Microbial Interactions with Dissolved Organic Matter Are Central to Coral Reef Ecosystem Function and Resilience

Annual Review of Marine Science, Journal Year: 2022, Volume and Issue: 15(1), P. 431 - 460

Published: Sept. 13, 2022

To thrive in nutrient-poor waters, coral reefs must retain and recycle materials efficiently. This review centers microbial processes facilitating the persistence stability of reefs, specifically role these transforming recycling dissolved organic matter (DOM) that acts as an invisible currency reef production, nutrient exchange, organismal interactions. The defining characteristics including high productivity, balanced metabolism, biodiversity, retention, structural complexity, are inextricably linked to processing DOM. composition microbes DOM is summarized, spatial temporal dynamics biogeochemical carried out by microorganisms diverse habitats explored a variety key processes, decomposition, accretion, trophictransfer, macronutrient recycling. Finally, we examine how widespread habitat degradation altering important microbe–DOM interactions, creating feedbacks reduce resilience global change.

Language: Английский

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Partitioning of the denitrification pathway and other nitrite metabolisms within global oxygen deficient zones

ISME Communications, Journal Year: 2023, Volume and Issue: 3(1)

Published: July 20, 2023

Abstract Oxygen deficient zones (ODZs) account for about 30% of total oceanic fixed nitrogen loss via processes including denitrification, a microbially mediated pathway proceeding stepwise from NO3− to N2. This process may be performed entirely by complete denitrifiers capable all four enzymatic steps, but many organisms possess only partial denitrification pathways, either producing or consuming key intermediates such as the greenhouse gas N2O. Metagenomics and marker gene surveys have revealed diversity genes within ODZs, whether these co-occur identities denitrifying taxa remain open questions. We assemble genomes metagenomes spanning ETNP Arabian Sea, map metagenome-assembled (MAGs) 56 three major ODZs reveal predominance denitrifiers, particularly single-step denitrifiers. find niche differentiation among nitrogen-cycling organisms, with communities performing each transformation distinct in taxonomic identity motility traits. Our collection 962 MAGs presents largest pelagic ODZ microorganisms reveals clearer picture cycling community this environment.

Language: Английский

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Denitrifying bacteria respond to and shape microscale gradients within particulate matrices

Communications Biology, Journal Year: 2021, Volume and Issue: 4(1)

Published: May 13, 2021

Abstract Heterotrophic denitrification enables facultative anaerobes to continue growing even when limited by oxygen (O 2 ) availability. Particles in particular provide physical matrices characterized reduced O permeability well-oxygenated bulk conditions, creating microenvironments where microbial denitrifiers may proliferate. Whereas numerical particle models generally describe as a function of radius, here we evidence for heterogeneity intraparticle activity due local interactions within and among microcolonies. Pseudomonas aeruginosa cells microcolonies act metabolically shade each other, fostering anaerobic processes just microns from -saturated water. Even fluid, suboxia reproducibly developed migrated along sharp 10 100 µm gradients, driven the balance oxidant diffusion respiration. Moreover, metabolic differentiation densely packed is dictated diffusional supply , leading distinct bimodality distribution nitrate nitrite reductase expression. The initial seeding density controls speed at which anoxia develops, particles seeded with few bacteria remain capable becoming anoxic. Our empirical results capture dynamics denitrifier gene expression direct association concentrations over microscale matrices, providing observations co-occurrence spatial arrangement aerobic processes.

Language: Английский

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Nitrite accumulation and anammox bacterial niche partitioning in Arctic Mid-Ocean Ridge sediments

ISME Communications, Journal Year: 2023, Volume and Issue: 3(1)

Published: March 29, 2023

Abstract By consuming ammonium and nitrite, anammox bacteria form an important functional guild in nitrogen cycling many environments, including marine sediments. However, their distribution impact on the substrate nitrite has not been well characterized. Here we combined biogeochemical, microbiological, genomic approaches to study other groups two sediment cores retrieved from Arctic Mid-Ocean Ridge (AMOR). We observed accumulation these cores, a phenomenon also recorded at 28 sites analogous aquatic environments. The maximum coincides with reduced abundance of bacteria. Anammox bacterial abundances were least one order magnitude higher than those reducers maxima detected layers above below maximum. Nitrite AMOR co-occurs niche partitioning between families (Candidatus Bathyanammoxibiaceae Candidatus Scalinduaceae), likely dependent availability. Through reconstructing comparing dominant genomes (Ca. Bathyanammoxibius amoris Ca. Scalindua sediminis), revealed that B. fewer high-affinity transporters S. sediminis lacks capacity access alternative substrates and/or energy sources such as urea cyanate. These features may restrict conditions concentrations. findings improve our understanding about sediments by revealing coincident

Language: Английский

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Greenhouse Gas Emissions from Salt-Affected Soils: Mechanistic Understanding of Interplay Factors and Reclamation Approaches

Sustainability, Journal Year: 2022, Volume and Issue: 14(19), P. 11876 - 11876

Published: Sept. 21, 2022

Salt-affected soils contain high levels of soluble salts (saline soil) and exchangeable sodium (alkali soil). Globally, about 932 million ha (Mha), including 831 Mha agricultural land, is salt-affected. Salinity sodicity adversely affect soil microbial diversity enzymatic activities, thereby carbon nitrogen dynamics greenhouse gas (GHG) emissions from soils. In this review article, we synthesize published information to understand the impact salinity on GHG production salt-affected soils, how various reclamation amendments (gypsum, phosphogypsum, organic manure, biochar, etc.) reclaimed Nitrous oxide (N2O) methane (CH4) are greater concern due their 298 28 times higher global warming potential, respectively, compared dioxide (CO2), a 100-year time scale. Therefore, CO2 given negligible/smaller significance other two. Generally, nitrous at lower reduced mainly to: (a) ammonification nitrification resulting in substrate for denitrification; (b) denitrifying bacteria lowered down microbial-mediated denitrification process; (c) dissimilatory nitrate reduction ammonium (DNRA), processes compete with each common substrate/nitrate. Overall, normal than those High suppresses activity both methanogens (CH4 production) methanotrophs consumption). However, it imposes more inhibitory effects methanotrophs, CH4 subsequent these may enhance N2O emissions. gypsum best agent, which significantly mitigates paddy cultivation sodic non-sodic mitigation rate its application. Gypsum amendment increases sulfate ion concentrations reduces inhibition methanogenesis by reductase enhancement redox potential. Biochar also good among mitigating emission The application fresh matter FYM This suggests need systematic investigations studying impacts technologies order develop low that can sequestration potential

Language: Английский

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Divergent responses of the coral holobiont to deoxygenation and prior environmental stress

Frontiers in Marine Science, Journal Year: 2024, Volume and Issue: 10

Published: Feb. 1, 2024

Ocean deoxygenation is intensifying globally due to human activities – and emerging as a grave threat coral reef ecosystems where it can cause bleaching mass mortality. However, one of many threats reefs, making essential understand how prior environmental stress may influence responses deoxygenation. To address this question, we examined the holobiont (i.e., host, Symbiodiniaceae, microbiome) in corals with different backgrounds. We outplanted Acropora cervicornis fragments known genotypes from an situ nursery two sites Florida Keys spanning inshore-offshore gradient. After four months, were transferred laboratory, tested differences survivorship, tissue loss, photosynthetic efficiency, Symbiodiniaceae cell density, microbiome composition after persistent exposure oxygen treatments ranging extreme (0.5 mg L -1 ) normoxia (6 ). found that, for short duration study (four days), entire was resistant dissolved (DO) concentrations low 2.0 , but that members decoupled at 0.5 . In most treatment, host showed decreased mortality, lower densities response, microbial taxa remained stable. Although did not major community shifts composition, population abundance some respond. Site history influenced endosymbiont, microbiome, more stressful inshore site showing greater susceptibility subsequent Our reveals respond differently deoxygenation, sensitivity resistance decrease tolerance

Language: Английский

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A genome-centric view of the role of the Acropora kenti microbiome in coral health and resilience

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: April 4, 2024

Abstract Microbial diversity has been extensively explored in reef-building corals. However, the functional roles of coral-associated microorganisms remain poorly elucidated. Here, we recover 191 bacterial and 10 archaeal metagenome-assembled genomes (MAGs) from coral Acropora kenti (formerly A. tenuis ) adjacent seawater, to identify microbial functions metabolic interactions within holobiont. We show that 82 MAGs were specific holobiont, including members Pseudomonadota, Bacteroidota, Desulfobacterota. -specific displayed significant differences their genomic features potential relative seawater-specific MAGs, with a higher prevalence genes involved host immune system evasion, nitrogen carbon fixation, synthesis five essential B-vitamins. find encode biosynthesis amino acids, such as tryptophan, histidine, lysine, which cannot be de novo synthesised by or Symbiodiniaceae. Across water quality gradient spanning 2° latitude, community composition is correlated increased temperature dissolved inorganic nitrogen, corresponding enrichment molecular chaperones, nitrate reductases, heat-shock protein. reveal mechanisms -microbiome-symbiosis on Great Barrier Reef, highlighting underpinning health this keystone

Language: Английский

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Differential resistance and acclimation of two coral species to chronic nutrient enrichment reflect life‐history traits

Functional Ecology, Journal Year: 2021, Volume and Issue: 35(5), P. 1081 - 1093

Published: Feb. 27, 2021

Abstract The effects of nutrient pollution on coral reef ecosystems are multifaceted. Numerous experiments have sought to identify the physiological enrichment reef‐building corals, but results been variable and sensitive choices quantity, chemical composition exposure duration. To test chronic, ecologically relevant growth photophysiology, we conducted a 5‐week continuous dosing experiment two Hawaiian species, Porites compressa Pocillopora acuta . We acclimated fragments five concentrations (0.1–7 µM 0.06–2.24 ) with constant stoichiometry 2.5:1 nitrate phosphate) bracketing in situ observations from reefs throughout Pacific. Nutrient linearly increased photophysiological performance both species within 3 weeks. effect nutrients P. photochemical efficiency through time while consistent response indicated acclimation elevated 5 Endosymbiont densities total chlorophyll also proportionally , not revealing contrasting patterns host–symbiont acclimatization. exhibited skeletal growth. Calcification was enhanced at low (1 comparable control higher concentrations, whereas calcification reduced (30%–35%) above Stable isotope analysis revealed species‐specific nitrogen uptake dynamics coral–algal symbiosis. endosymbionts (decreased δ 15 N) incorporation (19%–31% decrease C:N ratios) across treatments. In contrast, maintained N values levels (9%–11% ratios). inability regulate endosymbiont may indicate an emerging destabilization symbiosis under that could compromise resistance additional environmental stressors. Our highlight differences symbiosis, which influence responses chronic enrichment. These findings showcase how symbioses can vary among closely related taxa underscore importance considering life‐history traits modify change. A free Plain Language Summary be found Supporting Information this article.

Language: Английский

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Holobiont nitrogen control and its potential for eutrophication resistance in an obligate photosymbiotic jellyfish

Microbiome, Journal Year: 2021, Volume and Issue: 9(1)

Published: June 2, 2021

Abstract Background Marine holobionts depend on microbial members for health and nutrient cycling. This is particularly evident in cnidarian-algae symbioses that facilitate energy acquisition. However, this partnership highly sensitive to environmental change—including eutrophication—that causes dysbiosis contributes global coral reef decline. Yet, some exhibit resistance eutrophic environments, including the obligate photosymbiotic scyphomedusa Cassiopea xamachana . Methods Our aim was assess mechanisms C. stabilize symbiotic relationships. We combined labelled bicarbonate ( 13 C) nitrate 15 N) with metabarcoding approaches evaluate cycling community composition aposymbiotic medusae. Results C-fixation by algal Symbiodiniaceae essential as even at high heterotrophic feeding rates medusae continuously lost weight. Heterotrophically acquired C N were readily shared among host algae. sharp contrast assimilation Symbiodiniaceae, which appeared be strongly restricted. Instead, bacterial microbiome seemed play a major role holobiont’s DIN uptake showed significant positive relationship phylogenetic diversity of medusa-associated bacteria. corroborated inferred functional capacity links dominant taxa (~90 %) nitrogen Observed structure differed between apo- putatively highlighting enrichment ammonium oxidizers nitrite reducers depletion nitrogen-fixers Conclusion Host, symbionts, associates contribute regulated xamachana. found seemingly structured increase removal enforce N-limitation—a mechanism would help host-algae under conditions.

Language: Английский

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How Symbiodiniaceae meets the challenges of life during coral bleaching

Coral Reefs, Journal Year: 2021, Volume and Issue: 40(4), P. 1339 - 1353

Published: June 15, 2021

Language: Английский

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