps are indiscriminate feeders that produce very large, fast-sinking (42 to 2700 m d −1 ) 'fecal flakes' that greatly enhance the efficiency of POC transport to depth (Anderson 1998, Madin & Deibel 1998, Yoon et al 2001, Phillips et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Time series of vertical flux of zooplankton fecal pellets on the continental shelf of the western Antarctic Peninsula

Gleiber¹,

Steinberg²,

Ducklow³

2012

Mar. Ecol. Prog. Ser.

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Zooplankton fecal pellet contribution to particulate organic carbon (POC) flux over the continental shelf of the western Antarctic Peninsula (WAP) was investigated to better understand the possible effects of changes in zooplankton community structure, due to climate change, on carbon export. Fecal pellets were collected at 170 m depth in a moored sediment trap from January 2004 to January 2009. Fecal pellet shape and size (i.e., carbon content) were quantified to assess flux of pellets from different zooplankton taxa and compared between seasons and years. Fecal pellet POC constituted the dominant proportion of total POC flux, with summer (November to April) pellet POC flux (67%) significantly higher than winter (May to October) pellet POC flux (34%), while phytodetritus or fecal 'fluff' constituted the remainder. Cylindrical euphausiid pellets contributed to a monthly mean of 72% of total fecal pellet flux; ovoid copepod and tabular salp pellets contributed significantly less (22 and 6%, respectively). Cylindrical and ovoid pellet export was significantly higher in summer, while 48% of tabular pellet flux occurred in winter. Tabular pellets had the highest carbon content (median = 1.03 µgC pellet ) and ovoid (0.04 µgC pellet −1 ) pellets. As krill fecal pellets are the dominant component of particle export in the WAP, we hypothesize that a decrease in krill and increase in salps in the region could alter the export of POC to the deep sea.KEY WORDS: Southern Ocean · Particle flux · Sediment trap · Krill · Salp · Copepod · Climate Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 471: [23][24][25][26][27][28][29][30][31][32][33][34][35][36] 2012 variable sinking rates of 16 to 1218 m d −1 (Turner 2002, Atkinson et al. 2012). Copepods produce ellipsoid or ovoid pellets. They have round or pointed ends and are encased in a peritrophic membrane that makes the pellets more resistant to bacterial degradation and breakage (Gauld 1957, Yoon et al. 2001, Köster et al. 2011. Copepod fecal pellet sinking rates range from 5 to 220 m d −1 (Turner 2002, Møller et al. 2011, Patonai et al. 2011. Salps are indiscriminate feeders that produce very large, fast-sinking (42 to 2700 m d −1 ) 'fecal flakes' that greatly enhance the efficiency of POC transport to depth (Anderson 1998, Madin & Deibel 1998, Yoon et al. 2001, Phillips et al. 2009).Long-term zooplankton time series from a variety of environments indicate that climate is changing zooplankton community structure (Richardson 2008 and that these changes can lead to changes in the efficiency of the biological pump . The western Antarctic Peninsula (WAP) is experiencing one of the most rapid rates of warming on Earth; since 1950, the annual mean air temperature has increased by 2°C, with average mid-winter temperatures rising by 6°C (Vaughan et al. 2003, Ducklow et al. 2012. As a result, the WAP is changing from a cold, dry, polar climate to a warm, humid, maritime climate (Ducklow et al. 2012), with a 40% decrease in s...

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Sinking velocities of fecal pellets of doliolids and calanoid copepods

Cited by 24 publications

References 15 publications

Degradation of copepod faecal pellets in the upper layer: role of microbial community and Calanus finmarchicus

Degradation of copepod faecal pellets in the upper layer: role of microbial community and Calanus finmarchicus

In situ observations of a doliolid bloom in a warm water filament using a video plankton recorder: Bloom development, fate, and effect on biogeochemical cycles and planktonic food webs

Time series of vertical flux of zooplankton fecal pellets on the continental shelf of the western Antarctic Peninsula

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