Search results for "Respiration rate"
showing 10 items of 26 documents
Physiological advantages of dwarfing in surviving extinctions in high-CO2 oceans
2015
Excessive CO2 in the present-day ocean-atmosphere system is causing ocean acidification, and is likely to cause a severe biodiversity decline in the future, mirroring effects in many past mass extinctions. Fossil records demonstrate that organisms surviving such events were often smaller than those before, a phenomenon called the Lilliput effect. Here, we show that two gastropod species adapted to acidified seawater at shallow-water CO2 seeps were smaller than those found in normal pH conditions and had higher mass-specific energy consumption but significantly lower whole-animal metabolic energy demand. These physiological changes allowed the animals to maintain calcification and to partial…
Seawater carbonate chemistry and kelp densities and coral coverages at three study locations and photosynthesis and calcification of corals measured …
2021
Ocean warming is altering the biogeographical distribution of marine organisms. In the tropics, rising sea surface temperatures are restructuring coral reef communities with sensitive species being lost. At the biogeographical divide between temperate and tropical communities, warming is causing macroalgal forest loss and the spread of tropical corals, fishes and other species, termed “tropicalization”. A lack of field research into the combined effects of warming and ocean acidification means there is a gap in our ability to understand and plan for changes in coastal ecosystems. Here, we focus on the tropicalization trajectory of temperate marine ecosystems becoming coral-dominated systems…
Individual and population-level responses to ocean acidification
2016
Ocean acidification is predicted to have detrimental effects on many marine organisms and ecological processes. Despite growing evidence for direct impacts on specific species, few studies have simultaneously considered the effects of ocean acidification on individuals (e.g. consequences for energy budgets and resource partitioning) and population level demographic processes. Here we show that ocean acidification increases energetic demands on gastropods resulting in altered energy allocation, i.e. reduced shell size but increased body mass. When scaled up to the population level, long-term exposure to ocean acidification altered population demography, with evidence of a reduction in the pr…
Seagrass ecosystem response to long-term high CO2 in a Mediterranean volcanic vent
2014
We examined the long-term effect of naturally acidified water on a Cymodocea nodosa meadow growing at a shallow volcanic CO2 vent in Vulcano Island (Italy). Seagrass and adjacent unvegetated habitats growing at a low pH station (pH = 7.65 ± 0.02) were compared with corresponding habitats at a control station (pH = 8.01 ± 0.01). Density and biomass showed a clear decreasing trend at the low pH station and the below- to above-ground biomass ratio was more than 10 times lower compared to the control. C content and delta 13C of leaves and epiphytes were significantly lower at the low pH station. Photosynthetic activity of C. nodosa was stimulated by low pH as seen by the significant increase in…
Effect of 1-methylcyclopropene on cactus pear fruit at different maturity stages during storage
2019
1-Methylcyclopropene (1‑MCP) is an ethylene antagonist widely used to retain quality and prolong the postharvest storage period of various climacteric fruits. To date, there is little information about the effects of 1‑MCP on postharvest storage performance of cactus pear fruits. Recently, data revealed that exposure of 1‑MCP at 1000 ppb had several beneficial effects in preserving postharvest quality of cactus pear fruits, as indicated by inhibition of peel color change. In this paper, we investigated the effect of 1‑MCP on quality of cactus pear fruit harvested from the scozzolatura crop at early and late ripeness stages. Fruit was tested at two different ripening stages: “commercial ripe…
Toward the definition of a carbon budget model: seasonal variation and temperature effect on respiration rate of vegetative and reproductive organs o…
2009
Summary This study, as a preliminary step toward the definition of a carbon budget model for pistachio trees (Pistacia vera L.), aimed at estimating and evaluating the dynamics of respiration of vegetative and reproductive organs of pistachio tree. Trials were performed in 2005 in a commercial orchard located in Sicily (370 m a.s.l.) on five bearing 20-year-old pistachio trees of cv. Bianca grafted onto Pistachio terebinthus L. Growth analyses and respiration measurements were done on vegetative (leaf) and reproductive (infructescence) organs during the entire growing season (April–September) at biweekly intervals. Results suggested that the respiration rates of pistachio reproductive and v…
NADH dehydrogenase deficiency results in low respiration rate and improved aerobic growth of Zymomonas mobilis.
2008
The respiratory chain of the ethanol-producing bacterium Zymomonas mobilis is able to oxidize both species of nicotinamide cofactors, NADH and NADPH. A mutant strain with a chloramphenicol-resistance determinant inserted in ndh (encoding an NADH : CoQ oxidoreductase of type II) lacked the membrane NADH and NADPH oxidase activities, while its respiratory d-lactate oxidase activity was increased. Cells of the mutant strain showed a very low respiration rate with glucose and no respiration with ethanol. The aerobic growth rate of the mutant was elevated; exponential growth persisted longer, resulting in higher biomass densities. For the parent strain a similar effect of aerobic growth stimulat…
Estimating oxygen consumption from heart rate and heart rate variability without individual calibration
2011
Heart rate (HR) as an estimator of oxygen consumption (VO(2) ) usually requires HR to be individually calibrated in a separate test. This study examined the validity of a new HR - and HR variability-based method (Firstbeat PRO heartbeat analysis software) in the estimation of VO(2) in real-life tasks. The method takes into account the respiration rate determined from HR variability and the differences in the on/off dynamics of HR and VO(2) , and no calibration tests are needed. Ten men and nine women performed 25 tasks representing different types of daily activities. Portable devices were used to measure R-to-R intervals (ECG), VO(2) and respiration rate. In pooled regression analysis, the…
Quality changes in fresh-cut mango cubes submitted to different gas partial pressure of active MAPs
2018
The study was performed to assess chemical-physical and sensory quality changes in 4±1°C stored fresh-cut mangos and to test the effect of active modified atmosphere packaging (MAP) with different gas partial pressures. Sicilian fruits of ‘Keitt’ mango (Mangifera indica L.) were immerged in hydrogen peroxide (H2O2) after being peeled. Next, the flesh was cut in cubes and dipped in citric acid (0.5%, w/v) and ascorbic acid (0.5%, w/v). Treated fruits were placed in a non-perforated high density polyethylene package flushing different gas mixtures and kept at 4°C for 21 days. We used four different gas partial pressures: a) 60 kPa N2, 30 kPa CO2 and 10 kPa O2; b) 30 kPa CO2 and 70 kPa N2; c) …
Qualitative traits and shelf life of fig fruit (cv Melanzana) treated with Aloe vera gel coating
2021
The fig (Ficus carica L.) cv Melanzana is typical of Southern Italy. This cultivar produces breba fruit in June and fig fruit in August. Some previous studies on the use of coatings extracted from stems of Aloe vera showed positive effects to maintain fruit quality during shelf life. However, there are no studies on breba fig fruit treated with Aloe vera coating. In this study breba fig fruit, cv Melanzana, was treated with an application of Aloe vera gel, sealed in macro-perforated bag and stored at 5°C for 10 days. The effect of application of the Aloe vera gel on the shelf-life of this fruit, and its quality attributes after application were evaluated measuring fresh weight, total solubl…