Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Dr, La Jolla, CA, 92093, USA.
University of Southern California, 3620 S Vermont Ave, Los Angeles, CA, 90007, USA.
Sci Rep. 2024 Sep 28;14(1):22408. doi: 10.1038/s41598-024-69991-3.
The relative prevalence of endemic and cosmopolitan biogeographic ranges in marine microbes, and the factors that shape these patterns, are not well known. Using prokaryotic and eukaryotic amplicon sequence data spanning 445 near-surface samples in the Southern California Current region from 2014 to 2020, we quantified the proportion of taxa exhibiting endemic, cosmopolitan, and generalist distributions in this region. Using in-situ data on temperature, salinity, and nitrogen, we categorized oceanic habitats that were internally consistent but whose location varied over time. In this context, we defined cosmopolitan taxa as those that appeared in all regional habitats and endemics as taxa that only appeared in one habitat. Generalists were defined as taxa occupying more than one but not all habitats. We also quantified each taxon's habitat affinity, defined as habitats where taxa were significantly more abundant than expected. Approximately 20% of taxa exhibited endemic ranges, while around 30% exhibited cosmopolitan ranges. Most microbial taxa (50.3%) were generalists. Many of these taxa had no habitat affinity (> 70%) and were relatively rare. Our results for this region show that, like terrestrial systems and for metazoans, cosmopolitan and endemic biogeographies are common, but with the addition of a large number of taxa that are rare and randomly distributed.
海洋微生物的地方性和世界性生物地理分布的相对流行程度，以及塑造这些模式的因素，目前还不太清楚。本研究利用了 2014 年至 2020 年期间在南加州海域采集的 445 个近地表样本的原核生物和真核生物扩增子序列数据，量化了该地区具有地方性、世界性和广布性分布的分类群的比例。利用关于温度、盐度和氮的原位数据，我们对海洋生境进行了分类，这些生境在内部是一致的，但位置随时间而变化。在这种情况下，我们将世界性分类群定义为出现在所有区域生境中的分类群，地方性分类群定义为仅出现在一个生境中的分类群。广布性分类群则被定义为占据多个但不是所有生境的分类群。我们还量化了每个分类群的生境偏好，即分类群在特定生境中显著更丰富的程度。大约 20%的分类群具有地方性分布，而约 30%的分类群具有世界性分布。大多数微生物分类群（50.3%）是广布性的。这些分类群中有许多没有生境偏好（>70%），而且相对较少见。我们对该地区的研究结果表明，与陆地系统和后生动物一样，世界性和地方性生物地理学是常见的，但同时也存在大量稀有且随机分布的分类群。
