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Ascending marine particles: Significance of transparent exopolymer particles (TEP) in the upper ocean
Author(s) -
Azetsu-Scott Kumiko,
Passow Uta
Publication year - 2004
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.2004.49.3.0741
Subject(s) - exopolymer , particle (ecology) , settling , water column , particle aggregation , mixed layer , surface layer , pycnocline , chemistry , environmental chemistry , materials science , oceanography , environmental science , layer (electronics) , geology , nanotechnology , nanoparticle , paleontology , environmental engineering , bacteria
The high abundance of transparent exopolymer particles (TEP) in marine and freshwater greatly affects particle dynamics. TEP act as glue for colliding particles and form the matrix in aggregates, thereby altering aggregation dynamics. We studied the sinking behavior of freshly produced, particle‐free TEP and of aggregates composed of TEP and latex spheres in a laboratory using water collected from Santa Barbara Channel, California. Particle‐free TEP ascend and accumulate in the surface layer of a settling column at an average velocity of 1.6 x 10 −4 cm s −1 . The estimated density of TEP ranges from 0.70 to 0.84 g cm −3 . TEP also transported latex spheres of 45.6 and 1.82 µm in diameter and a density of 1.05 g cm −3 to the surface layer. We describe a simple model illustrating the role of TEP for the vertical transport of solid particles. The densities and relative proportions of TEP, solid particles, and interstitial water within an aggregate determine its sinking or ascending velocity. High ratios of TEP to solid particles retard the sinking of aggregates, prolonging their residence time in the surface ocean. Our results demonstrate that TEP can provide a vehicle for the upward flux of biological and chemical components in the marine environment, including bacteria, phytoplankton, carbon, and reactive trace elements.