The intertidal zone experiences significant fluctuations in temperature and pH, posing significant challenges to marine organisms. Perinereis aibuhitensis, a eurythermal and euryhaline polychaete inhabiting estuaries, where pH is often lower than in the open ocean and further reduced within sediments, has likely evolved robust adaptations to such stresses. We investigated its behavioral, physiological, and metabolic responses under combined temperature (15°C, 20°C, 25°C) and seawater acidification (pH 5.5, 6.7, 8.0) conditions. P. aibuhitensis exhibited stable behavioral performance and metabolic homeostasis under control conditions (20°C, pH 8.0). It maintained burrowing activity and activated physiological and metabolic regulation at pH 6.7. However, its motion significantly declined with failed behavioral regulation under pH 5.5: radial undulation duration decreased by 97.63% and pumping volume by 97.97%. Energy was reallocated toward antioxidant defense and maintenance of basic physiological functions, reflected in downregulation of the γ-aminobutyric acid (GABA) metabolic pathway alongside upregulation of ABC transporter and arachidonic acid metabolism. At 25°C, combined warming and acidification disrupted energy allocation under pH 5.5. This disruption was accompanied by enhanced motion, which further constrained energy allocation, leading to significant oxidative damage (MDA content increased by 94.54%) and concurrently impairing tryptophan metabolism, glycerophospholipid metabolism, and ABC transporter function, with the entire cascade ultimately collapsing its adaptive mechanisms. This demonstrates that severe acidification, especially under warming, compromises bioturbation and metabolic stability in P. aibuhitensis, with potential negative impacts on polychaete communities and their vital ecological functions in intertidal ecosystems. Our findings provide critical insights for predicting climate change impacts on marine infauna.
Continue reading ‘Behavioral and physiological-biochemical responses of a polychaete (Perinereis aibuhitensis) under severe seawater acidification at different temperatures’Posts Tagged 'annelids'
Behavioral and physiological-biochemical responses of a polychaete (Perinereis aibuhitensis) under severe seawater acidification at different temperatures
Published 11 December 2025 Science ClosedTags: annelids, biological response, laboratory, multiple factors, performance, physiology, temperature
Sediment topography enhances the response of coral reef carbonate sediment dissolution to ocean acidification
Published 13 November 2025 Science ClosedTags: annelids, biological response, BRcommunity, calcification, chemistry, community composition, laboratory, mollusks, otherprocess, primary production, respiration, sediment
The interaction between water flow and sediment topography (e.g., surface ripples) in shallow, permeable coral reef carbonate sediments establishes pressure gradients that increase the rate of sediment–water solute exchange relative to water flow along a flat bottom. It is unknown how this effect from surface ripples may modify the rate at which the sediment porewater is exposed to future chemical changes in the overlying water column, such as elevated pCO2 that is causing ocean acidification (OA). To address this question, this study used a series of 22-h incubations in flume aquaria with live permeable calcium carbonate sediment communities and examined the interactive effect of pCO2 (400 and 1000 µatm) and surface topography (flat and rippled sediments) on invertebrate infaunal activity, carbonate sediment microbial metabolism, and inorganic carbonate dissolution. Results show that the introduction of oxygen into flat sediments was largely driven by infaunal activity, whereas introduction of oxygen into rippled sediments was largely driven by physical flow processes. Rippled sediments exhibited rates of respiration and gross primary production that were ~ 45% and ~ 50% higher, respectively, than flat sediments. An increase in pCO2 shifted the sediments in the flat flumes from net calcifying to net dissolving, an effect that was amplified an additional ~ 60% in rippled sediments. These results suggest that current estimates of coral reef carbonate sediment calcification may be underestimating the dissolution response to OA where the carbonate sediment environment exhibits ripples in the topography.
Continue reading ‘Sediment topography enhances the response of coral reef carbonate sediment dissolution to ocean acidification’Impact of CO2-induced seawater acidification at increased hydrostatic pressure on cellular-level responses of the infaunal nereid Hediste diversicolor
Published 3 November 2025 Science ClosedTags: annelids, Baltic, biological response, laboratory, physiology
Carbon Capture and Storage (CCS) provides a promising mitigation technology for reducing the anthropogenic emission of carbon dioxide (CO2) to the atmosphere. Despite CO2 having been stored safely below the seafloor and the likelihood of leakage is considered small, experimental studies addressing the environmental impacts of potential leaks still present important support to ecological risk assessment. This study investigated biological responses at the cellular level to seawater acidification in a range simulating pH reduction in the overlying bottom water due to potential CO2 leakage from the CCS site in the Baltic Sea. In a series of 40-day laboratory experiments, the infaunal polychaete Hediste diversicolor was exposed in a hyperbaric TiTank to three pH levels (7.7, 7.0 and 6.3) at increased hydrostatic pressure (900 kPa) mimicking the actual situation at 80 m water depth. Hypercapnic conditions, particularly pH 7.0, induced oxidative stress in cells activating the defence mechanisms that included inhibition of GST and activation of CAT and GPx. The acidic environment did also cause damage to cellular membranes as indicated by an increase in the concentration of MDA. The activation of defence processes in the polychaetes did not interfere, however, with the energetic metabolism and aerobiosis remained the principal energy production pathway. Patterns of temporal variation of most cellular biomarkers revealed that after a 15–20 day initial response, the antioxidant and detoxification systems recovered their capabilities to cope with acidification highlighting the acclimatisation potential of the nereids to hypercapnia.
Continue reading ‘Impact of CO2-induced seawater acidification at increased hydrostatic pressure on cellular-level responses of the infaunal nereid Hediste diversicolor’Sibling species differently distributed around a CO2 vent show transplantation proteomic remodelling, while displaying metabolomic signatures associated with their origin
Published 2 October 2025 Science ClosedTags: adaptation, annelids, biological response, BRcommunity, field, Mediterranean, otherprocess, physiology, vents
The cellular homeostatic response (CHR) and cellular stress response (CSR) work together to maintain homeostasis. Studying phylogenetically closely-related species inhabiting different environments can help investigate the interplay between the CHR and CSR. We conducted reciprocal in situ transplant experiments in a natural CO2 vent (Ischia, Italy), using the sibling annelid species Platynereis cf.. dumerilii and Platynereis cf.. massiliensis which have been shown to have different preferential distributions around the CO2 vent. Following transplantations, we characterised the response of each individual’s proteome, metabolome, and lipidome, to short or long-term exposure to different pCO2 regimes (i.e., high and low), and confirmed its genetic identity. Here we show that different components of the CHR and CSR are utilised at different rates when Platynereis spp. are exposed to different pCO2 regimes, with cellular responses shown to be conserved across species. Metabolome and lipidome responses were dependent on regime of origin, and changed relatively slowly, whereas proteome responses were dependent on transplant type and changed more rapidly. Our results provide new insights to improve our understanding of the interplay between different cellular physiological responses involved in defining the functional phenotype of marine species, and their ability to acclimatise to future projected high pCO2 conditions.
Continue reading ‘Sibling species differently distributed around a CO2 vent show transplantation proteomic remodelling, while displaying metabolomic signatures associated with their origin’Hydrothermal vents as observatories for future ocean acidification (OA) scenarios: an in-situ study to unravel the involvement of ATP binding cassette transporters in the adaptation of marine polychaetes Platynereis spp. to OA
Published 16 May 2025 Science ClosedTags: annelids, biological response, laboratory, Mediterranean, molecular biology, vents
The marine annelid Platynereis dumerilii, is a key model in genetics, evolution, neurobiology, ecology, and ecotoxicology. Along with its sibling species, P. cfr massiliensis, it thrives in both normal and naturally acidified environments. This makes these species ideal candidates for studying mechanisms of tolerance to acidified conditions, resembling future ocean acidification (OA) scenarios. The ATP-binding cassette (ABC) transport proteins help mitigating the adverse impacts of drugs, xenobiotics and physical stressors. There is growing evidence for their involvement to mediate tolerance towards acid-stress in bacteria and tumor cell lines. Such a function may be relevant for the ability of marine species to cope with OA and may be important to consider when predicting future OA scenarios for marine fauna. Here we addressed the question if ABC transporters of Platynereis spp. are involved in compensating adverse effects of low pH by studying ABC transporter transcript levels in marine animals exposed to various pH levels. We firstly examined P. dumerilii whole genome data (version EMBL_pdum_1.0, Genbank assembly: GCA_026936325.1) for the presence of ABC transporter genes, by homology searches, and, using the single-cell atlas database with P. dumerilii gene expression data, we then determined the presence of a potentially relevant subset of ABC transporters from the ABCB, C and G subfamilies in different organs/tissues. Finally, to assess how seawater pH affects ABC transporter expression, we conducted an in-situ reciprocal transplant experiment involving individuals of P. dumerilii/P. cfr massiliensis. Adult specimens were collected inside and outside the CO2 vents off Castello Aragonese (Ischia Island, Italy). Individuals collected from normal pH areas (8.18 ± 0.005) were transplanted to acidified conditions (7.33 ± 0.312), and vice versa, while others were placed in their original areas. We found 81 orthologs from ABC transporter subfamilies A-G, expressed in different organs/tissues including midgut, neurons, body epidermis and ectodermal cells, and somatic and visceral muscle. Following the 30 days transplant experiment, qPCR analyses were performed to examine the expression levels of seven selected genes from the ABCB, ABCC, and ABCG subfamilies (abcb_1, abcb_2, abcb_3, abcc_1, abcc_2, abcc_3, and abcg). Three of these genes were differentially expressed in specimens transplanted from normal pH to low pH areas (abcb_1 and abcg up-regulated while abcb_3 down-regulated). Based on the homology with human ABCB1 and ABCG2, which are crucial in tumor cell adaptation to acidified environments, it seems reasonable to hypothesize that abcb_1, abcb_3 and abcg play a similar role in Platynereis spp. helping in maintaining cellular homeostasis and surviving acid stress.
Continue reading ‘Hydrothermal vents as observatories for future ocean acidification (OA) scenarios: an in-situ study to unravel the involvement of ATP binding cassette transporters in the adaptation of marine polychaetes Platynereis spp. to OA’Toxicity of PAHs-enriched sediments on meiobenthic communities under ocean warming and CO2-driven acidification scenarios
Published 6 January 2025 Science ClosedTags: annelids, biological response, BRcommunity, community composition, crustaceans, laboratory, mollusks, multiple factors, nematodes, otherprocess, platyhelminthes, sediment, South Atlantic, tardigrada, temperature, toxicants, zooplankton
Highlights
- Temperature rise reduced the densities of Copepoda and certain Nematoda groups.
- CO2 acidification prevented some Nematoda groups from increasing at high temperatures.
- CO2 acidification reduced Copepoda and nauplii densities, but increased Ostracoda.
- Complex interactions increased certain meiobenthic groups exposed to sediment PAHs.
- Global change and pollution showed interactive effects in meiobenthic communities.
Abstract
This study aimed to assess the interactive effects of CO2-driven acidification, temperature rise, and PAHs toxicity on meiobenthic communities. Laboratory microcosms were established in a full factorial experimental design, manipulating temperature (25 °C and 27 °C), pH (8.1 and 7.6), and PAH contamination (acenaphthene + benzo(a)pyrene spiked sediments and negative control). Temperature rise and CO2-driven acidification led to a decrease in the densities of Copepoda. The density of nematodes Pseudochromadora and Daptonema also decreased, while Sphaerotheristus and Sabatieria densities increased, particularly in the absence of CO2-driven acidification. Ostracoda densities increased in the acidified scenario. PAH contamination resulted in decreased Daptonema densities but increased Turbellaria and certain Nematoda genera (e.g. Pseudochromadora). Overall, the results indicate that the changes of meiobenthic communities caused by CO2 acidification, warming, and PAH contamination are shaped by the vulnerability and tolerance of each taxonomic group, alongside indirect effects observed in Nematoda assemblages.
Continue reading ‘Toxicity of PAHs-enriched sediments on meiobenthic communities under ocean warming and CO2-driven acidification scenarios’Functional diversity and metabolic response in benthic communities along an ocean acidification gradient
Published 1 May 2024 Science ClosedTags: abundance, annelids, biological response, BRcommunity, chemistry, community composition, crustaceans, echinoderms, field, Mediterranean, mollusks, otherprocess, vents
Highlights
- Ocean acidification (OA) affect the distribution of traits within a community leading to the selection of specific functional traits.
- Along with the selection of traits, OA led to differences in oxygen consumption between benthic communities following acidification gradient.
- Altered acidified condition have a negative effect on the stability of the community resulting from changes in functional evennes of benthic communities.
Abstract
Altered ocean chemistry caused by ocean acidification (OA) is expected to have negative repercussions at different levels of the ecological hierarchy, starting from the individual and scaling up to the community and ultimately to the ecosystem level. Understanding the effects of OA on benthic organisms is of primary importance given their relevant ecological role in maintaining marine ecosystem functioning. The use of functional traits represents an effective technique to investigate how species adapt to altered environmental conditions and can be used to predict changes in the resilience of communities faced with stresses associated with climate change. Artificial supports were deployed for 1-y along a natural pH gradient in the shallow hydrothermal systems of the Bottaro crater near Panarea (Aeolian Archipelago, southern Tyrrhenian Sea), to explore changes in functional traits and metabolic rates of benthic communities and the repercussions in terms of functional diversity. Changes in community composition due to OA were accompanied by modifications in functional diversity. Altered conditions led to higher oxygen consumption in the acidified site and the selection of species with the functional traits needed to withstand OA. Calcification rate and reproduction were found to be the traits most affected by pH variations. A reduction in a community’s functional evenness could potentially reduce its resilience to further environmental or anthropogenic stressors. These findings highlight the ability of the ecosystem to respond to climate change and provide insights into the modifications that can be expected given the predicted future pCO2 scenarios. Understanding the impact of climate change on functional diversity and thus on community functioning and stability is crucial if we are to predict changes in ecosystem vulnerability, especially in a context where OA occurs in combination with other environmental changes and anthropogenic stressors.
Continue reading ‘Functional diversity and metabolic response in benthic communities along an ocean acidification gradient’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’Effects of reduced seawater pH and oil contamination on bacterial communities and biochemical markers of estuarine animal hosts
Published 18 March 2024 Science ClosedTags: annelids, biological response, chemistry, community composition, laboratory, molecular biology, mollusks, mortality, North Atlantic, otherprocess, performance, physiology, toxicants
Ecosystem functioning depends on complex interactions between microorganisms, hosts, and the environment. Changes in environmental conditions (e.g., ocean acidification) in combination with anthropogenic pollution have been shown to affect the composition and function of free-living microbial communities, but little is known about the effects these stressors on host-associated communities. This study aims to characterize the response of host-associated bacterial communities of the bottom-dwelling polychaete Hediste diversicolor and the epibenthic gastropod Peringia ulvae to oil contamination and reduced seawater pH. The independent and interactive effects of both stressors were simulated under controlled conditions. The response of host-associated bacterial communities was assessed using the high-throughput sequencing of the 16S rRNA gene and several biochemical markers related to host metabolic pathways, e.g., neurotransmission, anaerobic metabolism, biotransformation, oxidative stress, and energy consumption. In H. diversicolor, reduced seawater pH was associated with a high relative abundance of Cyanobacteria, while in P. ulvae oil contamination was associated with a reduction in the relative abundance of Chitinophagales. In P. ulvae, enrichment with oil hydrocarbon-degrading bacteria suggests a possible role of these organisms in the dispersion of oil hydrocarbon degraders. Furthermore, oil supplementation shifted some specific biochemical markers of gastropods related to oxidative stress and energy consumption, which suggests host stress. In general, the bacterial communities and biochemical markers of the gastropod were more affected by stressors than those of the polychaete. Overall, this study contributes to a better understanding of the response of host-associated bacterial communities of benthic macrofauna to anthropogenic contamination and environmental change.
Continue reading ‘Effects of reduced seawater pH and oil contamination on bacterial communities and biochemical markers of estuarine animal hosts’Fouling communities from the South African west coast are vulnerable to cooling and ocean acidification
Published 15 March 2024 Science ClosedTags: abundance, annelids, biological response, BRcommunity, bryozoa, chordata, community composition, crustaceans, fish, mollusks, multiple factors, otherprocess, prokaryotes, South Atlantic, temperature
Changing temperature and ocean acidification are well-recognised consequences of climate change in marine systems. In contrast to global trends, the South African west coast is experiencing cooling due to increased frequency and intensity of upwelling. The implications of concurrent cooling and acidification for marine biota are poorly understood, particularly at the community level. This laboratory study assessed how cooling and acidification might affect fouling communities along the South African west coast. Communities were experimentally exposed to two temperatures, 13℃ (current) and 9℃ (cooling), and three pH treatments, 7.9 (current), 7.6 and 7.4, for 18 days. Cooling and acidification altered community structure. Species diversity declined in response to acidification but was not affected by cooling. This was driven by greatest loss of species at 7.4 pH. Notably, acidification reduced the abundance of both calcifying and soft-bodied taxa, highlighting the vulnerability of taxa like ascidians to acidification. Overall, these results highlight the dominant threat posed by acidification, even for alien taxa that are often perceived as resilient to climate change. Additionally, in regions experiencing cooling, acidification may pose a greater threat to fouling communities than thermal changes.
Continue reading ‘Fouling communities from the South African west coast are vulnerable to cooling and ocean acidification’Early stage ecological communities on artificial algae showed no difference in diversity and abundance under ocean acidification
Published 24 January 2024 Science ClosedTags: abundance, algae, annelids, biological response, BRcommunity, calcification, chemistry, community composition, crustaceans, echinoderms, field, Mediterranean, mesocosms, mitigation, mollusks, otherprocess, photosynthesis, protists, respiration
Marine habitat-forming species create structurally complex habitats that host macroinvertebrate communities characterized by remarkable abundance and species richness. These habitat-forming species also play a fundamental role in creating favourable environmental conditions that promote biodiversity. The deployment of artificial structures is becoming a common practice to help offset habitat loss although with mixed results. This study investigated the suitability of artificial flexible turfs mimicking the articulated coralline algae (mimics) as habitat providers and the effect of ocean acidification (OA) on early stage ecological communities associated to flexible mimics and with the mature community associated to Ellisolandia elongata natural turfs. The mimics proved to be a suitable habitat for early stage communities. During the OA mesocosms experiment, the two substrates have been treated and analysed separately due to the difference between the two communities. For early stage ecological communities associated with the mimics, the lack of a biologically active substrate does not exacerbate the effect of OA. In fact, no significant differences were found between treatments in crustaceans, molluscs and polychaetes diversity and abundance associated with the mimics. In mature communities associated with natural turfs, buffering capability of E. elongata is supporting different taxonomic groups, except for molluscs, greatly susceptible to OA.
Continue reading ‘Early stage ecological communities on artificial algae showed no difference in diversity and abundance under ocean acidification’Infestation of cultivated Pacific oysters by shell-boring polychaetes along the US West Coast: Prevalence is associated with season, culture method, and pH
Published 10 November 2023 Science ClosedTags: abundance, annelids, biological response, chemistry, community composition, field, molecular biology, mollusks, North Pacific, otherprocess, physiology
Shell-boring polychaetes have contributed to the collapse of several mariculture operations around the world. These pests burrow into the shells of bivalves, creating mud blisters that are unappealing to consumers and which make oysters less valuable on the half-shell market. The US Pacific region produces 38% of the farmed shellfish in the US, making it important to understand the prevalence and drivers of parasite infestation in this region. We sampled Pacific oysters (Crassostrea gigas; n = 4158) from 35 shellfish farms over four seasons (two winters and two summers) in four states (northern California (CA), Oregon (OR), Washington (WA), and Alaska (AK)) to document the prevalence of shell-boring polychaetes. We extracted worms from infested oysters and used mitochondrial (CO1, n = 139) and nuclear (18S rRNA, n = 224) markers to determine species identities. To identify the environmental correlates that were associated with infestation, we pooled environmental data from seven monitoring stations in Washington. We assessed whether seawater surface temperature (SST), salinity, and pH were associated with shell-boring polychaete infestation. Our sampling confirmed the presence of Polydora websteri in the study region, in addition to four other species of shell-boring polychaetes and seven unidentified haplotypes. The mean prevalences across all shell-boring polychaete species ranged from 23 to 45% across seasons between states. In general, prevalence was higher in the winter and among oysters cultured on the bottom versus in tumbled bags, but these results varied across states. We also found greater infestation by shell-boring polychaetes at less acidified sites (pH = 8–8.2). This work is the most comprehensive dataset to characterize shell-boring polychaetes along the US West Coast, providing an important baseline of prevalence, species distribution, and environmental associations.
Continue reading ‘Infestation of cultivated Pacific oysters by shell-boring polychaetes along the US West Coast: Prevalence is associated with season, culture method, and pH’Characteristics of meiofaunal community in the subtidal zone near Hupo, anticipating ocean acidification in the East Sea of Korea
Published 19 June 2023 Science ClosedTags: abundance, annelids, biological response, BRcommunity, chemistry, community composition, crustaceans, field, nematodes, North Pacific, otherprocess, protists, zooplankton
This study aimed to investigate the meiofauna community characteristics in coastal waters highly affected by ocean acidification. Therefore, the meiofauna communities in the coastal waters of Hupo in Uljin-gun, a county bordering the East Sea of Korea, were monitored over five years. During the study period, the mean abundance of total meiofauna communities expressed in population density was 614.4 individuals (Inds.)/10 cm2, similar to the reported meiofauna abundance in the subtidal zone in the Yellow Sea of Korea, an area with sandy sedimentary facies. The most dominant taxa were nematodes (65–70%) and harpacticoids (7–20%); these two taxa accounted for approximately 80% of the total meiofauna abundance. Among the stations studied, station (St.) 10 showed the lowest seawater pH value, and in 2011, when the measured pH was the lowest at 7.82, St. 10 showed the lowest abundance values for total meiofauna and harpacticoids in the 5-year period. To examine the effect of ocean acidification on meiofauna communities at the species level, species of nematodes, the most dominant taxon, were analyzed. The results indicated that the number of nematode species at St. 10 in 2009, when the pH value was low, was 8, which was very low compared to that in the other years of the study period. According to the feeding type, epistrate feeders (2A) accounted for a remarkably high proportion at St. 10, which showed a low pH. This study provides various data on meiobenthic community characteristics to understand the effects of ocean acidification on coastal ecosystems.
Continue reading ‘Characteristics of meiofaunal community in the subtidal zone near Hupo, anticipating ocean acidification in the East Sea of Korea’Marine macroinvertebrate ecosystem services under changing conditions of seagrasses and mangroves
Published 5 June 2023 Science ClosedTags: abundance, annelids, biological response, BRcommunity, chemistry, cnidaria, community composition, crustaceans, echinoderms, Indian, mollusks, otherprocess, phanerogams, phytoplankton, primary production, review, socio-economy
Highlights
- Overfishing and climate change show potential effects on MMI ES.
- MMI regulating ES can be quantified using species richness and functional traits.
- Digital platforms are valuable tools to retrieve data but have limitations.
- Baseline data and information on environmental changes and MMI ES is provided.
Abstract
This study aimed to investigate the impact of changing environmental conditions on MMI ES in seagrasses and mangroves. We used data from satellite and biodiversity platforms combined with field data to explore the links between ecosystem pressures (habitat conversion, overexploitation, climate change), conditions (environmental quality, ecosystem attributes), and MMI ES (provisioning, regulation, cultural). Both seagrass and mangrove extents increased significantly since 2016. While sea surface temperature showed no significant annual variation, sea surface partial pressure CO2, height above sea level and pH presented significant changes. Among the environmental quality variables only silicate, PO4 and phytoplankton showed significant annual varying trends. The MMI food provisioning increased significantly, indicating overexploitation that needs urgent attention. MMI regulation and cultural ES did not show significant trends overtime. Our results show that MMI ES are affected by multiple factors and their interactions can be complex and non-linear. We identified key research gaps and suggested future directions for research. We also provided relevant data that can support future ES assessments.
Continue reading ‘Marine macroinvertebrate ecosystem services under changing conditions of seagrasses and mangroves’High sclerobiont calcification in marginal reefs of the eastern tropical Pacific
Published 8 November 2022 Science ClosedTags: annelids, biological response, BRcommunity, bryozoa, calcification, chemistry, community composition, field, mollusks, multiple factors, North Pacific, nutrients, otherprocess, protists, review
Graphical abstract.
A sclerobiont is any organism capable of fouling hard substrates. Sclerobionts have recently received attention due to their notable calcium carbonate contributions to reef structures and potential to offset drops in carbonate budgets in degraded reefs. However, due to their encrusting nature, it is difficult to quantify net calcium carbonate production at the level of individual taxonomic groups, and knowledge regarding the main environmental factors that regulate their spatial distributions is limited. In addition, the material types used to create experimental substrates, their orientations, and their overall deployment times can influence settlement and the composition of the resulting communities. Thus, comparative evaluations of these variables are necessary to improve future research efforts. In this study, we used calcification accretion units (CAUs) to quantify the calcium carbonate contributions of sclerobionts at the taxonomic group level and evaluated the effects of two frequently used materials [i.e., polyvinyl chloride (PVC) and terracotta (TCT) tiles] on the recruitment and calcification of the sclerobiont community in the tropical Mexican Pacific and the Midriff Island Region of the Gulf of California over 6 and 15 months [n = 40; 5 CAUs x site (2) x deployment time (2) x material type (2)]. The net sclerobiont calcification rate (mean ± SD) reached maximum values at six months and was higher in the Mexican Pacific (2.15 ± 0.99 kg m−2 y−1) than in the Gulf of California (1.70 ± 0.67 kg m−2 y−1). Moreover, the calcification rate was slightly higher on the PVC-CAUs compared to that of the TCT-CAUs, although these differences were not consistent at the group level. In addition, cryptic microhabitats showed low calcification rates when compared to those of exposed microhabitats. Crustosecoralline algae and barnacles dominated the exposed experimental surfaces, while bryozoans, mollusks, and serpulid polychaetes dominated cryptic surfaces. Regardless of the site, deployment time, or material type, barnacles made the greatest contributions to calcimass production (between 41 and 88%). Our results demonstrate that the orientation of the experimental substrate, and the material to a lesser extent, influence the sclerobiont community and the associated calcification rate. Upwelling-induced surface nutrient levels, low pH levels, and the aragonite saturation state (ΩAr) limit the early cementation of reef-building organisms in the tropical Mexican Pacific and promote high bioerosion rates in corals of the Gulf of California. Our findings demonstrate that sclerobionts significantly contribute to calcium carbonate production even under conditions of high environmental variability.
Continue reading ‘High sclerobiont calcification in marginal reefs of the eastern tropical Pacific’Ocean acidification modifies behaviour of shelf seabed macrofauna: a laboratory study on two ecosystem engineers, Abra alba and Lanice conchilega
Published 7 November 2022 Science ClosedTags: annelids, biological response, laboratory, mollusks, North Atlantic, performance
The feeding activity and burrow ventilation by benthic invertebrates importantly affect the biodiversity and functioning of seafloor sediments. Here we investigated how ocean acidification can modify these behavioural activities in two common and abundant macrofaunal ecosystem engineering species in temperate continental shelf communities: the white furrow shell Abra alba and the sand mason Lanice conchilega. Using time-lapse imagery and sediment porewater hydraulic signatures we show that both species adapt their behaviour in response to predicted future pH conditions (−0.3 units). During a three-week laboratory experiment, A. alba reduced the duration per feeding event when suspension and deposit feeding (by 86 and 53%, respectively), and almost completely ceased suspension feeding under reduced seawater pH in comparison to ambient seawater pH (pH ∼ 8.2). This behavioural change reduces the intake of low pH water during feeding and respiration. L. conchilega increased its piston-pumping frequency by 30 and 52%, respectively, after one and two weeks of exposure to future pH conditions (−0.3 units) relative to ambient conditions. This change in irrigation activity suggests higher metabolic demands under low seawater pH, and also extended low water column pH conditions deeper into the seafloor. Because the distribution of other populations depends on the physicochemical setting by our focal species, we argue that the demonstrated behavioural plasticity will likely have cascading effects on seafloor diversity and functioning, highlighting the complexity of how ocean acidification, and climate change in general, will affect seafloor ecology.
Continue reading ‘Ocean acidification modifies behaviour of shelf seabed macrofauna: a laboratory study on two ecosystem engineers, Abra alba and Lanice conchilega’Assessment of paracetamol toxic effects under varying seawater pH conditions on the marine polychaete Hediste diversicolor using biochemical endpoints
Published 13 April 2022 Science ClosedTags: annelids, biological response, BRcommunity, laboratory, multiple factors, North Atlantic, physiology, toxicants
Simple Summary
Context of climate change is being widely studied, nevertheless its effects in the toxicity of other contaminants have been poorly study. Particularly, the effects of ocean acidification on the modulation of pharmaceutical absorption and consequent effects, have not been extensively addressed before. In this study, we aimed to assess the effects of ocean acidification (specifically pH values of 8.2, 7.9, and 7.6) combined with paracetamol exposure (0, 30, 60, and 120 µg/L) on the polychaeta Hediste diversicolor. To do so, specific biomarkers were measured namely (CAT), glutathione S-transferases (GSTs), acetylcholinesterase (AChE), and cyclooxygenase (COX) activities, as well as thiobarbituric acid reactive substance (TBARS), were quantified to serve as ecotoxicological endpoints. Alterations of CAT, and GSTs activities, and TBARS levels indicate an alteration in redox balances. Differences in exposed pH levels indicate the possible modulation of the absorption of this pharmaceutical in ocean acidifications scenarios. Alterations in AChE were only observed following paracetamol exposure, not being altered by media pH. Hereby obtained results suggest that seawater acidification is detrimental to marine wildlife, since it may enhance toxic effects caused by environmental realistic concentrations of pharmaceuticals. This work is crucial to understand the potential effects of pharmaceuticals in a climate change scenario.
Abstract
Increasing atmospheric carbon dioxide (CO2) levels are likely to lower ocean pH values, after its dissolution in seawater. Additionally, pharmaceuticals drugs are environmental stressors due to their intrinsic properties and worldwide occurrence. It is thus of the utmost importance to assess the combined effects of pH decreases and pharmaceutical contamination, considering that their absorption (and effects) are likely to be strongly affected by changes in oceanic pH. To attain this goal, individuals of the marine polychaete Hediste diversicolor were exposed to distinct pH levels (8.2, 7.9, and 7.6) and environmentally relevant concentrations of the acidic drug paracetamol (PAR: 0, 30, 60, and 120 µg/L). Biomarkers such as catalase (CAT), glutathione S-transferases (GSTs), acetylcholinesterase (AChE), and cyclooxygenase (COX) activities, as well as peroxidative damage (through thiobarbituric acid reactive substance (TBARS) quantification), were quantified to serve as ecotoxicological endpoints. Data showed a general increase in CAT and a decrease in GST activities (with significant fluctuations according to the tested conditions of PAR and pH). These changes are likely to be associated with alterations of the redox cycle driven by PAR exposure. In addition, pH levels seemed to condition the toxicity caused by PAR, suggesting that the toxic effects of this drug were in some cases enhanced by more acidic conditions. An inhibition of AChE was observed in animals exposed to the highest concentration of PAR, regardless of the pH value. Moreover, no lipid peroxidation was observed in most individuals, although a significant increase in TBARS levels was observed for polychaetes exposed to the lowest pH. Finally, no alterations of COX activities were recorded on polychaetes exposed to PAR, regardless of the pH level. The obtained results suggest that seawater acidification is detrimental to marine wildlife, since it may enhance toxic effects caused by environmental realistic concentrations of acidic drugs, such as PAR. This work was crucial to evidence that ocean acidification, in the context of a global change scenario of increased levels of both atmospheric and oceanic CO2, is a key factor in understanding the putative enhanced toxicity of most pharmaceutical drugs that are of an acidic nature.
Continue reading ‘Assessment of paracetamol toxic effects under varying seawater pH conditions on the marine polychaete Hediste diversicolor using biochemical endpoints’Biomineralization: integrating mechanism and evolutionary history
Published 22 March 2022 Science ClosedTags: annelids, brachiopods, bryozoa, cnidaria, echinoderms, mollusks, morphology, porifera, review
Calcium carbonate (CaCO3) biomineralizing organisms have played major roles in the history of life and the global carbon cycle during the past 541 Ma. Both marine diversification and mass extinctions reflect physiological responses to environmental changes through time. An integrated understanding of carbonate biomineralization is necessary to illuminate this evolutionary record and to understand how modern organisms will respond to 21st century global change. Biomineralization evolved independently but convergently across phyla, suggesting a unity of mechanism that transcends biological differences. In this review, we combine CaCO3 skeleton formation mechanisms with constraints from evolutionary history, omics, and a meta-analysis of isotopic data to develop a plausible model for CaCO3 biomineralization applicable to all phyla. The model provides a framework for understanding the environmental sensitivity of marine calcifiers, past mass extinctions, and resilience in 21st century acidifying oceans. Thus, it frames questions about the past, present, and future of CaCO3 biomineralizing organisms.
Continue reading ‘Biomineralization: integrating mechanism and evolutionary history’Seasonal carbonate system vis-a-vis pH and salinity in selected tropical estuaries: implications on polychaete diversity and composition towards predicting ecological health
Published 16 February 2022 Science ClosedTags: annelids, biogeochemistry, biological response, Indian, laboratory, multiple factors, salinity, sediment
Highlights
- The role of salinity-pH gradient coupled with carbonate species on the polychaete community distribution was studied.
- Salinity-pH was positively correlated with carbonate and DOC.
- pCO2 was positively correlated with POC, DIC and CO2.
- High levels of carbonate species and low pH have a greater impact on polychaete diversity and richness.
Abstract
Salinity and pH play a fundamental role in structuring spatial patterns of physical properties, biota, and biogeochemical processes in the estuarine ecosystem. In this study, the influence of salinity-pH gradient and carbonate system on polychaete diversity in Ennore, Uppanar, Vellar, and Kaduvaiyar estuaries was investigated. Water and sediment samples were collected from September 2017 to August 2018. Univariate and multivariate statistical analyses were employed to define ecological status. Temperature, Salinity, pH, and partial pressure of carbon-di-oxide varied between 21 and 30°C; 29 and 39 ppt; 7.4 and 8.3; and 89.216 and 1702.558 µatm, respectively. PCA and CCA results revealed that DO, chlorophyll, carbonate species, and sediment TOC have a higher influence on polychaete community structure. Forty-two species such as Ancistrosyllis parva, Cossura coasta, Eunice pennata, Euclymene annandalei, Lumbrineris albidentata, Capitella capitata, Prionospio cirrifera, P. pinnata, P. cirrobranchiata, and Notomastus sp. were found dominantly in all estuaries. Shannon index values ranged between 1.619 (UE-1) and 3.376 (VE-2). Based on these findings, high levels of carbonate species and low pH have a greater impact on polychaete diversity and richness values. The results of the AMBI Index revealed that stations UE-1, UE-2, UE-3 in Uppanar, EC-1, EC-2 in Ennore indicate “moderately disturbed”, while other stations are under the “slightly disturbed” category. This trend was quite evident in M-AMBI as well.
Continue reading ‘Seasonal carbonate system vis-a-vis pH and salinity in selected tropical estuaries: implications on polychaete diversity and composition towards predicting ecological health’
