Feeding experiments of the seep-associated foraminifer Nonionellina labradorica with a marine methanotroph from the Arctic

2021 ◽  
Author(s):  
Christiane Schmidt ◽  
Geslin Emmanuelle ◽  
Bernhard Joan M. ◽  
LeKieffre Charlotte ◽  
Roberge Helene ◽  
...  
Keyword(s):  
Barents Sea ◽  
Feeding Habits ◽  
The Arctic ◽  
Type I ◽  
Intracytoplasmic Membrane ◽  
Organic Detritus ◽  
Feeding Experiments ◽  
Food Vacuoles ◽  
Species Specific

<p>Foraminifera on the seafloor are known to have species-specific feeding habits. Among those are deposit feeders, eating organic detritus and bacteria. Little is known about the feeding habits of foraminifera from Arctic seep environments. That is, in particular, of interest as variable δ<sup>13</sup>C values in the tests of foraminifera have been suggested to be partly linked with a diet rich in bacteria, themselves lighter in δ<sup>13</sup>C values. As there is little information on the ecology of the foraminifer <em>Nonionellina labradorica</em> (Dawson, 1860), this study examined feeding habits on bacteria and compared them to in situ collected specimens, using Transmission Electron microscopy (TEM). As bacterial food, the marine methane-oxidizing bacterium <em>Methyloprofundus sedimenti</em> was chosen, which is an important representative of methanotrophs in the marine environment near methane seeps. Sediment samples containing living N. labradorica specimens collected in close vicinity(approx. 5 m) from an active methane seep in Storfjordrenna, Barents Sea (382-m water depth).  We performed a feeding experiment on <em>N. labradorica </em>(n=17 specimen), which were incubated in the dark at in situ temperature. Specimens were fed at the beginning of the experiment, except the un-fed controls, and incubations terminated after 4, 8 and 20 h. After fixation in epoxy resin the ultrastructure of all specimens and their food vacuoles was observed and compared using a TEM. All examined specimens were living at the time of fixation, based on observation of intact mitochondrial membranes. In all specimens, inorganic detritus was preserved inside food vacuoles. Closer observation of food vacuoles also revealed that in addition to inorganic debris, such as clay, occasionally bacteria were visible. This led us to conclude that our <em>N. labradorica </em>can  generally be classified as a deposit feeder, which is rather a generalist than a specialist. Regarding uptake of <em>M. sedimenti</em>, the timing of the experimentation seemed to be critical. We did not observe methanotrophs preserved in the resin at the 4 and 8 h incubations, but found two putative methanotrophs near the apertural region after the 20-h incubation. After closer observation, we could identify one of those two putative specimen as the menthanothroph <em>M. sedimenti</em> near the foraminiferal aperture, based on presence of a typical type I stacked intracytoplasmic membrane (ICM) and storage granules (SC). We concluded that <em>N. labradorica</em> may ingest <em>M. sedimenti</em> via “untargeted grazing” in seeps. Further studies must examine the exact relationship between diet and δ<sup>13</sup>C in foraminiferal test on several different paleo-oceanographically relevant species.</p>

Selected mitochondrial genes as species markers of the Arctic Contracaecum osculatum complex

2011 ◽  
Vol 86 (2) ◽  
pp. 252-258 ◽  
Author(s):  
J. Dzido ◽  
A. Kijewska ◽  
J. Rokicki
Keyword(s):  
Barents Sea ◽  
Intraspecific Variability ◽  
Mitochondrial Genes ◽  
Intraspecific Diversity ◽  
The Arctic ◽  
Protein Coding ◽  
As Species ◽  
Contracaecum Osculatum ◽  
Species Markers ◽  
Species Specific

AbstractThis study, aimed at testing the hypothesis that some mitochondrial genes can serve as species-specific markers, involved a comparison of the sequence variance of selected mitochondrial DNA genes of the Arctic Contracaecum osculatum species (C. osculatum A, C. osculatum B and C. osculatum C). We compared differences between five complete (ND2, CYTB, ND3, ND4L and ND6) and three partial (CO1, CO3 and ND5) protein-coding genes. The total length of the sequence of each of the 13 specimens was 4830 bp. The sample consisted of C. osculatum L3 larvae collected from Reinhardtius hippoglossoides and Gadus ogac from the Barents Sea and Davis Strait. The K2P distance values between the species ranged within 0.06–0.12, the intraspecific variability (0.01–0.03) proving 3–6 times lower. The lowest interspecific divergence was observed between C. osculatum A and C. osculatum B, whereas the highest intraspecific diversity was typical of C. osculatum C. Among the C. osculatum species studied, the highest nucleotide diversity was recorded in the CYTB, CO3 and ND5 genes. These genes may be useful in species identification of the very closely related Contracaecum sibling species.

scholarly journals Volume and temperature transports through the main Arctic Gateways: A comparative study between an ocean reanalysis and mooring-derived data

2017 ◽  
Author(s):  
Marianne Pietschnig ◽  
Michael Mayer ◽  
Takamasa Tsubouchi ◽  
Andrea Storto ◽  
Sebastian Stichelberger ◽  
...  
Keyword(s):  
Cross Sections ◽  
Barents Sea ◽  
The Arctic ◽  
Data Sets ◽  
Ocean Reanalysis ◽  
Polar Climate ◽  
East Greenland Current ◽  
First Time ◽  
Climate Studies

Abstract. Oceanic transports through the Arctic gateways represent an integral part of the polar climate system, but comprehensive in-situ-based estimates of this quantity have been lacking in the past. New observation-based estimates of oceanic volume, temperature and freshwater transports have recently become available. Those estimates have been derived from moored observations in the four major gateways by applying mass and salinity constraints. We seize this opportunity to compare a recent ocean reanalysis release with those observation-based estimates. First, time series of integrated volume and temperature transports through each strait are considered. Good agreement is found for Davis Strait volume transports, but considerable disagreement of up to 1.1 Sv in Fram Strait and the Barents Sea Opening. The annual mean net volume export through the gateways is −0.03 ± 0.23 Sv in the reanalysis, weaker than the −0.15 ± 0.06 Sv derived from the observation-based estimate (uncertainties represent the monthly standard deviation). The net ocean heat transport to the Arctic Ocean is similar in the two datasets (observation-based: 153 ± 44 TW, reanalysis: 145 ± 35 TW). Discrepancies in the integrated transports are further investigated by studying cross-sections of velocity, temperature and temperature flux density. These reveal good qualitative agreement in all straits, but considerable differences in the strength of major features like the East Greenland Current and the West Spitzbergen Current. Examination of the instrumental coverage reveals that areas of discrepancy are often co-located with poorly observed regions. In conclusion, both types of data sets have their merits and are recommended to be used complementarily for climate studies in this data-sparse region. We hope that the results presented in this study can assist in planning future observational efforts and in the development of ocean reanalysis products.

scholarly journals Termite mounds mitigate half of termite methane emissions

2018 ◽  
Vol 115 (52) ◽  
pp. 13306-13311 ◽  
Author(s):  
Philipp A. Nauer ◽  
Lindsay B. Hutley ◽  
Stefan K. Arndt
Keyword(s):  
Feeding Habits ◽  
Field Tests ◽  
Tracer Test ◽  
Transport Processes ◽  
Termite Mounds ◽  
Termite Species ◽  
Field Methods ◽  
Independent Field ◽  
Species Specific

Termites are responsible for ∼1 to 3% of global methane (CH4) emissions. However, estimates of global termite CH4emissions span two orders of magnitude, suggesting that fundamental knowledge of CH4turnover processes in termite colonies is missing. In particular, there is little reliable information on the extent and location of microbial CH4oxidation in termite mounds. Here, we use a one-box model to unify three independent field methods—a gas-tracer test, an inhibitor approach, and a stable-isotope technique—and quantify CH4production, oxidation, and transport in three North Australian termite species with different feeding habits and mound architectures. We present systematic in situ evidence of widespread CH4oxidation in termite mounds, with 20 to 80% of termite-produced CH4being mitigated before emission to the atmosphere. Furthermore, closing the CH4mass balance in mounds allows us to estimate in situ termite biomass from CH4turnover, with mean biomass ranging between 22 and 86 g of termites per kilogram of mound for the three species. Field tests with excavated mounds show that the predominant location of CH4oxidation is either in the mound material or the soil beneath and is related to species-specific mound porosities. Regardless of termite species, however, our data and model suggest that the fraction of oxidized CH4(fox) remains well buffered due to links among consumption, oxidation, and transport processes via mound CH4concentration. The meanfoxof 0.50 ± 0.11 (95% CI) from in situ measurements therefore presents a valid oxidation factor for future global estimates of termite CH4emissions.

Carbon-dependent growth, community structure, and methane oxidation performance of a soil-derived methanotrophic mixed culture

2020 ◽  
Author(s):  
Nadine Praeg ◽  
Iris Schachner ◽  
Lisa Schuster ◽  
Paul Illmer
Keyword(s):  
Mixed Culture ◽  
Heterotrophic Bacteria ◽  
Type I ◽  
Ch4 Oxidation ◽  
Feeding Experiments ◽  
Oxidation Performance ◽  
Dependent Growth ◽  
Global Carbon ◽  
Similar Soil

Abstract Soil-borne methane-oxidizing microorganisms act as a terrestrial methane (CH4) sink and are potentially useful in decreasing global CH4 emissions. Understanding the ecophysiology of methanotrophs is crucial for a thorough description of global carbon cycling. Here, we report the in situ balance of soils from abandoned landfills, meadows and wetlands, their capacities to produce and oxidize CH4 at laboratory-scale and the isolation of a soil-borne methanotrophic-heterotrophic mixed culture that was used for carbon (C1 and C2) feeding experiments. We showed that even with similar soil properties, the in situ CH4 balance depends on land-use. Different soils had different potentials to adapt to increased CH4 availability, leading to the highest CH4 oxidation capacities for landfill and wetland soils. The most efficient mixed culture isolated from thelandfill was dominated by the methanotrophs Methylobacter sp. and Methylosinus sp., which were accompanied by Variovorax sp. and Pseudomonas sp. and remained active in oxidizing CH4 when supplied with additional C-sources. The rations between type I and type II methanotrophs and between methanotrophic and heterotrophic bacteria changed when C-sources were altered. A significant effect of the application of the mixed culture on the CH4 oxidation of soils was established but the extent varied depending on soil type.

scholarly journals Deposit feeding of a foraminifera from an Arctic methane seep site and possible association with a methanotroph revealed by transmission electron microscopy

2021 ◽  
Author(s):  
Christiane Schmidt ◽  
Emmanuelle Geslin ◽  
Joan M. Bernhard ◽  
Charlotte LeKieffre ◽  
Mette Marianne Svenning ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Methane Emission ◽  
Barents Sea ◽  
Substantial Contribution ◽  
Type I ◽  
Feeding Experiment ◽  
Organic Detritus ◽  
Transmission Electron ◽  
Deposit Feeding

Abstract. Several foraminifera are deposit feeders that consume organic detritus (dead particulate organic material along with entrained bacteria). However, the role of such foraminifera in the benthic food-web remains understudied. As foraminifera may associate with methanotrophic bacteria, which are 13C-depleted, feeding on them has been suggested to cause negative δ13C values in the foraminiferal cytoplasm and/or calcite. To test whether the foraminiferal diet includes methanotrophs, we performed a short-term (1 d) feeding experiment with Nonionellina labradorica from an active Arctic methane-emission site (Storfjordrenna, Barents Sea) using the marine methanotroph Methyloprofundus sedimenti, and analyzed N. labradorica cytology via Transmission Electron microscopy (TEM). We hypothesized that M. sedimenti would be visible, as evidenced by their ultrastructure, in degradation vacuoles after this feeding experiment. Sediment grains (mostly clay) occurred inside one or several degradation vacuoles in all foraminifers. In 24 % of the specimens from the feeding experiment degradation vacuoles also contained bacteria, although none could be confirmed to be the offered M. sedimenti. Observations of the area adjacent to the aperture after 20 h incubation revealed three putative methanotrophs, close to clay particles. These methanotrophs were identified based on internal characteristics such as a type I stacked intracytoplasmic membranes (ICM), storage granules (SG) and gram-negative cell walls (GNCW). Furthermore, N. labradorica specimens were examined for specific adaptations to this active Arctic methane-emission site; we noted the absence of bacterial endobionts in all specimens examined but confirmed the presence of kleptoplasts, which were often partially degraded. Based on these observations, we suggest that M. sedimenti can be consumed by N. labradorica via untargeted grazing in seeps and that N. labradorica can be generally classified as a deposit feeder at this Arctic site. These results suggest that if methanothrophs are available to the foraminifera in their habitat, their non-selective uptake could make a substantial contribution to altering δ13Ctest values. This in turn may impact metazoans grazing on benthic foraminifera by altering their δ13C signature.

Summer phytoplankton of the northern Barents Sea (75–80º N)

2019 ◽  
pp. 8-19
Author(s):  
Larisa A. Pautova ◽  
Vladimir A. Silkin ◽  
Marina D. Kravchishina ◽  
Valeriy G. Yakubenko ◽  
Anna L. Chultsova
Keyword(s):  
Barents Sea ◽  
Weighted Average ◽  
Arctic Basin ◽  
High Arctic ◽  
Alexandrium Tamarense ◽  
Warm Water ◽  
The Arctic ◽  
Absolute Maximum ◽  
Deep Trench ◽  
Maximum Biomass

The structure of the summer planktonic communities of the Northern part of the Barents sea in the first half of August 2017 were studied. In the sea-ice melting area, the average phytoplankton biomass producing upper 50-meter layer of water reached values levels of eutrophic waters (up to 2.1 g/m3). Phytoplankton was presented by diatoms of the genera Thalassiosira and Eucampia. Maximum biomass recorded at depths of 22–52 m, the absolute maximum biomass community (5,0 g/m3) marked on the horizon of 45 m (station 5558), located at the outlet of the deep trench Franz Victoria near the West coast of the archipelago Franz Josef Land. In ice-free waters, phytoplankton abundance was low, and the weighted average biomass (8.0 mg/m3 – 123.1 mg/m3) corresponded to oligotrophic waters and lower mesotrophic waters. In the upper layers of the water population abundance was dominated by small flagellates and picoplankton from, biomass – Arctic dinoflagellates (Gymnodinium spp.) and cold Atlantic complexes (Gyrodinium lachryma, Alexandrium tamarense, Dinophysis norvegica). The proportion of Atlantic species in phytoplankton reached 75%. The representatives of warm-water Atlantic complex (Emiliania huxleyi, Rhizosolenia hebetata f. semispina, Ceratium horridum) were recorded up to 80º N, as indicators of the penetration of warm Atlantic waters into the Arctic basin. The presence of oceanic Atlantic species as warm-water and cold systems in the high Arctic indicates the strengthening of processes of “atlantificacion” in the region.

Routine identification of four sympatric species of calanoid copepods Pseudocalanus spp. in the Atlantic Arctic using a species-specific polymerase chain reaction

2020 ◽  
Vol 48 (1) ◽  
pp. 62-72
Author(s):  
E. A. Ershova
Keyword(s):  
Polymerase Chain Reaction ◽  
Life Cycles ◽  
The Arctic ◽  
Relative Distribution ◽  
Chain Reaction ◽  
Specific Polymerase Chain Reaction ◽  
Routine Identification ◽  
Polymerase Chain ◽  
Species Specific ◽  
Plankton Communities

Сalanoid copepods of the genus Pseudocalanus play an important role in the plankton communities of the Arctic and boreal seas, often dominating in numbers and constituting a significant proportion of the biomass of zooplankton. Despite their high presence and significance in the shelf plankton communities, species-specific studies of the biology of these are significantly hampered by extremely small morphological differences between them, especially at the juvenile stages, at which they are virtually indistinguishable. In this paper, we describe a new, routine and low-cost molecular method for identifying all Pseudocalanus species found in the Atlantic sector of the Arctic: the Arctic P. acuspes, P. minutus and the boreal P. moultoni and P. elongatus, and apply it to describe the relative distribution of these species in four locations of the Arctic and sub-Arctic. With this method, species-specific polymerase chain reaction (ssPCR), mass identification of individuals of any developmental stage, including nauplii, is possible. This method can serve as an excellent tool for studying the species-specific biology of this group, describing their life cycles, as well as monitoring changes in Arctic marine ecosystems under the influence of changing climate.

STORM ICE OIL WIND WAVE WATCH SYSTEM (SIOWS): WEB GIS APPLICATION FOR MONITORING THE ARCTIC

2017 ◽  
Author(s):  
Alexander Myasoedov ◽  
Alexander Myasoedov ◽  
Sergey Azarov ◽  
Sergey Azarov ◽  
Ekaterina Balashova ◽  
...  
Keyword(s):  
Satellite Data ◽  
Wind Wave ◽  
Arctic Region ◽  
Web Gis ◽  
The Arctic ◽  
Flexible Tool ◽  
In Situ Data ◽  
Current State ◽  
Watch System

Working with satellite data, has long been an issue for users which has often prevented from a wider use of these data because of Volume, Access, Format and Data Combination. The purpose of the Storm Ice Oil Wind Wave Watch System (SIOWS) developed at Satellite Oceanography Laboratory (SOLab) is to solve the main issues encountered with satellite data and to provide users with a fast and flexible tool to select and extract data within massive archives that match exactly its needs or interest improving the efficiency of the monitoring system of geophysical conditions in the Arctic. SIOWS - is a Web GIS, designed to display various satellite, model and in situ data, it uses developed at SOLab storing, processing and visualization technologies for operational and archived data. It allows synergistic analysis of both historical data and monitoring of the current state and dynamics of the "ocean-atmosphere-cryosphere" system in the Arctic region, as well as Arctic system forecasting based on thermodynamic models with satellite data assimilation.

scholarly journals Variability in nitrogen-derived trophic levels of Arctic marine biota

Polar Biology ◽  
2020 ◽  
Author(s):  
Renske P. J. Hoondert ◽  
Nico W. van den Brink ◽  
Martine J. van den Heuvel-Greve ◽  
Ad M. J. Ragas ◽  
A. Jan Hendriks
Keyword(s):  
Stable Isotopes ◽  
Enrichment Factors ◽  
Trophic Levels ◽  
The Arctic ◽  
Marine Biota ◽  
Arctic Ecosystems ◽  
Arctic Species ◽  
Single Region ◽  
Benthic Food ◽  
Species Specific

AbstractStable isotopes are often used to provide an indication of the trophic level (TL) of species. TLs may be derived by using food-web-specific enrichment factors in combination with a representative baseline species. It is challenging to sample stable isotopes for all species, regions and seasons in Arctic ecosystems, e.g. because of practical constraints. Species-specific TLs derived from a single region may be used as a proxy for TLs for the Arctic as a whole. However, its suitability is hampered by incomplete knowledge on the variation in TLs. We quantified variation in TLs of Arctic species by collating data on stable isotopes across the Arctic, including corresponding fractionation factors and baseline species. These were used to generate TL distributions for species in both pelagic and benthic food webs for four Arctic areas, which were then used to determine intra-sample, intra-study, intra-region and inter-region variation in TLs. Considerable variation in TLs of species between areas was observed. This is likely due to differences in parameter choice in estimating TLs (e.g. choice of baseline species) and seasonal, temporal and spatial influences. TLs between regions were higher than the variance observed within regions, studies or samples. This implies that TLs derived within one region may not be suitable as a proxy for the Arctic as a whole. The TL distributions derived in this study may be useful in bioaccumulation and climate change studies, as these provide insight in the variability of trophic levels of Arctic species.

Species-diagnostic and species-specific DNA sequences evenly distributed throughout pine and spruce chromosomes

Genome ◽  
2010 ◽  
Vol 53 (10) ◽  
pp. 769-777 ◽  
Author(s):  
Melanie Mehes-Smith ◽  
Paul Michael ◽  
Kabwe Nkongolo
Keyword(s):  
Dna Sequences ◽  
Random Amplified Polymorphic Dna ◽  
Inter Simple Sequence Repeat ◽  
Issr Markers ◽  
Pinus Monticola ◽  
The Family ◽  
Species Specific ◽  
Rapd And Issr ◽  
Specific Sequences

Genome organization in the family Pinaceae is complex and largely unknown. The main purpose of the present study was to develop and physically map species-diagnostic and species-specific molecular markers in pine and spruce. Five RAPD (random amplified polymorphic DNA) and one ISSR (inter-simple sequence repeat) species-diagnostic or species-specific markers for Picea mariana , Picea rubens , Pinus strobus , or Pinus monticola were identified, cloned, and sequenced. In situ hybridization of these sequences to spruce and pine chromosomes showed the sequences to be present in high copy number and evenly distributed throughout the genome. The analysis of centromeric and telomeric regions revealed the absence of significant clustering of species-diagnostic and species-specific sequences in all the chromosomes of the four species studied. Both RAPD and ISSR markers showed similar patterns.

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