Summer phyto- and bacterioplankton communities during low and high productivity scenarios in the Western Antarctic Peninsula
Phytoplankton blooms taking place during the warm season drive high productivity in Antarctic coastal seawaters. Important temporal and spatial variations exist in productivity patterns, indicating local constraints influencing the phototrophic community. Surface water in Chile Bay (Greenwich Island, South Shetlands) is influenced by freshwater from the melting of sea ice and surrounding glaciers; however, it is not a widely studied system. The phyto- and bacterioplankton communities in Chile Bay were studied over two consecutive summers; during a low productivity period (chlorophyll a < 0.05 mg m−3) and an ascendant phototrophic bloom (chlorophyll a up to 2.38 mg m−3). Microbial communities were analyzed by 16S rRNA—including plastidial—gene sequencing. Diatoms (mainly Thalassiosirales) were the most abundant phytoplankton, particularly during the ascendant bloom. Bacterioplankton in the low productivity period was less diverse and dominated by a few operational taxonomic units (OTUs), related to Colwellia and Pseudoalteromonas. Alpha diversity was higher during the bloom, where several Bacteroidetes taxa absent in the low productivity period were present. Network analysis indicated that phytoplankton relative abundance was correlated with bacterioplankton phylogenetic diversity and the abundance of several bacterial taxa. Hubs—the most connected OTUs in the network—were not the most abundant OTUs and included some poorly described taxa in Antarctica, such as Neptunomonas and Ekhidna. In summary, the results of this study indicate that in Antarctic Peninsula coastal waters, such as Chile Bay, higher bacterioplankton community diversity occurs during a phototrophic bloom. This is likely a result of primary production, providing a source of fresh organic matter to bacterioplankton.
KeywordsBacterioplankton Phytoplankton Antarctic Peninsula 16S rRNA gene sequencing
The authors gratefully acknowledge the Armada de Chile staff at Arturo Prat Station and the staff from the Chilean Antarctic Institute (INACH); their support made possible the sampling in Chile Bay. The authors also thank the Department of Climatology, Centro Meteorológico de Valparaíso, Armada de Chile, for the meteorological data and María Estrella Alcamán, Cynthia Sanhueza, Laura Farías and Josefa Verdugo for their assistance with sample collection.
This work was financially supported by the grants INACH15-10, INACH_RG_09_17, CONICYT for international cooperation DPI20140044, FONDAP N°15110009, FONDECYT postdoctoral N°3160424, CONICYT PhD scholarship N°21130515 and CONICYT magister scholarship N°22172113.
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Conflict of interest
The authors declare that they have no conflict of interest.
Research involved in human and animal rights
This article does not contain any studies with human participants or animals performed by any of the authors.
- Amaro AM, Fuentes MS, Ogalde SR et al (2005) Identification and characterization of potentially algal-lytic marine bacteria strongly associated with the toxic dinoflagellate Alexandrium catenella. J Eukaryot Microbiol 52:191–200. https://doi.org/10.1111/j.1550-7408.2005.00031.x CrossRefPubMedGoogle Scholar
- Dinasquet J, Richert I, Logares R et al (2017) Mixing of water masses caused by a drifting iceberg affects bacterial activity, community composition and substrate utilization capability in the Southern Ocean. Environ Microbiol 19:2453–2467. https://doi.org/10.1111/1462-2920.13769 CrossRefPubMedGoogle Scholar
- Gutt J, Adams B, Bracegirdle T et al (2012) Antarctic thresholds—Ecosystem resilience and adaptation: a new SCAR-biology programme. Polarforschung 82:147–150Google Scholar
- Lovejoy C, Bowman JP, Hallegraeff GM (1998) Algicidal effects of a novel marine Pseudoalteromonas isolate (class Proteobacteria, Gamma subdivision) on harmful algal bloom species of the genera Chattonella, Gymnodinium, and Heterosigma. Appl Environ Microbiol 64:2806–2813PubMedPubMedCentralGoogle Scholar
- Milici M, Vital M, Tomasch J et al (2017) Diversity and community composition of particle-associated and free-living bacteria in mesopelagic and bathypelagic Southern Ocean water masses: evidence of dispersal limitation in the Bransfield Strait. Limnol Oceanogr 62:1080–1095. https://doi.org/10.1002/lno.10487 CrossRefGoogle Scholar
- Strickland JDH, Parsons TR (1972) A practical handbook of seawater analysis, 2nd edn. The Alger Press Ltd, OttawaGoogle Scholar
- West NJ, Obernosterer I, Zemb O, Lebaron P (2008) Major differences of bacterial diversity and activity inside and outside of a natural iron-fertilized phytoplankton bloom in the Southern Ocean. Environ Microbiol 10:738–756. https://doi.org/10.1111/j.1462-2920.2007.01497.x CrossRefPubMedGoogle Scholar