Sedimentation of copepod fecal material in the coastal northern Baltic Sea: Where did all the pellets go?

Viitasalo, Markku; Rosenberg, Mirja; Heiskanen, Anna-Stiina; Koski, Marja

doi:10.4319/lo.1999.44.6.1388

Cited by 57 publications

(46 citation statements)

References 55 publications

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“…These estimates are somewhat higher than the published values from the area (9-22 pellets m 22 d 21 ; Viitasalo et al 1999). However, Viitasalo et al concluded that less than 1% of copepod fecal pellets sedimented; most of them were probably broken up and decomposed in the water column.…”

Section: Discussioncontrasting

confidence: 54%

Pectenotoxin-2 and dinophysistoxin-1 in suspended and sedimenting organic matter in the Baltic Sea

et al. 2006

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Dinophysis acuminata, D. norvegica, and D. rotundata occur regularly in the Baltic Sea summer plankton. They are known to produce diarrhetic shellfish poisoning (DSP) toxins in coastal areas worldwide, but so far, evidence from the Baltic Sea is scarce, and the fate and transfer of their toxins in the ecosystem is poorly known. Occurrence of Dinophysis and DSP toxins was studied on the southwest coast of Finland in late July-September 2004 by sampling the water column down to the thermocline. DSP toxin profiles were analyzed using highperformance liquid chromatography-mass spectrometry from the thermocline sample from material collected with a sediment trap. Maximum abundances of D. acuminata (7,280 cells L 21 ) and D. rotundata (880 cells L 21 ) were above the thermocline, but D. norvegica (maximum 200 cells L 21 ) was most abundant in the thermocline region. Pectenotoxin-2 (PTX-2) was found during the entire study period. Cellular PTX-2 content in Dinophysis varied between 1.6 and 19.9 pg PTX-2 cell 21 . Dinophysistoxin-1 (DTX-1) was found in samples after mid-August in concentrations ranging from 0.2 to 149 pg DTX-1 cell 21 . PTX-2 and DTX-1 were found in all sediment trap samples. The estimated sedimentation rate of PTX-2 was 0 to 15.4 ng m 22 d 21 and DTX-1 0 to 190 ng m 22 d 21 , corresponding ,0.01% of PTX-2 and 1% of DTX-1 of the integrated water column DSP pool during a 6-week period. Sedimenting organic matter did not contain intact Dinophysis cells, but copepod fecal pellets found in the sediment traps indicated that fecal pellets are the major pathway of DSP toxins to the bottom. The major fraction of the PTX-2 and DTX-1 was either decomposed in the water column or transferred to higher trophic levels in the planktonic food chain.

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Section: Discussioncontrasting

confidence: 54%

Pectenotoxin-2 and dinophysistoxin-1 in suspended and sedimenting organic matter in the Baltic Sea

et al. 2006

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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 Implicationssupporting

confidence: 63%

“…The increasing clearance of fecal pellets with decreasing pellet size may also explain the higher vertical flux of fecal pellets observed when large Calanus species as opposed to small copepod species dominate the zooplankton community (González et al 1994a, Viitasalo et al 1999, Wassmann et al 2000. 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.…”

Section: Ecological Implicationsmentioning

confidence: 97%

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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“…Pellet number was counted, and their average length and width were measured under a binocular microscope. Pellet volume was calculated assuming pellets to be cylinders with spherical ends (Viitasalo et al 1999). From each treatment, 200 pellets and various numbers of living copepods were frozen at -20°C for toxin analyses.…”

Section: Methodsmentioning

confidence: 99%

“…Zooplankton faecal pellets either sink to deep waters and sediment to the bottom (Turner & Ferrante 1979, Dagg & Walser 1986, Fowler et al 1991, or are recycled in the euphotic zone by other zooplankton (Frankenberg & Smith 1967, Smetacek 1980, Hofmann et al 1981, Lampitt et al 1990, Ayukai & Hattori 1992, Viitasalo et al 1999, reviewed by Turner 2002. If toxic pellets are recycled in the mixed layer, toxins may disperse further and accumulate in the pelagic food web.…”

Section: Introductionmentioning

confidence: 99%

Fate of cyanobacterial toxins in the pelagic food web: transfer to copepods or to faecal pellets?

Lehtiniemi¹,

Engström‐Öst²,

Karjalainen³

et al. 2002

Mar. Ecol. Prog. Ser.

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Toxic cyanobacterial blooms are a common phenomenon in the Baltic Sea. The fate of the toxin in the food web is largely unknown. We studied the effect of algal diets on production of pellets and toxin content of the calanoid copepod Eurytemora affinis in the northern Baltic Sea. Fieldcollected copepods were fed with (1) cultured toxic cyanobacteria Nodularia spumigena; (2) cultured non-toxic flagellates Brachiomonas submarina; and (3) a natural phytoplankton assemblage. Natural phytoplankton was dominated by non-toxic cyanobacteria Aphanizomenon flos-aquae, but also remnants of toxic N. spumigena were found. Pellet production was highest on cultured B. submarina, second highest on N. spumigena and lowest on natural phytoplankton. Because pellets were produced on cultured N. spumigena, this shows that toxic cyanobacteria are consumed if no other food is available. The toxin content of E. affinis was highest in copepods fed with cultured N. spumigena, but toxin was also found in lower concentrations in animals fed with natural phytoplankton. Results indicate that an accumulation of toxins mainly occurs during a growing phase of cyanobacterial blooms. The toxin concentration in the pellets was approximately 6 to 12 times lower than in the copepods. We suggest that a large part of the ingested toxin accumulates in copepod tissues, although some is egested with pellets. This may lead to transport and, possibly, accumulation of cyanobacterial toxin in higher pelagic trophic levels in the Baltic Sea. KEY WORDS: Cyanobacterial toxin · Nodularia spumigena · Toxin transfer · Copepods · Faecal pelletsResale or republication not permitted without written consent of the publisher

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Sedimentation of copepod fecal material in the coastal northern Baltic Sea: Where did all the pellets go?

Cited by 57 publications

References 55 publications

Pectenotoxin-2 and dinophysistoxin-1 in suspended and sedimenting organic matter in the Baltic Sea

Pectenotoxin-2 and dinophysistoxin-1 in suspended and sedimenting organic matter in the Baltic Sea

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

Fate of cyanobacterial toxins in the pelagic food web: transfer to copepods or to faecal pellets?

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