ORCID Profile
0000-0002-5285-6121
Current Organisation
NIWA - The National Institute of Water and Atmospheric Research Ltd.
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Publisher: Cold Spring Harbor Laboratory
Date: 15-09-2021
DOI: 10.1101/2021.09.12.459994
Abstract: Planktonic protists are an essential component of marine pelagic ecosystems where they mediate important trophic and biogeochemical functions. Although these functions are largely influenced by their taxonomic affiliation, the composition and spatial variability of planktonic protist communities remain poorly characterized in vast areas of the ocean. Here, we investigated the ersity of these communities in contrasting oceanographic conditions of the southwest Pacific sector (33-58°S) using DNA metabarcoding of the 18S rRNA gene. Seawater s les collected during twelve cruises (n = 482, 0-2000 m) conducted east of New Zealand were used to characterize protist communities in Subtropical (STW) and Subantarctic (SAW) water masses and the Subtropical Front (STF) that separates them. Diversity decreased with latitude and temperature but tended to be lowest in the STF. S le ordination resulting from the abundance of licon single variants (ASVs) corresponded to the different water masses. Overall, Dinophyceae (34% of standardized total number of reads) and Chlorophyta (27%) co-dominated the euphotic zone, but their relative abundance and composition at class and lower taxonomic levels varied consistently between water masses. Among Chlorophyta, several picoplanktonic algae species of the Mamiellophyceae class including Ostreococcus lucimarinus dominated in STW, while the Chloropicophyceae species Chloroparvula pacifica was most abundant in SAW. Bacillariophyta (7%), Prymnesiophyceae (5%), and Pelagophyceae (3%) classes were less abundant but showed analogous water mass specificity at class and finer taxonomic levels. Protist community composition in the STF had mixed characteristics and showed regional differences with the southern STF (50°S) having more resemblance with subantarctic communities than the STF over the Chatham Rise region (42-44°S). Below the euphotic zone, Radiolaria sequences dominated the dataset (52%) followed by Dinophyceae (27%) and other heterotrophic groups like Marine Stramenopiles and ciliates (3%). Among Radiolaria, several unidentified ASVs assigned to Spumellarida were most abundant, but showed significantly different distribution between STW and SAW highlighting the need to further investigate the taxonomy and ecology of this group. This study represents a significant step forward towards characterizing protistan communities composition in relation to major water masses and fronts in the South Pacific providing new insights about the biogeography and ecological preferences of different taxa from class to species and genotypic level. Water-mass preference of different taxa emerged at class, species and genotypic level. Mamiellophyceae green algae dominated in subtropical waters. Dinophyceae and Chloropicophyceae green algae dominated in subantarctic waters. A erse assemblage of Radiolaria dominated the mesopelagic zone. Small rather than large taxa dominated phytoplankton blooms in subtropical waters.
Publisher: Museum National D'Histoire Naturelle
Date: 15-09-2022
DOI: 10.5852/EJT.2022.837.1923
Abstract: The taxonomic status of Alcyonium aurantiacum Quoy & #38 Gaimard, 1833, an octocoral endemic to New Zealand, was reviewed through morpho-molecular data comparisons in an integrative approach. Molecular phylogenetic analyses (nuclear 28S and mitochondrial mtMutS) resolved New Zealand taxa as more closely related to other genera and nominal Alcyonium Linnaeus, 1758 from South America than to the genus’ North Atlantic type species. Due to low genetic variation, species delimitation relied predominantly on identifying consistent differences in sclerite and colony morphology. The former A. aurantiacum is reassigned to Kotatea gen. nov. as K. aurantiaca gen. et comb. nov. and seven new species are described in this genus (K. amicispongia gen. et sp. nov., K. lobata gen. et sp. nov., K. kapotaiora gen. et sp. nov., K. kurakootingotingo gen. et sp. nov., K. niwa gen. et sp. nov., K. raekura gen. et sp. nov., and K. teorowai gen. et sp. nov.). Three new species in Ushanaia gen. nov. are also described (U. ferruginea gen. et sp. nov., U. fervens gen. et sp. nov. and U. solida gen. et sp. nov. ). These descriptions increase our understanding of New Zealand’s endemic octocoral ersity and contribute to ongoing systematic revisions of Alcyonium.
Publisher: Springer Science and Business Media LLC
Date: 06-2023
DOI: 10.1007/S12526-023-01344-1
Abstract: In New Zealand, Kotatea aurantiaca and Kotatea lobata are two common, endemic, co-occurring, and morphologically similar soft coral species that currently cannot be distinguished without microscopic examination of sclerites and of which little is known regarding any aspect of their ecology or biology. The aim of the present study is to ascertain if, and in what ways, their colony growth forms differ, and to test the taxonomic value of macroscopic morphological character measurements using statistical discrimination analyses. A binary logistic regression model is developed whereby macroscopic characters of colony morphology can be used to assign specimens to either species with ~ 90% accuracy. Species assignment accuracy is greatest when ratios formed from morphological measurements are used rather than direct measurements. Here, these ratios are used for the first time to account for the appearance-altering habit among soft corals of hydrostatically expanding and contracting their coelenteron with seawater. Relationships between colony morphology and depth are also examined, and it is suggested that phenotypic plasticity detected in K. lobata , causing it to resemble K. aurantiaca more closely at greater depths, may contribute to their morphological overlap. It is anticipated that this discrimination technique will facilitate future research on the ecology and biology of these species and will be replicated on other sets of morphologically similar soft corals for which species discrimination has been problematic.
Publisher: Springer Netherlands
Date: 2001
Publisher: Public Library of Science (PLoS)
Date: 02-12-2019
Publisher: Informa UK Limited
Date: 02-03-2018
Publisher: Springer Science and Business Media LLC
Date: 29-07-2011
Publisher: Elsevier BV
Date: 08-2022
Publisher: Informa UK Limited
Date: 28-06-2018
Publisher: Elsevier BV
Date: 04-2014
DOI: 10.1016/J.YMPEV.2014.01.023
Abstract: The octocorals of the Ellisellidae constitute a erse and widely distributed family with sub isions into genera based on colonial growth forms. Branching patterns are repeated in several genera and congeners often display region-specific variations in a given growth form. We examined the systematic patterns of ellisellid genera and the evolution of branching form ersity using molecular phylogenetic and ancestral morphological reconstructions. Six of eight included genera were found to be polyphyletic due to biogeographical incompatibility with current taxonomic assignments and the creation of at least six new genera plus several reassignments among existing genera is necessary. Phylogenetic patterns of ersification of colony branching morphology displayed a similar transformation order in each of the two primary ellisellid clades, with a sea fan form estimated as the most-probable common ancestor with likely origins in the Indo-Pacific region. The observed parallelism in evolution indicates the existence of a constraint on the genetic elements determining ellisellid colonial morphology. However, the lack of correspondence between levels of genetic ergence and morphological ersity among genera suggests that future octocoral studies should focus on the role of changes in gene regulation in the evolution of branching patterns.
Publisher: Springer Netherlands
Date: 2013
Publisher: The Biological Society of Washington
Date: 08-2010
DOI: 10.2988/09-22.1
Publisher: Inter-Research Science Center
Date: 11-09-2008
DOI: 10.3354/MEPS07614
Publisher: Springer Netherlands
Date: 2013
Publisher: University of Queensland Library
DOI: 10.14264/UQL.2014.91
Publisher: Wiley
Date: 31-08-2022
Abstract: Advances in high-throughput sequencing (HTS) are revolutionizing monitoring in marine environments by enabling rapid, accurate and holistic detection of species within complex biological s les. Research institutions worldwide increasingly employ HTS methods for bio ersity assessments. However, variance in laboratory procedures, analytical workflows and bioinformatic pipelines impede the transferability and comparability of results across research groups. An international experiment was conducted to assess the consistency of metabarcoding results derived from identical s les and primer sets using varying laboratory procedures. Homogenized biofouling s les collected from four coastal locations (Australia, Canada, New Zealand and the USA) were distributed to 12 independent laboratories. Participants were asked to follow one of two HTS library preparation workflows. While DNA extraction, primers and bioinformatic analyses were purposefully standardized to allow comparison, many other technical variables were allowed to vary among laboratories ( lification protocols, type of instrument used, etc.). Despite substantial variation observed in raw results, the primary signal in the data was consistent, with the s les grouping strongly by geographical origin for all data sets. Simple post hoc data clean-up by removing low-quality s les gave the best improvement in s le classification for nuclear 18S rRNA gene data, with an overall 92.81% correct group attribution. For mitochondrial COI gene data, the best classification result (95.58%) was achieved after correction for contamination errors. The identified critical methodological factors that introduced the greatest variability (preservation buffer, s le defrosting, template concentration, DNA polymerase, PCR enhancer) should be of great assistance in standardizing future bio ersity studies using metabarcoding.
Location: New Zealand
No related grants have been discovered for Jaret Bilewitch.