PARENT SESSION

PH09 Plant Ecotoxicology
Exhibit Hall
8:00 AM - Thursday

(PH114) Effects of organic chemicals on the marine microalga Nannochloropsis oculata ST-3 strain.

Yoshida, Kosuke¹, Ishii, Hiroshi¹, Saito, Hiroshi¹, Kobayashi, Yukio¹, ¹ School of marine science and technology, Tokay University, Shizuoka city, Japan

ABSTRACT- In aquaculture food chain, marine microalga Nannochloropsis oculata is used as a primary productivity. Industrial pollution of organic chemicals (OCs) has recently broken out in the coastal aquaculture. In this study common microalgal species, N.oculata ST-3 strain was exposed to increasing concentrations of bisphenol A(BPA), p-nonylphenol(p-NP) and formaldehyde(FA). The concentration of BPA, p-NP and FA in the algal culture was controlled from 0.1ppm to 40ppm for examining growth curve of ST-3 strain. Growth experiments were conducted using 500ml flasks in a water bath at 25°C. Culture were kept under 80E/m²/s illumination with 12:12 light and dark cycle. Air permeation were conducted using millipore filter(45m). Effects of OCs on the marine microalga N.oculata ST-3 strain were investigated with BPA, p-NP and FA. ST-3 strain exposed at over 6ppm of BPA and at over 20ppm of p-NP and FA did not exhibit growth. The growth of ST-3 strain was observed by BPA up to 5ppm, by p-NP and FA up to 10ppm. But those cultures showed longer lag phase than in the absence of OCs(control). Especially, the growth of ST-3 strain exposed at 10ppm FA at first time showed lag phase for 11 days, but growth curve of ST-3 strain exposed at 10ppm FA at 2nd times showed lag phase only for a day. Therefore, ST-3 strain might adapt to FA at 10ppm. The concentration of BPA, p-NP and FA in the medium decreased along with growth of ST-3 strain. Therefore, there were possibilities that OCs stuck to the surface of ST-3 strain or moved into ST-3 strain, and changed the difference substance in ST-3 strain.

Key words: bisphenol A, marine microalga, p-nonylphenol, formaldehyde