CAJ | 학술논문

沙尘沉降是海洋营养元素的重要来源之一，对海洋异养细菌的意义十分重大。为研究沙尘沉降对于海洋异养细菌的作用过程，于2013年3月对A1、A2两个站位的海水进行了源地沙尘添加培养，探讨大、小两种粒径沙尘对南海东北部海域异养浮游细菌生物量及群落结构的影响过程和机制。结果表明，南海东北部海域海水营养物质的浓度和异养细菌生物量水平较低；而两种沙尘的添加在短期内都可以溶出DOC和DIN，在一定程度上能够缓解一部分营养限制；其中小粒径沙尘在短期内溶出的营养物质较多，平均使系统中DOC和DIN浓度增加了0.65倍和0.36倍。添加沙尘后，两个站位的培养系统中异养细菌生物量出现不同程度增长，沙尘的单独添加在短期和长期内都可以促进异养细菌生物量的增长；其短期内，小粒径沙尘的添加使得异养细菌生物量的增加比原位沙尘更明显；而在添加氮和磷的情况下，两种沙尘的添加并不能明显促进异养细菌生物量的增长，在长期内甚至起抑制作用。通过对A1在添加两种沙尘7 d前后的细菌群落结构的分析发现，培养后细菌群落的生物多样性降低并且群落结构趋于简化，其中小粒径沙尘的作用最为明显；而两种不同沙尘添加后细菌群落结构的更替情况基本一致，能够利用外源营养的α-变形菌纲（Alphaproteobacteria）和γ-变形菌纲（Gammaproteobacteria）成为培养结束后的优势菌群，而叶绿体（chloroplast）等自养菌在培养结束后的优势度消失，细菌群落偏向于异养。研究发现源地沙尘能够促进海洋异养细菌生长，改变了细菌群落结构，提高了其在海洋生态系统中的生态功能。
사진침강시해양영양원소적중요래원지일，대해양이양세균적의의십분중대。위연구사진침강대우해양이양세균적작용과정，우2013년3월대A1、A2량개참위적해수진행료원지사진첨가배양，탐토대、소량충립경사진대남해동북부해역이양부유세균생물량급군락결구적영향과정화궤제。결과표명，남해동북부해역해수영양물질적농도화이양세균생물량수평교저；이량충사진적첨가재단기내도가이용출DOC화DIN，재일정정도상능구완해일부분영양한제；기중소립경사진재단기내용출적영양물질교다，평균사계통중DOC화DIN농도증가료0.65배화0.36배。첨가사진후，량개참위적배양계통중이양세균생물량출현불동정도증장，사진적단독첨가재단기화장기내도가이촉진이양세균생물량적증장；기단기내，소립경사진적첨가사득이양세균생물량적증가비원위사진경명현；이재첨가담화린적정황하，량충사진적첨가병불능명현촉진이양세균생물량적증장，재장기내심지기억제작용。통과대A1재첨가량충사진7 d전후적세균군락결구적분석발현，배양후세균군락적생물다양성강저병차군락결구추우간화，기중소립경사진적작용최위명현；이량충불동사진첨가후세균군락결구적경체정황기본일치，능구이용외원영양적α-변형균강（Alphaproteobacteria）화γ-변형균강（Gammaproteobacteria）성위배양결속후적우세균군，이협록체（chloroplast）등자양균재배양결속후적우세도소실，세균군락편향우이양。연구발현원지사진능구촉진해양이양세균생장，개변료세균군락결구，제고료기재해양생태계통중적생태공능。
Dust deposition, one of the sources of marine nutrients, played a critical role in community dynamics of marine heterotrophic bacteria. Enrichment experiments were carried out in March 2013 at stations A1 and A2 in northeastern South China Sea to evaluate the process and mechanism of the dust originated from a dust storm outbreak affecting the biomass and community structure of heterotrophic bacteria. The results indicated that the heterotrophic bacterial biomass was low in the northeastern South China Sea and the dust could relieve nutrient limitation through inputs of DOC and DIN. Particularly, the dust with small grain size increased the DOC and DIN concentration in seawater by a factor of 0.65 and 0.36, respectively. The addition of dust triggered an increase in heterotrophic bacterial biomass in both stations. Dust addition alone facilitated heterotrophic bacterial biomass both in the long-term and short-term experiments, whereas the small grain size dust showed more significant effect in the long-term experiments than those in the short-term. With the simultaneous addition of nitrogen and phosphorus, the dust couldn’t enhance bacterial significantly, or even decreased bacterial biomass in the long-term experiments. Comparing the bacteria community with the dust addition before and after an incubation period of 7 days at station A1, we found that the bacterial biodiversity were decreased and bacteria community simplified after incubation, especially for the small grain size dust. The bacteria community structure responded similarly to the two types of dust, with Alphaproteobacteria and Gammaproteobacteria turning into dominant species after incubation whereas Chloroplast losing its dominance, and consequently the bacteria community becoming more heterothrophic. In conclusion, the dust originated from dust storms could obviously promote heterotrophic bacterial growth, significantly change its community structure, and enhance its function in marine ecosystem.