Oliver Kersten

• Kersten, Oliver; Vetter, Eric W.; Jungbluth, Michelle J.; Smith, Craig R. & Goetze, Erica (2019). Larval assemblages over the abyssal plain in the Pacific are highly diverse and spatially patchy. PeerJ.  ISSN 2167-8359.  7, s 1- 36 . doi: 10.7717/peerj.7691 Show summary

  Abyssal plains are among the most biodiverse yet least explored marine ecosystems on our planet, and they are increasingly threatened by human impacts, including future deep seafloor mining. Recovery of abyssal populations from the impacts of polymetallic nodule mining will be partially determined by the availability and dispersal of pelagic larvae leading to benthic recolonization of disturbed areas of the seafloor. Here we use a tree-of-life (TOL) metabarcoding approach to investigate the species richness, diversity, and spatial variability of the larval assemblage at mesoscales across the abyssal seafloor in two mining-claim areas in the eastern Clarion Clipperton Fracture Zone (CCZ; abyssal Pacific). Our approach revealed a previously unknown taxonomic richness within the meroplankton assemblage, detecting larvae from 12 phyla, 23 Classes, 46 Orders, and 65 Families, including a number of taxa not previously reported at abyssal depths or within the Pacific Ocean. A novel suite of parasitic copepods and worms were sampled, from families that are known to associate with other benthic invertebrates or demersal fishes as hosts. Larval assemblages were patchily distributed at the mesoscale, with little similarity in OTUs detected among deployments even within the same 30 × 30 km study area. Our results provide baseline observations on larval diversity prior to polymetallic nodule mining in this region, and emphasize our overwhelming lack of knowledge regarding larvae of the benthic boundary layer in abyssal plain ecosystems.

• Ottoni, Claudio; Guellil, Meriam; Ozga, Andrew; Stone, Anne; Kersten, Oliver; Bramanti, Barbara; Porcier, Stéphanie & Van Neer, Wim (2019). Metagenomic analysis of dental calculus in ancient Egyptian baboons. Scientific Reports.  ISSN 2045-2322.  9, s 1- 10 . doi: 10.1038/s41598-019-56074-x Show summary

  Dental calculus, or mineralized plaque, represents a record of ancient biomolecules and food residues. Recently, ancient metagenomics made it possible to unlock the wealth of microbial and dietary information of dental calculus to reconstruct oral microbiomes and lifestyle of humans from the past. Although most studies have so far focused on ancient humans, dental calculus is known to form in a wide range of animals, potentially informing on how human-animal interactions changed the animals’ oral ecology. Here, we characterise the oral microbiome of six ancient Egyptian baboons held in captivity during the late Pharaonic era (9th–6th centuries BC) and of two historical baboons from a zoo via shotgun metagenomics. We demonstrate that these captive baboons possessed a distinctive oral microbiome when compared to ancient and modern humans, Neanderthals and a wild chimpanzee. These results may reflect the omnivorous dietary behaviour of baboons, even though health, food provisioning and other factors associated with human management, may have changed the baboons’ oral microbiome. We anticipate our study to be a starting point for more extensive studies on ancient animal oral microbiomes to examine the extent to which domestication and human management in the past affected the diet, health and lifestyle of target animals.

• Guellil, Meriam; Kersten, Oliver; Namouchi, Amine; Bauer, Egil Lindhart; Derrick, Michael; Jensen, Anne Østergaard; Stenseth, Nils Christian & Bramanti, Barbara (2018). Genomic blueprint of a relapsing fever pathogen in 15th century Scandinavia. Proceedings of the National Academy of Sciences of the United States of America.  ISSN 0027-8424.  115(41), s 10422- 10427 . doi: 10.1073/pnas.1807266115 Full text in Research Archive. Show summary

  Louse-borne relapsing fever (LBRF) is known to have killed millions of people over the course of European history and remains a major cause of mortality in parts of the world. Its pathogen, Borrelia recurrentis, shares a common vector with global killers such as typhus and plague and is known for its involvement in devastating historical epidemics such as the Irish potato famine. Here, we describe a European and historical genome of B. recurrentis, recovered from a 15th century skeleton from Oslo. Our distinct European lineage has a discrete genomic makeup, displaying an ancestral oppA-1 gene and gene loss in antigenic variation sites. Our results illustrate the potential of ancient DNA research to elucidate dynamics of reductive evolution in a specialized human pathogen and to uncover aspects of human health usually invisible to the archaeological record.

• Namouchi, Amine; Guellil, Meriam; Kersten, Oliver; Hänsch, Stephanie; Ottoni, Claudio; Schmid, Boris Valentijn; Pacciani, Elsa; Quaglia, Luisa; Vermunt, Marco; Bauer, Egil Lindhart; Derrick, Michael; Jensen, Anne Østergaard; Kacki, Sacha; Cohn Jr., Samuel; Stenseth, Nils Christian & Bramanti, Barbara (2018). Integrative approach using Yersinia pestis genomes to revisit the historical landscape of plague during the Medieval Period. Proceedings of the National Academy of Sciences of the United States of America.  ISSN 0027-8424.  115(50), s E11790- E11797 . doi: 10.1073/pnas.1812865115 Full text in Research Archive. Show summary

  Over the last few years, genomic studies on Yersinia pestis, the causative agent of all known plague epidemics, have considerably increased in numbers, spanning a period of about 5,000 y. Nonetheless, questions concerning historical reservoirs and routes of transmission remain open. Here, we present and describe five genomes from the second half of the 14th century and reconstruct the evolutionary history of Y. pestis by reanalyzing previously published genomes and by building a comprehensive phylogeny focused on strains attributed to the Second Plague Pandemic (14th to 18th century). Corroborated by historical and ecological evidence, the presented phylogeny, which includes our Y. pestis genomes, could support the hypothesis of an entry of plague into Western European ports through distinct waves of introduction during the Medieval Period, possibly by means of fur trade routes, as well as the recirculation of plague within the human population via trade routes and human movement.

• Kersten, Oliver; Smith, Craig R. & Vetter, Eric W. (2017). Abyssal near-bottom dispersal stages of benthic invertebrates in the Clarion-Clipperton polymetallic nodule province. Deep Sea Research Part I: Oceanographic Research Papers.  ISSN 0967-0637.  127, s 31- 40 . doi: 10.1016/j.dsr.2017.07.001 Show summary

  Growing interest in polymetallic nodule mining has intensified the need to characterize the abundance, community structure and vertical flux of meroplankton in the Clarion-Clipperton Zone (CCZ) to facilitate the estimation of larval supply and potential connectivity of benthic populations. These ecological parameters are essential to predict recolonization processes following the expected large-scale, high intensity disturbances associated with nodule extraction. Here, we present the first description of the composition, abundance, temporal variability, and mesoscale distribution of dispersing stages of the benthos in two study areas in the eastern CCZ. Samples from free-vehicle plankton pumps showed little variation in meroplankton diversity and abundance over scales of 30–100 km for time scales of days to weeks. However, sediment-trap samples revealed high temporal variability in vertical flux over weeks to months. Larval abundances and fluxes measured in the abyssal CCZ are ~ 1–2 orders of magnitude lower than observed at deep-sea ridge and hydrothermal-vent habitats. We found significantly higher downward larval fluxes at 11 m above the bottom (mab) than at 146 mab, indicating accumulation or retention of meroplankton within the Benthic Boundary Layer (BBL). The high abundance of meroplankton in the BBL emphasizes its importance to dispersing stages and suggests that the creation of large sediment plumes in the BBL during nodule mining could compromise the dispersal and recruitment abilities of the abyssal benthos, potentially slowing rates and altering patterns of benthic community recovery following mining disturbance.

• Ajani, Penelope A.; Armbrecht, Linda H.; Kersten, Oliver; Kohli, Gurjeet S. & Murray, Shauna A. (2016). Diversity, temporal distribution and physiology of the centric diatom Leptocylindrus Cleve (Bacillariophyta) from a southern hemisphere upwelling system. Diatom Research.  ISSN 0269-249X.  31(4), s 351- 365 . doi: 10.1080/0269249X.2016.1260058

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• Kersten, Oliver; Star, Bastiaan; Anker-Nilssen, Tycho; Strøm, Hallvard & Boessenkool, Sanne (2019). Genomic population structure of the Atlantic Puffin – insights into the species’ taxonomy.
• Kersten, Oliver (2016). Yersinia pestis genomes from medieval Europe and Asia during the 2nd plague pandemic.

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