Microbial community structure in the sea surface microlayer at two contrasting coastal sites in the northwestern Mediterranean Sea
Microbial community structure in the sea surface microlayer at two contrasting coastal sites in the northwestern Mediterranean Sea
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DOI：
10.3354/ame042091
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发表时间：
2006-02-06
影响因子：
1.4
通讯作者：
Lebaron, P
中科院分区：
文献类型：
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作者：
Joux, F;Agogué, H;Lebaron, P
为了比较海表层微层（SML）和地下水（SSW）的微生物群落结构，我们确定了13个生物参数的富集因子（EF: SML的丰度或活性与SSW的丰度或活性之比）。样本取自地中海两个截然不同的沿海地区，分别是高城市化地区（西班牙巴塞罗那）和低城市化地区（法国滨海巴纽尔斯）。主成分分析表明，巴塞罗那的时间变异性比巴纽尔斯高得多，并且巴塞罗那的SML和SSW样品的特征更密切相关。在这两个位点，SML在异养细菌（平均1.1倍）、聚球菌（平均1.1倍）和光合微真核生物（平均1.5倍）中的富集较弱。相比之下，与SSW相比，SML中叶绿素a (chl a)（平均为1.9倍）、褐藻素a（平均为7.4倍）、自养（平均为6.1倍）和异养纳米鞭毛虫（平均为5.1倍）的含量显著丰富。细菌产量和可培养细菌的富集程度变化很大。两个地点之间的EF仅在chl a、b和c的浓度和自养纳米鞭毛虫的丰度上存在显著差异，其中巴塞罗那地点的EF更高。除自养鞭毛虫外，SML中测定的参数的丰度或活性与SSW中测定的参数的丰度或活性高度相关，表明SML的富集主要是由附着在浮力颗粒上的微生物向上运输或气泡清除引起的。相比之下，自养型纳米鞭毛虫对总植藻生物量的高贡献（平均=26%）可能是由于它们对SML的快速定植。SML中高丰度的自养和异养纳米鞭毛虫表明这些生物在气-海界面微生物食物网的功能中起着关键作用。
In an attempt to compare the microbial community structure between the sea surface microlayer (SML) and subsurface waters (SSW), we determined the enrichment factors (EF: the ratio of abundance or activity in the SML to abundance or activity in SSW) of 13 biological parameters. Samples were taken at 2 contrasting coastal sites in the Mediterranean Sea, corresponding to a high (Barcelona, Spain) and low (Banyuls-sur-Mer, France) urbanized area. Principal component analysis showed that temporal variability was much higher at Barcelona than at Banyuls, and that the characteristics of the SML and SSW samples were more closely related at Barcelona. At both sites, the SML was weakly enriched in heterotrophic bacteria (on average 1.1-fold), Synechococcus spp. (on average 1.1-fold), and photosynthetic picoeukaryotes (on average 1.5-fold) relative to SSW. In contrast, the SML was considerably enriched in chlorophyll a (chl a) (on average 1.9-fold), phaeophytin a (on average 7.4-fold), autotrophic (on average 6.1-fold) and heterotrophic nanoflagellates (on average 5.1-fold) relative to SSW. Enrichments in bacterial production and culturable bacteria were highly variable. EF were significantly different between the 2 sites only for concentrations of chl a, b, and c and the abundance of autotrophic nanoflagellates, with higher EF at the Barcelona site. Except for autotrophic flagellates, the abundance or activity of the parameters determined in the SML was highly correlated with that determined in SSW, suggesting that enrichment of the SML results mainly from upward transport of microorganisms attached to buoyant particles or bubble scavenging. In contrast, the high contribution of autotrophic nanoflagellates to overall phytoneuston biomass (mean=26%) is likely due to their rapid colonization of the SML. The high abundances of auto- and heterotrophic nanoflagellates in the SML indicated that these organisms play a key role in the functioning of the microbial food webs at the air-sea interface.