15 research outputs found
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Testing local and global stressor impacts on a coastal foundation species using an ecologically realistic framework
Despite the abundance of literature on organismal responses to multiple environmental stressors, most studies have not matched the timing of experimental manipulations with the temporal pattern of stressors in nature. We test the interactive effects of diel-cycling hypoxia with both warming and decreased salinities using ecologically realistic exposures. Surprisingly, we found no evidence of negative synergistic effects on Olympia oyster growth; rather, we found only additive and opposing effects of hypoxia (detrimental) and warming (beneficial). We suspect that diel-cycling provided a temporal refuge that allowed physiological compensation. We also tested for latent effects of warming and hypoxia to low-salinity tolerance using a seasonal delay between stressor events. However, we did not find a latent effect, rather a threshold survival response to low salinity that was independent of early life-history exposure to warming or hypoxia. The absence of synergism is likely the result of stressor treatments that mirror the natural timing of environmental stressors. We provide environmental context for laboratory experimental data by examining field time series environmental data from four North American west coast estuaries and find heterogeneous environmental signals that characterize each estuary, suggesting that the potential stressor exposure to oysters will drastically differ over moderate spatial scales. This heterogeneity implies that efforts to conserve and restore oysters will require an adaptive approach that incorporates knowledge of local conditions. We conclude that studies of multiple environmental stressors can be greatly improved by integrating ecologically realistic exposure and timing of stressors found in nature with organismal life-history traits
Recommended from our members
Testing local and global stressor impacts on a coastal foundation species using an ecologically realistic framework
Despite the abundance of literature on organismal responses to multiple environmental stressors, most studies have not matched the timing of experimental manipulations with the temporal pattern of stressors in nature. We test the interactive effects of diel-cycling hypoxia with both warming and decreased salinities using ecologically realistic exposures. Surprisingly, we found no evidence of negative synergistic effects on Olympia oyster growth; rather, we found only additive and opposing effects of hypoxia (detrimental) and warming (beneficial). We suspect that diel-cycling provided a temporal refuge that allowed physiological compensation. We also tested for latent effects of warming and hypoxia to low-salinity tolerance using a seasonal delay between stressor events. However, we did not find a latent effect, rather a threshold survival response to low salinity that was independent of early life-history exposure to warming or hypoxia. The absence of synergism is likely the result of stressor treatments that mirror the natural timing of environmental stressors. We provide environmental context for laboratory experimental data by examining field time series environmental data from four North American west coast estuaries and find heterogeneous environmental signals that characterize each estuary, suggesting that the potential stressor exposure to oysters will drastically differ over moderate spatial scales. This heterogeneity implies that efforts to conserve and restore oysters will require an adaptive approach that incorporates knowledge of local conditions. We conclude that studies of multiple environmental stressors can be greatly improved by integrating ecologically realistic exposure and timing of stressors found in nature with organismal life-history traits
Assessments of functional status, comorbidities, polypharmacy, nutritional status and sarcopenia in Turkish community-dwelling male elderly
Functionality, comorbidities, polypharmacy, nutritional status and sarcopenia affect the prognosis of elderly excessively. These parameters are influenced by the population, living settings and age. We aimed to study these parameters in Turkish community-dwelling male elderly. We studied 274 male elderly >= 60 years of age admitted to our Geriatrics outpatient clinics. Mean age was 74.4 +/- 7.1 years; 47.4% of the subjects were >= 75 years, 24.1% were >= 80 years. Mean activities-of-daily-living (ADL) and instrumental ADL (IADL) scores were 9.4 and 11.1, respectively. Patients with at least one-dependence at ADL-IADL were 22.6%-47.2%, and more than half-dependence at ADL-IADL were 2.8%-17.9%, respectively. Mean number of comorbidities were 2.6. Most common diagnosis was hypertension with 65%; mean number of drugs were 4.5; 55.3% were using >= 4 chronic drugs. Prevalences of malnutrition were 3.7%-6.9%, malnutrition risk were 23.5%-26.7% by the Mini Nutritional Assessment Test - Long Form and Short Form, respectively. Calf circumference was measured <31 cm in 10.5%. Our findings suggest that Turkish community-dwelling male elderly may have greater prevalences of functional dependence, sarcopenia but lower rates of malnutrition and similar rates of polypharmacy compared with the western developing countries and developed countries. This study emphasized the geographical differences in and/or between the individual countries highlighting the need for studies both country-and world-wide