Zooplankton population dynamics: measuring in situ growth and mortality rates using an Optical Plankton Counter

Edvardsen, Are; Zhou, Meng; Tande, Kurt S.; Zhu, Yiwu

doi:10.3354/meps227205

Cited by 44 publications

(30 citation statements)

References 61 publications

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“…In Wilhelmina Bay, the mortality for krill was much lower than that determined by Edvardsen et al (2002). The estimated daily consumption of ~306 whales in Wilhelmina Bay during our 34 d study was between 0.16 and 0.36% of krill biomass, equivalent to a predation mortality rate of less than 0.01 d -1…”

Section: Changes In Biomass and Abundance Of Different Trophic Levelsmentioning

confidence: 84%

Austral fall−winter transition of mesozooplankton assemblages and krill aggregations in an embayment west of the Antarctic Peninsula

Espinasse¹,

Zhou²,

Zhu³

et al. 2012

Mar. Ecol. Prog. Ser.

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To assess krill aggregations and humpback whale Megaptera novaeangliae foraging behavior, spatial and temporal relationships between Antarctic krill Euphausia superba and zooplankton taxonomic groups were studied during an interdisciplinary cruise conducted in May and June 2009 within Wilhelmina Bay on the western side of the Antarctic Peninsula. A vesselmounted acoustic Doppler current profiler (ADCP) and a calibrated EK-60 echo sounder were used to assess circulation patterns and krill distributions in the bay, and a multiple opening and closing net (with 333 µm mesh) and environmental sensing system (MOCNESS) was used to collect live samples of mesozooplankton and krill for taxonomic composition analysis. The results from this field study complement a previous one that examined an anticyclonic bay-scale circulation of Antarctic krill. This super-aggregation of krill covered ~100 km 2 , had a concentration of 1000s of individuals m -2 and was associated with more than 306 humpback whales present in Wilhelmina Bay. Our results from the mesozooplankton study revealed that krill continuously conducted diel vertical migrations and formed aggregations in the inner bay, while the chlorophyll concentration at the surface decreased from 2.2 to 0.6 g C m −2 due to the decrease of daylight, and zooplankton concentrations increased from 0.5 to 1.5 g C m −2 probably from advective influx. Most zooplankton were distributed below 200 m while krill fed in the upper 150 m. The spatial and temporal correlations between krill and small-to medium-sized mesozooplankton imply that krill may become omnivorous when there is a lack of phytoplankton in the late austral fall. Though both phytoplankton and zooplankton biomasses contributed only small fractions of the daily ration needed for krill metabolism in Wilhelmina Bay, it is not clear what caused krill to aggregate on such a large scale, as this led to high mortality as a result of starvation and predation by whales and other top predators.

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Section: Changes In Biomass and Abundance Of Different Trophic Levelsmentioning

confidence: 84%

Austral fall−winter transition of mesozooplankton assemblages and krill aggregations in an embayment west of the Antarctic Peninsula

Espinasse¹,

Zhou²,

Zhu³

et al. 2012

Mar. Ecol. Prog. Ser.

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“…growth dilution as a way of reducing PCBs concentrations, was one of the state variables with high influence on the output of the model. When parameterized for the Arctic ecosystem (Table 2), growth rate for copepods was assumed similar to Calanus finmarchicus from an Arctic fjord (Edvardsen et al, 2002). C. finmarchicus is an Atlantic relative that has distribution areas partly overlapping with the Arctic species of the present study, C. glacialis and C. hyperboreus.…”

Section: Maximizing Bioaccumulationmentioning

confidence: 99%

“…Feeding rate: Copepods- Halvorsen et al (2001), for small and large temperate copepods, Euphausiids-predicted from Båmstedt and Karlson (1998) and Dalpadado and Skjoldal (1996), Amphipods-Percy (1993a), Polar cod- . Growth rate: Copepods and Euphausiids- Edvardsen et al (2002), Amphipods-Percy (1993b), Polar cod- . Water and organic resistance used to predict the gastro-intestinal POP uptake efficiency was assumed by analogy to other systems where the model has been used successfully (Lake Ontario, in Campfens and Mackay (1997)).…”

Section: Total Particulate Matter Concentrationmentioning

confidence: 99%

Comparing measured and predicted PCB concentrations in Arctic seawater and marine biota

Borgå

Guardo

2005

Science of The Total Environment

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When a mechanistic food web model was parameterized for the Arctic marine ecosystem, it predicted PCB concentrations in zooplankton and fish that were two orders of magnitude lower than measured. PCB concentrations measured in zooplankton and fish were within the laboratory's accredited quality assured criteria, and were comparable to other Arctic regions. Although on a different scale, the predicted and measured PCB concentrations were highly correlated. As sensitivity analyses indicated water concentrations as the most sensitive parameter for the model output, dissolved water concentrations were predicted using measured zooplankton and air PCB concentrations, and empirical and mechanistic models. The food web model and the empirical relationship between bioaccumulation factor and octanol-water partitioning coefficient predicted mean dissolved water concentrations of 28 and 29 pg/L P PCB 6 (PCB-28, -52, -105, -118, -138, -153), respectively. Mean dissolved water concentration predicted from measured air concentrations in 1996 was 7.6 pg/L P PCB 5 (PCB-28 was not analysed). Mean dissolved water concentration measured in Barents Sea water sampled simultaneously as the biota in 1999 was 0.3 pg/L P PCB 6 . The dissolved water concentrations predicted from zooplankton PCB concentrations were comparable to water concentrations measured in 1996, whereas the dissolved water concentrations measured in 1999 were comparable to measurements from 2001. If the present high empirically derived bioaccumulation factors (log BAF 7.3-9.0) were realistic, this suggests that bioaccumulation in Arctic zooplankton is more efficient that previously assumed. The present study illustrates and discusses some of the difficulties encountered when different approaches to study environmental distribution of contaminants are compared. D

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“…Since there is a growing evidence that the MOCNESS and the OPC sample the zooplankton community differently (Edvardsen et al 2002), we have to be cautious when comparing the abundance of zooplankton from the MOCNESS with the abundance output from the OPC size spectra. Species present in more than 1% of the total abundance in the MOCNESS samples were considered to contribute to the OPC data, and the species was assigned to a size group as follows: in the laboratory, OPC size measurements were conducted on monocultures of all copepodite stages and adult females for Calanus finmarchicus together with Thysanoessa spp.…”

Section: Methodsmentioning

confidence: 99%

“…During each phase, the area was sampled by a towed, undulating vehicle (MKII SCANFISH, GMI, Snekkersten, Denmark) that sampled the water column from 1 to 100 m. An optical plankton counter (OPC; Focal Technologies) (Herman 1988(Herman , 1992 was mounted on the SCANFISH together with a CTD (Sea-Bird 911; Sea-Bird Electronics) and a fluorometer (Seapoint chlorophyll fluorometer; Seapoint Sensors). The OPC detects particles in 4096 digital sizes within a range of 0.25 to 14 mm equivalent ) and individual sizes (see Edvardsen et al 2002 for further details). The CTD measures conductivity (i.e.…”

Section: Methodsmentioning

confidence: 99%

Interactions between biological and environmental structures along the coast of northern Norway

Fossheim¹,

Zhou²,

Tande³

et al. 2005

Mar. Ecol. Prog. Ser.

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Spatial and temporal variability in physical conditions off the northern coast of Norway may affect the 3D distribution of mesozooplankton and capelin larvae (Mallotus villosus Müller) during the early capelin recruitment period. To monitor distribution patterns, we sampled the water masses down to 100 m on 3 successive occasions in May 2001 with a SCANFISH-OPC-CTD-F platform. We found distinct differences between coastal and oceanic waters in the study area. The water masses were most clearly distinguished by salinity and there was a tendency for higher zooplankton abundance and biomass in water of oceanic origin. Our study area was characterised by mesoscale eddies, translating in an easterly direction which follow the Norwegian Coastal Current. Cyclonic eddies contained oceanic water, high zooplankton abundance and biomass, whereas anti-cyclonic eddies contained water masses of coastal origin and low abundance of zooplankton. The eddies found in the spawning and hatching habitat of capelin were relatively small and of short duration; however, their impact on the biological community in terms of mediating exchange of biotas across the shelf can be significant. KEY WORDS: Optical plankton counter · Eddy · Barents Sea · Capelin larvae Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 300: [147][148][149][150][151][152][153][154][155][156][157][158] 2005 (Lobel & Robinson 1986, Boehlert et al. 1992, Bograd et al. 1994, Rodriguez et al. 2001, Halvorsen et al. 2003 and affect the biological productivity of coastal regions (Rey 1981, Kimura et al. 1997, Kasai et al. 2002). An eddy can concentrate buoyant passive materials when its secondary circulation converges. This mechanism may aggregate patches of plankton in confined areas and may provide favourable retention areas (Halvorsen et al. 2003). A divergent eddy on the other hand may increase primary production due to the upwelling of nutrient-rich deep water to the euphotic surface layer, which may further enhance zooplankton production (Kimura et al. 1997, Nakata et al. 2000.Abundant fish larvae have previously been observed in both cyclonic and anti-cyclonic (Schumacher et al. 1993) eddies. Canino et al. (1991) suggested that feeding and survival conditions may be better in eddies. Bograd et al. (1994) found that larvae retained within an eddy had a lower mortality rate than elsewhere. It has also been hypothesised that retention in eddies, that move downstream at slower rates than mean currents (Bograd et al. 1994), aid in delivering larvae to the nurseries. Eddies may aid in retention of fish larvae in coastal areas (Kasai et al. 2002) and may decrease the likelihood of them being transported into the oceanic regime (Bograd et al. 1994), or may function as a transport mechanism from coastal areas to offshore nursery grounds (Komatsu et al. 2002). Eddies are also important for larvae in helping them to avoid excessive transport (i.e. currents may carry them away from the nurseries) by retaining them in ...

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Zooplankton population dynamics: measuring in situ growth and mortality rates using an Optical Plankton Counter

Cited by 44 publications

References 61 publications

Austral fall−winter transition of mesozooplankton assemblages and krill aggregations in an embayment west of the Antarctic Peninsula

Austral fall−winter transition of mesozooplankton assemblages and krill aggregations in an embayment west of the Antarctic Peninsula

Comparing measured and predicted PCB concentrations in Arctic seawater and marine biota

Interactions between biological and environmental structures along the coast of northern Norway

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