scholarly journals Contrasting metabolic strategies of two co-occurring deep-sea octocorals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Rakka ◽  
S. R. Maier ◽  
D. Van Oevelen ◽  
A. Godinho ◽  
M. Bilan ◽  
...  
Keyword(s):  
Deep Sea ◽  
Experimental Approach ◽  
Food Sources ◽  
Coral Tissue ◽  
Organic C ◽  
Physiological Processes ◽  
Feeding Biology ◽  
Ecological Implications ◽  
C And N ◽  
Metabolic Strategies

AbstractThe feeding biology of deep-sea octocorals remains poorly understood, as attention is more often directed to reef building corals. The present study focused on two common deep-water octocoral species in the Azores Archipelago, Dentomuricea aff. meteor and Viminella flagellum, aiming at determining their ability to exploit different food sources. We adopted an experimental approach, with three different food sources, including live phytoplankton, live zooplankton and dissolved organic matter (DOM), that were artificially enriched with 13C and 15N (C and N tracers). The presence of tracers was subsequently followed in the coral tissue, C respiration and particulate organic C and N (POC and PON) release. In both species, feeding with zooplankton resulted in significantly higher incorporation of tracers in all measured variables, compared to the other food sources, highlighting the importance of zooplankton for major physiological processes. Our results revealed contrasting metabolic strategies between the two species, with D. aff. meteor acquiring higher amounts of prey and allocating higher percentage to respiration and release of POC and PON than V. flagellum. Such metabolic differences can shape species fitness and distributions and have further ecological implications on the ecosystem function of communities formed by different octocoral species.

Manipulation of rhizosphere organisms to enhance glomalin production and C sequestration: Pitfalls and promises

2014 ◽  
Vol 94 (6) ◽  
pp. 1025-1032 ◽  
Author(s):  
F. L. Walley ◽  
A. W. Gillespie ◽  
Adekunbi B. Adetona ◽  
J. J. Germida ◽  
R. E. Farrell
Keyword(s):  
Plant Growth ◽  
Mycorrhizal Fungi ◽  
Plant Growth Promoting Rhizobacteria ◽  
C Sequestration ◽  
Ionization Mass ◽  
Edge Structure ◽  
Organic C ◽  
Soil C ◽  
N Storage ◽  
C And N

Walley, F. L., Gillespie, A. W., Adetona, A. B., Germida, J. J. and Farrell, R. E. 2014. Manipulation of rhizosphere organisms to enhance glomalin production and C-sequestration: Pitfalls and promises. Can. J. Plant Sci. 94: 1025–1032. Arbuscular mycorrhizal fungi (AMF) reportedly produce glomalin, a glycoprotein that has the potential to increase soil carbon (C) and nitrogen (N) storage. We hypothesized that interactions between rhizosphere microorganisms, such as plant growth-promoting rhizobacteria (PGPR), and AMF, would influence glomalin production. Our objectives were to determine the effects of AMF/PGPR interactions on plant growth and glomalin production in the rhizosphere of pea (Pisum sativum L.) with the goal of enhancing C and N storage in the rhizosphere. One component of the study focussed on the molecular characterization of glomalin and glomalin-related soil protein (GRSP) using complementary synchrotron-based N and C X-ray absorption near-edge structure (XANES) spectroscopy, pyrolysis field ionization mass spectrometry (Py-FIMS), and proteomics techniques to characterize specific organic C and N fractions associated with glomalin production. Our research ultimately led us to conclude that the proteinaceous material extracted, and characterized in the literature, as GRSP is not exclusively of AMF origin. Our research supports the established concept that GRSP is important to soil quality, and C and N storage, irrespective of origin. However, efforts to manipulate this important soil C pool will remain compromised until we more clearly elucidate the chemical nature and origin of this resource.

scholarly journals Perennial herbaceous legumes as live soil mulches and their effects on C, N and P of the microbial biomass

2003 ◽  
Vol 60 (1) ◽  
pp. 139-147 ◽  
Author(s):  
Gustavo Pereira Duda ◽  
José Guilherme Marinho Guerra ◽  
Marcela Teixeira Monteiro ◽  
Helvécio De-Polli ◽  
Marcelo Grandi Teixeira
Keyword(s):  
Microbial Biomass ◽  
Soil Depth ◽  
Vegetation Management ◽  
Pueraria Phaseoloides ◽  
Organic C ◽  
Arachis Pintoi ◽  
Factorial Combination ◽  
C And N ◽  
Microbial C ◽  
Macroptilium Atropurpureum

The use of living mulch with legumes is increasing but the impact of this management technique on the soil microbial pool is not well known. In this work, the effect of different live mulches was evaluated in relation to the C, N and P pools of the microbial biomass, in a Typic Alfisol of Seropédica, RJ, Brazil. The field experiment was divided in two parts: the first, consisted of treatments set in a 2 x 2 x 4 factorial combination of the following factors: live mulch species (Arachis pintoi and Macroptilium atropurpureum), vegetation management after cutting (leaving residue as a mulch or residue remotion from the plots) and four soil depths. The second part had treatments set in a 4 x 2 x 2 factorial combination of the following factors: absence of live mulch, A. pintoi, Pueraria phaseoloides, and M. atropurpureum, P levels (0 and 88 kg ha-1) and vegetation management after cutting. Variation of microbial C was not observed in relation to soil depth. However, the amount of microbial P and N, water soluble C, available C, and mineralizable C decreased with soil depth. Among the tested legumes, Arachis pintoi promoted an increase of microbial C and available C content of the soil, when compared to the other legume species (Pueraria phaseoloides and Macroptilium atropurpureum). Keeping the shoot as a mulch promoted an increase on soil content of microbial C and N, total organic C and N, and organic C fractions, indicating the importance of this practice to improve soil fertility.

scholarly journals Trophic state of benthic deep-sea ecosystems from two different continental margins off Iberia

2013 ◽  
Vol 10 (5) ◽  
pp. 2945-2957 ◽  
Author(s):  
A. Dell'Anno ◽  
A. Pusceddu ◽  
C. Corinaldesi ◽  
M. Canals ◽  
S. Heussner ◽  
...  
Keyword(s):  
Organic Matter ◽  
Water Depth ◽  
Surface Waters ◽  
Deep Sea ◽  
Nutritional Value ◽  
Trophic State ◽  
Phytoplankton Bloom ◽  
Continental Margins ◽  
Organic C ◽  
Deep Sea Sediments

Abstract. The bioavailability of organic matter in benthic deep-sea ecosystems, commonly used to define their trophic state, can greatly influence key ecological processes such as biomass production and nutrient cycling. Here, we assess the trophic state of deep-sea sediments from open slopes and canyons of the Catalan (NW Mediterranean) and Portuguese (NE Atlantic) continental margins, offshore east and west Iberia, respectively, by using a biomimetic approach based on enzymatic digestion of protein and carbohydrate pools. Patterns of sediment trophic state were analyzed in relation to increasing water depth, including repeated samplings over a 3 yr period in the Catalan margin. Two out of the three sampling periods occurred a few months after dense shelf water cascading events. The benthic deep-sea ecosystems investigated in this study were characterized by high amounts of bioavailable organic matter when compared to other deep-sea sediments. Bioavailable organic matter and its nutritional value were significantly higher in the Portuguese margin than in the Catalan margin, thus reflecting differences in primary productivity of surface waters reported for the two regions. Similarly, sediments of the Catalan margin were characterized by significantly higher food quantity and quality in spring, when the phytoplankton bloom occurs in surface waters, than in summer and autumn. Differences in the benthic trophic state of canyons against open slopes were more evident in the Portuguese than in the Catalan margin. In both continental margins, bioavailable organic C concentrations did not vary or increase with increasing water depth. Overall, our findings suggest that the intensity of primary production processes along with the lateral transfer of organic particles, even amplified by episodic events, can have a role in controlling the quantity and distribution of bioavailable organic detritus and its nutritional value along these continental margin ecosystems.

scholarly journals Opportunistic feeding on various organic food sources by the cold-water coral <i>Lophelia pertusa</i>

2014 ◽  
Vol 11 (1) ◽  
pp. 123-133 ◽  
Author(s):  
C. E. Mueller ◽  
A. I. Larsson ◽  
B. Veuger ◽  
J. J. Middelburg ◽  
D. van Oevelen
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
De Novo ◽  
Cold Water ◽  
Feeding Strategy ◽  
Food Sources ◽  
Coral Tissue ◽  
Lophelia Pertusa ◽  
Opportunistic Feeding ◽  
Water Coral

Abstract. The ability of the cold-water coral Lophelia pertusa to exploit different food sources was investigated under standardized conditions in a flume. The tested food sources, dissolved organic matter (DOM, added as dissolved free amino acids), bacteria, algae, and zooplankton (Artemia) were deliberately enriched in 13C and 15N. The incorporation of 13C and 15N was traced into bulk tissue, fatty acids, hydrolysable amino acids, and the skeleton (13C only) of L. pertusa. Incorporation rates of carbon (ranging from 0.8–2.4 μg C g−1 DW d–1) and nitrogen (0.2–0.8 μg N g−1 DW d–1) into coral tissue did not differ significantly among food sources indicating an opportunistic feeding strategy. Although total food assimilation was comparable among sources, subsequent food processing was dependent on the type of food source ingested and recovery of assimilated C in tissue compounds ranged from 17% (algae) to 35% (Artemia). De novo synthesis of individual fatty acids by L. pertusa occurred in all treatments as indicated by the 13C enrichment of individual phospholipid-derived fatty acids (PLFAs) in the coral that were absent in the added food sources. This indicates that the coral might be less dependent on its diet as a source of specific fatty acids than expected, with direct consequences for the interpretation of in situ observations on coral nutrition based on lipid profiles.

scholarly journals Arsenic speciation in food chains from mid-Atlantic hydrothermal vents

2012 ◽  
Vol 9 (2) ◽  
pp. 130 ◽  
Author(s):  
Vivien F. Taylor ◽  
Brian P. Jackson ◽  
Matthew R. Siegfried ◽  
Jana Navratilova ◽  
Kevin A. Francesconi ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Deep Sea ◽  
Hydrothermal Vents ◽  
Arsenic Speciation ◽  
Inorganic Arsenic ◽  
Food Sources ◽  
Arsenic Compounds ◽  
Marine Animals ◽  
Δ13c And Δ15n ◽  
Organic Arsenic

Environmental contextArsenic occurs in marine organisms at high levels and in many chemical forms. A common explanation of this phenomenon is that algae play the central role in accumulating arsenic by producing arsenic-containing sugars that are then converted into simpler organic arsenic compounds found in fish and other marine animals. We show that animals in deep-sea vent ecosystems, which are uninhabited by algae, contain the same organic arsenic compounds as do pelagic animals, indicating that algae are not the only source of these compounds. AbstractArsenic concentration and speciation were determined in benthic fauna collected from the Mid-Atlantic Ridge hydrothermal vents. The shrimp species, Rimicaris exoculata, the vent chimney-dwelling mussel, Bathymodiolus azoricus, Branchipolynoe seepensis, a commensal worm of B. azoricus and the gastropod Peltospira smaragdina showed variations in As concentration and in stable isotope (δ13C and δ15N) signature between species, suggesting different sources of As uptake. Arsenic speciation showed arsenobetaine to be the dominant species in R. exoculata, whereas in B. azoricus and B. seepensis arsenosugars were most abundant, although arsenobetaine, dimethylarsinate and inorganic arsenic were also observed, along with several unidentified species. Scrape samples from outside the vent chimneys covered with microbial mat, which is a presumed food source for many vent organisms, contained high levels of total As, but organic species were not detectable. The formation of arsenosugars in pelagic environments is typically attributed to marine algae, and the pathway to arsenobetaine is still unknown. The occurrence of arsenosugars and arsenobetaine in these deep sea organisms, where primary production is chemolithoautotrophic and stable isotope analyses indicate food sources are of vent origin, suggests that organic arsenicals can occur in a foodweb without algae or other photosynthetic life.

Soil organic carbon and nitrogen sequestration and turnover in aggregates under subtropical leucaena–grass pastures

Soil Research ◽  
2018 ◽  
Vol 56 (6) ◽  
pp. 632 ◽  
Author(s):  
Kathryn Conrad ◽  
Ram C. Dalal ◽  
Ryosuke Fujinuma ◽  
Neal W. Menzies
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Soil Aggregates ◽  
Soil Mass ◽  
Δ13c And Δ15n ◽  
Organic C ◽  
Carbon And Nitrogen ◽  
Nitrogen Sequestration ◽  
C And N

Stabilisation and protection of soil organic carbon (SOC) in macroaggregates and microaggregates represents an important mechanism for the sequestration of SOC. Legume-based grass pastures have the potential to contribute to aggregate formation and stabilisation, thereby leading to SOC sequestration. However, there is limited research on the C and N dynamics of soil organic matter (SOM) fractions in deep-rooted legume leucaena (Leucaena leucocephala)–grass pastures. We assessed the potential of leucaena to sequester carbon (C) and nitrogen (N) in soil aggregates by estimating the origin, quantity and distribution in the soil profile. We utilised a chronosequence (0–40 years) of seasonally grazed leucaena stands (3–6 m rows), which were sampled to a depth of 0.3 m at 0.1-m intervals. The soil was wet-sieved for different aggregate sizes (large macroaggregates, >2000 µm; small macroaggregates, 250–2000 µm; microaggregates, 53–250 µm; and <53 µm), including occluded particulate organic matter (oPOM) within macroaggregates (>250 µm), and then analysed for organic C, N and δ13C and δ15N. Leucaena promoted aggregation, which increased with the age of the leucaena stands, and in particular the formation of large macroaggregates compared with grass in the upper 0.2 m. Macroaggregates contained a greater SOC stock than microaggregates, principally as a function of the soil mass distribution. The oPOM-C and -N concentrations were highest in macroaggregates at all depths. The acid nonhydrolysable C and N distribution (recalcitrant SOM) provided no clear distinction in stabilisation of SOM between pastures. Leucaena- and possibly other legume-based grass pastures have potential to sequester SOC through stabilisation and protection of oPOM within macroaggregates in soil.

scholarly journals Oogenesis and lipid metabolism in the deep-sea sponge Phakellia ventilabrum: an histological, lipidomic and transcriptomic approach

2021 ◽  
Author(s):  
Vasiliki Koutsouveli ◽  
David Balgoma ◽  
Antonia Checa ◽  
Mikael Hedeland ◽  
Ana Riesgo ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Lipid Metabolism ◽  
Deep Sea ◽  
Expression Patterns ◽  
Rna Seq ◽  
Beta Oxidation ◽  
Animal Reproduction ◽  
Physiological Processes ◽  
Key Species ◽  
Fatty Acid Beta Oxidation

Abstract Background Sponges contain an astounding diversity of lipids which serve in several biological functions, including yolk formation in their oocytes and the embryos. On animal reproduction, lipids constitute one of the main energy storage forms for the adult and the offspring. The study of lipid metabolism during reproduction can provide information on food-web dynamics and energetic needs of the populations in their habitats, however, there are no studies focusing on the lipid metabolism of sponges during seasonal reproduction. The deep-sea sponge Phakellia ventilabrum (Demospongiae, Bubarida) is a key species of North-Atlantic sponge grounds, but its reproductive biology is not known. In this study, we used histological sections, lipidome profiling (UHPLC-MS), and transcriptomic analysis (RNA-seq) with goal to i. assess the reproductive strategy and seasonality of this species, ii. examine the relative changes in the lipidome signal, and the gene expression patterns (RNA-seq) of enzymes participating in lipid metabolism in female specimens during gametogenesis.Results P. ventilabrum is an oviparous and most certainly gonochoristic species, reproducing in May and September in the different studied areas. Half of specimens were reproducing, generating two to five oocytes per mm2. Oocytes accumulated both protein and lipid droplets. As oogenesis progressed, the signal of most of the unsaturated and monounsaturated triacylglycerides increased, as well as of few other phospholipids. Most of the other lipids and especially those with > 3 unsaturations showed a decrease in signal during the oocyte maturation. In parallel, we detected upregulated genes in female tissues related to triacylglyceride biosynthesis and others related to fatty acid beta-oxidation.Conclusions Triacylglycerides are probably the main type of lipid forming the yolk since this lipid category has the most marked changes, while some other phospholipids may also have a role in oogenesis. In parallel, other lipid categories were oxidized, leading to fatty acid beta-oxidation to cover the energy requirements of female individuals during oogenesis. Variations in the signal of most lipids between the different locations and months suggest that sponges, apart from their own mechanisms of lipid biosynthesis, exploit the food availability in their surroundings to cover the energetic demands in their physiological processes.

scholarly journals Microbial soil characteristics of grassland and arable soils linked to thermogravimetry data: correlations, use and limits

2021 ◽  
Author(s):  
Helena Doležalová-Weissmannová ◽  
Stanislav Malý ◽  
Martin Brtnický ◽  
Jiří Holátko ◽  
Michael Scott Demyan ◽  
...  
Keyword(s):  
Soil Properties ◽  
Soil Parameters ◽  
Organic Carbon Content ◽  
Regression Equations ◽  
Arable Soils ◽  
Grassland Soils ◽  
Simple Method ◽  
Organic C ◽  
Mass Losses ◽  
C And N

Abstract. Thermogravimetry (TG) is a simple method that enables rapid analysis of soil properties such as the content of total organic C, nitrogen, clay and C fractions with different stability. However, the possible link between TG data and microbiological soil properties has not been systematically tested yet and limits TG application for soil and soil organic matter assessment. This work aimed to search and to validate relationships of thermal mass losses (TML) to total C and N contents, microbial biomass C and N, basal and substrate-induced respiration, extractable organic carbon content, anaerobic ammonification, urease activity, short-term nitrification activity, specific growth rate, and time to reach the maximum respiration rate for two sample sets of arable and grassland soils. Analyses of the training soil set revealed significant correlations of TML with basic soil properties such as carbon and nitrogen content with distinguishing linear regression parameters and temperatures of correlating mass losses for arable and grassland soils. In a second stage the equations of significant correlations were used for validation with an independent second sample set. This confirmed applicability of developed equations for prediction of microbiological properties mainly for arable soils. For grassland soils was the applicability lower, which was explained as the influence of rhizosphere processes. Nevertheless, the application of TG can facilitate the understanding of changes in soil caused by microorganism’s activity and the different regression equations between TG and soil parameters reflect changes in proportions between soil components caused by land use management.

Sign in / Sign up

Export Citation Format

Share Document