Effects of preservation on wet weight, dry weight, nitrogen and carbon contents of Calanus helgolandicus (Crustacea: Copepoda)

Williams, Richard; Robins, David

doi:10.1007/bf00397044

Cited by 72 publications

(34 citation statements)

References 6 publications

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“…DFDW per unit volume increased uniformly from 0.06 mg mm -3 in CI to 0.15 mg mm -3 in adults, DW per unit volume rose from 0.092 mg mm -3 in CI to 0.38 mg mm -3 in CV and then reduced to 0.21 mg mm -3 in females and 0.27 mg mm -3 in males. Similar DW content have been reported for CV and adults of C. helgolandicus from the Celtic Sea (Williams & Robins 1982).…”

Section: Ontogenetic Changes In Size-weight Characteristics Of Calanusupporting

confidence: 84%

Development of Calanus euxinus during spring cold homothermy in the Black Sea

Svetlichny¹,

Yuneva²,

Hubareva³

et al. 2009

Mar. Ecol. Prog. Ser.

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In copepodites and adults of Calanus euxinus abundance, body length and weight, chemical composition and respiration rate in relation to age were studied during the cruise of R/V 'Knorr' in April 2003 in the southwestern Black Sea and in laboratory experiments. Data on morphology and physiology of C. euxinus collected during other seasons were also used in comparative analyses. At high concentrations of the diatom Proboscia alata during spring homothermy (6.8 to 8.5°C) C. euxinus did not undertake diel vertical migrations to the oxygen minimum zone (OMZ). The majority of the population was located above the OMZ, feeding on phytoplankton during nighttime and daytime whilst nearly 10% of copepodite stages IV and V (CIV and CV) and adults remained constantly in the OMZ. Although a diapausing stock of the population began to form in the OMZ, the majority of CV developed without diapause. The development times of copepodite stages at 8°C were determined on the basis of field observations of ontogenetic changes in carbon content and calculated absolute growth rates. Development time from CI to CV amounted to 22 d. In CV the time for lipid deposition from 0.008 ± 0.007 mm 3 in postmolts up to a maximum volume of 0.165 ± 0.054 mm 3 in intermolts constituted 26 d. The total generation time from eggs to adults is not less than about 66 d. KEY WORDS: Calanus euxinus · Lipid storage · Respiration · Growth · Black Sea · Spring cold · HomothermyResale or republication not permitted without written consent of the publisher Mar Ecol Prog Ser 374: 199-213, 2009 other hypothesis, Calanus, like other 'boreal relicts', entered the Black Sea when it was connected with the North Sea across Europe during the period of retreating glaciers (Zaitsev 2006). This is in agreement with the results of Papadopoulos et al. (2005) suggesting that the divergences between the northeastern Atlantic, Mediterranean and Black Sea C. helgolandicus populations are much older than the estimated dates of colonization of the Mediterranean and Black Seas. However, according to Polischuk (1984) the last connection between the North and Black Seas could have been in the Late Holocene (2800 to 2700 BP).Calanus euxinus is a dominant component of the zooplankton biomass in the Rim Current system of the Black Sea. The ecology of this species differs significantly from that of C. helgolandicus in other European seas due to the characteristics of the basin.Calanus helgolandicus typically inhabits saline waters (32 to 39 ‰) with temperatures of 9 to 20°C. This wide range is mainly due to seasonal variation; the temperature does not range widely between populations. Seasonal changes in abundance of C. helgolandicus are positively correlated with temperature (Bonnet et al. 2005) and food availability (Rey-Rassat et al. 2004). Overwintering C. helgolandicus descend to deep water and are separated spatially from the part of the population that develops in surface layers.In contrast, Calanus euxinus has adapted to the low salinity of the Black Sea waters (18...

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Section: Ontogenetic Changes In Size-weight Characteristics Of Calanusupporting

confidence: 84%

Development of Calanus euxinus during spring cold homothermy in the Black Sea

Svetlichny¹,

Yuneva²,

Hubareva³

et al. 2009

Mar. Ecol. Prog. Ser.

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“…Carbon weight was calculated assuming 41% carbon content of the ash-free dry weight (Williams & Robins 1982).…”

Section: Methodsmentioning

confidence: 99%

Role of essential lipids in copepod nutrition: no evidence for trophic upgrading of food quality by a marine ciliate

Breteler¹,

Koski²,

Rampen³

2004

Mar. Ecol. Prog. Ser.

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The ciliate Strombidium sulcatum was used to feed and grow young stages of the copepods Temora longicornis (Müller) and Pseudocalanus elongatus (Boeck). The ciliate was cultured in the laboratory using either bacteria or the green alga Dunaliella sp. as a food source. Young copepodites of both copepod species consumed S. sulcatum at significant rates, but after 3 d, weightspecific ingestion decreased more than 2-fold. Larvae and copepodites feeding on S. sulcatum developed at suboptimal rates, survived poorly and showed abnormal morphology in comparison to control individuals fed a good-quality Rhodomonas sp. diet. The specific mass of fatty acids in S. sulcatum was much lower than in the Dunaliella sp. diet. However, the fatty acid composition of the protozoan more or less resembled that of the food, lacking long-chain highly unsaturated fatty acids (HUFAs). Sterols only occurred in Dunaliella sp., although in low abundance of unuseful ∆7 sterols. Obviously, S. sulcatum did not biochemically enhance bacterial or algal food for subsequent use at higher trophic levels, and only transferred fatty acids without further conversion. The results indicate a deficiency in the ciliate of HUFAs and sterols which are essential nutrients for copepod growth. Apart from energy, ciliates seem to contribute little nutritive value to the diet of higher trophic levels, and this may limit secondary production during periods of low algal abundance. KEY WORDS: Copepods · Ciliates · Grazing · Food quality · Fatty acids · SterolsResale or republication not permitted without written consent of the publisher

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“…Freshly collected organisms from the study site were returned to the laboratory for biomass analyses. Freshly killed individuals were used because of possible error introduced into dry weight estimates by preservation or freezing of samples (Williams & Robins 1982). Organisms were anaesthetized with an isotonic solution of MgCl,, assigned to a morphotype, measured and assigned length classes.…”

Section: Methodsmentioning

confidence: 99%

“…If the length-weight regression for a morphotype was non-significant ( p > 0.05) the mean weight of the morphotype was used for biomass estimates. Regression equations derived by Williams & Robins (1982) and Sogard (1982) were used for calanoid copepods and amphipods, respectively.…”

Section: Methodsmentioning

confidence: 99%