Comparative population genomics reveals key barriers to dispersal in Southern Ocean penguins

The mechanisms that determine patterns of species dispersal are important factors in the production and maintenance of biodiversity. Understanding these mechanisms helps to forecast the responses of species to environmental change. Here, we used a comparative framework and genomewide data obtained through RAD-Seq to compare the patterns of connectivity among breeding colonies for five penguin species with shared ancestry, overlapping distributions and differing ecological niches, allowing an examination of the intrinsic and extrinsic barriers governing dispersal patterns. Our findings show that at-sea range and oceanography underlie patterns of dispersal in these penguins. The pelagic niche of emperor (Aptenodytes forsteri), king (A. patagonicus), Adélie (Pygoscelis adeliae) and chinstrap (P. antarctica) penguins facilitates gene flow over thousands of kilometres. In contrast, the coastal niche of gentoo penguins (P. papua) limits dispersal, resulting in population divergences. Oceanographic fronts also act as dispersal barriers to some extent. We recommend that forecasts of extinction risk incorporate dispersal and that management units are defined by at-sea range and oceanography in species lacking genetic data.

Bioinformatics delimitation of the psychrophilic and psychrotolerant actinobacteria isolated from the Polar Frontal waters of the Southern Ocean

Identification of microorganisms plays a key role in the determination of the composition of microbial diversity for bioprospecting of biotechnologically important biomolecules. Digitalization is the process that solve discrepancies in microbial identification and cataloguing their diversity in distinct ecological habitats. In view of this connection, the psychrophilic and psychrotolerant actinobacteria were isolated from the water samples of the Polar Frontal region of the Southern Ocean. 16S rRNA gene sequencing for identification of psychrophiles was carried out and sequences were deposited in NCBI GeneBank. 16S rRNA gene sequences were used to create QR codes, CGR, FCGR and GC plot. This generated digital data help to relate the diversity amongst the isolated actinobacterial strains. The digital data showed considerable divergence among the actinobacterial strains. This generated bioinformatics data is helpful in the delimitation of the psychrophilic and psychrotolerant actinobacteria. Thus, the present study is a robust and accurate method for the identification of Polar microorganisms in a fixed boundary. Hence, this work will help to assign a unique digital identity to microorganisms in near future [9-19].

Microplastics in the Antarctic marine system: An emerging area of research

It was thought that the Southern Ocean was relatively free of microplastic contamination; however, recent studies and citizen science projects in the Southern Ocean have reported microplastics in deep-sea sediments and surface waters. Here we reviewed available information on microplastics (including macroplastics as a source of microplastics) in the Southern Ocean. We estimated primary microplastic concentrations from personal care products and laundry, and identified potential sources and routes of transmission into the region. Estimates showed the levels of microplastic pollution released into the region from ships and scientific research stations were likely to be negligible at the scale of the Southern Ocean, but may be significant on a local scale. This was demonstrated by the detection of the first microplastics in shallow benthic sediments close to a number of research stations on King George Island. Furthermore, our predictions of primary microplastic concentrations from local sources were five orders of magnitude lower than levels reported in published sampling surveys (assuming an even dispersal at the ocean surface). Sea surface transfer from lower latitudes may contribute, at an as yet unknown level, to Southern Ocean plastic concentrations. Acknowledging the lack of data describing microplastic origins, concentrations, distribution and impacts in the Southern Ocean, we highlight the urgent need for research, and call for routine, standardised monitoring in the Antarctic marine system.