Babić Ivana, Petrić Ines, Bosak Sunčica, Mihanović Hrvoje, Dupčić Radić Iris, Ljubešić Zrinka
Department of Biology, Faculty of Science, University of Zagreb, Rooseveltov trg 6, 10000 Zagreb, Croatia.
Division for Marine and Environmental Research, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia.
Mar Genomics. 2017 Dec;36:3-11. doi: 10.1016/j.margen.2017.05.014. Epub 2017 Jun 7.
Adriatic, the northernmost part of the Mediterranean Sea, due its oligotrophy, topography, and hydrology dynamics, and complex circulation patterns, was suggested as an important study site for rapid climatology impacts. Its southern part is mainly oligotrophic and dominated by picophytoplankton, with cyanobacteria as main representatives. Diversity and distribution patterns of different Prochlorococcus ecotypes were investigated by molecular tools and flow cytometry during the winter convection event in the southern Adriatic (BIOTA winter cruise; February/March 2015). Phylogenetic diversity based on clone libraries of the 16S-23S ribosomal DNA ITS region, as well as flow cytometry (histograms of red fluorescence), indicated presence of 2 different Prochlorococcus in the Adriatic. HLI, as a typical clade for Mediterranean Sea, was likewise found to be dominant Prochlorococcus in the Adriatic, followed by less abundant LLI clade. In addition, Prochlorococcus were found to co-occur with diverse Synechococcus population (53% and 47% of obtained ITS sequences, respectively). Different Prochlorococcus ecotypes had similar patterns of vertical distribution, predominantly occupying upper 100m depth layer, but their distribution was clearly affected by the heterogeneity of hydrological conditions, nitrogen concentration and temperature along vertical and horizontal sampling points. Different studies pointed out that, as a consequence of climate changes, serious alteration of biological and ecological patterns are already taking place Therefore, understanding of the distribution and abundance of picophytoplankton in Adriatic, being still limited, is much needed baseline for predicting possible biogeochemical impact of future environmental changes.
亚得里亚海是地中海最北部的海域，因其贫营养状态、地形、水文动力学以及复杂的环流模式，被认为是快速气候变化影响研究的重要地点。其南部主要为贫营养海域，以微微型浮游植物为主，蓝细菌是主要代表。在亚得里亚海南部冬季对流事件期间（BIOTA冬季航次；2015年2月/3月），利用分子工具和流式细胞术研究了不同原绿球藻生态型的多样性和分布模式。基于16S - 23S核糖体DNA ITS区域克隆文库的系统发育多样性以及流式细胞术（红色荧光直方图）表明，亚得里亚海中存在2种不同的原绿球藻。作为地中海典型分支的高光强适应型（HLI）同样被发现是亚得里亚海中占主导地位的原绿球藻，其次是丰度较低的低光强适应型（LLI）分支。此外，还发现原绿球藻与不同的聚球藻群体共存（分别占所获ITS序列的53%和47%）。不同的原绿球藻生态型具有相似的垂直分布模式，主要占据上层100米深度层，但其分布明显受到垂直和水平采样点处水文条件、氮浓度和温度异质性的影响。不同研究指出，由于气候变化，生物和生态模式已经发生了严重改变。因此，鉴于目前对亚得里亚海微微型浮游植物分布和丰度的了解仍然有限，这是预测未来环境变化可能产生的生物地球化学影响所急需的基线。
