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Over the past several years, we have sought to quantify time-varying changes in picoplankton productivity, biomass, and diversity at Station ALOHA in the subtropical North Pacific. Through a combination of approaches, including isotopic labeling, flow cytometric sorting, and amplification and sequencing of target genes, this work has highlighted several important pathways for the movement of energy and material through picoplankton biomass in this ecosystem. In particular, numerous lines of evidence indicate mixotrophy is an important pathway supporting the metabolism and nutritional demands of both photosynthetic cyanobacteria and eukaryotic picoplankton. Forms of mixotrophy that appear significant at ALOHA include assimilation of organic matter by cyanobacteria and possible phagotrophic growth by major groups of photosynthetic eukaryotic picoplankton found at ALOHA. In addition, analyses of eukaryotic picoplankton community structure suggest parasitism is a widespread, but largely uncharacterized, trait among picoplankton at Station ALOHA. Despite their potential importance, to date there has been relatively little effort to incorporate such processes into quantitative or conceptual models of food web dynamics in the open sea. This presentation will examine the current state of understanding of such dynamics at Station ALOHA, and provide commentary on potentially fruitful future research directions to elucidate the significance of these pathways to food web ecology and biogeochemistry in the open sea.


Church, M. J., University of Montana, USA,

Bjorkman, K. M., University of Hawaii, USA,

Karl, D. M., University of Hawaii, USA,

Rii, Y. M., University of Hawaii, USA,

Viviani, D. A., University of Hawaii, USA,


Oral presentation

Session #:040
Date: 03/01/2017
Time: 12:45
Location: 314

Presentation is given by student: No