Data from: Oceanic swarms of Antarctic krill perform satiation sinking ...
Antarctic krill form some of the highest concentrations of animal biomass observed in the world’s ocean potentially due to their prolific ability to swarm. Determining the movement of Antarctic krill within swarms is important to identify drivers of their behaviour and their biogeochemical impact on...
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| Format: | Dataset |
| Language: | English |
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Dryad
2017
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| Subjects: | |
| Online Access: | https://dx.doi.org/10.5061/dryad.p46k6 https://datadryad.org/stash/dataset/doi:10.5061/dryad.p46k6 |
| Summary: | Antarctic krill form some of the highest concentrations of animal biomass observed in the world’s ocean potentially due to their prolific ability to swarm. Determining the movement of Antarctic krill within swarms is important to identify drivers of their behaviour and their biogeochemical impact on their environment. We examined vertical velocity within approximately 2000 krill swarms through the combined use of a shipborne echosounder and an acoustic Doppler current profiler (ADCP). We revealed a pronounced downward anomaly in vertical velocity within swarms of -0.6 cm.s-1 compared with vertical motion outside the swarm. The anomaly changed over the diel cycle, with smaller downward anomalies occurring at night. Swarms in regions of high phytoplankton concentrations (a proxy for food availability) also exhibited significantly smaller downward anomalies. We propose that the anomaly is the result of downward velocities generated by the action of krill beating their swimming appendages. During the night and ... : Antarctic krill swarms in Scotia Sea Summer 2003The dataset contains 2043 krill swarms detected using an EK60 echosounder during transects of the Scotia Sea during Jan and Feb 2003. Each of the swarms was detected using the dB difference method described in Tarling et al. 2009. Corresponding measurements of the vertical velocity within and above and below each swarm were made using an acoustic Doppler current profiler (ADCP). Velocities above and below the swarm were taken from velocities within the swarm to derive a residual. The dataset gives a time and location of each swarm, mean depth of swarm midpoint below surface, swarm properties (depth, length, thickness, packing concentrations) and vertical velocities within, above and below each swarm. There is a further mask which excludes any measurements where there was another swarm present in the ADCP depth/time bin. [Tarling GA, Klevjer T, Fielding S, Watkins JL, Atkinson A, Murphy E, Korb R, Whitehouse M, Leaper R (2009) Variability and predictability of ... |
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