Isotopic evidence for the spatial heterogeneity of the planktonic food webs in the transition zone between river and lake ecosystems

Resources and organisms in food webs are distributed patchily. The spatial structure of food webs is important and critical to understanding their overall structure. However, there is little available information about the small-scale spatial structure of food webs. We investigated the spatial structure of food webs in a lake ecosystem at the littoral transition zone between an inflowing river and a lake. We measured the carbon isotope ratios of zooplankton and particulate organic matter (POM; predominantly phytoplankton) in the littoral zone of a saline lake. Parallel changes in the δ 13C values of zooplankton and their respective POMs indicated that there is spatial heterogeneity of the food web in this study area. Lake ecosystems are usually classified at the landscape level as either pelagic or littoral habitats. However, we showed small-scale spatial heterogeneity among planktonic food webs along an environmental gradient. Stable isotope data is useful for detecting spatial heterogeneity of habitats, populations, communities, and ecosystems

Intraspecific structure of the Coregonus lavaretus complex in water bodies of Siberia: a case of postglacial allopatric origin of Yukagirian whitefish

The results of morphological and genetic analyses of forms/species of the Coregonus lavaretus pidschian (Gmelin, 1789) complex from the Indigirka and Kolyma river basins are presented in the context of there being recent postglacial speciation events. It has been found that the studied whitefishes belong to the sparsely rakered and low lateral-line forms and have previously been described as Coregonus lavaretus pidschian n. jucagiricus Drjagin (Berg), 1932. Based on these characters, this whitefish does not differ from most Arctic whitefish populations (in particular from Coregonus lavaretus glacialis Kirillov, 1972). Analysis of variability of the ND1 gene (mtDNA) showed that whitefishes from the Indigirka and Kolyma basins belong to a distant phylogenetic lineage, which is significantly different from all previously studied whitefish lineages from the Ob, Yenisei, Lena, Anadyr, and Amur river basins. Analysis of variability of the ITS1 fragment (nDNA) showed that all studied forms/species (from Ob River to Amur River basins), including C. l. pidschian n. jucagiricus, have a tandem arrangement of two identical nucleotide fragments and very similar nucleotide composition of the ITS1 region. Based on contemporary data, this phylogenetic lineage of the C. pidschian complex could be considered a young postglacial allopatric species.info:eu-repo/semantics/acceptedVersio

Mitochondrial Lineage Diversity and Phylogeography of Daphnia (Daphnia) (Crustacea: Cladocera) in North-East Russia

The variability of the 12S gene fragment of the mtDNA for taxa belonging to subgenus Daphnia (Daphnia) O.F. Müller, 1776 (Crustacea: Cladocera) in NE Russia is studied, and their phylogenetic analysis performed. We identified (based both on morphological and molecular data) nine species belonging to four species complexes, namely: (A) D. longispina s.l.: (1) D. longispina O.F. Müller, 1776; (2) D. dentifera Forbes, 1893; (3) D. galeata Sars, 1864; (4) D. umbra Taylor, Hebert et Colbourne, 1996; (B) D. cristata s.l.: (5) D. cristata Sars, 1862; (6) D. longiremis Sars, 1862; (C) D. curvirostris s.l.: (7) D. curvirostris Eylmann, 1887; (D) D. pulex s.l.: (8) D. pulex Leydig, 1860; (9) D. middendorffiana Fischer, 1851. Rare arcto-mountainous taxon D. umbra was found in the mountains of the Sakha (Yakutia) Republic for the first time. Species diversity in NE Asia is relatively low, and the most revealed taxa are trans-Beringian. We also performed a phylogeographic analysis of D. dentifera and D. pulex s.l., the two most common species in NE Russia. Our new data allow us to assume that the daphniids of NE Asia have undergone various evolutionary scenarios during the Pleistocene period: survival is within some local refugia, and re-colonization from these areas and from North America through the Beringian land bridge, etc. We agree with previous authors who revealed that the patterns in the studied species groups are relatively recent (of Late Pleistocene or even Holocene age), although the main phylogenetic daphniid lineages (mainly congruent with the biological species) are very old. Our results provide convincing evidence for the hypothesis that NE Russia is a very important source of modern haplotypic diversity for the cladocerans

Redescription of Daphnia turbinata Sars, 1903 (Crustacea: Cladocera: Daphniidae)

Zuykova, Elena I., Sheveleva, Natalia G., Kotov, Alexey A. (2019): Redescription of Daphnia turbinata Sars, 1903 (Crustacea: Cladocera: Daphniidae). Zootaxa 4658 (2): 317-330, DOI: https://doi.org/10.11646/zootaxa.4658.2.

Spatial changes in carbon and nitrogen stable isotopes of the plankton food web in a saline lake ecosystem. Hydrobiologia 571: 395–400

Abstract We investigated spatial changes in the isotope ratios of the plankton food web in Lake Chany, Siberia, Russia, especially at an estuarine transition zone of the lake. The d 13 C values of particulate organic matter (POM) varied among the sampling sites, and increased with increasing pH of the lake water. This may reflect a shift by phytoplankton from using CO 2 to using bicarbonate for photosynthesis with increasing pH. The d 13 C values of zooplankton community also changed at each site along with those of the POM. This was indicative of carbon isotope changes of plankton food webs between the stations along an environmental gradient

Unexpected endemism in the Daphnia longispina complex (Crustacea: Cladocera) in Southern Siberia.

The biological significance of regional cladoceran morphotypes in the montane regions of the central Palearctic remains poorly understood. In the Holarctic Daphnia longispina complex (Cladocera: Daphniidae), several variants, lineages and species have been proposed as endemic for Southern Siberia. Daphnia turbinata Sars, for example, named after its unusual head shape, is known only from Southern Siberia. Here we sequence DNA of Daphnia from three mitochondrial genes (12S rRNA, 16S rRNA, and NADH dehydrogenase subunit 2, ND2) from 57 localities in Russia and Mongolia (the majority being from Southern Siberia) and place them in evolutionary context with existing data. Our aim was to examine regional endemism of the Daphnia longispina complex in Southern Siberian; to improve the phylogenetic understanding with improved taxonomic and regional sampling, and to better understand the influence of Pleistocene glaciation on the biogeography of these lineages. At least three lineages showed genetic evidence for endemism in Southern Siberia. There was strong support for D. turbinata as a sister lineage to to D. longispina/D. dentifera. Another endemic, Siberian D. cf. longispina, is a sister group to the longispina group in general. Within D. longispina s. str. there was an endemic Siberian clade with a western range boundary near the Yenisei River Basin. Gene flow estimates among populations (based on FST values) were very low for clades of D. longispina on a regional (the original 12S dataset), and on a pan-Eurasian (the extended 12S dataset) scale. Negative values of Fu's FS and Tajima's D tests prevailed for the species examined with significant values found for two D. longispina clades, D. dentifera, D. galeata and D. cristata. Our results support the notion that Southern Siberia is an important biogeographic region for cladocerans as it contained unexpected diversity of endemics (such as D. turbinata, D. cf. longispina and lineages of D. umbra and D. longsipina s.str.) and from being the geographic meeting place of expanding postglacial lineages from eastern and western refugia

Morphological Differentiation, Mitochondrial and Nuclear DNA Variability Between Geographically Distant Populations of Daphnia galeata and Daphnia cucullata (Anomopoda, Daphniidae)

Несмотря на то, что представители р. Daphnia (Anomopoda, Daphniidae) являются одними из наиболее распространенных водных беспозвоночных и используются в качестве модельных организмов в таксономических, экологических и эволюционных исследованиях, их систематика остается весьма запутанной. Настоящее исследование посвящено изучению морфологической дифференциации и генетической изменчивости географически удаленных популяций сестринских видов Daphnia galeata Sars, 1864 и Daphnia cucullata Sars, 1862 (Anomopoda, Daphniidae) из пресноводной части Балтийского моря - Куршского залива (Россия, Калининградская область) и Новосибирского водохранилища (Россия, Новосибирская область). Морфологическая дивергенция между видами и их популяциями оценивалась по диагностическим признакам и на основании анализа изменчивости формы тела по набору морфометрических признаков. Самыми изменчивыми были признаки, характеризующие форму головы, шлема и хвостовой иглы. Реконструкция филогенетических отношений между видами выполнена на основе изменчивости 16S и 12S генов митохондриальной ДНК и фрагмента ITS2 ядерной ДНК. Дивергенция между видами D. galeata и D. cucullata на основе генов митохондриальной ДНК была значительной и свидетельствует об их монофилетическом происхождении, тогда как внутривидовые генетические дистанции оцениваются как незначительные.Although members of genus Daphnia (Anomopoda, Daphniidae) are the most common water invertebrates and are considered as model organisms for many taxonomic, ecological and evolutionary studies their systematics remains unresolved. Here, morphological differentiation and genetic polymorphism between the geographically distant populations of the sister species Daphnia galeata Sars, 1864 and Daphnia cucullata Sars, 1862 in the Curonian Lagoon, a large shallow freshwater lagoon of the Baltic Sea (Russia, Kaliningrad Oblast) and Novosibirsk Reservoir (Russia, Novosibirsk Oblast) are presented. The divergence between species and their populations was analyzed based on traditional morphological traits and a large set of morphometric traits describing the body shape. The traits describing the shape of head and helmet, and spine were the most variable morphological characters. Phylogenetic relationships between species and populations were constructed based on variation in mitochondrial 16S and 12S rRNA genes and nuclear ITS2 rDNA sequences. The mitochondrial DNA divergence between D. galeata and D. cucullata species was significant and reflected their monophyletic origin, whereas intraspecific genetic distances are estimated as insignificant

Evidence of dispersal between the Yenisei and the Lena river basins during the late Pleistocene within the whitefish (Coregonus lavaretus pidschian) complex

The Coregonus lavaretus (Linnaeus, 1758) complex is a morphologically and genetically diverse group of whitefish. Its taxonomic structure has been controversial for almost a century. At least 25 forms of C. lavaretus have been described in Siberia, but there is still no consensus on their intraspecific structure and taxonomy. Coregonus lavaretus pidschian (Gmelin, 1789) was described as a subspecies of C. lavaretus. Recently, it was assumed that this subspecies is also a complex. The purpose of this study was to compare the distributions of pidschian-like whitefish haplotypes in two basins of large Siberian rivers, Yenisei and Lena, and to assess the gene flow between basins of these rivers, which were connected after the last glaciation. The sequence of the following mitochondrial DNA genes, 16S rRNA (partial), tRNA-Leu (full), NADH dehydrogenase subunit 1 (full), tRNA-Ile (full), and tRNA-Gln (partial), were used for the inference of intraspecific genetic structure of C. l. pidschian. Whitefish haplotypes were clustered into two groups according to their distribution between two large Siberian river basins; however, there were shared haplotypes indicating events of migration and hybridization, which could occur when Bolshoi Yenisei and Lena river systems were connected after the last glaciation (the Late Pleistocene).info:eu-repo/semantics/acceptedVersio