DIEL CHANGES IN MESOZOOPLANKTON VERTICAL MICROSTRUCTURE AND IMPLICATIONS FOR PREDATION AND CARBON CYCLING: VIEWS FROM A ZOOGLIDER
The vertical microstructure of mesozooplankton is thought to be related to both biotic and physical properties within the water column. When observed at fine (1-10 m) and micro (<1 m) scales, planktonic organisms are highly patchy. These patches can have significant ecological consequences (e.g., enhanced water column productivity, increased encounter rates, differential grazing rates, altered carbon cycling). However, conventional sampling techniques do not resolve fine scales of patchiness and predator-prey interactions in the ocean environment. The Zooglider, our new autonomous zooplankton glider, is outfitted with a low power optical imaging system and dual frequency sonars (200/1000 kHz). It is able to resolve mesozooplankton within a well-defined sample volume, at a vertical scale of 5 cm, while making concurrent physical and acoustic measurements. The Zooglider was used to resolve vertical micro-scale distributions of mesozooplankton and marine snow from the Scripps Canyon and nearby waters. Analysis of mesozooplankton throughout the diel cycle suggests variable overlap between predatory mesozooplankton (e.g., chaetognaths and larger copepods) and their prey (e.g., smaller copepods). Spatial overlap tends to be more pronounced during daylight hours. The extent of collocation of mesozooplankton functional groups (e.g., flux feeders, true filter feeders, active suspension feeders, fragmenters) with peak marine snow will help assess whether mesozooplankton are sources or sinks for marine snow within the region.
Whitmore, B. M., Scripps Institution of Oceanography, University of California, San Diego, USA, firstname.lastname@example.org
Ohman, M. D., Scripps Institution of Oceanography, University of California, San Diego, USA, email@example.com
Sherman, J. T., Scripps Institution of Oceanography, University of California, San Diego, USA, firstname.lastname@example.org
Davis, R. E., Scripps Institution of Oceanography, University of California, San Diego, USA, email@example.com
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