North Pacific Central Gyre Research Articles

Scavenging abyssal benthic amphipods trapped under oligotrophic central North Pacific Gyre waters

Two traps baited with fish were placed on the bottom (5720 m) of the central North Pacific Gyre. A total of 1793 lyssianassid amphipods were collected no ovigerous females and no identifiable males were caught. Five amphipod species were represented [1 undescribed species of Orchomene; 2 undescribed species of Paralicella; Eurythenes gryllus (Lichtenstein); and Cyclocaris sp.], 2 by single specimens. Amphipod samples give no evidence of size-classes. Evidence for scavenging as the amphipods' primary mode of existence is discussed. Forty-four copepods, of a single harpacticoid genus (Tisbella), were also collected.

The distribution and significance of Richelia intracellularis Schmidt in the North Pacific Central Gyre1

Localized blooms of phytoplankton observed in the upper 60 m of the North Pacific Central Gyre during three expeditions are accompanied and often dominated by an increase in the abundance of species of the diatom genus Rhizosolenia that contain the endophytic cyanophyte Richelia intracellularis, which may fix molecular nitrogen. It is hypothesized that the phytoplankton blooms are stimulated and sustained by an increase in the available nitrogenous nutrients resulting from nitrogen fixation by Richelia.