Annual cycle in abundance, distribution, and size in relation to hydrography of important copepod species in the western Arctic Ocean

Ashjian, Carin J.; Campbell, Robert G.; Welch, H. E.; Butler, Margaret R.; Keuren, Donna Van

doi:10.1016/s0967-0637(03)00129-8

Cited by 195 publications

(160 citation statements)

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“…Generally assumed is that DVM at high latitudes slows down or ceases during wintertime as food availability decreases and some zooplankton species enter diapause and so spend the winter in the deep, dark and presumably safer interior of the ocean (Atkinson, 1998;Ashjian et al, 2003). Our data but show that DVM persisted throughout winter even at the The deep DVM during the polar night in our results suggests a biological clock as…”

Section: Dvm During Polar Nightmentioning

confidence: 43%

Acoustic insights into the zooplankton dynamics of the eastern Weddell Sea

Cisewski

Strass

2016

Progress in Oceanography

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The success of any efforts to determine the effects of climate change on marine ecosystems depends on understanding in the first instance the natural variations, which contemporarily occur on the interannual and shorter time scales. Here we present results on the environmental controls of zooplankton distribution patterns and behaviour in the eastern Weddell Sea, Southern Ocean. Zooplankton abundance and vertical migration are derived from the mean volume backscattering strength (MVBS) and the vertical velocity measured by moored acoustic Doppler current profilers (ADCPs), which were deployed simultaneously at 64°S, 66.5°S and 69°S along the Greenwich Meridian from February, 2005, until March, 2008 While these time series span a period of full three years they resolve hourly changes.A highly persistent behavioural pattern found at all three mooring locations is the synchronous diel vertical migration (DVM) of two distinct groups of zooplankton that migrate between a deep residence depth during daytime and a shallow depth during nighttime. The DVM was closely coupled to the astronomical daylight cycles. However, while the DVM was symmetric around local noon, the annual modulation of the DVM was clearly asymmetric around winter solstice or summer solstice, respectively, at all three mooring sites. DVM at our observation sites persisted throughout winter, even at the highest latitude exposed to the polar night. Since the magnitude as well as the relative rate of change of illumination is minimal at this time, we propose that the ultimate causes of DVM separated from the light-mediated proximal cue that coordinates it. In all three years, a marked change in the migration behaviour occurred in late spring (late October/early November), when DVM ceased. The complete suspension of DVM after early November is possibly caused by the combination of two factors: (1) increased availability of food in the surface mixed layer provided by the phytoplankton spring bloom, and (2) vanishing diurnal enhancement of the threat from visually oriented predators when the illumination is quasi-continuous during the polar and subpolar summer. 3Zooplankton abundance in the water column, estimated as the mean MVBS in the depth range 50 -300 m, was highest end of summer and lowest mid to end winter on the average annual cycle. However, zooplankton abundance varied several-fold between years and between locations. Based on satellite and in situ data of chlorophyll and sea ice as well as on hydrographic measurements, the interannual and spatial variations of zooplankton mean abundance can be explained by differences in the magnitude of the phytoplankton spring bloom, which develops during the seasonal sea ice retreat. Whereas the vernal ice melt appears necessary to stimulate the blooming of phytoplankton, it is not the determinator of the blooms magnitude, its areal extent and duration. A possible explanation for the limitation of the phytoplankton bloom in some years is top-down control. We hypothesize that the phytoplankton spring ...

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Section: Dvm During Polar Nightmentioning

confidence: 43%

Acoustic insights into the zooplankton dynamics of the eastern Weddell Sea

Cisewski

Strass

2016

Progress in Oceanography

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“…In contrast to the Amundsen Gulf during the IPY, a clear seasonal pattern was observed in the production of the small cyclopoid Oithona similis in the western Arctic and central Barents Sea (Arashkevich et al 2002;Ashjian et al 2003). The start of the period of highest abundances of cyclopoid nauplii coincided with the phytoplankton bloom although young stages indicative of reproduction for Oithona similis were also observed in winter in these regions.…”

Section: The Winter Microbial Food Webmentioning

confidence: 88%

“…Mesozooplankton composition in the southeastern Beaufort Sea The Amundsen Gulf, and the southeastern Beaufort Sea in general (Darnis et al 2008), host a mesozooplankton assemblage typical of arctic waters (Arashkevich et al 2002;Ashjian et al 2003;Auel and Hagen 2002) with a composition strongly dominated by copepods. Although much less abundant than the small organisms, the fraction of large zooplankton (>1000 μm) was seven times more important in terms of biomass than the fraction of small zooplankton (200-1000 μm) during the 2007-2008 overwintering period.…”

Section: Mesozooplankton Activity During the Dark Seasonmentioning

confidence: 99%

“…Thus, the high energy lipid compounds and essential fatty acids concentrated in Calanus species make them key drivers of the transfer of energy through arctic marine ecosystems. Furthermore, these same species perform long-range seasonal vertical migrations to depths of several hundred meters where the late developmental stages overwinter in a resting state for much of the ice-covered period (Ashjian et al 2003;Hirche 1997). Mortality and respiration in the populations of Calanus spp.…”

Section: Introductionmentioning

confidence: 99%

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Current state and trends in Canadian Arctic marine ecosystems: II. Heterotrophic food web, pelagic-benthic coupling, and biodiversity

et al. 2012

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As part of the Canadian contribution to the International Polar Year (IPY), several major international research programs have focused on offshore arctic marine ecosystems. The general goal of these projects was to improve our understanding of how the response of arctic marine ecosystems to climate warming will alter food web structure and ecosystem services provided to Northerners. At least four key findings from these projects relating to arctic heterotrophic food web, pelagic-benthic coupling and biodiversity have emerged: (1) Contrary to a long-standing paradigm of dormant ecosystems during the long arctic winter, major food web components showed relatively high level of winter activity, well before the spring release of ice algae and subsequent phytoplankton bloom. Such phenological plasticity among key secondary producers like zooplankton may thus narrow the risks of Climatic Change

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“…There is little evidence for transport of Arctic zooplankton species onto the Chukchi shelf, except near the shelf edge (Ashjian et al, 2003;Plourde et al, 2005), where localized upwelling (e.g., Aagaard and Roach, 1990;Mountain et al, 1976;Woodgate et al, 2005a) may transport zooplankton from the Arctic Basin. In the western Chukchi Sea, the Siberian Coastal Current is apparently not a conduit for large-bodied zooplankton from the central Arctic Basin (Hopcroft et al, 2010;Kulikov, 1992;Pavshtiks, 1984).…”

Section: Tablementioning

confidence: 99%