In the North Pacific Subtropical Gyre (NPSG), the regular occurrence of summer phytoplankton blooms contributes to marine ecosystem productivity and the annual carbon export. The mechanisms underlying the formation, maintenance, and decay of these blooms remain largely unknown; nitrogen fixation, episodic vertical mixing of nutrients, and meso- (<100 km) and...
Sustained time series have provided compelling evidence for progressive acidification of the
surface oceans through exchange with the growing atmospheric reservoir of carbon dioxide. However,
few long-term programs exist, and extrapolation of results from one site to larger oceanic expanses is
hampered by the lack of spatial coverage inherent to...
Sustained time series have provided compelling evidence for progressive acidification of the
surface oceans through exchange with the growing atmospheric reservoir of carbon dioxide. However,
few long-term programs exist, and extrapolation of results from one site to larger oceanic expanses is
hampered by the lack of spatial coverage inherent to...
The particle size distribution (PSD) is a critical aspect of the oceanic ecosystem. Local variability in the PSD can be indicative of shifts in microbial community structure and reveal patterns in cell growth and loss. The PSD also plays a central role in particle export by influencing settling speed. Satellite-based...
Time-series observations are critical to understand the structure, function, and dynamics of marine ecosystems. The Hawaii Ocean Time-series program has maintained near-monthly sampling at Station ALOHA (22°45′N, 158°00′W) in the oligotrophic North Pacific Subtropical Gyre (NPSG) since 1988 and has identified ecosystem variability over seasonal to interannual timescales. To further...
During the summer of 2012, we used laser diffractometry to investigate the temporal and vertical variability of the particle size spectrum (1.25–100 µm in equivalent diameter) in the euphotic zone of the North Pacific Subtropical Gyre. Particles measured with this optical method accounted for ∼40% of the particulate carbon stocks...
Sustained time series have provided compelling evidence for progressive acidification of the surface oceans through exchange with the growing atmospheric reservoir of carbon dioxide. However, few long-term programs exist, and extrapolation of results from one site to larger oceanic expanses is hampered by the lack of spatial coverage inherent to...
We examined short-term (24–72 h) responses of naturally occurringmarine N2 fixing microorganisms (termed diazotrophs) to abrupt increases in the partial pressure of carbon dioxide (pCO2) in seawater during nine incubation experiments conducted between May 2010 and September 2012 at Station ALOHA (A Long-term Oligotrophic Habitat Assessment) (22°45′N, 158°W) in the...
We conducted 11 independent short-term carbon dioxide (CO₂) manipulation experiments using colonies of
the filamentous cyanobacteria Trichodesmium isolated on three cruises in the North Pacific Subtropical Gyre
(NPSG). Dinitrogen (N₂) and carbon (C) fixation rates of these colonies were compared over CO₂ conditions
ranging from ~ 18 Pa (equivalent to...
We present a spatially extensive record of dinitrogen (N₂) fixation rates and distributions
of N₂ fixing microorganisms along with the results of exogenous phosphorus (P) addition experiments
conducted during a series of cruises in the North Pacific Subtropical Gyre (NPSG). We measured the
N₂ and carbon (C) fixation rates of...