Zooplankton in a Canadian Arctic Estuary

Evans, Mike; Grainger, E. H.

doi:10.1016/b978-0-12-404060-1.50025-3

Cited by 9 publications

(5 citation statements)

References 15 publications

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“…The last of the adult females from the previous winter disappear by late summer. The findings of Evans & Grainger (1980), that D. bungei Sars in arctic estuarine waters produces a single generation each year, with overwintering adults producing young copepodites in the first month of summer, is consistent with the sequence described here for D. bispinosus. Throughout spring and early summer adult females greatly outnumber adult males (Table 12), and no male was found after 21 December.…”

Section: Life History Sex Ratio and Seasonal Changes In Population Stsupporting

confidence: 73%

Ecology of the zooplankton of a meromictic antarctic lagoon with special reference to Drepanopus bispinosus (Copepoda: Calanoida)

Bayly

1986

Hydrobiologia

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The zooplankton of Burton Lake, a meromictic lagoon with a tenuous connection to Crooked Fjord near Davis, Antarctica, was studied during the summer of 1981, when the lake was still ice-covered. Sampling occurred through a 10 cm diameter ice-hole. A plankton pump was used to investigate vertical changes in population density. A newly designed collapsible net was hauled vertically through the entire oxylimnion (6.5 m thick) to examine temporal changes in population structure and in the species composition of the zooplanktonic community.Four metazoan species occurred in the zooplankton: Drepanopus bispinosus and Paralabidocera antarctica (Copepoda), Rathkea lizzioides (Anthomedusae) and a cydippid ctenophore. Except for R. lizzioides, the lower limit of the vertical distributions occurred precisely at the oxycline at a depth of 8.15 m. The densities of both R. lizzioides and the ctenophore were low throughout the depth range 5.0-7.25 m and considerably higher above and below this stratum. The density of R. lizzioides increased greatly in a downward direction starting about 35 cm above the oxycline, and many individuals were capable of making excursions of about 10 cm downward past the chemocline into anoxic water. D. bispinosus had a more even vertical distribution than the medusa and ctenophore, but densities were higher in that portion of the oxylimnion lying below 6.0 m than above. The vertical distributions of R. lizzioides and D. bispinosus were stable over 24 h, but vertical migration occurred in that portion of the ctenophore population located above the low-density stratum. I? antarctica occurred in very small numbers.The ctenophore was uniformly distributed horizontally, but significant horizontal differences (among four stations) in mean vertical density occurred in adult D. bispinosus and R. lizzioides. The lowest density of D. bispinosus occurred at the station with the highest density of R. lizzioides.In early summer (11 December 1981), the mean densities of zooplankters within that portion of the oxylimnion overlying the anoxylimnion were D. bispinosus 550 mm3, ctenophore 410 me3 and R. lizzioides 230 rne3. Throughout summer the absolute density and relative community proportion of R. fizzioides fell continuously, and these measures showed a comparable decline for adult D. bispinosus (almost entirely females). At the same time there was a consistent increase in the numbers of immature D. bispinosus. The density and community percentage of the ctenophore remained high (c. 480 me3 and 44%, respectively) throughout December and early January, but declined thereafter. D. bispinosus is univoltine. Mature males appear in late autumn and mating occurs mainly in early winter, when significant numbers of mature females first appear. The species overwinters as adults, and ovigerous females first appear in midwinter. Males are short-lived and are already rare by the end of winter. Stage I nauplii are present in early spring, and naupliar development continues throughout spring and into early summer in company wi...

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Section: Life History Sex Ratio and Seasonal Changes In Population Stsupporting

confidence: 73%

Ecology of the zooplankton of a meromictic antarctic lagoon with special reference to Drepanopus bispinosus (Copepoda: Calanoida)

Bayly

1986

Hydrobiologia

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“…Duff et al 1999;Hay et al 2000), and/or due to evaporative concentration of solutes (Keatley et al 2007). Other studies conducted in the Mackenzie River delta and Tuktoyaktuk Peninsula lakes also reported relatively high conductivity, silica and major ions concentrations (Fee et al 1988;Ramlal et al 1991); much higher conductivity levels (> ca 5000 µS cm -1 ) have been found in the Husky Lakes due to marine influence (Evans & Grainger 1980). Contrary to the above named studies, Pienitz et al (1997a, b) found higher levels of major ions and DIC in boreal forest lakes compared to Arctictundra sites.…”

Section: Physical and Chemical Limnologymentioning

confidence: 99%

Limnological features and models of chlorophyll-a in 30 lakes located in the lower Mackenzie River basin, Northwest Territories (Canada)

Ogbebo¹,

Evans²,

Brua³

et al. 2009

J Limnol

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“…Third, because shear dispersion itself is a very patchy process, any future quantification of mixing will require attention to complex motions and detailed modeling. Indeed, it is clear that the remarkable zonation of the lakes' biology (e.g., Evans and Grainger, 1980) is tied to strong vertical mixing in narrow reaches and the subsequent upwelling and recycling of nutrients that support primary production.…”

Section: Valuementioning

confidence: 99%

Water and Ice-Related Phenomena in the Coastal Region of the Beaufort Sea: Some Parallels between Native Experience and Western Science

Carmack¹,

Macdonald²

2009

ARCTIC

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ABSTRACT. Information gained through Native experience is combined here with scientific measurements to describe aspects of the wintertime oceanography of the Eskimo Lakes and Mackenzie River delta regions of the Canadian Beaufort Sea. The experiences of Jimmy Jacobson, a Tuktoyaktuk elder who lived in this region for over 70 years, were used as the basis for scientific planning and measurement. We focus on phenomena of special relevance to winter travel and fishing in four specific examples of Native insight guiding scientific inquiry. First, we examine local knowledge of ice characteristics and fish abundance in terms of tidal dispersion and its effect on mixing patterns during winter. Second, we relate the maintenance of a small ice-free area, used by caribou as a salt lick, to the vertical heat flux associated with flow through narrow channels. Third, we look at potentially dangerous episodes of overflooding of snow and ice in the nearshore zone in midwinter, caused by strong westerly winds, through the analysis of oxygen isotope distributions in ice cores. Fourth, we discuss the important influence of wind direction on ice conditions, lead formation, and brine production in semi-enclosed coastal bays. Finally, we note certain circulation features of ecological significance relevant to concerns about development and the transport of pollutants. We conclude that by not requiring agreement between indigenous knowledge and Western science, or ranking one above the other, we can realize the values of each approach. Specifically, indigenous knowledge can provide direction to scientific inquiry, while Western science can be used to measure, model, and predict where development or change might have the most serious impact.

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Zooplankton in a Canadian Arctic Estuary

Cited by 9 publications

References 15 publications

Ecology of the zooplankton of a meromictic antarctic lagoon with special reference to Drepanopus bispinosus (Copepoda: Calanoida)

Ecology of the zooplankton of a meromictic antarctic lagoon with special reference to Drepanopus bispinosus (Copepoda: Calanoida)

Limnological features and models of chlorophyll-a in 30 lakes located in the lower Mackenzie River basin, Northwest Territories (Canada)

Water and Ice-Related Phenomena in the Coastal Region of the Beaufort Sea: Some Parallels between Native Experience and Western Science

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