Ocean acidification (OA) driven by increasing atmospheric CO2 is altering marine biodiversity. However, impacts of OA on ecosystem functioning at the community level, including calcification, primary production and nutrient uptake, remain largely unknown. Here, we conducted community transplant experiments at natural CO2 vents to assess how declining pH affects marine community species composition, biomass, and key ecosystem processes over time. Our results indicate that community shifts caused by declining pH lead to decreased biomass and calcification rates, while photosynthesis and nutrient uptake rates increased. By leveraging OA field model systems and in situ measurements of ecosystem functioning, this study provides critical insights into how OA-induced biodiversity loss reshapes the structure and functioning of temperate marine coastal ecosystems.
Continue reading ‘Unravelling marine benthic functioning shifts under ocean acidification’Posts Tagged 'porifera'
Unravelling marine benthic functioning shifts under ocean acidification
Published 10 April 2026 Science Leave a CommentTags: algae, biological response, BRcommunity, calcification, community composition, crustaceans, field, Mediterranean, mollusks, morphology, otherprocess, photosynthesis, physiology, porifera, respiration, vents
Metabolic rate measurements of two benthic invertebrates under simulated climate change conditions
Published 30 March 2026 Science ClosedTags: adaptation, biological response, laboratory, Mediterranean, mollusks, morphology, multiple factors, otherprocess, porifera, respiration, temperature
Background
Climate change is profoundly altering marine ecosystems through ocean warming and acidification. These stressors are especially pronounced in the Mediterranean Sea, a climate change hotspot projected to warm faster than the global average. Increased temperatures and reduced pH directly affect metabolic processes in marine invertebrates by elevating respiration rates up to species-specific thermal limits, beyond which physiological performance declines. Ocean acidification further disrupts metabolic processes by increasing energetic maintenance costs. Sessile and sedentary marine invertebrates, such as sponges and benthic gastropods, are particularly exposed to such environmental shifts due to their limited ability to escape unfavorable conditions, making physiological plasticity and local adaptation crucial for persistence.
New information
This manuscript presents a dataset of oxygen consumption rates and wet weight measurements for two low-mobility marine species, the gastropod Hexaplex trunculus and the sponge Chondrilla nucula. Using a common garden experiment, individuals from North and South Aegean populations were exposed for three months to simulated climate change conditions combining increased temperature and reduced pH. The dataset documents respiration measurements obtained using metabolic chambers after three months of exposure, allowing comparisons across species, geographic origin, and experimental treatments.The dataset accounts for intraspecific variation in these responses, providing insight into potential adaptive differences among geographically distinct populations. These data provide a resource for future analyses of metabolic responses of marine invertebrates to combined warming and acidification conditions.
Continue reading ‘Metabolic rate measurements of two benthic invertebrates under simulated climate change conditions’Experimental exposure to climate change scenarios imposed alterations on the morphological traits of sessile and low-motility marine invertebrates
Published 24 March 2026 Science ClosedTags: biological response, laboratory, Mediterranean, methods, mollusks, morphology, multiple factors, porifera, temperature
Background
Over the past 50 years, the oceans have absorbed over 90% of global warming heat, leading to warming, acidification and declining oxygen levels that are disrupting marine ecosystems and altering species distributions and productivity. The vulnerability of marine organisms to these changes depends on their biological traits, habitat conditions and adaptive capacity, influencing their growth, behaviour and overall population health. Micro-computed tomography (micro-CT) has been previously used for studying the morphological traits of marine invertebrates, which provide important insights into species functionality and responses to climate change and ocean acidification. Micro-CT enables non-destructive, high-resolution 3D analysis of internal and external structures, allowing precise measurement of traits such as density, porosity and morphology that are valuable for climate change research.
New information
The present manuscript describes micro-CT imaging datasets generated to investigate the effects of climate change on the morphological structure of two benthic marine invertebrates: the low-motility gastropod Hexaplex trunculus (Linnaeus, 1758) and the sessile sponge Chondrilla nucula Schmidt, 1862. Both species are considered particularly vulnerable to environmental stressors. To date, no study has investigated the effects of ocean warming and acidification on sponges using micro-CT technology. Using a common garden experimental design, individuals from geographically distinct populations exposed to different natural environmental regimes were subjected to combined warming and acidification scenarios to assess their morphological responses and adaptive capacity.
Continue reading ‘Experimental exposure to climate change scenarios imposed alterations on the morphological traits of sessile and low-motility marine invertebrates’A standardised experimental setup for simulating ocean warming and acidification in benthic marine invertebrates
Published 26 February 2026 Science ClosedTags: biological response, laboratory, Mediterranean, methods, mollusks, multiple factors, porifera, temperature
Recent studies identify ocean warming and acidification as major drivers of ecological change in the Eastern Mediterranean, posing serious threats to marine biodiversity, particularly for sessile or low-mobility organisms that cannot escape unfavourable conditions. At the same time, the need for standardised experimental approaches capable of generating high-quality data on organismal responses to multiple climate stressors has become increasingly evident. This manuscript presents a fully detailed and replicable experimental framework for simulating ocean warming and acidification in benthic marine invertebrates under controlled laboratory conditions. Detailed protocols include the technical set-up, experimental design, selection of climate scenarios, monitoring procedures and criteria for species selection and demonstrating its application through a validation case study from the MACCIMO project.
Continue reading ‘A standardised experimental setup for simulating ocean warming and acidification in benthic marine invertebrates’Indo-Pacific coral reef sponge diversity declines under predicted future ocean conditions
Published 19 February 2026 Science ClosedTags: abundance, biological response, BRcommunity, community composition, corals, laboratory, mesocosms, multiple factors, North Pacific, otherprocess, porifera, temperature
Future oceans are predicted to favor groups like sponges over calcifying taxa such as scleractinian corals. Here, we test this hypothesis by examining the development of coral reef communities in experimental mesocosms over 23 months. 85 sponge species among the calcifying class Calcarea (~33%), and non-calcifying Demospongiae (~60%) and Homoscleromorpha (<10%) recruited to warming (+2°C), acidification (-0.2 pH), and warming+acidification (+2°C, -0.2 pH) future ocean treatments. The diversity of calcifying sponges was unimpacted across any treatment, whereas non-calcifying classes showed greatest declines. 57-66% of demosponges decreased under future ocean conditions, and homoscleromorphs were entirely absent from acidified treatments. Through the sponge loop, sponges play a fundamental role in coral reef nutrient cycling, and altered coral reef community composition likely has functional consequences. This study challenges the assumption that non-calcifying species are less impacted and highlights the importance of understanding how community composition may alter ecosystem functioning under future ocean conditions.
Continue reading ‘Indo-Pacific coral reef sponge diversity declines under predicted future ocean conditions’Population-level transcriptomic datasets from two benthic invertebrates exposed to long-term experimental warming and acidification
Published 18 February 2026 Science ClosedTags: biological response, laboratory, Mediterranean, molecular biology, mollusks, multiple factors, porifera, temperature
Ocean warming and acidification are major drivers of change in marine ecosystems, with particularly strong impacts on low-mobility benthic organisms. Despite their ecological importance, genomic and transcriptomic resources for sponges (Phylum: Porifera) and marine gastropods (Phylum Mollusca) that capture responses to long-term, combined climate stressors and population-level variability remain limited. Herein, we present population-level RNA-seq datasets from the sponge Chondrilla nucula and the gastropod Hexaplex trunculus, collected from northern and southern Aegean Sea (Eastern Mediterranean) populations and exposed for three months to elevated temperature and reduced pH in a common garden experiment simulating near-future climate change conditions. The datasets comprise high-quality paired-end Illumina reads, a complete de novo transcriptome assembly for C. nucula, and genome-guided alignments for H. trunculus. These datasets provide a valuable resource for investigating transcriptional plasticity and climate change resilience in benthic marine invertebrates.
Continue reading ‘Population-level transcriptomic datasets from two benthic invertebrates exposed to long-term experimental warming and acidification’Metabolic rate measurements of two benthic invertebrates under simulated climate change conditions
Published 16 February 2026 Science ClosedTags: adaptation, biological response, laboratory, Mediterranean, mollusks, morphology, multiple factors, otherprocess, porifera, respiration, temperature
Climate change is profoundly altering marine ecosystems through ocean warming and acidification. These stressors are especially pronounced in the Mediterranean Sea, a climate change hotspot projected to warm faster than the global average. Increased temperatures and reduced pH directly affect metabolic processes in marine invertebrates by elevating respiration rates up to species-specific thermal limits, beyond which physiological performance declines. Ocean acidification further disrupts metabolic processes by increasing energetic maintenance costs. Sessile and sedentary marine invertebrates, such as sponges and benthic gastropods, are particularly exposed to such environmental shifts due to their limited ability to escape unfavorable conditions, making physiological plasticity and local adaptation crucial for persistence.
This manuscript presents a dataset of oxygen consumption rates and wet weight measurements for two low-mobility marine species, the gastropod Hexaplex trunculus and the sponge Chondrilla nucula. Using a common garden experiment, individuals from North and South Aegean populations were exposed for three months to simulated climate change conditions combining increased temperature and reduced pH. The dataset documents respiration measurements obtained using metabolic chambers after three months of exposure, allowing comparisons across species, geographic origin, and experimental treatments.The dataset accounts for intraspecific variation in these responses, providing insight into potential adaptive differences among geographically distinct populations. These data provide a resource for future analyses of metabolic responses of marine invertebrates to combined warming and acidification conditions.
Continue reading ‘Metabolic rate measurements of two benthic invertebrates under simulated climate change conditions’Experimental exposure to climate change scenarios imposed alterations on the morphological traits of sessile and low-motility marine invertebrates
Published 6 February 2026 Science ClosedTags: biological response, laboratory, Mediterranean, methods, mollusks, morphology, multiple factors, porifera, temperature
Over the past 50 years, the oceans have absorbed over 90% of global warming heat, leading to warming, acidification, and declining oxygen levels that are disrupting marine ecosystems and altering species distributions and productivity. The vulnerability of marine organisms to these changes depends on their biological traits, habitat conditions, and adaptive capacity, influencing their growth, behavior, and overall population health. Micro-computed tomography (micro-CT) has been previously used for studying the morphological traits of marine invertebrates, which provide important insights into species functionality and responses to climate change and ocean acidification. Micro-CT enables non-destructive, high-resolution 3D analysis of internal and external structures, allowing precise measurement of traits such as density, porosity, and morphology that are valuable for climate change research.
The present manuscript describes micro-CT imaging datasets generated to investigate the effects of climate change on the morphological structure of two low-motility benthic marine invertebrates: the gastropod Hexaplex trunculus and the sponge Chondrilla nucula. Both species are considered particularly vulnerable to environmental stressors. To date, no study has investigated the effects of ocean warming and acidification on sponges using micro-CT technology. Using a common garden experimental design, individuals from geographically distinct populations exposed to different natural environmental regimes were subjected to combined warming and acidification scenarios to assess their morphological responses and adaptive capacity.
Continue reading ‘Experimental exposure to climate change scenarios imposed alterations on the morphological traits of sessile and low-motility marine invertebrates’Assessing sponge resilience to ocean acidification in natural reef environments
Published 28 January 2026 Science ClosedTags: biological response, BRcommunity, community composition, field, otherprocess, photosynthesis, porifera, prokaryotes, respiration, South Pacific, vents
Highlights
- Sponges are key components of coral reefs globally providing a range of important functional roles.
- We used in situ incubation chambers to measure chlorophyll concentrations, oxygen fluxes and microbial communities for two common Indo-Pacific sponge species (Melophlus sarasinorum and Neopetrosia chaliniformis) at a natural CO2 vent (pHT 7.6–7.7) and control site in Papua New Guinea.
- We found little evidence for any physiological differences between vent and control sponges, and no differences in the overall microbial communities
- Overall, our results support the emerging evidence that heterotrophic sponges will likely be resilient to future ocean acidification.
Abstract
Sponges are key components of coral reefs globally providing a range of important functional roles. While sponges are under threat from the impacts of global climate change, there is an emerging picture of sponge tolerance to ocean acidification (OA). However, to date all physiological studies on sponge tolerance to OA have been under ex-situ experimental conditions and only for a limited number of sponge species. Instead, here we used in situ incubation chambers to measure chlorophyll concentrations and oxygen fluxes for two common Indo-Pacific sponge species (Melophlus sarasinorum and Neopetrosia chaliniformis) at a natural CO2 vent (pHT 7.6–7.7) and control site in Papua New Guinea. We also explored differences between the sponge microbial community composition between control and vent locations for N. chaliniformis. We found very low concentrations of chlorophyll in both species, compared to other sponges, suggesting these species are largely heterotrophic. We also found little evidence for any physiological differences between vent and control sponges, and no differences in the overall microbial communities, except some specific microbes. Overall, our results support the emerging evidence that heterotrophic sponges will likely be resilient to future ocean acidification.
Continue reading ‘Assessing sponge resilience to ocean acidification in natural reef environments’An experimental approach to study climate change stress in benthic marine invertebrates
Published 26 January 2026 Science ClosedTags: biological response, laboratory, Mediterranean, methods, mollusks, multiple factors, porifera, temperature
Climate change is altering ocean temperature and chemistry, with ocean warming and acidification posing serious threats to marine biodiversity, particularly for sessile or low-mobility organisms that cannot escape unfavorable conditions. The MACCIMO project investigated the effects of these stressors on the sponge Chondrilla nucula and the gastropod Hexaplex trunculus using an integrative approach that examined molecular, physiological, morphological, and symbiotic responses. By applying a common garden experiment to populations from different Mediterranean regions, the study aimed to distinguish genetic and environmental influences on stress tolerance and assess intraspecific variability. Three experimental scenarios were simulated, including a control treatment and two climate change treatments based on the “high GHG emissions” RCP 8.5 scenario. A semi-enclosed experimental system with precise control of temperature and pH was designed which can be easily replicated to support laboratory studies on the effects of climate change and ocean acidification on small marine invertebrates across multiple biological levels.
Continue reading ‘An experimental approach to study climate change stress in benthic marine invertebrates’The larva-Symbiodiniaceae association at risk: putative impacts of climate change on reproduction, dispersal, and recruitment in coral reefs
Published 24 November 2025 Science ClosedTags: biological response, BRcommunity, cnidaria, corals, mollusks, physiology, phytoplankton, porifera, reproduction, review
The relationship between invertebrates and Symbiodiniaceae dinoflagellates is the ecological foundation of diverse and productive coral reef ecosystems. Climate change-induced breakdown of this partnership, i.e., bleaching, is repeatedly driving widespread reef degradation. Thus, the future trajectory of this ecosystem depends on the reproduction and dispersal capacity of invertebrate-Symbiodiniaceae symbiosis. This review examines how climate change affects the biology of larvae from three invertebrate phyla—Porifera, Cnidaria, and Mollusca—that host Symbiodiniaceae, focusing on differences in symbiont transmission mode, symbiont location, and the larvae´s reliance on these associations. Due to limited research on Porifera and Mollusca hosts, most knowledge of larvae-Symbiodiniaceae associations stems from coral larvae patterns. The myriads of combinations of genetic and ecophysiologically distinct hosts and symbionts result in highly context-dependent responses to warming, but symbiotic larvae tend to be more susceptible to oxidative stress and show higher mortality than aposymbiotic larvae. While ocean acidification has little direct effect on the algal symbionts, it impacts larvae variably, especially calcifying larvae (e.g., mollusks), which suffer from impaired calcification and higher mortality. Climate change also impairs the reproductive processes of Symbiodiniaceae-bearing invertebrates, reducing gamete output, causing asynchronous spawning, and lowering larval survival. These effects will result in a persistent decline in recruitment with increased larval retention, consequently reducing reef connectivity and genetic diversity, thus weakening ecosystem resilience. This underscores the urgent need to hasten knowledge on larval ecology under climate change and the functional role of symbionts to better inform marine conservation planning and to incorporate larval ecology in the future predictions.
Continue reading ‘The larva-Symbiodiniaceae association at risk: putative impacts of climate change on reproduction, dispersal, and recruitment in coral reefs’Genomic analysis reveals broad adaptability of coral-killing sponge (Terpios hoshinota) under environmental stress
Published 1 October 2025 Science ClosedTags: biological response, laboratory, molecular biology, North Pacific, porifera
The coral-killing sponge, Terpios hoshinota, poses a significant ecological threat to coral reefs, exhibiting rapid expansion and competitive overgrowth. Despite its invasiveness, the genomic basis underlying its adaptability and resilience remains largely unexplored. Here, we present a high-quality genome assembly of T. hoshinota, comprising 169.4 Mb with 40,945 predicted genes. Phylogenomic analysis estimated its divergence from other demosponges during the Ordovician (~ 471 million years ago), even though its simple morphology suggests a more ancient evolutionary origin. Comparative genomic analyses revealed enrichment of genes related to substrate adhesion, innate immunity, and developmental pathways, including expansions of Wnt signaling, homeobox genes, and cell migration gene ontologies which may contribute to its aggressive growth and resilience. Transcriptomic responses under simulated climate stress conditions (heat stress at 31 °C and acidification at 700 ppm pCO₂) indicated dynamic gene regulation, with upregulation of neurotransmitter metabolism, cellular maintenance, and ion homeostasis responses. Despite these stressors, it remained stable. This suggests that T. hoshinota exhibits strong adaptability and resilience through rapid gene regulation. In conclusion, these findings provide molecular insights into T. hoshinota’s ecological success, its potential expansion under climate change, and its broader impact on coral reef ecosystems.
Continue reading ‘Genomic analysis reveals broad adaptability of coral-killing sponge (Terpios hoshinota) under environmental stress’Can sclerosponge skeletons record ocean acidification?: boron and carbon isotope ratios (δ11B and δ13C) in Acanthochaetetes wellsi from Okinoerabu Island, southwestern Japan
Published 21 July 2025 Science ClosedTags: biological response, laboratory, methods, North Pacific, paleo, porifera
Boron stable isotope ratios in biogenic calcium carbonate minerals are known to reflect the decreasing of seawater pH, and thus they can be a useful tracer to track the trend of the ocean acidification. While validation of boron isotopes as a tracer for seawater pH has mainly focused on foraminiferal and coral CaCO3, a few studies examined CaCO3 skeletons produced by sclerosponges. In this study, we investigated stable boron and carbon isotope ratios in two sclerosponge specimens (Acanthochaetetes wellsi), collected from Okinoerabu Island, Japan. Carbon isotope ratios in both specimens showed a continuous decrease over the estimated growth periods, indicating that the Suess effect is recorded in sclerosponge skeletons. In contrast, boron isotope ratios in one specimen decreased over time, but not in the other. These findings suggest further analysis of additional specimens is necessary to determine whether boron isotope ratios in sclerosponge skeletons are reliable recorder of ocean acidification.
Continue reading ‘Can sclerosponge skeletons record ocean acidification?: boron and carbon isotope ratios (δ11B and δ13C) in Acanthochaetetes wellsi from Okinoerabu Island, southwestern Japan’Effects of ocean acidification on the interaction between calcifying oysters (Ostrea chilensis) and bioeroding sponges (Cliona sp.)
Published 18 November 2024 Science ClosedTags: biological response, BRcommunity, calcification, community composition, dissolution, laboratory, mollusks, otherprocess, porifera, respiration
Ocean acidification can negatively affect a broad range of physiological processes in marine shelled molluscs. Marine bioeroding organisms could, in contrast, benefit from ocean acidification due to reduced energetic costs of bioerosion. Ocean acidification could thus exacerbate negative effects (e.g. reduced growth) of ocean acidification and shell borers on oysters. The aim of this study was to assess the impact of ocean acidification on the oyster Ostrea chilensis, the boring sponge Cliona sp., and their host-parasite relationship. We exposed three sets of organisms 1) O. chilensis, 2) Cliona sp., and 3) O. chilensis infested with Cliona sp. to pHT 8.03, 7.83, and 7.63. Reduced pH had no significant effect on calcification, respiration and clearance rate of uninfested O. chilensis. Low pH significantly reduced calcification leading to net dissolution of oyster shells at pHT 7.63 in sponge infested oysters. Net dissolution was likely caused by increased bioerosion by Cliona sp. at pHT 7.63. Additionally, declining pH and sponge infestation had a significant negative antagonistic effect (less negative than predicted additively) on clearance rate. This interaction suggests that sponge infested oysters increase clearance rates to cope with higher energy demand of increased shell repair resulting from higher boring activity of Cliona sp. at low seawater pH. O. chilensis body condition was unaffected by sponge infestation, pH, and the interaction of the two. The reduction in calcification rate suggests sponge infestation and ocean acidification together would exacerbate direct (reduced growth) and indirect (e.g., increased predation) negative effects on oyster health and survival. Our results indicate that ocean acidification by the end of the century could have severe consequences for marine molluscs with boring organisms.
Continue reading ‘Effects of ocean acidification on the interaction between calcifying oysters (Ostrea chilensis) and bioeroding sponges (Cliona sp.)’Evolution of chitin-synthase in molluscs and their response to ocean acidification
Published 17 September 2024 Science ClosedTags: biological response, BRcommunity, chordata, cnidaria, molecular biology, mollusks, physiology, porifera
Highlights
- The metazoan chitin synthase (CHS) gene family is highly extended in bivalves.
- CHS gene number is not related to the presence of a mineralized exoskeleton.
- The tissue distribution of CHS genes is coherent with diverse biological functions.
- The effect of OA on shell formation is not through a direct action on CHS.
Abstract
Chitin-synthase (CHS) is found in most eukaryotes and has a complex evolutionary history. Research into CHS has mainly been in the context of biomineralization of mollusc shells an area of high interest due to the consequences of ocean acidification. Exploration of CHS at the genomic level in molluscs, the evolution of isoforms, their tissue distribution, and response to environmental challenges are largely unknown. Exploiting the extensive molecular resources for mollusc species it is revealed that bivalves possess the largest number of CHS genes (12–22) reported to date in eukaryotes. The evolutionary tree constructed at the class level of molluscs indicates four CHS Type II isoforms (A-D) probably existed in the most recent common ancestor, and Type II-A (Type II-A-1/Type II-A-2) and Type II-C (Type II-C-1/Type II-C-2) underwent further differentiation. Non-specific loss of CHS isoforms occurred at the class level, and in some Type II (B-D groups) isoforms the myosin head domain, which is associated with shell formation, was not preserved and highly species-specific tissue expression of CHS isoforms occurred. These observations strongly support the idea of CHS functional diversification with shell biomineralization being one of several important functions. Analysis of transcriptome data uncovered the species-specific potential of CHS isoforms in shell formation and a species-specific response to ocean acidification (OA). The impact of OA was not CHS isoform-dependent although in Mytilus, Type I-B and Type II-D gene expression was down-regulated in both M. galloprovincialis and M. coruscus. In summary, during CHS evolution the gene family expanded in bivalves generating a large diversity of isoforms with different structures and with a ubiquitous tissue distribution suggesting that chitin is involved in many biological functions. These findings provide insight into CHS evolution in molluscs and lay the foundation for research into their function and response to environmental changes.
Continue reading ‘Evolution of chitin-synthase in molluscs and their response to ocean acidification’Responses of the temperate calcareous sponge Grantia sp. to ocean acidification
Published 13 June 2024 Science ClosedTags: biological response, chemistry, laboratory, porifera, respiration, South Pacific
Sponges are important components of marine systems globally, and while sponges have generally been shown to tolerate ocean acidification (OA), most earlier studies have focused on demosponges with siliceous skeletons. In contrast, little is known of how calcareous sponges, with calcite or aragonite skeletons, may react to OA conditions. Here we measured tissue necrosis and respiration rate of the temperate New Zealand calcareous sponge Grantia sp. to simulated OA. Our treatment conditions were based on the IPCC RCP8.5 (pCO2 1131.9 ± 113 μatm) scenario over a 28 day experiment, and responses were compared to current day control conditions (pCO2 512.59 ± 23 μatm). Sponge respiration rate was not significantly different between the control and treatment sponges and there was no evidence of tissue necrosis over the course of the experiment. Overall, our study is consistent with earlier studies on demosponges, showing calcareous sponges to be resilient to OA.
Continue reading ‘Responses of the temperate calcareous sponge Grantia sp. to ocean acidification’Decline of a distinct coral reef holobiont community under ocean acidification
Published 22 April 2024 Science ClosedTags: algae, annelids, biological response, BRcommunity, bryozoa, chemistry, cnidaria, corals, laboratory, molecular biology, physiology, porifera, prokaryotes, sediment, South Pacific
Background
Microbes play vital roles across coral reefs both in the environment and inside and upon macrobes (holobionts), where they support critical functions such as nutrition and immune system modulation. These roles highlight the potential ecosystem-level importance of microbes, yet most knowledge of microbial functions on reefs is derived from a small set of holobionts such as corals and sponges. Declining seawater pH — an important global coral reef stressor — can cause ecosystem-level change on coral reefs, providing an opportunity to study the role of microbes at this scale. We use an in situ experimental approach to test the hypothesis that under such ocean acidification (OA), known shifts among macrobe trophic and functional groups may drive a general ecosystem-level response extending across macrobes and microbes, leading to reduced distinctness between the benthic holobiont community microbiome and the environmental microbiome.
Results
We test this hypothesis using genetic and chemical data from benthic coral reef community holobionts sampled across a pH gradient from CO2 seeps in Papua New Guinea. We find support for our hypothesis; under OA, the microbiome and metabolome of the benthic holobiont community become less compositionally distinct from the sediment microbiome and metabolome, suggesting that benthic macrobe communities are colonised by environmental microbes to a higher degree under OA conditions. We also find a simplification and homogenisation of the benthic photosynthetic community, and an increased abundance of fleshy macroalgae, consistent with previously observed reef microbialisation.
Conclusions
We demonstrate a novel structural shift in coral reefs involving macrobes and microbes: that the microbiome of the benthic holobiont community becomes less distinct from the sediment microbiome under OA. Our findings suggest that microbialisation and the disruption of macrobe trophic networks are interwoven general responses to environmental stress, pointing towards a universal, undesirable, and measurable form of ecosystem change.
Continue reading ‘Decline of a distinct coral reef holobiont community under ocean acidification’Divergent morphological and microbiome strategies of two neighbor sponges to cope with low pH in Mediterranean CO2 vents
Published 14 February 2024 Science ClosedTags: abundance, biological response, BRcommunity, community composition, field, Mediterranean, molecular biology, morphology, otherprocess, porifera, prokaryotes, vents
Highlights
- Sponges are seen as winner taxa of future OA, yet not all species respond equally.
- Neighbor sponges had different morphology and microbiome patterns in CO2 vents.
- Vent S. cunctatrix displayed morphology changes and incipient microbial dysbiosis.
- C. reniformis microbiomes were normobiotic, diverse and functionally flexible.
- Symbioses supplying C–N–S cycles, vitamins and probiotics uphold resilience to OA.
Abstract
Ocean Acidification (OA) profoundly impacts marine biochemistry, resulting in a net loss of biodiversity. Porifera are often forecasted as winner taxa, yet the strategies to cope with OA can vary and may generate diverse fitness status. In this study, microbial shifts based on the V3–V4 16S rRNA gene marker were compared across neighboring Chondrosia reniformis sponges with high microbial abundance (HMA), and Spirastrella cunctatrix with low microbial abundance (LMA) microbiomes. Sponge holobionts co-occurred in a CO2 vent system with low pH (pHT ~ 7.65), and a control site with Ambient pH (pHT ~ 8.05) off Ischia Island, representing natural analogues to study future OA, and species’ responses in the face of global environmental change. Microbial diversity and composition varied in both species across sites, yet at different levels. Increased numbers of core taxa were detected in S. cunctatrix, and a more diverse and flexible core microbiome was reported in C. reniformis under OA. Vent S. cunctatrix showed morphological impairment, along with signs of putative stress-induced dysbiosis, manifested by: 1) increases in alpha diversity, 2) shifts from sponge related microbes towards seawater microbes, and 3) high dysbiosis scores. Chondrosia reniformis in lieu, showed no morphological variation, low dysbiosis scores, and experienced a reduction in alpha diversity and less number of core taxa in vent specimens. Therefore, C. reniformis is hypothesized to maintain an state of normobiosis and acclimatize to OA, thanks to a more diverse, and likely metabolically versatile microbiome. A consortium of differentially abundant microbes was identified associated to either vent or control sponges, and chiefly related to carbon, nitrogen and sulfur-metabolisms for nutrient cycling and vitamin production, as well as probiotic symbionts in C. reniformis. Diversified symbiont associates supporting functional convergence could be the key behind resilience towards OA, yet specific acclimatization traits should be further investigated.
Continue reading ‘Divergent morphological and microbiome strategies of two neighbor sponges to cope with low pH in Mediterranean CO2 vents’The deep-sea ecosystem engineer Geodia barretti (Porifera, Demospongiae) maintains basic physiological functions under simulated future ocean pH and temperature conditions
Published 6 February 2024 Science ClosedTags: abundance, biological response, BRcommunity, laboratory, multiple factors, North Atlantic, otherprocess, physiology, porifera, prokaryotes, respiration, temperature
Global ocean warming and acidification will alter the physicochemical conditions in the deep North-Atlantic Ocean. Here, extensive sponge grounds, often dominated by the demosponge species Geodia barretti, provide three-dimensional structure, habitat and significantly contribute to benthic-pelagic coupling and nutrient cycling processes in the deep sea. It is unknown if G. barretti remains physiologically functional under the future physicochemical properties of an Anthropocene ocean. In this study, individuals of G. barretti collected from 300 m water depth in the Barents Sea, were exposed to four treatments resembling future ocean conditions (no treatment, 4 °C increase in seawater temperature, decrease of seawater pH by 0.3, and a combination of the high temperature, low pH). Over the course of 39 weeks, oxygen consumption, dissolved inorganic nutrient fluxes, and bacterioplankton clearance rates were measured as indicators of metabolic activity. We found that all indicators within each sponge individual and per treatment were highly variable over time and no effect of manipulated seawater treatments on these parameters could be demonstrated. Oxygen consumption rates in all groups closely followed a seasonal pattern, potentially caused by (a)biotic cues in the seawater flowing through the experimental aquaria. While similar metabolic rates across all treatments suggest that G. barretti physiologically coped with simulated future ocean conditions, observed tissue necrosis in experimental animals might indicate that the response of the complex, high microbial G. barretti sponge (i.e., sponge host and microbial symbionts) to future ocean conditions may not be reflected in basic physiological processes.
Continue reading ‘The deep-sea ecosystem engineer Geodia barretti (Porifera, Demospongiae) maintains basic physiological functions under simulated future ocean pH and temperature conditions’The interactive effects of ocean acidification and warming on bioeroding sponge Spheciospongia vesparium microbiome indicated by metatranscriptomics
Published 16 November 2023 Science ClosedTags: adaptation, biological response, BRcommunity, laboratory, molecular biology, multiple factors, North Pacific, otherprocess, physiology, porifera, prokaryotes, temperature
Global climate change will cause coral reefs decline and is expected to increase the reef erosion potential of bioeroding sponges. Microbial symbionts are essential for the overall fitness and survival of sponge holobionts in changing ocean environments. However, we rarely know about the impacts of ocean warming and acidification on bioeroding sponge microbiome. Here, the structural and functional changes of the bioeroding sponge Spheciospongia vesparium microbiome, as well as its recovery potential, were investigated at the RNA level in a laboratory system simulating 32 °C and pH 7.7. Based on metatranscriptome analysis, acidification showed no significant impact, while warming or simultaneous warming and acidification disrupted the sponge microbiome. Warming caused microbial dysbiosis and recruited potentially opportunistic and pathogenic members of Nesiotobacter, Oceanospirillaceae, Deltaproteobacteria, Epsilonproteobacteria, Bacteroidetes and Firmicutes. Moreover, warming disrupted nutrient exchange and molecular interactions in the sponge holobiont, accompanied by stimulation of virulence activity and anaerobic metabolism including denitrification and dissimilatory reduction of nitrate and sulfate to promote sponge necrosis. Particularly, the interaction between acidification and warming alleviated the negative effects of warming and enhanced the Rhodobacteraceae-driven ethylmalonyl-CoA pathway and sulfur-oxidizing multienzyme system. The microbiome could not recover during the experiment period after warming or combined stress was removed. This study suggests that warming or combined warming and acidification will irreversibly destabilize the S. vesparium microbial community structure and function, and provides insight into the molecular mechanisms of the interactive effects of acidification and warming on the sponge microbiome.
Continue reading ‘The interactive effects of ocean acidification and warming on bioeroding sponge Spheciospongia vesparium microbiome indicated by metatranscriptomics’
