Boreal Tintinnid Assemblage in the Northwest Pacific and Its Connection with the Japan Sea in Summer 2014

Tintinnids are planktonic ciliates that play an important role in marine ecosystem. According to their distribution in the world oceans, tintinnid genera were divided into several biogeographical types such as boreal, warm water, austral and neritic. Therefore, the oceanic tintinnid assemblage could be correspondingly divided into boreal assemblage, warm water assemblage and austral assemblage. The purpose of this study was to investigate the characteristics of boreal tintinnid assemblage in the Northwest Pacific and the Arctic, and to identify the connection between boreal tintinnid assemblage and neighboring assemblages. Surface water samples were collected along a transect from the East China Sea to the Chukchi Sea in summer 2014. According to the presence of boreal genera and warm water genera, three tintinnid assemblages (the East China Sea neritic assemblage, the Japan Sea warm water assemblage, and the boreal assemblage) were identified along the transect. The boreal assemblage extended from the Chukchi Sea to the waters north of the Sōya Strait. Densities peaks occurred at stations in the two branches of the Alaska Current and decreased both northward and southward. The densities were <10 ind./dm³ at most stations in Arctic region. The dominant genera (Acanthostomella, Codonellopsis, Parafavella, and Ptychocylis) accounted for 79.07±29.67% (n = 49) of the abundance in the boreal assemblage. The densities of the dominant genera covaried with strongly significant positive correlations. Tintinnids with lorica oral diameter of 22–26 μm and 38–42 μm were dominant and contributed 67.35% and 15.13%, respectively, to the total abundance in the boreal assemblage. The distribution and densities of tintinnids in the study area suggest that the Sōya Strait might be a geographical barrier for tintinnids expansion.     

Occurrence of Giardia duodenalis assemblages in alpacas in the Andean region

In this study, 352 fecal samples were analyzed for G. duodenalis from alpaca mothers and crias from three different areas of highland in Peru. The triosephosphate isomerase (TPI) gene of Giardia was amplified using a nested PCR protocol. Forty-six G. duodenalis-PCR positive samples were sequenced. G. duodenalis assemblage A was the most frequent followed by assemblage E. The former was seen in 37 animals whereas the latter was seen in nine. Most of the assemblage A infections were caused by the A1 subtype of sub-assemblage AI, except for three, which were caused by the A2 subtype of sub-assemblage AI. Assemblage A was found in all three geographic regions, while assemblage E was detected in crias from two regions. Among the four alpaca mothers positive for Giardia, three had assemblage AI and one had assemblage AII. Results of this study indicate that possible zoonotic transmission human to alpacas.     

The Pleistocene easternmost distribution in Eurasia of the species associated with the Eemian Palaeoloxodon antiquus assemblage

• 1 The Palaeoloxodon antiquus large‐mammal assemblage was typical of the late middle and late Pleistocene interglacials in Europe. This review examines the assemblage's origins, dispersal and cohesiveness in Eurasia.
• 2 During the more climatically equable middle‐Pleistocene periods, the Palaeoloxodon assemblage (or closely related) species occurred across central Eurasia almost simultaneously. In Central and Western Europe, these species responded to climatic changes together as an unvarying interglacial assemblage, whereas in Eastern Europe and Siberia, they occurred in diverging assemblages. The boundary of the Palaeoloxodon assemblage can be drawn roughly from Poland to Romania.
• 3 In Central and Western Europe this interglacial assemblage last occurred during the Eemian. During this period many of the Palaeoloxodon assemblage species may also have co‐occurred in south‐eastern Europe and, except for Bubalus murrensis and Hippopotamus amphibius, further eastwards. The extinct species of the Palaeoloxodon assemblage disappeared in Siberia and Central Asia prior to Europe and the Caucasus whereas the extant species were already present in their modern distribution areas.
• 4 A quantitative study of faunal associations across Eurasia, following much‐needed comprehensive systematic reviews, would further elucidate the patterns of faunal change associated with local and global climatic changes during the middle to late Pleistocene.

     

Foraminiferal distribution on the continental margin off Nova Scotia

Q-mode factor analysis of total foraminiferal abundance data (living plus dead) from 250 grab samples taken from the continental margin off Nova Scotia allows the determination of eight factor assemblages. On the northeastern shelf, an exclusively agglutinated assemblage dominated byAdercotryma glomerata occupies both banks and basins. Central shelf basins contain a predominantly calcareous assemblage dominated byGlobobulimina auriculata andNonionellina labradorica. Transitional between these two factor assemblages is an agglutinated assemblage dominated bySaccammina atlantica. Consistently present along the shelf edge is aTrifarina angulosa assemblage. In northeastern bays and a few samples near Sable Island, an agglutinatedEggerella advena assemblage is found. A relict and transport affected assemblage dominated byElphidium excavatum occurs in the southwestern approaches to Emerald Basin. Sandy/gravelly areas of the inner shelf and outer bank regions are characterized by aCibicides lobatulus assemblage.The statistical relationships of these defined assemblages to various aspects of the marine environment (depth, temperature, salinity, percent gravel, sand and mud) were investigated through multiple regression techniques. Results indicate that the present foraminiferal distribution patterns off Nova Scotia are influenced by the prevailing watermass characters and substrate. TheAdercotryma glomerata assemblage is influenced by the presence of cold, (0–4°C) low salinity waters (32–33‰) of arctic, Labrador Current origin. The central basin assemblage (G. auriculata) is related to warmer (8–12°C) more saline waters (35‰) of slope origin. The transition between these two bottom waters is marked by the opportunisticSaccammina atlantica assemblage. Preferred substrate character possibly determines the occurrence of theCibicides lobatulus, Islandiella islandica andEggerella advena assemblages.Trifarina angulosa shows a significant relationship to salinity and depth.Although the surficial sediments on the Nova Scotian Shelf are largely the product of reworking of glacial deposits during late glacial and early Holocene times, all but theE. excavatum factor assemblage appear to be in equilibrium with the modern oceanographic regime.     

The beginnings of the Sargasso assemblage in the Tethys?

An assemblage of organisms, here termed “quasi-Sargasso”, occurs in the Oligocene menilite beds of the Carpathian flysch. It is suggested that this assemblage migrated into the Atlantic Ocean, probably during the Miocene. Its further evolution, which gave rise to the present-day Sargasso assemblage, took place in the middle Atlantic area.     

Distribution patterns of diatom surface sediment assemblages in the Laptev Sea (Arctic Ocean)

The modern diatom distribution in the Laptev Sea, Arctic Ocean, was investigated in 89 surface sediment samples. Diatom concentrations are relatively low showing values between 0.01×10⁶ and 6.7×10⁶ valves per gram dry sediment. Based on a factor analysis using seventeen taxa or taxa groups five diatom surface sediment assemblages can be defined: the ice diatom assemblage of the central region of the Laptev Sea, the Chaetoceros assemblage of the eastern and southeastern shelf, the Thalassiosira antarctica assemblage of the continental slope and deep sea, the freshwater diatom assemblage in the vicinity of river mouths and deltas, and the Thalassiosira nordenskioeldii assemblage which shows a patchy occurrence on the central Laptev Sea shelf. The distribution pattern of diatom assemblages in surface sediment is significantly related to oceanographic conditions of surface water masses. The main factors controlling the distribution of diatoms in the Laptev Sea are the riverine freshwater input during the summer which strongly affects the salinity conditions, and the sea-ice extent. Furthermore, the composition of the Thalassiosira antarctica assemblage of the continental slope is largely influenced by dissolution and lateral transport processes.     

A balance of winners and losers in the Anthropocene

Scientists disagree about the nature of biodiversity change. While there is evidence for widespread declines from population surveys, assemblage surveys reveal a mix of declines and increases. These conflicting conclusions may be caused by the use of different metrics: assemblage metrics may average out drastic changes in individual populations. Alternatively, differences may arise from data sources: populations monitored individually, versus whole‐assemblage monitoring. To test these hypotheses, we estimated population change metrics using assemblage data. For a set of 23 241 populations, 16 009 species, in 158 assemblages, we detected significantly accelerating extinction and colonisation rates, with both rates being approximately balanced. Most populations (85%) did not show significant trends in abundance, and those that did were balanced between winners (8%) and losers (7%). Thus, population metrics estimated with assemblage data are commensurate with assemblage metrics and reveal sustained and increasing species turnover.     

Microfossils from the Krol ‘A’ of the Lesser Himalaya,India: Additional supporting data for its early Ediacaran age

An assemblage of microfossils of moderate diversity, with the remarkable occurrence of ECAP acritarchs, is reported from the Ediacaran Krol ‘A’ (= the Mahi Formation) succession of Lesser Himalaya, India. Microfossils occur in the chert nodules exposed in Solan district, Himachal Pradesh. Two microfossils, Barogophycus symmetricus n. gen. n. sp. and Botominella lineata are new to the well-established Krol assemblage. The paper concentrates predominantly on fossil eukaryotic filamentous and coccoidal micro-organism of simple morphology. The assemblage is dominated by remains of prokaryotic cyanobacteria and demonstrates the diversity achieved by microorganisms at the beginning of the Ediacaran Period in the aftermath of the Marinoan glaciation. Filamentous and coccoidal microorganisms differ in taxonomic composition from the Mesoproterozoic microbiotas. The Krol microfossils assemblage has biostratigraphic potential and usefulness in broadly demarcating the different levels of the Ediacaran strata. Because of the presence of ECAP acritarchs, along with the appearance of other eukaryotic microorganisms of filamentous and coccoidal morphology, the general level of the Krol ‘A’ assemblage is considered as Ediacaran.     

Bryozoans from the Mitikha Formation (Lower Famennian, Upper Devonian) of the Kuznetsk Basin, Russia

Bryozoans from the Mitikha Formation (Lower Famennian, Upper Devonian) in the Kuznetsk depression are described for the first time. This bryozoan assemblage comprises both the well-known species Leioclema numerosum Moroz., L. ramosum Nekh., and Nicklesopora graciosa Troiz. and new taxa: L. kusmense sp. nov. and Megacanthopora glubokaensis sp. nov. The bryozoan assemblage contains some species common with the Famennian bryozoan assemblage of Kazakhstan.     

Holocene paleoclimate change in the Antarctic Peninsula: evidence from the diatom,sedimentary and geochemical record

Holocene, marine deposition in Lallemand Fjord, Antarctic Peninsula, is reinterpreted using statistical analyses (cluster analysis, analysis of variance, nonmetric multidimensional scaling and multiple regression) to compare diatom assemblages and the primary sedimentological proxies. The assemblages have been deposited in a variable sea ice zone over the last ca. 10,500 yr BP in response to a climate change. In the Late Pleistocene/early Holocene (10,580–7890 yr BP), a sea ice diatom assemblage was deposited in the presence of a retreating ice shelf at the head of the fjord. In the mid Holocene (7890–3850 yr BP), an open water assemblage was deposited and sea ice cover was at a minimum. We associate the assemblage with climatic warming, which characterizes much of the Antarctic Peninsula during this time. A second sea ice assemblage, different from that deposited in the early Holocene, has been deposited in Lallemand Fjord since the late Holocene (<3850 yr BP). The assemblage reflects Neoglacial cooling, an increase in sea ice extent and/or an advance of the Müller Ice Shelf.     

Implications of an early land plant spore assemblage for the late Silurian age of the Si Ka Formation,northern Vietnam

The first plant microfossil assemblage from the Si Ka Formation of the Song Cau Group, northern Vietnam is reported. It is composed of cryptospores in dyads and tetrads, trilete spores, tubular remains consisting of an association of smooth, banded, and externally thickened tubes, and cuticle-like fragments. The biostratigraphic assemblage of sporomorphs indicates a late Silurian (late Ludfordian) to Early Devonian (early Lochkovian) age. Further comparison with coeval reports using the characteristic features of the assemblage confines their age to the late Ludlow (late Ludfordian) to early Přídolí. This report presents the oldest spore assemblage from Vietnam and contributes to a broader understanding of its paleo-landscape during the late Silurian.     

Black liquor and the hangover effect: fish assemblage recovery dynamics following a pulse disturbance

Anthropogenic perturbations impact aquatic systems causing wide‐ranging responses, from assemblage restructuring to assemblage recovery. Previous studies indicate the duration and intensity of disturbances play a role in the dynamics of assemblage recovery. In August 2011, the Pearl River, United States, was subjected to a weak black liquor spill from a paper mill which resulted in substantial loss of fish in a large stretch of the main channel. We quantified resilience and recovery of fish assemblage structure in the impacted area following the event. We compared downstream (impacted) assemblages to upstream (unimpacted) assemblages to determine initial impacts on structure. Additionally, we incorporated historic fish collections (1988–2011) to examine impacts on assemblage structure across broad temporal scales. Based on NMDS, upstream and downstream sites generally showed similar assemblage structure across sample periods with the exception of the 2 months postdischarge, where upstream and downstream sites visually differed. Multivariate analysis of variance (PERMANOVA) indicated significant seasonal variation among samples, but found no significant interaction between impacted and unimpacted assemblages following the discharge event. However, multivariate dispersion (MVDISP) showed greater variance among assemblage structure following the discharge event. These results suggest that 2 months following the disturbance represent a time period of stochasticity in regard to assemblage structure dynamics, and this was followed by rapid recovery. We term this dynamic the “hangover effect” as it represents the time frame from the cessation of the perturbation to the assemblage's return to predisturbance conditions. The availability and proximity of tributaries and upstream refugia, which were not affected by the disturbance, as well as the rapid recovery of abiotic parameters likely played a substantial role in assemblage recovery. This study not only demonstrates rapid recovery in an aquatic system, but further demonstrates the value of continuous, long‐term, data collections which enhance our understanding of assemblage dynamics.     

A remarkable assemblage of terrestrial tetrapods from the Zechstein (Upper Permian: Tatarian) near Korbach (northwestern Hesse)

We present a preliminary report on the first diverse central European assemblage of Late Permian terrestrial tetrapods from a fissure-filling in marine sediments of the lower Zechstein near Korbach (northwestern Hesse, Germany). It includes therapsids (cynodonts and dicynodonts), archosauromorph diapsids, and pareiasaurs. Similar assemblages were previously known only from the Upper Permian of Russia, Scotland, and South and East Africa. The occurrence of the basal cynodontProcynosuchus is paleobiogeographically significant because this taxon was previously known only from theDicynodon lacerticeps-Whaitsia assemblage zone of South Africa and the Madumabisa Mudstone of Zambia. The geological context of the Korbach site permits a rather precise chronostratigraphic placement of the tetrapod assemblage in the interval between Zechstein 1 and 3. The Korbach tetrapod assemblage is late Tatarian in age.     

Fossil Plants and Their Assemblages from the Early Carboniferous in Guangdong

This paper deals with the Lower Carboniferous fossil plants, 19 genera and 41 species including 10 new species, such as Sublepidodeneron wcwgtanense, Lepidodendron sophoroides, Adiantites lianpingensis, A. matouensis, Archaeopteridium shaoguanense, Rhacopteris angusta, Rhodeites lanceolata, Neuropteris shaoguanensis, Potoniea turbinata and P. racemicarpa. According to the distributive regularity of those fossils in stratigraphic section of Early Carboniferous from Guangdong area, the authors propose to divide the flora into three assemblages from lower to upper, namely, 1, Sublepidodendron mirabile assemblage; 2. Cardiopteridium spetsbergense-Adiantites gothanii assemblage; 3. Archaeopteridium-Sphenopteris obtusiloba assemblage, which separately represent the dispositions of Dahu Formation (the 1st assemblage), the lower part of Ceshui Formation (the 2nd assemblage) and upper part of Ceshui Formation or middle part of Zhongxin Formation (the 3rd assemblage).     

Contribution to the study of the structure of amber forest communities based on analysis of syninclusions in the Rovno amber (Late Eocene of Ukraine)

The composition of syninclusions was analyzed in three representative samples of the Late Eocene Rovno amber. Statistical analysis revealed a stable connection between three pairs of taxa in all three samples, viz., the midges Chironomidae and Ceratopogonidae; the flies Dolichopodidae and aphids Germaraphis; and the mite Glaesacarus rhombeus and Sciara zone dipterans (Sciaroidea, Tipuloidea, etc.). The first pair is interpreted as representing the assemblage of aeroplankton insects; the second, the assemblage of dwellers of the trunks of amber trees; and the third pair, the assemblage of dead wood consumers. The results, although provisional, support the idea that the study of syninclusions is a useful instrument for understanding the structure of past communities.     

Taxonomic Composition and Trophic Structure of the Continental Bony Fish Assemblage from the Early Late Cretaceous of Southeastern Morocco

The mid-Cretaceous vertebrate assemblage from south-eastern Morocco is one of the most diversified continental vertebrate assemblages of this time worldwide. The bony fish component (coelacanths, lungfishes and ray-finned fishes) is represented by relatively complete specimens and, mostly, by fragmentary elements scattered along 250 kilometres of outcrops. Here we revisit the bony fish assemblage by studying both isolated remains collected during several fieldtrips and more complete material kept in public collections. The assemblage comprises several lungfish taxa, with the first mention of the occurrence of Arganodus tiguidiensis, and possibly two mawsoniid coelacanths. A large bichir cf. Bawitius, is recorded and corresponds to cranial elements initially referred to ‘Stromerichthys’ from coeval deposits in Egypt. The ginglymodians were diversified with a large ‘Lepidotes’ plus two obaichthyids and a gar. We confirm here that this gar belongs to a genus distinctive from Recent gars, contrary to what was suggested recently. Teleosteans comprise a poorly known ichthyodectiform, a notopterid, a probable osteoglossomorph and a large tselfatiiform, whose cranial anatomy is detailed. The body size and trophic level for each taxon are estimated on the basis of comparison with extant closely related taxa. We plotted the average body size versus average trophic level for the Kem Kem assemblage, together with extant marine and freshwater assemblages. The Kem Kem assemblage is characterized by taxa of proportionally large body size, and by a higher average trophic level than the trophic level of the extant compared freshwater ecosystems, but lower than for the extant marine ecosystems. These results should be regarded with caution because they rest on a reconstructed assemblage known mostly by fragmentary remains. They reinforce, however, the ecological oddities already noticed for this mid-Cretaceous vertebrate ecosystem in North Africa.     

The distribution of Recent benthic foraminifera in the Polar Front region, southwest Atlantic

Twenty-five core-top samples from the Maurice Ewing Bank (MEB) and Islas Orcadas Rise (IOR) were examined to determine the distribution of benthic foraminifera in the vicinity of the Polar Front in the southwest Atlantic Ocean. The Polar Front has a subsurface expression that effects the areal and depth distribution of benthic foraminifera in this region.Three faunal assemblages were identified by Q-mode factor analysis. The shallowest assemblage, dominated by Bulimina aculeata, is present from 1500 to 2600 m on the Maurice Ewing Bank and is associated with potential temperatures of 1.71-0.50°C, salinities of 34.74-34.70‰ and potential density values of 45.84–46.04 sigma-4. A second assemblage, dominated by Uvigerina peregrina, occurs in water depths from 2600 to 3100 m and is associated with potential temperatures of 0.40-0.26°C, salinities of 34.70-34.69‰ and potential density values of 46.05–46.07 sigma-4. The third assemblage is dominated by Nuttallides umbonifera, Ehrenbergina trigona and secondarily by Oridorsalis umbonatus and Pullenia bulloides (the N. umbonifera-E. trigona assemblage) is present form 2770 to 3120 m on the Islas Orcadas Rise. This assemblage is associated with potential temperatures of 0.36-0.14°C, salinities of 34.69-34.68‰, and potential density values of 46.06–46.09 sigma-4. Although the U. peregrina assemblage and the N. umbonifera-E. trigona assemblage overlap bathymetrically, they are present in waters of slightly different properties. The Bulimina aculeata assemblage is within the core of the Lower Circumpolar Deep Water (LCDW), while the other two assemblages occur within transition zones between the LCDW and Weddell Sea Deep Water (WSDW).The difference in the benthic foraminiferal assemblages at similar depths on the Islas Orcadas Rise and the Maurice Ewing Bank is the result of different water-mass regimes separated by the Polar Front.     

Movement of oceanic fronts south of Australia during the last 10 ka: interpretation of calcareous nannoplankton in surface sediments from the Southern Ocean

Preservation of calcareous nannoplankton in surface sediment samples from the Southern Ocean south of Australia and adjacent to New Zealand record a single assemblage. The dominant species are Emiliania huxleyi, Gephyrocapsa muellerae, Calcidiscus leptoporus, Helicosphaera carteri and Coccolithus pelagicus. The assemblage varies little in abundance and diversity with minor correlation to present-day overlying surface water masses and oceanic fronts. Increase in abundance of H. carteri and C. pelagicus in the region of the Subtropical Front may reflect higher nutrients associated with this front. The assemblage, although altered by dissolution, represents a warmer climatic interval than present-day with the presence of preferentially dissolved, warm-water species preserved as far south as the Polar Front. The presence of warm-water species under sub-Antarctic waters at the Polar Front is interpreted as a relic population from the Holocene climatic optimum of 10–8 ka. The absence of coccoliths in sediments poleward of the Polar Front suggests an equatorward shift of this front following the climatic optimum, resulting in increased productivity of siliceous phytoplankton associated with the colder waters and increased dissolution of coccoliths. Movement of the Subtropical Front for the same interval is not recorded in the preserved coccoliths. The more heavily calcified form of E. huxleyi which dominates the living assemblage north of the Subtropical Front is subject to dissolution in this region and is poorly preserved in the sediment assemblage.     

Geographic and temporal variation in the ant–seed dispersal assemblage of the perennial herb Helleborus foetidus L. (Ranunculaceae)

Spatio-temporal variations in the composition of the animal interactive assemblages may result in variations in selective pressures on the plants. In ant–seed dispersal mutualisms, the study of the magnitude of spatial and temporal variation of ant assemblages is rarely studied, limiting inferences and generalizations on the evolution of this mutualism. Here, we describe the ant–disperser assemblage of the myrmecochorous herb Helleborus foetidus in 14 populations across the Iberian Peninsula, and dissect the variation in the assemblage into spatial and temporal components as a first step to evaluate the evolutionary potential of this interaction. The ant–visitor assemblage of H. foetidus was mainly represented by species of Formicinae and it was highly diverse and variable in composition and function. Ants behaving as legitimate dispersers and those with mixed behaviour numerically dominated the assemblage compared with elaiosome consumers. The magnitude of the spatial variation was higher than the temporal variation, suggesting that the relative frequency of each functional group will be more foreseeable among years in each population than among populations. At the expense of further analysis of the effects of such variation on dispersal success, we can envisage a selection mosaic scenario, where local adaptive responses of plants might arise as a result of local variations in the specific composition and function of the assemblage.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 92 , 135–150.     

Comparison study of the modern ostracod associations in the Kara and Laptev seas: Ecological aspects

Recent ostracod assemblages were investigated from coretop sediment samples collected in the eastern Kara Sea from water depths down to 300 m. A total of 45 species were identified, 27 of them were reported for the Kara Sea for the first time. The Kara Sea data were compared with our results on the distribution of ostracods in the eastern Laptev Sea. The spatial distribution of recent taxa and the ecological groupings demonstrate a clear relation to dominant environmental factors which range from estuarine to full-marine conditions. Four assemblages related to average summer bottom water salinities were established: (1) a freshwater assemblage from the inner estuaries of the Ob' and Yenisei rivers with salinities less than 2 and from thermokarst lagoons of the southern Laptev Sea coast with strong salinization in winter; (2) a brackishwater assemblage of the outer estuaries of the Ob' and Yenisei rivers with salinities up to 26; (3) a mixed euryhaline–marine assemblage dominated by euryhaline species Paracyprideis pseudopunctillata and Heterocyprideis sorbyana from the inner shelf river-affected zone of the Kara and Laptev seas, where salinities range between 26 and 32; (4) a taxonomically diverse marine assemblage dominated by shallow-water marine taxa from the northern parts of the Kara and Laptev shelves and upper continental slope with stable bottom environments and a salinity higher than 32. Abundant euryhaline species found at greater water depths are identified as part of an ice-rafted assemblage. They are possibly entrained into the newly formed fast ice during autumn storms and freeze-up period and then transported to the distal open-sea areas during summer.