Hänselmann, Kristin; Walter, Bettina (2013): Grazing rate of microzooplankton measured experimentally in the North Atlantic during the Maria S. Merian cruise MSM26, spring 2013 [dataset]. Institut für Hydrobiologie und Fischereiwissenschaften, Universität Hamburg, PANGAEA, https://doi.org/10.1594/PANGAEA.819256
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Abstract:
The microzooplankton grazing dilution experiments were conducted at stations 126, 127, 131 and 133-137, following Landry & Hassett (1982). Seawater samples (whole seawater – WSW) were taken via Niskin bottles mounted on to a CTD Rosette out of the chlorophyll maximum at each station. Four different dilution levels were prepared with WSW and GF/F filtered seawater – 100% WSW, 75% WSW, 50% WSW and 25% WSW. The diluted WSW was filled in 2.4 L polycarbonate bottles (two replicates for every dilution level). Three subsamples (250 - 500 mL depending on in situ chlorophyll) of the 100% WSW were filtered on to GF/F filters (25 mm diameter) and chlorophyll was extracted in 5 mL 96% ethanol for 12-24 hours. Afterwards it was measured fluorometrically before and after the addition of HCl with a Turner fluorometer according to Jespersen and Christoffersen (1987) on board of the ship. In addition, one 250 mL subsample of the 100% WSW was fixed in 2% Lugol (final concentration), to determine the microzooplankton community when back at the Institute for Hydrobiology and Fisheries Science in Hamburg. Also, one 50 mL subsample of the 100% WSW was fixed in 1 mL glutaraldehyde, to quantify bacteria abundance. The 2.4 L bottles were put in black mesh-bags, which reduced incoming radiation to approximately 50% (to minimize chlorophyll bleaching). The bottles were incubated for 24 hours in a tank on deck with flow-through water, to maintain in situ temperature. An additional experiment was carried out to test the effect of temperature on microzooplankton grazing in darkness. Therefore, 100% WSW was incubated in the deck tank and in two temperature control rooms of 5 and 15°C in darkness (two bottles each). The same was done with bottles where copepods were added (five copepods of Calanus finmarchicus in each bottle; males and females were randomly picked and divided onto the bottles). In addition, two 100% WSW bottles with five copepods each were incubated at in situ temperature at 100% light level (without mesh-bags). All experiments were incubated for 24 hours and afterwards two subsamples of each bottle were filtered on to GF/F filters (25 mm diameter); 500 - 1000 mL depending on in situ chlorophyll. One 250 mL subsample of one of the two replicates of each dilution level and each additional experiment (temperature and temperature/copepods) was fixed in 5 mL lugol for microzooplankton determination. One 50 mL subsample of one of the two 100% WSW bottles as well as of one of the additional experiments without copepods was fixed in 1 mL glutaraldehyde for bacteria determination later on. Copepods were fixed in 4% formaldehyde for length measurements and sex determination.
Further details:
Jespersen, A-M; Christoffersen, Kirsten Seestern (1987): Measurements of chlorophylla from phytoplankton using ethanol as extraction solvent. Archiv für Hydrobiologie, 109, 445-454
Landry, Michael R; Hassett, R P (1982): Estimating the grazing impact of marine micro-zooplankton. Marine Biology, 67(3), 283-288, https://doi.org/10.1007/BF00397668
Project(s):
Basin Scale Analysis, Synthesis and Integration (EURO-BASIN)
Funding:
Seventh Framework Programme (FP7), grant/award no. 264933: Basin Scale Analysis, Synthesis and Integration
Coverage:
Median Latitude: 59.694500 * Median Longitude: -34.200978 * South-bound Latitude: 53.358000 * West-bound Longitude: -55.977000 * North-bound Latitude: 62.857000 * East-bound Longitude: -11.000160
Date/Time Start: 2013-03-24T19:30:00 * Date/Time End: 2013-04-13T13:49:00
Minimum DEPTH, water: 20 m * Maximum DEPTH, water: 50 m
Event(s):
MSM26_126-1 * Latitude: 61.500000 * Longitude: -11.000160 * Date/Time: 2013-03-24T19:30:00 * Elevation: -1329.3 m * Location: North Atlantic * Campaign: MSM26 * Basis: Maria S. Merian * Method/Device: CTD/Rosette (CTD-RO)
MSM26_127-4 * Latitude: 62.857000 * Longitude: -21.441000 * Date/Time: 2013-03-27T18:08:00 * Elevation: -1133.0 m * Location: North Atlantic * Campaign: MSM26 * Basis: Maria S. Merian * Method/Device: CTD/Rosette (CTD-RO) * Comment: rope length max. 1097m /EL1
MSM26_131-18 * Latitude: 60.520000 * Longitude: -23.753000 * Date/Time: 2013-03-31T13:44:00 * Elevation: -2057.0 m * Location: North Atlantic * Campaign: MSM26 * Basis: Maria S. Merian * Method/Device: CTD/Rosette (CTD-RO) * Comment: rope length max. 1972m /EL I
Parameter(s):
# | Name | Short Name | Unit | Principal Investigator | Method/Device | Comment |
---|---|---|---|---|---|---|
1 | Event label | Event | ||||
2 | Date/Time of event | Date/Time | ||||
3 | Latitude of event | Latitude | ||||
4 | Longitude of event | Longitude | ||||
5 | Elevation of event | Elevation | m | |||
6 | DEPTH, water | Depth water | m | Geocode | ||
7 | Duration | Duration | h | Hänselmann, Kristin | of experiment | |
8 | Dilution | Dilution | % | Hänselmann, Kristin | ||
9 | Copepoda | Copepoda | Hänselmann, Kristin | |||
10 | Light intensity | Io | % | Hänselmann, Kristin | ||
11 | Temperature, water | Temp | °C | Hänselmann, Kristin | minimum | |
12 | Temperature, water | Temp | °C | Hänselmann, Kristin | maximum | |
13 | Experiment | Exp | Hänselmann, Kristin | |||
14 | Chlorophyll a | Chl a | µg/l | Hänselmann, Kristin | at start of experiment | |
15 | Chlorophyll a | Chl a | µg/l | Hänselmann, Kristin | at end of experiment | |
16 | Growth rate | µ | 1/day | Hänselmann, Kristin |
License:
(UNKNOWN)
Size:
1536 data points