指導教授 : 蔣國平 博士

報告學生 : 王榮

INTRODUCTION

Heterotrophic bacteria constitute a fundamental component of marine ecosystems, with important roles in the biogeochemical cycles of key elements (Sherr & Sherr 2000).

Bacteria with high nucleic acid (HNA) content were the active fraction (e.g. Gasol & del Giorgio 2000).

Bacteria with low nucleic acid (LNA) content are not metabolically inactive and can be an integral part of the microbial food web (Zubkov et al. 2001, Jochem et al. 2004, Longnecker et al. 2005).

MATERIALS AND METHODS

2000.5/30~6/9

kD = 1/t × (dC/dt)

kD = μn – g × D

μ0 = g + kD0,

Cincorporated = μ × B0(e(μ – g)t –1) × (μ – g)–1

Cgrazed = g × B0(e(μ – g)t –1) × (μ – g) –1

15 fg C cell–1

C/μ=ΔBk/K

淨細菌數量增加量

( 對 T 時間的數量作積分 )

RESULTS AND DISCUSSION

Surface ,DCM 差 4~6 C

Freshwater 影響深度 10~30m( 北向南遞減 )

表水溫 18.5~19.8C( 北至南 )

Surface Chl a :0.12±0.05 gl-1

DCM Chl a :0.74±0.30 gl-1

Bac. Size: surface HNA >surface LNA >DCM HNA LNA

(p<0.01) (p<0.001)

Bacterial concentration

Growth and grazing

Bac. Abundance

Surface:4.5~13.3x105(7.2±2.9x105)

DCM:6.4~9x105(7.4±1.1x105)

HNA 比例

Surface:34~55%(49.4±5.3%)

DCM:39~47%(43.0±2.9%)

s:0.88±0.43d-1

D:0.71±0.23d-1

gs:0.75±0.23d-1

gD:0.58±0.29d-1

HNA:1.18±0.60d-1

LNA:0.47±0.28d-1

HNA:0.36±0.23d-1

LNA:0.90±0.46d-1

HNA:1.02±0.31d-1

LNA:0.37±0.19d-1

HNA:0.26±0.17d-1

LNA:0.77±0.50d-1

Bacterial C flux

Surface: 10.9±4.40 mgCl-1

DCM: 11.1±1.69 mgCl-1

Incorporation:10.2±6.4 gCl-1d-1

Grazed: 9.0±3.2 gCl-1d-1

Incorporation: 8.7±4.3 gCl-1d-1

Grazed: 6.9±4.0 gCl-1d-1

(70%HNA)

(80%LNA)

Bacterial C flux :10gCl-1d-1

Phytoplanlton C flux :4.6gCl-1d-1200% (surface)

photosynthesis versus irradiance (P-E)3.48 ± 2.02 mg of C mg–1 chlorophyll a h–1( 與前六年相當 )

Cincorporated = μ × B0(e(μ – g)t –1) × (μ – g)–1

growth rates 0.88d-1 > 0.25d-1 ( 之前的報告 )

dilution growth and grazing rates > C14 , 餵珠子

m > 1d-1 : 低 grazing, 排除大型攝食者

log10 BP= 0.07 × T + 0.40 log10 chlorophyll a (Pedrós-Alió et al.,2000)

Gasol et al. (2002) high intrinsic growth rates when bacterial abundances are limited by predation and low growth rates when limited by resources.

g: Vaqué et al. (2001) for the area, but are consistent with or even lower than rates reported from elsewhere

15fgC cell-1

END