scholarly journals Global distribution patterns of marine nitrogen-fixers by imaging and molecular methods

2020 ◽  
Author(s):  
Juan José Pierella Karlusich ◽  
Eric Pelletier ◽  
Madeline Carsique ◽  
Etienne Dvorak ◽  
Sébastien Colin ◽  
...  
Keyword(s):  
Distribution Patterns ◽  
Molecular Data ◽  
Deep Chlorophyll Maximum ◽  
New Production ◽  
Analysis Pipeline ◽  
Sources And Sinks ◽  
Nitrogen Fixers ◽  
Abundance Patterns ◽  
Quantitative Image ◽  
Biological Nitrogen

AbstractBiological nitrogen fixation sustains ~50% of ocean primary production. However, our understanding of marine N2-fixers (diazotrophs) is hindered by limited observations. Here, we developed a quantitative image analysis pipeline in concert with mapping of molecular markers for mining >2,000,000 images and >1,300 metagenomes from Tara Oceans, covering surface, deep chlorophyll maximum and mesopelagic layers across 6 organismal size fractions (0-2000 μm). Imaging and molecular data were remarkably congruent. Diazotrophs were detected from ultrasmall bacterioplankton (<0.2 μm) to mesoplankton (180 to 2000 μm). We identified several new high density regions of diazotrophs. Distributional and abundance patterns support the previous canonical view that larger sized diazotrophs (>10 μm) dominate the tropical belts, while unicellular diazotrophs were found in surface and mesopelagic samples. Multiple co-occurring diazotrophic lineages were frequently encountered, suggesting that complex overlapping niches are common. Overall, this work provides an updated global snapshot of marine diazotroph biogeographical diversity and highlights new sources and sinks of diazotroph-fueled new production.

scholarly journals Global distribution patterns of marine nitrogen-fixers by imaging and molecular methods

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Juan José Pierella Karlusich ◽  
Eric Pelletier ◽  
Fabien Lombard ◽  
Madeline Carsique ◽  
Etienne Dvorak ◽  
...  
Keyword(s):  
Critical Role ◽  
Distribution Patterns ◽  
Molecular Data ◽  
Global Scale ◽  
Global Ocean ◽  
Nitrogen Fixers ◽  
Quantitative Image ◽  
Seawater Samples ◽  
Globally Distributed ◽  
Marine Primary Production

AbstractNitrogen fixation has a critical role in marine primary production, yet our understanding of marine nitrogen-fixers (diazotrophs) is hindered by limited observations. Here, we report a quantitative image analysis pipeline combined with mapping of molecular markers for mining >2,000,000 images and >1300 metagenomes from surface, deep chlorophyll maximum and mesopelagic seawater samples across 6 size fractions (<0.2–2000 μm). We use this approach to characterise the diversity, abundance, biovolume and distribution of symbiotic, colony-forming and particle-associated diazotrophs at a global scale. We show that imaging and PCR-free molecular data are congruent. Sequence reads indicate diazotrophs are detected from the ultrasmall bacterioplankton (<0.2 μm) to mesoplankton (180–2000 μm) communities, while images predict numerous symbiotic and colony-forming diazotrophs (>20 µm). Using imaging and molecular data, we estimate that polyploidy can substantially affect gene abundances of symbiotic versus colony-forming diazotrophs. Our results support the canonical view that larger diazotrophs (>10 μm) dominate the tropical belts, while unicellular cyanobacterial and non-cyanobacterial diazotrophs are globally distributed in surface and mesopelagic layers. We describe co-occurring diazotrophic lineages of different lifestyles and identify high-density regions of diazotrophs in the global ocean. Overall, we provide an update of marine diazotroph biogeographical diversity and present a new bioimaging-bioinformatic workflow.

scholarly journals Relicts from Glacial Times: The Ground Beetle Pterostichus adstrictus Eschscholtz, 1823 (Coleoptera: Carabidae) in the Austrian Alps

Insects ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 84
Author(s):  
Wolfgang Paill ◽  
Stephan Koblmüller ◽  
Thomas Friess ◽  
Barbara-Amina Gereben-Krenn ◽  
Christian Mairhuber ◽  
...  
Keyword(s):  
Ground Beetle ◽  
Distribution Patterns ◽  
Morphological Characters ◽  
Molecular Data ◽  
Ice Age ◽  
Dispersal Ability ◽  
Austrian Alps ◽  
Alpine Regions ◽  
Extant Species ◽  
Limited Dispersal

The last ice age considerably influenced distribution patterns of extant species of plants and animals, with some of them now inhabiting disjunct areas in the subarctic/arctic and alpine regions. This arctic-alpine distribution is characteristic for many cold-adapted species with a limited dispersal ability and can be found in many invertebrate taxa, including ground beetles. The ground beetle Pterostichus adstrictus Eschscholtz, 1823 of the subgenus Bothriopterus was previously known to have a holarctic-circumpolar distribution, in Europe reaching its southern borders in Wales and southern Scandinavia. Here, we report the first findings of this species from the Austrian Ötztal Alps, representing also the southernmost edge of its currently known distribution, confirmed by the comparison of morphological characters to other Bothriopterus species and DNA barcoding data. Molecular data revealed a separation of the Austrian and Finish specimens with limited to no gene flow at all. Furthermore, we present the first data on habitat preference and seasonality of P. adstrictus in the Austrian Alps.

scholarly journals Disentangling relationships among eastern Mediterranean Cymbalaria including description of a novel species from the southern Peloponnese (Greece)

2021 ◽  
Vol 307 (2) ◽  
Author(s):  
Pau Carnicero ◽  
Núria Garcia-Jacas ◽  
Llorenç Sáez ◽  
Theophanis Constantinidis ◽  
Mercè Galbany-Casals
Keyword(s):  
Eastern Mediterranean ◽  
Phylogenetic Analyses ◽  
Taxonomic Revision ◽  
Distribution Patterns ◽  
Morphological Characters ◽  
Molecular Data ◽  
Morphological Data ◽  
Long Distance ◽  
Aegean Islands ◽  
Molecular Phylogenetic

AbstractThe eastern Mediterranean basin hosts a remarkably high plant diversity. Historical connections between currently isolated areas across the Aegean region and long-distance dispersal events have been invoked to explain current distribution patterns of species. According to most recent treatments, at least two Cymbalaria species occur in this area, Cymbalaria microcalyx and C. longipes. The former comprises several intraspecific taxa, treated at different ranks by different authors based on morphological data, evidencing the need of a taxonomic revision. Additionally, some populations of C. microcalyx show exclusive morphological characters that do not match any described taxon. Here, we aim to shed light on the systematics of eastern Mediterranean Cymbalaria and to propose a classification informed by various sources of evidence. We performed molecular phylogenetic analyses using ITS, 3’ETS, ndhF and rpl32-trnL sequences and estimated the ploidy level of some taxa performing relative genome size measures. Molecular data combined with morphology support the division of traditionally delimited C. microcalyx into C. acutiloba, C. microcalyx and C. minor, corresponding to well-delimited nrDNA lineages. Furthermore, we propose to combine C. microcalyx subsp. paradoxa at the species level. A group of specimens previously thought to belong to Cymbalaria microcalyx constitute a well-defined phylogenetic and morphological entity and are described here as a new species, Cymbalaria spetae. Cymbalaria longipes is non-monophyletic, but characterized by being glabrous and diploid, unlike other eastern species. The nrDNA data suggest at least two dispersals from the mainland to the Aegean Islands, potentially facilitated by marine regressions.

Prochlorococcuscontributes to new production in the Sargasso Sea deep chlorophyll maximum

2007 ◽  
Vol 34 (10) ◽  
Author(s):  
John R. Casey ◽  
Michael W. Lomas ◽  
Joanna Mandecki ◽  
Donald E. Walker
Keyword(s):  
Sargasso Sea ◽  
Deep Chlorophyll Maximum ◽  
New Production ◽  
Chlorophyll Maximum

Patterns of abundance and size of Dictyoceratid sponges among neighbouring islands in central Torres Strait, Australia

2007 ◽  
Vol 58 (2) ◽  
pp. 204 ◽  
Author(s):  
Alan R. Duckworth ◽  
Carsten W. Wolff
Keyword(s):  
Spatial Scales ◽  
Distribution Patterns ◽  
Small Scale ◽  
Size Frequency Distribution ◽  
Abundance Patterns ◽  
Size Frequency ◽  
Dysidea Herbacea ◽  
Torres Strait ◽  
Study Sites ◽  
Species Specific

Distribution and size frequency patterns of sessile organisms such as sponges may vary among and within neighbouring reefs. In the present study, we examined small-scale variation of dictyoceratid sponges (class Demospongiae), commonly found on coral reefs, by surveying six neighbouring islands in central Torres Strait. Each island had four study sites, at least 1 km apart, with each site consisting of three shallow (4 to 6 m) and three deep (10 to 15 m) 20 m2 transects. For each transect, we recorded the number of each species and measured the size of the more common dictyoceratid sponges. Seven species of dictyoceratid were recorded in central Torres Strait, with only three species, Coscinoderma sp., Dysidea herbacea and Hyrtios erecta, common to all six islands. Abundance patterns generally varied greatly among islands or sites within islands, perhaps resulting from a combination of physical, biological and stochastic factors. More dictyoceratids were found in deeper water; however, abundance across depth for some species varied among islands or sites. Size-frequency distribution patterns also varied greatly among islands and dictyoceratid species, indicating that factors that may promote growth for one species may not necessarily promote growth for a related species. This study shows that patterns of abundance and size of dictyoceratids can vary greatly over small spatial scales, and that patterns are species-specific.

scholarly journals Cryptic species in sympatry: Nonrandom small-scale distribution patterns in Bostrychia intricata (Ceramiales, Rhodophyta)

2020 ◽  
Author(s):  
N Muangmai ◽  
U Von Ammon ◽  
Giuseppe Zuccarello
Keyword(s):  
Cryptic Species ◽  
Algal Species ◽  
Sun Exposure ◽  
Distribution Patterns ◽  
Molecular Data ◽  
Small Scale ◽  
Ecological Resources ◽  
Intertidal Habitats ◽  
Multiple Species ◽  
Multiple Samples

© 2016 International Phycological Society. Sympatric coexistence of cryptic species, indistinguishable morphological taxa, has increasingly been detected on the basis of molecular data. This discovery raises the interesting question of how cryptic species can coexist, as hypothetically they would need identical ecological resources. The red alga Bostrychia intricata is commonly found along New Zealand shores. Previous studies indicated several cryptic species within this morphospecies, and that some populations have multiple species. This study aimed to determine how coexisting cryptic B. intricata distribute at a small scale. Along the shore of Moa Point, Wellington, we conducted intensive sampling of B. intricata in different habitats with respect to tidal position, wave and sun exposure levels. Our genetic data clearly documented the coexistence of three cryptic species of B. intricata: N2, N4 and N5. Multiple samples from individual algal patches indicated that each patch was made of the same ramet. Our analyses revealed a habitat-related pattern in small-scale distribution of different cryptic B. intricata, suggesting that the distribution of these cryptic species was not random. Cryptic species N4 was found at a higher tidal position than species N2 and N5, whereas cryptic species N2 occurred in more wave-exposed areas than the other species. Discriminant analysis indicated that tidal height strongly influenced the distribution pattern among these cryptic species. Our observations demonstrated that the co-occurrence of three cryptic B. intricata can partly be explained by their occupation of different intertidal habitats, highlighting the nonrandom distribution of coexisting cryptic algal species.

scholarly journals Effect of bio-fertilizers on foliage and floral traits of chrysanthemum cv Little Pink

2021 ◽  
Vol 17 (2) ◽  
pp. 162-166
Author(s):  
Shashank Dixit ◽  
A.K. Panday ◽  
Anurag Bajpay
Keyword(s):  
Growth Habit ◽  
Floral Traits ◽  
Live Cells ◽  
Dendranthema Grandiflora ◽  
Nitrogen Fixers ◽  
Phosphate Solubilizing ◽  
Biological Nitrogen ◽  
Asteraceae Family ◽  
Vast Range ◽  
Pot Plant

Chrysanthemum (Dendranthema grandiflora) is a leading commercial flower crop from asteraceae family grown for cut and loose flowers and also as a pot plant. It is preferred practically due to vast range of shapes and size of flowers, brilliance of colour tones, long lasting floret life, diversity of height and growth habit of the plant, especially hardy nature, relative ease to grow all the year round and versatility of use. Biofertilizers are the multiplied live cells of beneficial strains of micro-organism, are used as biological nitrogen fixers, Phosphate solubilizing, and also used for mineralization of nitrogen and transformation of several elements like sulphur and iron etc. into available forms. The present investigation was conducted at the Horticulture experimental field of Janta College, Bakewar in Complete Randomize Design with 4 treatments and 4 replications. Observations were recorded for vegetative and floral traits upon various biofertilizers treatments viz., T1: Control, T2: (FYM 50% + Soil 50% + 2gm PSB @Per pot), T3 : (FYM 50% + Soil 50% + 2gm Azotobacter @Per pot) and T4: (FYM 50% + Soil 50% + 1gm PSB + 1g Azotobacter@Per pot).

scholarly journals Heterotrophic bacterial diazotrophs are more abundant than their cyanobacterial counterparts in metagenomes covering most of the sunlit ocean

2021 ◽  
Author(s):  
Tom O. Delmont ◽  
Juan Jose Pierella Karlusich ◽  
Iva Veseli ◽  
Jessika Fuessel ◽  
A. Murat Eren ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Nitrogen Balance ◽  
Large Scale ◽  
Current View ◽  
Low Oxygen ◽  
Nitrogen Fixers ◽  
Large Size ◽  
Genomic Characterization ◽  
Biological Nitrogen ◽  
Nifh Genes

Biological nitrogen fixation is a major factor contributing to microbial primary productivity in the open ocean. The current view depicts a few cyanobacterial diazotrophs as the most relevant marine nitrogen fixers, whereas heterotrophic diazotrophs are more diverse and considered to have lower impacts on the nitrogen balance. Here, we used 891 Tara Oceans metagenomes to create a manually curated, non-redundant genomic database corresponding to free-living, as well as filamentous, colony-forming, particle-attached and symbiotic bacterial and archaeal populations occurring in the surface of five oceans and two seas. Notably, the database provided the genomic content of eight cyanobacterial diazotrophs including Trichodesmium populations and a newly discovered population similar to Richelia, as well as 40 heterotrophic bacterial diazotrophs organized into three main functional groups that considerably expand the known diversity of abundant marine nitrogen fixers compared to previous genomic surveys. Critically, these 48 populations may account for more than 90% of cells containing known nifH genes and occurring in the sunlit ocean, suggesting that the genomic characterization of the most abundant marine diazotrophs may be nearing completion. The newly identified heterotrophic bacterial diazotrophs are widespread, express their nifH genes in situ, and co-occur under nitrate-depleted conditions in large size fractions where they might form aggregates providing the low-oxygen microenvironments required for nitrogen fixation. Most significantly, we found heterotrophic bacterial diazotrophs to be more abundant than cyanobacterial diazotrophs in most metagenomes from the open oceans and seas. This large-scale environmental genomic survey emphasizes the considerable potential of heterotrophs in the marine nitrogen balance.

scholarly journals Framework for community functioning: synthesis of stress gradient and resource partitioning concepts

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3885 ◽  
Author(s):  
Sophia I. Passy
Keyword(s):  
Resource Partitioning ◽  
Stress Gradient ◽  
Variance Partitioning ◽  
Spatial Effects ◽  
Positive Direction ◽  
Nitrogen Fixers ◽  
Spatial Mechanisms ◽  
Abundance Patterns ◽  
Low Profile ◽  
Motile Species

To understand how communities function and generate abundance, I develop a framework integrating elements from the stress gradient and resource partitioning concepts. The framework suggests that guild abundance depends on environmental and spatial factors but also on inter-guild interactions (competitor or facilitator richness), which can alter the fundamental niche of constituent species in negative (competition) or positive direction (facilitation). Consequently, the environmental and spatial mechanisms driving guild abundance would differ across guilds and interaction modes. Using continental data on stream diatoms and physico-chemistry, the roles of these mechanisms were tested under three interaction modes—shared preference, distinct preference, and facilitative, whereby pairs of guilds exhibited, respectively, a dominance-tolerance tradeoff along a eutrophication gradient, specialization along a pH gradient, or a donor-recipient relationship along a nitrogen gradient. Representative of the shared preference mode were the motile (dominant) and low profile (tolerant) guilds, of the distinct preference mode—the acidophilous and alkaliphilous (low profile) guilds, and of the facilitative mode—nitrogen fixers (donors) and motile species (recipients). In each mode, the influences of environment, space (latitude and longitude), and competitor or facilitator richness on guild density were assessed by variance partitioning. Pure environment constrained most strongly the density of the dominant, the acidophilous, and the recipient guild in the shared preference, distinct preference, and facilitative mode, respectively, while spatial effects were important only for the low profile guild. Higher competitor richness was associated with lower density of the tolerant guild in the shared preference mode, both guilds in the distinct preference mode, and the donor guild in the facilitative mode. Conversely, recipient density in the facilitative mode increased with donor richness in stressful nitrogen-poor environments. Thus, diatom guild abundance patterns were determined primarily by biotic and/or environmental impacts and, with the exception of the low profile guild, were insensitive to spatial effects. This framework identifies major sources of variability in diatom guild abundance with implications for the understanding of biodiversity-ecosystem functioning.

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