The Effect of Marine Snow Particle Distribution on Copepod Behavior
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Description
Marine snow is a major component of the biological pump, through which carbon is exported to the deep ocean. The sinking of marine snow can be disrupted by organisms that ingest or breakup the falling aggregates. Previous studies have found that zooplankton ingest these aggregates, which may have important impacts on carbon export. Marine snow can have patchy distributions, occurring in layers, which may further impact interactions with zooplankton; however, no experimental study has looked specifically at how the presence of a marine snow layer could affect zooplankton foraging behavior. In this study we examined how the distribution of marine snow particles affected copepod foraging and behavior, specifically with regard to their swimming patterns. We conducted a series of experiments in which copepods of the species Calanus pacificus were exposed to three different feeding environments: a layer of marine snow, a homogenous distribution of marine snow, and a control treatment without marine snow. Copepod behavior was recorded with two cameras that were set up perpendicular to one another, imaging the sides of the tank. MATLAB was used to reconstruct 3D copepod tracks, allowing us to calculate copepod location, velocity, and turning rate throughout the experiments. We observed that copepods performed a spiraling swimming behavior, likely in response to chemical plumes from the sinking marine snow aggregates, most frequently in the homogenous treatment. These results can further our understanding of interactions between zooplankton and marine snow, and thereby provide a contribution to the broader research of marine carbon cycling.
The Effect of Marine Snow Particle Distribution on Copepod Behavior
Marine snow is a major component of the biological pump, through which carbon is exported to the deep ocean. The sinking of marine snow can be disrupted by organisms that ingest or breakup the falling aggregates. Previous studies have found that zooplankton ingest these aggregates, which may have important impacts on carbon export. Marine snow can have patchy distributions, occurring in layers, which may further impact interactions with zooplankton; however, no experimental study has looked specifically at how the presence of a marine snow layer could affect zooplankton foraging behavior. In this study we examined how the distribution of marine snow particles affected copepod foraging and behavior, specifically with regard to their swimming patterns. We conducted a series of experiments in which copepods of the species Calanus pacificus were exposed to three different feeding environments: a layer of marine snow, a homogenous distribution of marine snow, and a control treatment without marine snow. Copepod behavior was recorded with two cameras that were set up perpendicular to one another, imaging the sides of the tank. MATLAB was used to reconstruct 3D copepod tracks, allowing us to calculate copepod location, velocity, and turning rate throughout the experiments. We observed that copepods performed a spiraling swimming behavior, likely in response to chemical plumes from the sinking marine snow aggregates, most frequently in the homogenous treatment. These results can further our understanding of interactions between zooplankton and marine snow, and thereby provide a contribution to the broader research of marine carbon cycling.