scholarly journals Dissolved Oxygen in Heterogeneous Environments Dictates the Metabolic Rate and Thermal Sensitivity of a Tropical Aquatic Crab

2021 ◽  
Vol 8 ◽  
Author(s):  
Marco Fusi ◽  
Daniele Daffonchio ◽  
Jenny Booth ◽  
Folco Giomi
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Saturation ◽  
Thermal Sensitivity ◽  
Thermal Response ◽  
Respiratory Physiology ◽  
Heterogeneous Environments ◽  
Mud Crab ◽  
Low Oxygen ◽  
Coastal Habitats ◽  
Seagrass Meadows

Oxygen availability, together with water temperature, greatly varies in coastal habitats, especially in those characterized by elevated primary production. In this study, we investigate the combined role of dissolved oxygen and temperature on the thermal physiological response of the mud crab Thalamita crenata living in an equatorial system of coastal habitats. We sampled temperature, oxygen and salinity in T. crenata habitats, mangrove creeks and fringes and seagrass meadows, at Gazi Bay (Kenya). We found that seagrass meadows exhibited higher temperature and oxygen saturation than the mangrove habitats during the day, creating conditions of oxygen supersaturation. By investigating the effect of different levels of oxygen saturation on the thermal response of T. crenata, we demonstrated that the respiratory physiology of this ectotherm has a pronounced resistance to heat, directly influenced by the amount of dissolved oxygen in the water. Under low oxygen saturation levels, the mud crab significantly reduced its metabolism, becoming temperature-independent. This result shows that aquatic species can modulate their thermal response in a stringent dependency with water oxygen saturation, corroborating previous findings on the thermal response of T. crenata under supersaturation. This contribution provides further support for the need to adopt an ecologically-relevant approach to forecast the effect of climate change on marine ectothermal species.

scholarly journals Diel oxygen fluctuation drives the thermal response and metabolic performance of coastal marine ectotherms

2021 ◽  
Vol 288 (1953) ◽  
pp. 20211141
Author(s):  
J. M. Booth ◽  
M. Fusi ◽  
F. Giomi ◽  
E. C. N. Chapman ◽  
K. Diele ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Marine Invertebrates ◽  
Metabolic Response ◽  
Thermal Sensitivity ◽  
Thermal Response ◽  
Oxygen Availability ◽  
Coastal Vegetation ◽  
Climate Anomalies ◽  
Coastal Marine ◽  
Metabolic Performance

Coastal marine systems are characterized by high levels of primary production that result in diel oxygen fluctuations from undersaturation to supersaturation. Constant normoxia, or 100% oxygen saturation, is therefore rare. Since the thermal sensitivity of invertebrates is directly linked to oxygen availability, we hypothesized that (i) the metabolic response of coastal marine invertebrates would be more sensitive to thermal stress when exposed to oxygen supersaturation rather than 100% oxygen saturation and (ii) natural diel fluctuation in oxygen availability rather than constant 100% oxygen saturation is a main driver of the thermal response. We tested the effects of oxygen regime on the metabolic rate, and haemocyanin and lactate levels, of velvet crabs ( Necora puber ) and blue mussels ( Mytilus edulis ), under rising temperatures (up to 24°C) in the laboratory. Oxygen supersaturation and photosynthetically induced diel oxygen fluctuation amplified animal metabolic thermal response significantly in both species, demonstrating that the natural variability of oxygen in coastal environments can provide considerable physiological benefits under ocean warming. Our study highlights the significance of integrating ecologically relevant oxygen variability into experimental assessments of animal physiology and thermal response, and predictions of metabolic performance under climate warming. Given the escalating intensity and frequency of climate anomalies, oxygen variation caused by coastal vegetation will likely become increasingly important in mitigating the effects of higher temperatures on coastal fauna.

scholarly journals Breathing space: deoxygenation of aquatic environments can drive differential ecological impacts across biological invasion stages

2021 ◽  
Author(s):  
James W. E. Dickey ◽  
Neil E. Coughlan ◽  
Jaimie T. A. Dick ◽  
Vincent Médoc ◽  
Monica McCard ◽  
...  
Keyword(s):  
Climate Change ◽  
Oxygen Saturation ◽  
Ecological Impacts ◽  
Neogobius Melanostomus ◽  
Aquatic Environments ◽  
Relative Impact ◽  
Low Oxygen ◽  
Per Capita ◽  
The Impact ◽  
Prey Populations

AbstractThe influence of climate change on the ecological impacts of invasive alien species (IAS) remains understudied, with deoxygenation of aquatic environments often-overlooked as a consequence of climate change. Here, we therefore assessed how oxygen saturation affects the ecological impact of a predatory invasive fish, the Ponto-Caspian round goby (Neogobius melanostomus), relative to a co-occurring endangered European native analogue, the bullhead (Cottus gobio) experiencing decline in the presence of the IAS. In individual trials and mesocosms, we assessed the effect of high, medium and low (90%, 60% and 30%) oxygen saturation on: (1) functional responses (FRs) of the IAS and native, i.e. per capita feeding rates; (2) the impact on prey populations exerted; and (3) how combined impacts of both fishes change over invasion stages (Pre-invasion, Arrival, Replacement, Proliferation). Both species showed Type II potentially destabilising FRs, but at low oxygen saturation, the invader had a significantly higher feeding rate than the native. Relative Impact Potential, combining fish per capita effects and population abundances, revealed that low oxygen saturation exacerbates the high relative impact of the invader. The Relative Total Impact Potential (RTIP), modelling both consumer species’ impacts on prey populations in a system, was consistently higher at low oxygen saturation and especially high during invader Proliferation. In the mesocosm experiment, low oxygen lowered RTIP where both species were present, but again the IAS retained high relative impact during Replacement and Proliferation stages at low oxygen. We also found evidence of multiple predator effects, principally antagonism. We highlight the threat posed to native communities by IAS alongside climate-related stressors, but note that solutions may be available to remedy hypoxia and potentially mitigate impacts across invasion stages.

Minimal Dissolved Oxygen Requirements of Aquatic Life with Emphasis on Canadian Species: a Review

1975 ◽  
Vol 32 (12) ◽  
pp. 2295-2332 ◽  
Author(s):  
John C. Davis
Keyword(s):  
Dissolved Oxygen ◽  
Water Body ◽  
Physical Factors ◽  
Seasonal Temperature ◽  
Low Oxygen ◽  
Aquatic Life ◽  
Invertebrate Species ◽  
Oxygen Regime ◽  
Response Thresholds ◽  
Oxygen Requirements

This article reviews the sensitivity, responses, response thresholds, and minimum oxygen requirements of marine and freshwater organisms with strong emphasis on Canadian species. The analysis attempts to define low dissolved oxygen thresholds which produce some physiological, behavioral, or other response in different species.Oxygen availability is discussed with reference to seasonal, geographical, or spatial variation in dissolved oxygen. Factors affecting availability of dissolved oxygen include atmospheric exchange, mixing of water masses, upwelling, respiration, photosynthesis, ice cover, and physical factors such as temperature and salinity. Dissolved oxygen terminology is summarized and tables are included for both fresh and saltwater O2 solubility at different temperatures.Incipient O2 response thresholds are used in a statistical analysis to develop oxygen criteria for safeguarding various groups of freshwater and marine fish. These include mixed freshwater fish populations including or excluding salmonids, freshwater salmonid populations, salmonid larvae or mature salmonid eggs, marine anadromous and nonanadromous species. Criteria are based on threshold oxygen levels which influence fish behavior, blood O2 saturation, metabolic rate, swimming ability, viability and normal development of eggs and larvae, growth, circulatory dynamics, ventilation, gaseous exchange, and sensitivity to toxic stresses. The criteria provide three levels of protection for each fish group and are expressed as percentage oxygen saturation for a range of seasonal temperature maxima.Oxygen tolerances and responses of aquatic invertebrates to low oxygen are reviewed for freshwater and marine species according to habitat. No invertebrate criteria are proposed owing to the capacity for many invertebrate species to adopt anaerobic metabolism during low O2 stress. It is suggested that the criteria proposed for fish species will provide a reasonable safeguard to most invertebrate species. It appears likely, however, that a change in oxygen regime to one of increased O2 scarcity will probably influence invertebrate community structure.It is suggested that criteria for protection of aquatic life be implemented by groups of experienced individuals. The group should consider the natural oxygen regime for a specific water body and its natural variability, the aquatic life therein and its value, importance, relative O2 sensitivity, and the possibility of interactions with toxicants and other factors that may compound the stress produced by low O2 on aquatic life. Each water body and its aquatic life should be considered as a unique situation and criteria application should not encompass diverse areas, habitats, or biological associations as if they were identical.

Low-Oxygen-Saturation Quantification in Human Arterial and Venous Circulation

2009 ◽  
Vol 56 (3) ◽  
pp. 846-854 ◽  
Author(s):  
J. Schoevers ◽  
C. Scheffer ◽  
R. Dippenaar
Keyword(s):  
Oxygen Saturation ◽  
Low Oxygen ◽  
Venous Circulation

scholarly journals Challenges associated with modeling low-oxygen waters in Chesapeake Bay: a multiple model comparison

2016 ◽  
Vol 13 (7) ◽  
pp. 2011-2028 ◽  
Author(s):  
Isaac D. Irby ◽  
Marjorie A. M. Friedrichs ◽  
Carl T. Friedrichs ◽  
Aaron J. Bever ◽  
Raleigh R. Hood ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Chesapeake Bay ◽  
Mixed Layer ◽  
Model Comparison ◽  
Three Dimensional ◽  
Surface Mixed Layer ◽  
Multiple Model ◽  
Low Oxygen ◽  
Mixing Depth ◽  
Biogeochemical Models

Abstract. As three-dimensional (3-D) aquatic ecosystem models are used more frequently for operational water quality forecasts and ecological management decisions, it is important to understand the relative strengths and limitations of existing 3-D models of varying spatial resolution and biogeochemical complexity. To this end, 2-year simulations of the Chesapeake Bay from eight hydrodynamic-oxygen models have been statistically compared to each other and to historical monitoring data. Results show that although models have difficulty resolving the variables typically thought to be the main drivers of dissolved oxygen variability (stratification, nutrients, and chlorophyll), all eight models have significant skill in reproducing the mean and seasonal variability of dissolved oxygen. In addition, models with constant net respiration rates independent of nutrient supply and temperature reproduced observed dissolved oxygen concentrations about as well as much more complex, nutrient-dependent biogeochemical models. This finding has significant ramifications for short-term hypoxia forecasts in the Chesapeake Bay, which may be possible with very simple oxygen parameterizations, in contrast to the more complex full biogeochemical models required for scenario-based forecasting. However, models have difficulty simulating correct density and oxygen mixed layer depths, which are important ecologically in terms of habitat compression. Observations indicate a much stronger correlation between the depths of the top of the pycnocline and oxycline than between their maximum vertical gradients, highlighting the importance of the mixing depth in defining the region of aerobic habitat in the Chesapeake Bay when low-oxygen bottom waters are present. Improvement in hypoxia simulations will thus depend more on the ability of models to reproduce the correct mean and variability of the depth of the physically driven surface mixed layer than the precise magnitude of the vertical density gradient.

scholarly journals Mortality Risk Factors in Tetralogy of Fallot Patients Undergoing Total Correction

2021 ◽  
Vol 57 (2) ◽  
pp. 151
Author(s):  
Juliana Juliana ◽  
Yan Efrata Sembiring ◽  
Mahrus Abdur Rahman ◽  
Heroe Soebroto
Keyword(s):  
Risk Factors ◽  
Developing Countries ◽  
Oxygen Saturation ◽  
Tetralogy Of Fallot ◽  
Mortality Risk ◽  
Operative Risk ◽  
Average Height ◽  
Low Oxygen ◽  
Total Correction ◽  
Ventilator Time

A total correction is a preferred treatment for Tetralogy of Fallot patients in every part of the world. However, the mortality in developing countries was as high as 6.9% to 15.3%. This was a retrospective analytic study that analyzed pre and post-operative risk factors that affected mortality on TOF patients that were performed total correction in Indonesia. A total of 47 TOF patients that were performed total correction from January 2016 to September 2019 were enrolled in this study based on the inclusion criteria. Preoperative and post-operative data were obtained from medical records. In this research, the majority of mortality was found in male patients (39.3%), while the female’s rate was lower (36.8%). Overall mortality was 38.3% and one operative death was found. The average age of patients was 84.12 months (12-210 months), whereas the average height (85.56 ± 36.17cm vs. 112.93 ± 21.73) and weight (17.22kg vs. 28.21kg) were lower for mortality patients. Some significant preoperative variables were identified as mortality risk factors such as: age below 60 months (p=0.047), smaller weight and height (p=0.008; p=0.002), abnormal hematocrit (p=0.002), and oxygen saturation below 75% (p=0.018). Significant post-operative risk factors included: temperature above 38.5⁰C (p=0.000), and ventilator time of more than 48 hours (p=0.033). In conclusion, the mortality of TOF patients undergoing a total correction in developing countries was quite high. It was associated with some risk factors, such as younger age, lower weight and height, low oxygen saturation, post-operative fever, and prolonged ventilator time.

scholarly journals COVID-19 in Northeast Bosnia and Herzegovina and patients length of hospitalization

2020 ◽  
Author(s):  
Alma Trnacevic ◽  
Amer Mujkanovic ◽  
Noura Al-Salloum ◽  
Amra Sakusic ◽  
Emir Trnacevic ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Bosnia And Herzegovina ◽  
Clinical Factors ◽  
Low Oxygen ◽  
The World ◽  
The Mean ◽  
Elevated Creatinine ◽  
Underlying Diseases ◽  
Time Of Admission ◽  
Length Of Hospitalization

Abstract Background Since outbreak of COVID-19 pandemic clinical data from various parts of the world have been reported, until now there has been no provide data from Bosnia and Herzegovina (B&H) about COVID-19. Aim was to report on the first cohort of patients from B&H and to analyze clinical factors of COVID-19 patients that influence the length of hospitalization. Methods Retrospective cohort study conducted at UKC Tuzla. The study included 25 COVID-19 positive patients that were hospitalized between March 28th and April 27th 2020. The LOH was measured from the time of admission to discharge. Hospitalization greater than 10 days was considered as prolonged. Factors analyzed induced age, BMI, comorbidities, serum creatinine and oxygen saturation upon admission.Results The mean age was 52.92±19.15 years and BMI 28.80±4.22. LOH for patients with normal BMI was 9±SE2.646 days (CI 95% 3.814-14.816) vs 14.182 ±SE .937 (CI 95% 12.346-16.018; p<0.05) for ≥25 BMI. Patients without underlying diseases had a LOH of 11.70 ±SE1.075 (CI 95% 9.592-13.808), while those with comorbidities 14.8 ±SE1.303 (CI95% 12.247-17.353; p<0.05). Conclusion LOH varied among COVID-19 patients and was prolonged when clinical characteristics such as elevated BMI, comorbidities, elevated creatinine and low oxygen saturation levels were taken into consideration. Furthermore, risk factors for COVID-19 patients in B&H do not deviate from data reported in other countries.

scholarly journals Sequestro Leucocitário de Oxigénio

2016 ◽  
Vol 29 (5) ◽  
pp. 343
Author(s):  
Miguel Pinto da Costa ◽  
Henrique Pimenta Coelho
Keyword(s):  
Oxygen Saturation ◽  
Pulse Oximetry ◽  
Arterial Oxygen Saturation ◽  
Gas Analysis ◽  
Lymphocytic Leukemia ◽  
Red Blood Cell Transfusion ◽  
Clinical State ◽  
Arterial Oxygen ◽  
Low Oxygen ◽  
Arterial Blood

<p>The authors present a case of a 60-year-old male patient, previously diagnosed with B-cell chronic lymphocytic leukemia, who was admitted to the Emergency Room with dyspnea. The initial evaluation revealed severe anemia (Hgb = 5.0 g/dL) with hyperleukocytosis (800.000/µL), nearly all of the cells being mature lymphocytes, a normal chest X-ray and a low arterial oxygen saturation (89%; pulse oximetry). After red blood cell transfusion, Hgb values rose (9.0 g/dL) and there was a complete reversion of the dyspnea. Yet, subsequent arterial blood gas analysis, without the administration of supplemental oxygen, systematically revealed very low oxygen saturation values (~ 46%), which was inconsistent with the patient’s clinical state and his pulse oximetry values (~ 87%), and these values were not corrected by the administration of oxygen via non-rebreather mask. The investigation performed allowed to establish the diagnosis of oxygen leukocyte larceny, a phenomenon which conceals the true oxygen saturation due to peripheral consumption by leukocytes.</p>

scholarly journals Warming effect on nitrogen fixation in Mediterranean macrophyte sediments

2019 ◽  
Vol 16 (1) ◽  
pp. 167-175 ◽  
Author(s):  
Neus Garcias-Bonet ◽  
Raquel Vaquer-Sunyer ◽  
Carlos M. Duarte ◽  
Núria Marbà
Keyword(s):  
N2 Fixation ◽  
Thermal Sensitivity ◽  
Thermal Response ◽  
Sharp Decrease ◽  
Posidonia Oceanica ◽  
Global Ocean ◽  
Thermal Dependence ◽  
High Productivity ◽  
Marine Macrophytes ◽  
The Impact

Abstract. The Mediterranean Sea is warming faster than the global ocean, with important consequences for organisms and biogeochemical cycles. Warming is a major stressor for key marine benthic macrophytes. However, the effect of warming on marine N2 fixation remains unknown, despite the fact that the high productivity of macrophytes in oligotrophic waters is partially sustained by the input of new nitrogen (N) into the system by N2 fixation. Here, we assess the impact of warming on the N2 fixation rates of three key marine macrophytes: Posidonia oceanica, Cymodocea nodosa, and Caulerpa prolifera. We experimentally measured N2 fixation rates in vegetated and bare sediments at temperatures encompassing current summer mean (25 and 27 ∘C), projected summer mean (29 and 31 ∘C), and projected summer maximum (33 ∘C) seawater surface temperatures (SSTs) by the end of the century under a scenario of moderate greenhouse gas emissions. We found that N2 fixation rates in vegetated sediments were 2.8-fold higher than in bare sediments at current summer mean SST, with no differences among macrophytes. Currently, the contribution of N2 fixation to macrophyte productivity could account for up to 7 %, 13.8 %, and 1.8 % of N requirements for P. oceanica, C. nodosa, and C. prolifera, respectively. We show the temperature dependence of sediment N2 fixation rates. However, the thermal response differed for vegetated sediments, in which rates showed an optimum at 31 ∘C followed by a sharp decrease at 33 ∘C, and bare sediments, in which rates increased along the range of the experimental temperatures. The activation energy and Q10 were lower in vegetated than bare sediments, indicating the lower thermal sensitivity of vegetated sediments. The projected warming is expected to increase the contribution of N2 fixation to Mediterranean macrophyte productivity. Therefore, the thermal dependence of N2 fixation might have important consequences for primary production in coastal ecosystems in the context of warming.

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