Horizontal and Vertical Distribution of Gelatinous Zooplankton

The first part of this study examines the horizontal distribution of gelatinous zooplankton along a Pacific transect from Hawaii to Palmyra Atoll. Gelatinous zooplankton are able to survive with limited food sources in part because of their ability to “degrow”. Their relative abundance, size and diversity were compared to productivity to see if this ability was influencing there distribution in oligotrophic zones. Plankton net tows were used to sample the water column at several stations along the transect. No relationships were found between the relative abundance, diversity or average size of gelatinous zooplankton and the concentration of chlorophyll-a. A positive relationship was found between gelatinous zooplankton diversity and distance from nearest land, which indicates that the North Pacific gyre influences their distribution.
The second part of this study used a Remotely Operated Vehicle to examine the vertical distribution of a ctenophore species in the West Lagoon of Palmyra Atoll. A strong negative relationship was found between ctenophore abundance and depth at night. This indicates either a constant distribution gradient or the result of nightly migrations to the surface.