pCO2 Levels Research Articles

Ocean acidification induced changes in Ulva fasciata biochemistry may improve Dicentrarchus labrax aquaculture via enhanced antimicrobial activity

Changes in seawater carbonate chemistry including increased seawater carbon dioxide concentrations (pCO2), commonly known as ocean acidification (OA), can impact metabolic activities and phytochemical production in marine algae. While OA impacts typically reduce animal health, this study investigated the potential of OA-induced changes in methanol bioactivity from the macroalgae Ulva fasciata, to enhance larval European sea bass (Dicentrarchus labrax) aquaculture via increasing antimicrobial activity. After exposing U. fasciata to four pCO2 levels ~280, 550, 750 and 1050 μatm, macroalgae methanol extracts at pCO2–750 exhibited the highest total phenolic content (TPC), flavonoid content (TFC) and yielded the highest antioxidant and antimicrobial activities. After using extracts as a daily water additive for sea bass larvae, U. fasciata methanolic extract at pCO2–750 yielded the greatest reduction in pathogenic bacterial community and the highest survival rate for sea bass larvae. Sea bass larvae growth was also highest after exposure to methanolic extract of U. fasciata grown at pCO2–750, potentially due to higher TPC, TFC and polyunsaturated fatty acid levels. Such nutritional benefits may have been acquired by sea bass larvae via direct uptake or via indirect transfer, by which live feed (Brachionus or Artemia) consumed by larvae accumulated more nutrients. Our results suggest that pCO2–750 has a significant physiological impact on U. fasciata, potentially allowing macroalgae under OA conditions to function as nutritional supplements to increase the performance of sea bass aquaculture

Histological Injury to Rat Brain, Liver, and Kidneys by Gold Nanoparticles is Dose-Dependent.

Gold nanoparticles (GNPs) possess various interesting plasmonic properties that can provide a variety of diagnostic and therapeutic functionalities for biomedical applications. Compared to other inorganic metal nanoparticles (NPs), GNPs are less toxic and more biocompatible. However, the in vivo toxicity of gold nanoparticles on humans can be significant due to the size effect. This work aims to study the effect of multiple doses of small-size (≈20 nm) GNPs on the vital organs of Wistar rats. The study includes the oxidative stress in vital organs (liver, brain, and kidney) caused by GNPs and histopathology analysis. The rats were given a single caudal injection of NPs dispersed in PBS at 25, 50, 100, and 250 mg/kg of body weight. After sacrifice, both plasma and organs were collected for the determination of oxidant/antioxidant markers and histological studies. Our data show the high sensitivity of oxidative stress parameters to the GNPs in the brain, liver, and kidneys. However, the response to this stress is different between the organs and depends upon the antioxidant defense, where GSH levels control the MDA and PCO levels. Histological alterations are mild at 25, 50, and 100 mg/kg but significant at higher concentrations of 250 mg/kg. Therefore, histological impairments are shown to be dependent on the dose of GNPs. The results contribute to the understanding of oxidative stress and cellular interaction induced by nanoparticles.

Seawater Acidification Exacerbates the Negative Effects of UVR on the Growth of the Bloom-Forming Diatom Skeletonema costatum

Climate changes such as seawater acidification caused by rising atmospheric CO2 and increased ultraviolet radiation (UVR) intensity resulting from shoaling of the upper mixed layer may interact to influence the physiological performance of marine primary producers. But few studies have investigated long-term (>30 days) effects of UVR under seawater acidification conditions, along with less attention on the differential effects of long- and short-wavelength UVA. In the present study, four spectral treatments (>280, >320, >360, and >400 nm) under two pCO2 levels (400 and 1,000 μatm) were set to investigate the interactive effects of seawater acidification and UVR on the bloom-forming diatom Skeletonema costatum. The results showed that UVR decreased growth and effective quantum yield of Photosystem II (PSII) by 9%–16% and 11%–24%, respectively, but it enhanced cell sizes significantly. Long- and short-wavelength UVA showed differential effects on cell volume and the effective quantum yield of PSII, especially at the elevated CO2 level. Generally, seawater acidification depressed the effective quantum yield of PSII and cell volume by 6%–18% and 8%–39%, respectively. Additionally, the contents of key PSII proteins (D1 and D2) decreased at the elevated CO2 level. Elevated CO2 significantly increased the inhibition of UVR on growth in the >280 nm spectral treatment when compared with ambient CO2, while it showed no effects in other spectral treatments. Overall, the results indicate that the effects of seawater acidification on the ubiquitous diatom are light wavelength-dependent.

Meta-analysis suggests negative, but pCO2-specific, effects of ocean acidification on the structural and functional properties of crustacean biomaterials.

Crustaceans comprise an ecologically and morphologically diverse taxonomic group. They are typically considered resilient to many environmental perturbations found in marine and coastal environments, due to effective physiological regulation of ions and hemolymph pH, and a robust exoskeleton. Ocean acidification can affect the ability of marine calcifying organisms to build and maintain mineralized tissue and poses a threat for all marine calcifying taxa. Currently, there is no consensus on how ocean acidification will alter the ecologically relevant exoskeletal properties of crustaceans. Here, we present a systematic review and meta‐analysis on the effects of ocean acidification on the crustacean exoskeleton, assessing both exoskeletal ion content (calcium and magnesium) and functional properties (biomechanical resistance and cuticle thickness). Our results suggest that the effect of ocean acidification on crustacean exoskeletal properties varies based upon seawater pCO2 and species identity, with significant levels of heterogeneity for all analyses. Calcium and magnesium content was significantly lower in animals held at pCO2 levels of 1500–1999 µatm as compared with those under ambient pCO2. At lower pCO2 levels, however, statistically significant relationships between changes in calcium and magnesium content within the same experiment were observed as follows: a negative relationship between calcium and magnesium content at pCO2 of 500–999 µatm and a positive relationship at 1000–1499 µatm. Exoskeleton biomechanics, such as resistance to deformation (microhardness) and shell strength, also significantly decreased under pCO2 regimes of 500–999 µatm and 1500–1999 µatm, indicating functional exoskeletal change coincident with decreases in calcification. Overall, these results suggest that the crustacean exoskeleton can be susceptible to ocean acidification at the biomechanical level, potentially predicated by changes in ion content, when exposed to high influxes of CO2. Future studies need to accommodate the high variability of crustacean responses to ocean acidification, and ecologically relevant ranges of pCO2 conditions, when designing experiments with conservation‐level endpoints.

Impact of Elevated Levels of Dissolved CO2 on Performance and Proteome Response of an Industrial 2'-Fucosyllactose Producing Escherichia coli Strain.

Large-scale microbial industrial fermentations have significantly higher absolute pressure and dissolved CO2 concentrations than otherwise comparable laboratory-scale processes. Yet the effect of increased dissolved CO2 (dCO2) levels is rarely addressed in the literature. In the current work, we have investigated the impact of industrial levels of dCO2 (measured as the partial pressure of CO2, pCO2) in an Escherichia coli-based fed-batch process producing the human milk oligosaccharide 2′-fucosyllactose (2′-FL). The study evaluated the effect of high pCO2 levels in both carbon-limited (C-limited) and carbon/nitrogen-limited (C/N-limited) fed-batch processes. High-cell density cultures were sparged with 10%, 15%, 20%, or 30% CO2 in the inlet air to cover and exceed the levels observed in the industrial scale process. While the 10% enrichment was estimated to achieve similar or higher pCO2 levels as the large-scale fermentation it did not impact the performance of the process. The product and biomass yields started being affected above 15% CO2 enrichment, while 30% impaired the cultures completely. Quantitative proteomics analysis of the C-limited process showed that 15% CO2 enrichment affected the culture on the protein level, but to a much smaller degree than expected. A more significant impact was seen in the dual C/N limited process, which likely stemmed from the effect pCO2 had on nitrogen availability. The results demonstrated that microbial cultures can be seriously affected by elevated CO2 levels, albeit at higher levels than expected.

Hazards of administration of benzodiazepines in patients with adaptive hyperventilation: a case rapport

IntroductionOnly three population-based observational human studies provided evidence that benzodiazepines (BZD) are associated with clinically adverse respiratory outcome. Striking was the finding that BZD drug exposure was associated with a 32% significantly increased adjusted risk of all-cause mortality, including, of note, the subgroup of individuals with no comorbidities. Causation, however, cannot be inferred in observational study design and, highly likely, recipients received BZD’s in these studies to help treating anxiety related to inter alia pre-existing respiratory symptoms.ObjectivesBased on one fatal particular case, authors of current rapport explain what can go wrong when BZD’s are given in patient with respiratory impairment.MethodsAuthors provide a model on how an increase in carbon dioxide can lead to impaired cerebral autoregulation in a person with pre-existing respiratory decompensation. Discussion of integrative metabolic and vascular physiology.ResultsCase rapport of a 18 y.o. otherwise healthy man, who was hospitalized with a novel episode of diabetic ketoacidosis accompanied by profound hypocapnia and anxiety, and who deteriorated and died shortly after airway management because of a clinically important acid-base balance disturbance caused by increased carbon dioxide. All the blood tests and results of respiratory monitoring were collected and carefully assessed.ConclusionsCurrent case suggests that the P(CO(2))--HCO(3) hypothesis is consistent with known data on impaired cerebral autoregulation in diabetic ketoacidosis, driven mainly by increased levels of pCO2. In our opinion, it indicates the recommendation not to administrate BZD’s in patients with pre-existing compensatory hyperventilation as it may counter to the logic of adaptive physiology.DisclosureNo significant relationships.

TO STUDY PARAMETERS CO-RELATING OUTCOME OF NON-INVASIVE VENTILATION IN ACUTE RESPIRATORY FAILURE

Background: Respiratory failure is a condition in which the respiratory system fails in one or both of its gas-exchanging functions- oxygenation of pulmonary arterial blood and carbon dioxide elimination from mixed venous blood. NIV is used as a replacement for invasive ventilation in a few conditions, and its exibility also allows it to be a valuable component in patient management. Its use in acute respiratory failure is well accepted and widespread. AIM: This study was conducted to study various parameters such as baseline PCO2 levels, pH, PO2 levels, Heart rate, respiratory rate, and their correlation with the outcome of Non-invasive Ventilation. This is a prospective observational studyMethods: conducted on 100 patients admitted with either Type-I or Type -II respiratory failure. Results: Respiratory rate <30, Heart rate <130, PCO2 45-70 are associated with good outcomes of Non-invasive ventilation. Type of respiratory failure, sputum aerobic culture are not predictors of NIV outcomes. NIV in acute respiratory failure, irrespective of the type of respiratoryConclusion: failure helps in improving gas exchange, reduces intubation and length of hospital stay hence, its use as the rst modality of treatment in patients without overt contraindications is recommended. Overall, NIV is safe and effective in patients with acute respiratory failure as there are no major complications associated with its use.

Applying Dialysis Bags to Grow Microalgae and Measure Grazing Rates by Secondary Producers

Traditional methods using sealed bottles to determine the grazing rates by secondary producers neglect chemical changes induced by biological activities during the incubation, giving rise to instable levels of nutrients, pH, pCO2, pO2 and other chemicals along with changing microalgal cell concentrations and grazers’ metabolism. Here, we used dialysis bags, which allows exchanges of nutrients and gases, to grow microalgae and to determine grazing rates of secondary producers. The specific growth rate of diatom within the dialysis bags increased with increasing water velocities, indicating its suitability to grow microalgae under dynamic water conditions. Then, we compared the grazing rates by the heterotrophic dinoflagellate Noctiluca scintillans measured with the traditional method using polycarbonate (PC) bottles and the approach with the dialysis bags, and found that these two methods gave rise to comparable grazing rates. Nevertheless, the concentrations of inorganic nitrogen and phosphate in the closed PC bottles were about 89–94% lower than those in the dialysis bags due to the microalga’s assimilation. Subsequently, we applied it to determine the grazing rates by a copepod and an oyster (in the presence of other grazers). Consistent results were obtained using the dialysis bags to determine grazing rates by copepods. During the mesocosm (3000 L) experiment in the presence of primary and secondary producers, the grazing rates by the oyster Crassostrea angulata were determined based on the difference of phytoplankton biomass within and outside of the dialysis bags that held all organisms in the mesocosm except the oyster. Since the dialysis bags are permeable to gases, the grazing rates by the oyster under 410 (AC) and 1,000 (HC) μatm CO2 were successfully measured, with a promising result that HC significantly increased the oyster’s grazing. We concluded that using dialysis bags to grow microalgae and to determine grazing rates is a reliable approach, especially under different levels of CO2 and O2.

Study of Utility of Basic Arterial Blood Gas Parameters and Lactate as Prognostic Markers in Patients With Severe Dengue

BackgroundThe importance of prognostication in critical care cannot be over-emphasized, especially in the context of diseases like dengue, as their presentation may vary from mild fever to critical life-threatening illness. With the help of prognostic markers, it is possible to identify patients at higher risk and thus improve their outcome with timely intervention. Basic arterial blood gas (ABG) parameters, i.e., potential of hydrogen (pH), partial pressure of oxygen (PO2), partial pressure of carbon dioxide (PCO2) and bicarbonate are useful parameters, especially in critical care medicine as they are known to vary with the severity of illness. Hyperlactatemia is often referred to as a “powerful predictor of mortality”. Basic ABG parameters and lactate have been used as an essential prognostic modality in critically ill patients for decades; however, the evidence remains limited for their role as prognostic markers in patients with severe dengue.MethodWe carried out an observational retrospective cohort study comprising 163 patients with severe dengue, admitted between July 2021 and November 2021 at Medical Intensive Care Unit (MICU) of Shri Ram Murti Smarak Institute of Medical Sciences (SRMS IMS), Bareilly, Uttar Pradesh, India. Basic ABG parameters and lactate levels at the time of admission to MICU were compared between survivor and non-survivor groups of patients with severe dengue in order to evaluate their prognostic utility as predictors of mortality.ResultspH (p<0.0001), PO2 (p=0.01) and bicarbonate (<0.0001) levels were significantly lower, while PCO2 (p=0.002) and lactate (p<0.0001) levels were significantly higher in non-survivor group as compared to survivor group. Lactate was found to be the best prognostic marker with Area Under the Curve (AUC) of 88.7% on Receiver Operating Characteristics (ROC) analysis.ConclusionBasic arterial blood gas parameters and lactate can be used as feasible prognostic markers in patients with severe dengue.

Metabolomic Signatures of Ocean Acidification Stress in the Coral Acropora millepora

The rapid acidification of seawater poses a significant threat to the persistence of coral reefs. However, taxa‐specific, mechanistic understandings of holobiont responses to ocean acidification (OA) stress remain largely unknown. Understanding these mechanisms is crucial to uncovering predictive markers of OA stress. This could subsequently be used to assist field‐based conservation efforts. We hypothesized that exposure to elevated pCO2 levels would decrease the abundance of primary metabolites such as amino acids and carbohydrates and increase the production of secondary metabolites, specifically those involved in cnidarian‐symbiodinium cell signaling. In this study, we applied untargeted capillary electrophoresis time‐of‐flight mass spectrometry (CE‐TOFMS) to profile changes in the intracellular polar and semi‐polar metabolite composition of the coral holobiont after exposure to elevated pCO2 concentrations. Nubbins of Acropora millepora were exposed to ambient (410 µatm) or elevated (805 µatm) pCO2 levels under controlled conditions over a period of 10 days. Measurement of treatment‐induced bleaching was performed by quantification of symbiodinium cell density and chlorophyll a concentration. We hope to identify molecules in the metabolite profiles associated with the individual cellular responses of holobiont members to osmotic stress. Additionally, we hope to provide further insight into unknown roles of secondary and tertiary metabolite pools in cellular homeostasis and acclimation to thermal stress in the coral holobiont, and specifically the cnidarian‐symbiodinium symbiosis. Our goal is for these findings to assist conservation efforts, specifically in the development of rapid tests for field‐based conservation efforts.

The spatial distribution of surface ocean primary productivity in the wake of Marinoan global glaciation

Termination of the Marinoan global glaciation (~650–635 Ma) was followed by the diversification of eukaryotes (e.g., early animals) and oxygenation of deep oceans in the early Ediacaran Period. Previous studies indicate the recovery of marine primary productivity immediately before the cap carbonate precipitation but after melting of the Marinoan global glaciation. Pyrite concretions from the topmost Nantuo Formation in the Yangtze Block, South China, decrease in abundance from shelf to basin facies, while their high positive sulfur (S) isotope values argue the development of oceanic euxinia, which require ample supply of organic matter, presumably reflecting the recovery of marine productivity. However, pyrite contents and pyrite S isotopes alone cannot uniquely constrain the extent and spatial distribution of surface ocean organic matter production. In this study, we conducted in situ analyses of pyrite iron (Fe) (δ56Fepy) and S isotopes (δ34Spy) of pyrite concretions collected from four sections of the Nantuo Formation, spanning from shelf to basin environments. Pyrite from different facies has distinct δ34Spy and δ56Fepy values. In general, δ34Spy values display an increasing trend from shelf to basin, whereas δ56Fepy values demonstrate an opposite trend with the lowest value in the basin sections. The opposite δ34Spy and δ56Fepy shelf-basin gradients strongly argue against the hydrothermal origin, yet verify the diagenetic precipitation of Nantuo pyrite in sediment porewater. Numerical models were developed to quantify the microbial sulfate reduction (MSR), microbial iron reduction (MIR) and pyrite precipitation processes. The modeling results provide an explanation for the shelf-basin decrease of δ56Fepy values, indicating that both the fraction of MIR (fMIR) and the fraction of Fe2+ consumed by pyrite precipitation (fpy) increase from shelf to basin sections. In addition, high δ34Spy values and pyrite contents in the basin sections also imply more intense MSR and higher supplies of H2S from sulfidic seawater. Both MSR and MIR were fueled by organic matter, thus suggesting that the surface ocean primary productivity displayed an unusual increasing trend toward the open ocean, which was different from the higher productivity in modern near-shore regions. We speculate that the reversed shelf-basin gradient of surface ocean primary productivity might be attributed to high P concentration in the post-glacial ocean. Terrestrial riverine P supply, on the contrary, might have diluted seawater P concentration in the near-shore regions. Therefore, our result indicates that the recovery of marine productivity in the aftermath of the Marinoan global glaciation may be not controlled by the availability of nutrients, instead, the immediate recovery of productivity might have been prohibited by, e.g., low seawater pH at a high atmospheric pCO2 level in the initial melting of the Marinoan global glaciation. The marine primary productivity did not recover until a substantive rise of seawater pH, during which deglacial intense continental weathering delivered abundant P into the ocean and accordingly elevated the seawater P concentration.

The Serum Total and Lipid-Bound Sialic Acid with Hematological-Biochemical Parameter Levels in Dogs with Dirofilariosis

The present study was planned to investigate the potential changes in the levels of serum total sialic acid (TSA), lipid-bound sialic acid (LSA) and hematological-biochemical parameters in the dogs naturally infected by Dirofilaria immitis. The patient group included the 7 dogs clinically and parasitologically (Modified Knott and PCR) diagnosed with Dirofilaria immitis while 7 healthy dogs were assigned as the control group. The biochemical parameters, blood gas parameters and hematological parameters were tested in the blood samples taken properly according to the guidelines from all the study animals using modular auto-analyser, blood gas analyser and automated blood count devices, respectively. Serum TSA and LSA levels were measured spectrophotometrically using Sydow and Katapodis methods, respectively. Compared with the healthy group, the dogs diagnosed with dirofilariosis were found to have significantly increased levels of serum troponin, triglycerides, VLDL, LDL, BUN, urea and creatinine and enzymatic activities of CK-MB, ALT, AST, ALP and LDH, and statistically significantly decreased levels of cholesterol and HDL (p&lt;0.05). The increases in levels of total protein and total bilirubin, and enzymatic activity of CK were found statistically insignificant (p&gt;0.05). A significantly decreased level of RBC and a significantly increased level of WBC was determined in the dogs with dirofilariosis (p&lt;0.05). The decreases in the levels of Hct and Hb were found statistically insignificant (p&gt;0.05). The differential blood count test of the dogs with dirofilariosis indicated statistically significantly increased eosinophil count (p&lt;0.05). The increases in the neutrophil and basophil counts, and the decreases in the lymphocyte and monocyte counts were detected to be statistically insignificant (p&gt;0.05). In the dogs with dirofilariosis, the decreases in the levels of pCO2, HCO3 and BE as the venous blood gas parameters were detected to be statistically significant (p&lt;0.05). The decreases in the levels of pH and pO2 were determined to be insignificant (p&gt;0.05). The levels of serum TSA and LSA of the dogs with dirofilariosis were found statistically significantly higher than the healthy group (p&lt;0.05). As a conclusion, statistically significant differences were identified between the dogs with dirofilariosis and healthy dogs in terms of sialic acid levels and certain biochemical, venous blood gas and hematological parameters. On the other hand, the present study is the first to investigate the serum sialic acid levels in the dogs with dirofilariosis.

Seasonal and Spatial Variations of δ13CDIC Values in the Mun River, Northeast Thailand

As an important part of the global carbon cycle, dissolved inorganic carbon (DIC) concentration and its stable carbon isotopic composition (δ13CDIC) have been used to constrain the sources of DIC in rivers. In this study, we systematically investigated the water chemistry, DIC contents, and δ13CDIC values in a tropical agricultural river in northeast Thailand. The water temperature ranged from 20.3 to 31.3 °C, and water pH values ranged from 6.4 to 8.4, with seasonal variations. Based on the major ion compositions, the hydro-chemical type of the Mun River water was a unique Na–Ca–Cl–HCO3 type, controlled by evaporite and silicate weathering. Seasonal variation of DIC concentrations and its carbon isotopic composition was obvious; DIC and δ13CDIC were significantly lower in the wet season (135 to 3146 μmol/L and −31.0‰ to −7.0‰) compared to the dry season (185 to 5897 μmol/L and −19.6‰ to −2.7‰). A high level of 12C-enriched DIC/CO2 from soil respiration and organic matter oxidation may cause the low pH values, δ13CDIC values, and high partial pressure of CO2 (pCO2) in the middle and lower reaches during the wet/rainy season compared to the dry season. This may be responsible for the seasonal and spatial variations of DIC concentrations and δ13CDIC values in the Mun River. According to the relationship between pCO2 and δ13CDIC values, CO2 outgassing may be more significant in the dry season, due to the greater influx of groundwater with higher pCO2 levels; and the rapid CO2 diffusion into the atmosphere will continuously increase the δ13CDIC values and decrease pCO2 levels. These results show that riverine biologic effects and CO2 outgassing play important roles in the DIC and δ13CDIC evolution of this typical agriculturally-dominated watershed.

Direct effects of elevated dissolved CO2 can alter the life history of freshwater zooplankton

Dissolved CO2 levels (pCO2) are increasing in lentic freshwaters across the globe. Recent studies have shown that this will impact the nutritional quality of phytoplankton as primary producers. However, the extent to which freshwater zooplankton may also be directly affected remains unclear. We test this in three model species representative of the main functional groups of primary consumers in freshwaters; the water flea Daphnia magna, the seed shrimp Heterocypris incongruens and the rotifer Brachionus calyciflorus. We experimentally exposed individuals to three pCO2 levels (1,500; 25,500 and 83,000 ppm) to monitor changes in life history in response to current, elevated and extreme future pCO2 conditions in ponds and shallow lakes. All species had reduced survival under the extreme pCO2 treatment, but the water flea was most sensitive. Body size and reproduction were reduced at 25,500 ppm in the water flea and the seed shrimp and population growth was delayed in the rotifer. Overall, our results show that direct effects of pCO2 could impact the population dynamics of freshwater zooplankton. By differentially modulating the life history of functional groups of primary consumers, elevated pCO2 has the potential to change the evolutionary trajectories of populations as well as the ecological functioning of freshwater communities.

Urinary pCO2 Monitoring System with a Planar Severinghaus Type Sensor

AbstractA urinary pCO2 measurement system with a miniature planar CO2 probe has been developed for monitoring pCO2 levels in the urine (U‐pCO2) of catheterized septic shock patients. U‐pCO2 may provide timely recognition of changes in the microcirculatory status of patients and used as an “early” warning of metabolic‐cellular dysfunction. The utility of the U‐pCO2 sensor has been demonstrated in monitoring experiments in a model bladder. The agreement between U‐pCO2 values measured with the planar pCO2 probe and a commercial pCO2 probe in pooled urine samples projects the possibility of the implementation of the U‐pCO2 measurement system for bedside monitoring.

Warm mid-Pliocene conditions without high climate sensitivity: the CCSM4-Utrecht (CESM 1.0.5) contribution to the PlioMIP2

Abstract. We present the Utrecht contribution to the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2), using the Community Earth System Model version 1.0.5 (CCSM4-Utr). Using a standard pre-industrial configuration and the enhanced PlioMIP2 set of boundary conditions, we perform a set of simulations at various levels of atmospheric pCO2 (280, 400, and 560 ppm). This allows us to make an assessment of the mid-Pliocene reference (Eoi400) climate versus available proxy records and a pre-industrial control (E280), as well as determine the sensitivity to different external forcing mechanisms. We find that our simulated Pliocene climate is considerably warmer than the pre-industrial reference, even under the same levels of atmospheric pCO2. Compared to the E280 case, our simulated Eoi400 climate is on average almost 5 ∘C warmer at the surface. Our Eoi400 case is among the warmest within the PlioMIP2 ensemble and only comparable to the results of models with a much higher climate sensitivity (i.e. CESM2, EC-Earth3.3, and HadGEM3). This is accompanied by a considerable polar amplification factor, increased globally averaged precipitation, and greatly reduced sea ice cover with respect to the pre-industrial reference. In addition to radiative feedbacks (mainly surface albedo, CO2, and water vapour), a major contribution to the enhanced Pliocene warmth in these simulations is the warm model initialisation followed by a long spin-up, as opposed to starting from pre-industrial or present-day conditions. Added warmth in the deep ocean is partly the result of using an altered vertical mixing parameterisation in the Pliocene simulations, but this has a negligible effect at the surface. We find a stronger and deeper Atlantic meridional overturning circulation (AMOC) in the Eoi400 case, but the associated meridional heat transport is mostly unaffected. In addition to the mean state, we find significant shifts in the behaviour of the dominant modes of variability at annual to decadal timescales. The Eoi400 El Niño–Southern Oscillation (ENSO) amplitude is greatly reduced (−68 %) versus the E280 one, while the AMOC becomes more variable. There is also a strong coupling between AMOC strength and North Atlantic sea surface temperature (SST) variability in the Eoi400, while North Pacific SST anomalies seem to have a reduced global influence with respect to the E280 through the weakened ENSO.

Meeting abstracts from the 15th international conference on neonatal and childhood pulmonary vascular disease

Meeting abstracts from the 15th international conference on neonatal and childhood pulmonary vascular disease

Disorders of Blood Gases, Electrolytes, Magnesium, Albumin and Calcium Metabolism in SARS-CoV-2-infected Patients

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-infection is characterized by several malfunctions, including severe pulmonary disorders. Other metabolic consequences of SARS-CoV-2-infection have not been clearly defined. The present study assessed the status of blood gases, calcium metabolism, and electrolytes in SARS-CoV-2-infected individuals. One hundred and thirty-four newly diagnosed SARS-CoV-2-infected patients (age ranged 65-82years) attending Mullingar Regional Hospital, Republic of Ireland, participated in this study. They all had pulmonary disorders, pyrexia, body pains, etc. SARS-CoV-2 was confirmed in all patients using the RT-PCR molecular test method. The data of another 121 plasma samples of apparently normal, non-SARS-CoV-2-infected individuals taken before the emergence of Covid-19 served as controls. Levels of partial pressure of oxygen (pO2), saturated oxygen (SatO2), partial pressure of carbon dioxide (pCO2), and ionized calcium (Ca2+) were determined in all participants using the potentiometric method in RAPIDPOINT 500 Blood Gases System. Plasma vitamin-D was determined by immune enzymatically technique using DXi 800 Access Immunoassay System. Total calcium, phosphate, albumin, magnesium, and electrolytes were determined by the photometric method using Beckman Au680- Chemistry Analyzer. The results showed significantly (p&lt;0.05) higher levels of pCO2 and HCO3- in COVID-19-patients compared to controls. Significantly(p&lt;0.05) lower levels of pO2, SatO2, pH, K+, albumin, total-calcium, Ca2+, magnesium, and vitamin-D were observed in COVID-19 patients compared to controls. Corrected calcium, PO4-, Na+, and Cl- levels did not show significant (p&gt;0.05) changes in the COVID-19-patients compared to controls. Abnormal blood gases, acidosis, hypomagnesaemia, hypoalbuminemia, hypovitaminosis D and calcium metabolic disorders could be features of COVID-19-disease.

Parasitism by metacercariae modulates the morphological, organic and mechanical responses of the shell of an intertidal bivalve to environmental drivers

Environmental variation alters biological interactions and their ecological and evolutionary consequences. In coastal systems, trematode parasites affect their hosts by disrupting their life-history traits. However, the effects of parasitism could be variable and dependent on the prevailing environmental conditions where the host-parasite interaction occurs. This study compared the effect of a trematode parasite in the family Renicolidae (metacercariae) on the body size and the shell organic and mechanical characteristics of the intertidal mussels Perumytilus purpuratus, inhabiting two environmentally contrasting localities in northern and central Chile (ca. 1600 km apart). Congruent with the environmental gradient along the Chilean coast, higher levels of temperature, salinity and pCO2, and a lower pH characterise the northern locality compared to that of central Chile. In the north, parasitised individuals showed lower body size and shell resistance than non-parasitised individuals, while in central Chile, the opposite pattern was observed. Protein level in the organic matter of the shell was lower in the parasitised hosts than in the non-parasitised ones regardless of the locality. However, an increase in polysaccharide levels was observed in the parasitised individuals from central Chile. These results evidence that body size and shell properties of P. purpuratus vary between local populations and that they respond differently when confronting the parasitism impacts. Considering that the parasite prevalence reaches around 50% in both populations, if parasitism is not included in the analysis, the true response of the host species would be masked by the effects of the parasite, skewing our understanding of how environmental variables will affect marine species. Considering parasitism and identifying its effects on host species faced with environmental drivers is essential to understand and accurately predict the ecological consequences of climate change.

Impact of coastal upwelling dynamics on the pCO2 variability in the southeastern Arabian Sea

The southeastern Arabian Sea (SEAS) experiences moderate to weak upwelling along the southwest coast of India during the southwest monsoon (SM). The coastal upwelling initiates from mid-May along the southern-most tip of India, and with the advancement of SM, it propagates towards the northern latitude. This study examines the impact of coastal upwelling dynamics on the spatio-temporal variability of pCO2 in SEAS. It aims to identify the factors controlling the variability of pCO2 using high-resolution, regional ocean-ecosystem model-simulated outputs while available in situ and ship-based observations are used to establish the capability of the model. The cold deeper water that rises to the surface during upwelling decreases surface ocean pCO2 by 50 ± 2.4 µatm, whereas the presence of carbon-rich upwelling waters to a significantly shallower depth increases pCO2 by 52 ± 1.5 µatm of SEAS during SM. The salinity component increases surface ocean pCO2 by 2.0 ± 1.6 µatm. It has relatively less impact when compared with the individual effects of temperature and dissolved inorganic carbon components in controlling surface ocean pCO2 variability. The biological activities are profound only in the southern part of SEAS where biology-driven changes decrease surface ocean pCO2 by 4.0 ± 0.4 µatm during SM. The total biology-driven changes consist of both soft and hard tissues decrease the pCO2 level of SEAS by 2.0 ± 0.2 µatm during SM. Therefore, the upwelling-driven physical dynamics dominate the biological processes in controlling the spatio-temporal variability of surface ocean pCO2 in SEAS during SM, which contrasts the physical-biological dynamics of the sea east of Sri Lanka, where the biological processes dominate over physical dynamics in controlling surface ocean pCO2 variability.