Microbial stimulation of the aggregation process between submicron-sized particles and suspended particles in coastal waters

Aquatic Microbial Ecology

Isao Koike¹  Hideki Fukuda¹ 

关键词: Particle aggregation;    Colloidal particles;    Sinking flux;    Microbial food web;    Collision efficiency;    Sickness;    Extracellular release;   

DOI  :  10.3354/ame037063

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: Transfer rates of submicron-sized particles (SMP) to micro-suspended particles (5 to 20 µm in diameter) in coastal waters around Japan were measured using fluorescent beads (0.5 µm in diameter) and flow cytometry, with and withoutmetabolic inhibitors (thiuram or NaN₃). This flow cytometric technique has the advantage that it allows the number of beads stuck to suspended particles to be counted without any pre-treatment, such as filtration, that can introduce artifacts.The transfer rates to particles in the 5-20 µm fraction without inhibitors were on average 4.3 to 5.8 times higher than with added NaN₃. On the other hand, ingestion rates of fluorescent beads by protozoa in the 5-20µm fraction were less than 10% of the transfer rates to particles in the 5-20 µm fraction. These results indicate that biological activities were more efficient than physical mechanisms for the transfer process of SMP into the 5-20µm fraction separately from the grazing process. Also, the inhibitory effect of thiuram on the transfer rates suggests an involvement of eukaryotic cells in this stimulation. The intensity of this stimulation was positively correlated with thedensity of attached nanoflagellates per particle (Da) (R = 0.630, n = 22), bacterial abundance (R = 0.489, n = 22), concentration of chlorophyll a (R = 0.518, n = 18) and water temperature (R = 0.569, n = 22). These results indicate that biologicalprocesses are key mechanisms for the coagulation process of submicro- and micro-scale particles in coastal environments.

【 授权许可】

Unknown