Discriminate feeding of the calanoid copepod Acartia clausi in mixtures of phytoplankton and inert particles

Ayukai, Tenshi

doi:10.1007/bf00431404

Cited by 59 publications

(41 citation statements)

References 32 publications

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“…In contrast, A. discaudata ingests significantly more food at 20°C and its feeding rate is significantly greater than that of A. bifilosa at this higher temperature. These results correspond well with Mills (1997), who reported feeding rates of ~30 to 45 J mg dry wt , the present results are 2 to 3 orders of magnitude larger than those reported for A. clausi (Ayukai 1987) and A. tonsa (Cowles et al 1988). However, in both of these cases the initial food concentration was several orders of magnitude lower than in the present study, and copepod ingestion is known to increase linearly with food concentration (Frost 1972, Gaudy 1974.…”

Section: Discussionsupporting

confidence: 91%

Photoperiod and temperature regulation of diapause egg production in Acartia bifilosa from Southampton Water

Chinnery¹,

Williams²

2003

Mar. Ecol. Prog. Ser.

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In Southampton Water the copepod Acartia bifilosa presents a diapause reproductive strategy, where there is a switch from subitaneous to diapause egg production around May, prior to the species' disappearance from the water column between June and October. The effect of temperature and photoperiod on the production of diapause eggs by A. bifilosa was studied in an attempt to determine the primary cues for its summer diapause. A parallel study on the effect of temperature on metabolic efficiency of A. bifilosa and the non-diapause species A. discaudata, defined by the species' 'scope for growth' (SfG), was examined as a potential, ultimate reason behind the diapause stage. Photoperiod was identified as the primary proximate cue that induced diapause in A. bifilosa, and this response was temperature-mediated. Diapause was triggered by a 13:11 h light:dark photoperiod (day length), corresponding to a late-April photoperiodic regime, and resting eggs were produced even at temperatures as low as 5°C. A very low number of diapause eggs were, however, also produced after 6 d at a 12:12 h light:dark photoperiod at elevated temperatures between 14 and 20°C, but the mean percentage produced was significantly less (p < 0.05) than under the longer day lengths. The ultimate cause of the over-summering strategy of A. bifilosa is currently unknown, but the SfG assay indicated that at 10°C, SfG was twice that at 20 or 5°C, and so it may diapause to avoid the higher temperatures in summer. This pattern contrasted with the SfG of A. discaudata, which suggested a simple, positive relationship with temperature. In the field, competition is greatly reduced in the winter months, so A. bifilosa has a better chance of survival, even with its lower SfG.KEY WORDS: Acartia bifilosa · Diapause · Egg production · Photoperiod · Scope for growth Resale or republication not permitted without written consent of the publisher

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Section: Discussionsupporting

confidence: 91%

Photoperiod and temperature regulation of diapause egg production in Acartia bifilosa from Southampton Water

Chinnery¹,

Williams²

2003

Mar. Ecol. Prog. Ser.

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“…Most studies on invertebrates have been relatively short-term investigations that have not found acute negative effects (Thompson et al, 2004; Browne et al, 2008; Graham & Thompson, 2009), with the exception of an inflammatory immune response in mussels (Von Moos, Burkhardt-Holm & Köhler, 2012). In zooplankton, the presence of non-edible particles can reduce the rate of feeding on edible particles (Huntley, Barthel & Star, 1983; Ayukai, 1987; Cole et al, 2013), and physical interference with sensory apparatus may occur in very high-plastic environments (Cole et al, 2013). The lepadid barnacles in this study did not show evidence of acute harm (e.g., intestinal blockage or ulceration), though negative long-term effects cannot be ruled out.…”

Section: Discussionmentioning

confidence: 99%

Gooseneck barnacles (Lepasspp.) ingest microplastic debris in the North Pacific Subtropical Gyre

Goldstein

Goodwin

2013

PeerJ

209

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Substantial quantities of small plastic particles, termed “microplastic,” have been found in many areas of the world ocean, and have accumulated in particularly high densities on the surface of the subtropical gyres. While plastic debris has been documented on the surface of the North Pacific Subtropical Gyre (NPSG) since the early 1970s, the ecological implications remain poorly understood. Organisms associated with floating objects, termed the “rafting assemblage,” are an important component of the NPSG ecosystem. These objects are often dominated by abundant and fast-growing gooseneck barnacles (Lepas spp.), which predate on plankton and larval fishes at the sea surface. To assess the potential effects of microplastic on the rafting community, we examined the gastrointestinal tracts of 385 barnacles collected from the NPSG for evidence of plastic ingestion. We found that 33.5% of the barnacles had plastic particles present in their gastrointestinal tract, ranging from one plastic particle to a maximum of 30 particles. Particle ingestion was positively correlated to capitulum length, and no blockage of the stomach or intestines was observed. The majority of ingested plastic was polyethylene, with polypropylene and polystyrene also present. Our results suggest that barnacle ingestion of microplastic is relatively common, with unknown trophic impacts on the rafting community and the NPSG ecosystem.

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“…Furthermore, quality is not only an inherent feature of food particles, but is also a function of the copepod's perception. This we infer from observations that Acartia clausi is more effective at eliminating polystyrene beads from its diet (Donaghay & Small, 1979;Ayukai, 1987) than is Calanus pacificus (Paffenhofer & Strickland, 1970;Huntley et al, 1983). Thus, the best expression we shall probably achieve for the dependence of ingestion, I, on food quality is of the form:…”

Section: Food Qualitymentioning

confidence: 95%

“…Subsequent observations that Calanus would ingest Indian ink (Marshall & Orr, 1952) and polystyrene beads (Paffenhofer & Strickland, 1970) may have strengthened the argument that food selection was based on size alone (Frost, 1977). However, many quantitative studies now clearly demonstrate that Calanus and related genera prefer live algae to dead ones (Paffenhofer & Strickland, 1970;Bartram, 1980;Paffenhofer & Van Sant, 1985), algae to polystyrene beads (Fernhndez, 1979;Donaghay & Small, 1979;Huntley et al, 1983;Ayukai, 1987), nutritious particles to nonnutritious particles (Poulet & Marsot, 1978), and certain algae to others of the same size and in the same concentration (Urry, 1965;Huntley et al, 1986).…”

Section: Food Qualitymentioning

confidence: 99%

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Feeding biology of Calanus: a new perspective

Huntley

1988

Hydrobiologia

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Calanus has been, for a variety of reasons, one of the most popular subjects of copepod feeding studies, and much of what we have learned from studies of Calanus has been applied to other species of copepods. Nearly all the major factors controlling feeding rate and behavior in Calanus have been known for more than three decades. These forcing functions include light, body weight, temperature, the quantity, size and quality of food, and feeding history. The relationships between these variables are better understood than they were three decades ago, but the current knowledge of them still fails to explain extraordinary variance in observations of feeding rate.I suggest that the current understanding fails because our fundamental perception is incorrect. It is generally assumed that the feeding behavior we observe is the net response to instantaneous values of a suite of functions. Past values of forcing functions may be considered a factor, but subservient to those in the present. The critical change in perspective suggested here requires that we assume the integrals of forcing functions to be more significant than their present values in regulating feeding behavior.

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Discriminate feeding of the calanoid copepod Acartia clausi in mixtures of phytoplankton and inert particles

Cited by 59 publications

References 32 publications

Photoperiod and temperature regulation of diapause egg production in Acartia bifilosa from Southampton Water

Photoperiod and temperature regulation of diapause egg production in Acartia bifilosa from Southampton Water

Gooseneck barnacles (Lepasspp.) ingest microplastic debris in the North Pacific Subtropical Gyre

Feeding biology of Calanus: a new perspective

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