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Submicrometer particles in northwest Pacific coastal environments: Abundance, size distribution, and biological origins
Author(s) -
Yamasaki Akiko,
Fukuda Hideki,
Fukuda Rumi,
Miyajima Toshihiro,
Nagata Toshi,
Ogawa Hiroshi,
Koike Isao
Publication year - 1998
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.1998.43.3.0536
Subject(s) - abundance (ecology) , oceanography , trophic level , range (aeronautics) , seawater , environmental science , food web , microbial food web , particle size , chlorophyll a , organic matter , ecology , heterotroph , environmental chemistry , atmospheric sciences , chemistry , biology , botany , geology , bacteria , materials science , composite material , genetics
Submicrometer particles (SMP) are suggested to be a critical component for organic matter transitions in seawater, but little is known about variations and controls of SMP in coastal systems. We examined vertical and horizontal distributions of SMP (0.4–l µm in equivalent spherical diameter as measured by a resistive pulse particle counter) and biological variables (chlorophyll a concentration, abundance of bacteria, and heterotrophic nanoflagellates) in northwest Pacific coastal environments, The abundance and total volume of SMP in the upper 200 m varied in the range of 5 × 10 4 −3 × 10 7 particles ml −1 and 4 × 10 3 −3 × 10 6 µm 3 ml −1 , respectively. Over a large trophic gradient (Chl a , 0.02–4 µg liter −1 ), the total volume of SMP was strongly positively correlated with Chl a concentration ( r = 0.90, P < 0.0001, n = 47) and with other microbial variables ( r = 0.84–0.90) consistent with a hypothesis that SMP dynamics are closely related to microbial food‐web processes. Notably, size distribution of SMP in upper waters often exhibited a distinctive peak at a size range of 0.6–0.7 µm, which was most pronounced in productive nearshore waters and became less evident with depth and with distance from the shore. A sonication experiment revealed that the 0.6–0.7‐µm particles are primarily nonliving. We hypothesize that SMP, particularly the 0.6–0.7‐µm component, are directly produced by biological processes. Our data suggest that SMP are a highly reactive and abundant component of detrital colloids and play important roles in material cycles within coastal systems.