Program and Agenda

Abstract

SIZE STRUCTURE AND PARTICLE MAXIMA IN DIFFERENT LAYERS OF THE WATER COLUMN OF A SUBTROPICAL GYRE: INFLUENCES OF ALGAL ECOLOGY AND DENSITY STRATIFICATION

Particle size distribution plays a critical role in the structure and function of planktonic ecosystems. In order to study its temporal and vertical variability we used laser diffraction on three cruises in the North Pacific Subtropical Gyre. Our analyses indicate that particles around 5 µm in diameter dominate particulate carbon stocks in the range considered (1.25-250 µm), and that particles >10 µm are relatively less important than in other regions of the global ocean. Furthermore, particulate matter distributions are markedly heterogenous, with different size fractions varying independently with depth. Small particles, between 1.25 and 2 µm in diameter, reached their maximal abundance at the depth of the deep chlorophyll maximum (124 m), consistent with an increase in abundance of the picoeukaryotic phytoplankton. Particles of intermediate size (2-20 µm) accumulated at the base of the mixed layer (42 m), while a peak of large particles (100-250 µm) was observed within the layer of maximal stratification (72 m). These observations support the hypothesis that surface mixing and density gradients play important roles in the dynamics of particulate matter in stratified environments.

Authors

Barone, B., University of Hawaii at Manoa, USA, benedetto.barone@gmail.com

Church, M. J., University of Hawaii at Manoa, USA, mjchurch@hawaii.edu

Karl, D. M., University of Hawaii at Manoa, USA, dkarl@hawaii.edu

Letelier, R. M., Oregon State University, USA, letelier@coas.oregonstate.edu

White, A. E., Oregon State University, USA, awhite@coas.oregonstate.edu

Details

Oral presentation

Session #:049
Date: 2/27/2014
Time: 15:30
Location: 313 B

Presentation is given by student: No