As of 2007, the Hawaii Ocean Time-series has made near monthly measurements at Station ALOHA (22° 45'N, 158° 00'W) for the past 19 years. Data from this Eulerian Ocean Observatory have been supplemented by several transects of opportunity to detect spatial variations of key biogeochemical properties, including nutrients (N, P, Si), chlorophyll, DIC/Alkalinity, dissolved & particulate organic matter, pico- & nano-plankton biomass & activity, nitrogenase gene expression, and bio-optical characteristics to name a few. This HOT transect, from Hawaii to Alaska and back (April & October 2003, respectively) provided a comparative analysis of relavent biogeochemical properties across the gyre and its northern boundary.