Two Counting Cells for the Enumeration of Zooplankton Micro-Crustacea

Gannon, John E.

doi:10.2307/3225467

Cited by 92 publications

(46 citation statements)

References 4 publications

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“…Daphnia and ephippia were harvested and pooled according to treatment (1-4) and replicate group (A, B, C). Adult Daphnia were hand-picked from a Bogorov sorting tray (Gannon, 1971) with fine forceps under a binocular and freeze-dried, after which they were loaded into tin cups (6 × 4 mm, Lüdi Swiss, Switzerland; ∼ 10 to 12 individuals per measurement) for analysis of δ 13 C Daphnia , δ 15 N Daphnia and δ 18 O Daphnia values. For each treatment replicate group, three samples were prepared and measured, resulting in 36 measurements for each chemical element.…”

Section: Sample Collectionmentioning

confidence: 99%

The stable isotopic composition of Daphnia ephippia reflects changes in δ13C and δ18O values of food and water

et al. 2015

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Abstract. The stable isotopic composition of fossil resting eggs (ephippia) of Daphnia spp. is being used to reconstruct past environmental conditions in lake ecosystems. However, the underlying assumption that the stable isotopic composition of the ephippia reflects the stable isotopic composition of the parent Daphnia, of their diet and of the environmental water have yet to be confirmed in a controlled experimental setting. We performed experiments with Daphnia pulicaria cultures, which included a control treatment conducted at 12 • C in filtered lake water and with a diet of fresh algae and three treatments in which we manipulated the stable carbon isotopic composition (δ 13 C value) of the algae, stable oxygen isotopic composition (δ 18 O value) of the water and the water temperature, respectively. The stable nitrogen isotopic composition (δ 15 N value) of the algae was similar for all treatments. At 12 • C, differences in algal δ 13 C values and in δ 18 O values of water were reflected in those of Daphnia. The differences between ephippia and Daphnia stable isotope ratios were similar in the different treatments (δ 13 C: +0.2 ± 0.4 ‰ (standard deviation); δ 15 N: −1.6 ± 0.4 ‰; δ 18 O: −0.9 ± 0.4 ‰), indicating that changes in dietary δ 13 C values and in δ 18 O values of water are passed on to these fossilizing structures. A higher water temperature (20 • C) resulted in lower δ 13 C values in Daphnia and ephippia than in the other treatments with the same food source and in a minor change in the difference between δ 13 C values of ephippia and Daphnia (to −1.3 ± 0.3 ‰). This may have been due to microbial processes or increased algal respiration rates in the experimental containers, which may not affect Daphnia in natural environments. There was no significant difference in the offset between δ 18 O and δ 15 N values of ephippia and Daphnia between the 12 and 20 • C treatments, but the δ 18 O values of Daphnia and ephippia were on average 1.2 ‰ lower at 20 • C than at 12 • C. We conclude that the stable isotopic composition of Daphnia ephippia provides information on that of the parent Daphnia and of the food and water they were exposed to, with small offsets between Daphnia and ephippia relative to variations in Daphnia stable isotopic composition reported from downcore studies. However, our experiments also indicate that temperature may have a minor influence on the δ 13 C, δ 15 N and δ 18 O values of Daphnia body tissue and ephippia. This aspect deserves attention in further controlled experiments.

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Section: Sample Collectionmentioning

confidence: 99%

The stable isotopic composition of Daphnia ephippia reflects changes in δ13C and δ18O values of food and water

et al. 2015

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“…Before preparation, the sub-samples were deflocculated in 10% KOH and heated to 60ºC for 20 minutes. After this step, the sediment was sieved with a 100 µm mesh and poured into a Bogorov-counting tray (Gannon, 1971). All of the head capsules of chironomid larvae were handpicked under a stereo microscope at 40x magnification and mounted on microscope slides in Euparal mounting medium for microscopic identification.…”

Section: Chironomidsmentioning

confidence: 99%

How warm? How wet? Hydroclimate reconstruction of the past 7500 years in northern Carpathians, Romania

Diaconu

Tóth

Lamentowicz

et al. 2017

Palaeogeography, Palaeoclimatology, Palaeoecology

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As natural and anthropogenic ecosystems are dependent on the local water availability, understanding past changes in hydroclimate represents a priority in research concerning past climate variability. Here, we used testate amoebae (TA) and chironomid analysis on a radiocarbon dated complex of small pond and peat bog sediment profiles from an ombrotrophic bog (Tăul Muced, northern Carpathians, Romania) to quantitatively determine major hydrological changes and July air temperature over the last 7500 years.Wet mire surface conditions with a pH between 2.3 and 4.5 were inferred for the periods 4500-2700 and 1300-400 cal yr BP by the occurrence of Archerella flavum, Amphitrema wrightianum and Hyalosphenia papilio. Dry phases in mire surface conditions and a pH between 3 2.5 and 5 were inferred for 7550-4500, 2750-1300 and 0 cal yr BP-present by the dominance of Nebela militaris, Difflugia pulex and Phryganella acropodia. The quantitative reconstruction of mean July temperature based on the chironomid communities suggests low summer temperatures for the periods 6550-5600, 4500-3150 and 1550-600 cal yr BP, while periods of slightly higher summer temperatures were observed for 5600-4500, 3150-1550 and 100 cal yr BP-present.There is a general good agreement between drier phases of the peat surface conditions with higher July temperature, suggesting that temperature may have been a controlling factor for water table fluctuation.Our quantitative reconstructions, among the first for central eastern Europe, show a relatively good agreement with other palaeohydrological studies from central eastern Europe, but contrast with others estimates from north-west Europe. Another important aspect of our study is that it provides valuable information on changes in local hydrology and the potential effect of the mean summer temperature over these changes.

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“…Five 1.0 ml subsamples were counted and identified in a Sedgewick-Rafter counting cell using a binocular compound microscope at 40X total magnification. Separate counts were made to estimate the densities of Leptodora and Epischura using a Bogorov counting chamber (Gannon 1971) and a dissecting microscope at 38X total magnification. These organisms were relatively large, but seldom appeared in subsamples due to their low densities.…”

Section: Fish Food Availabilitymentioning

confidence: 99%

Quantification of Hungry Horse Reservoir Water Levels Needed to Maintain or Enhance Reservoir Fisheries, 1984 Final Report.

May¹

1984

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Two Counting Cells for the Enumeration of Zooplankton Micro-Crustacea

Cited by 92 publications

References 4 publications

The stable isotopic composition of <i>Daphnia</i> ephippia reflects changes in δ<sup>13</sup>C and δ<sup>18</sup>O values of food and water

The stable isotopic composition of <i>Daphnia</i> ephippia reflects changes in δ<sup>13</sup>C and δ<sup>18</sup>O values of food and water

How warm? How wet? Hydroclimate reconstruction of the past 7500 years in northern Carpathians, Romania

Quantification of Hungry Horse Reservoir Water Levels Needed to Maintain or Enhance Reservoir Fisheries, 1984 Final Report.

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Two Counting Cells for the Enumeration of Zooplankton Micro-Crustacea

Cited by 92 publications

References 4 publications

The stable isotopic composition of &lt;i&gt;Daphnia&lt;/i&gt; ephippia reflects changes in δ&lt;sup&gt;13&lt;/sup&gt;C and δ&lt;sup&gt;18&lt;/sup&gt;O values of food and water

The stable isotopic composition of &lt;i&gt;Daphnia&lt;/i&gt; ephippia reflects changes in δ&lt;sup&gt;13&lt;/sup&gt;C and δ&lt;sup&gt;18&lt;/sup&gt;O values of food and water

How warm? How wet? Hydroclimate reconstruction of the past 7500 years in northern Carpathians, Romania

Quantification of Hungry Horse Reservoir Water Levels Needed to Maintain or Enhance Reservoir Fisheries, 1984 Final Report.

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The stable isotopic composition of <i>Daphnia</i> ephippia reflects changes in δ<sup>13</sup>C and δ<sup>18</sup>O values of food and water

The stable isotopic composition of <i>Daphnia</i> ephippia reflects changes in δ<sup>13</sup>C and δ<sup>18</sup>O values of food and water