Impacts of experimental flooding on microbial communities and methane fluxes in an urban meadow, baton rouge, louisiana

© 2019 King and Henry. The impacts of extended flooding on microbial communities and their activities in natural and agricultural wetlands have been well-documented, but there is little basis for predicting the responses of urban soil microbial communities to infrequent, short-term flooding. To assess these responses, surface soil samples (0–1 cm) and intact soil cores (10 cm depth) were collected from an urban meadow in Baton Rouge, LA subsequent to an unprecedented flood during August 2016. During the flood, a topographically low region of the meadow (LM) was inundated for at least several days, while an elevated area (upper meadow or UM) was not flooded. Microbial community composition and diversity at each site were assessed for soils collected from cores at various depths over the upper 10 cm before and after 3 days of experimental flooding ex situ. Cores from LM and UM were also used to assess methane fluxes before and after the experimental flooding. The results indicated that methane fluxes differed between LM and UM sites, and that they were affected by flooding. LM cores emitted methane prior to flooding, and rates increased substantially post-flooding; UM cores consumed methane to levels below ambient atmospheric concentrations prior to flooding, but emitted methane post-flooding. In contrast both LM and UM microbial communities were resistant to short-term flooding, with no significant changes observed at either site, or at any depth interval from the surface to 10 cm. However, LM and UM soil communities differed significantly, with distinct distributions of Acidobacteria, Nitrospirae, and Thaumarchaeota among others. Based on responses of soil cores to experimental flooding, the differences between sites in microbial communities did not appear to be residual effects of the August, 2016 flood, but rather appeared to arise from physical, chemical, and biological variables that change along a 4-m elevation gradient. Collectively, the results suggest that the composition and diversity for some urban soils might be insensitive to short-term flooding, but that important biogeochemical processes, e.g., methane fluxes, might respond rapidly

The Difference in Efficiency and Pulmonary Function While Performing Cycle Ergometry on Land and in Water

The purpose of this study was to quantify the difference in net efficiency and pulmonary function while performing cycle ergometry on land in water. Thirty healthy adults (mean ± SD, age, 20 ± 2 y; stature, 165 ± 10 cm; mass, 70 ± 5 kg) participated in one day of testing consisting of both land and water conditions. Heart rate, O2 consumption, CO2 production, rated perceived exertion, and minute ventilation were measured for both conditions at rest, pedaling at no resistance, 50, and 100 W for two minutes. A repeated measures two-way ANOVA with post hoc tests was used to analyzed the data. The magnitude of physiological functions (rated perceived exertion, minute ventilation, energy expenditure, & heart rate) increased at higher resistance levels (50 and 100W) in water as compared to land. Efficiency decreased at 50 and 100W in water. Energy expenditure and minute ventilation both increase while cycling in water, resulting in a decrease of efficiency by 4.61%. This is due to the drag forces associated with fluid dynamics. This study and its results add to the understanding of water exercise and are beneficial to the rehabilitation and the general well-being and health of the population.Faculty Sponsor: Dr. Shawn Henr

The Difference in Efficiency and Pulmonary Function While Performing Cycle Ergometry on Land and in Water

The purpose of this study was to quantify the difference in net efficiency and pulmonary function while performing cycle ergometry on land in water. Thirty healthy adults (mean ± SD, age, 20 ± 2 y; stature, 165 ± 10 cm; mass, 70 ± 5 kg) participated in one day of testing consisting of both land and water conditions. Heart rate, O2 consumption, CO2 production, rated perceived exertion, and minute ventilation were measured for both conditions at rest, pedaling at no resistance, 50, and 100 W for two minutes. A repeated measures two-way ANOVA with post hoc tests was used to analyzed the data. The magnitude of physiological functions (rated perceived exertion, minute ventilation, energy expenditure, & heart rate) increased at higher resistance levels (50 and 100W) in water as compared to land. Efficiency decreased at 50 and 100W in water. Energy expenditure and minute ventilation both increase while cycling in water, resulting in a decrease of efficiency by 4.61%. This is due to the drag forces associated with fluid dynamics. This study and its results add to the understanding of water exercise and are beneficial to the rehabilitation and the general well-being and health of the population

Controls on boron incorporation in cultured tests of the planktic foraminifer Orbulina universa

Culture experiments with living planktic foraminifers reveal that the ratio of boron to calcium (B/Ca) in Orbulina universa increases from 56 to 92 μmol mol−1 when pH is raised from 7.61+/–0.02 to 8.67+/–0.03 (total scale). Across this pH range, the abundances of carbonate, bicarbonate, and borate ions also change (+530, −500, and +170 μmol kg−1, respectively). Thus specific carbonate system control(s) on B/Ca remain unclear, complicating interpretation of paleorecords. B/Ca in cultured O. universa also increases with salinity (55–72 μmol mol−1 from 29.9–35.4‰) and seawater boron concentration (62–899 μmol mol−1 from 4–40 ppm B), suggesting that these parameters may need to be taken into account for paleorecords spanning large salinity changes (~ 2‰) and for samples grown in seawater whose boron concentration ([B]SW) differs from modern by more than 0.25 ppm. While our results are consistent with the predominant incorporation of the charged borate species B(OH)4−into foraminiferal calcite, the behavior of the partition coefficient KD (defined as [B/Ca]calcite/[B(OH)4−/HCO3−]seawater) cannot be explained by borate incorporation alone, and suggests the involvement of other pH-sensitive ions such as CO3 2− For a given increase in seawater B(OH)4−, the corresponding increase in B/Ca is stronger when B(OH)4− is raised by increasing [B]SW than when it is raised by increasing pH. These results suggest that B incorporation controls should be reconsidered. Additional insight is gained from laser-ablation ICP-MS profiles, which reveal variable B/Ca distributions within individual shells

Carbon cycling in the deep eastern North Pacific benthic food web: Investigating the effect of organic carbon input

The deep ocean benthic environment plays a role in long-term carbon sequestration. Understanding carbon cycling in the deep ocean floor is critical to evaluate the impact of changing climate on the oceanic systems. Linear inverse modeling was used to quantify carbon transfer between compartments in the benthic food web at a long time-series study site in the abyssal northeastern Pacific (Station M). Linear inverse food web models were constructed for three separate years in the time-series when particulate organic carbon (POC) flux was relatively high (1990: 0.63 mean mmol C m?2 d?1), intermediate (1995: 0.24) and low (1996: 0.12). Carbon cycling in all years was dominated by the flows involved in the microbial loop; dissolved organic carbon uptake by microbes (0.80–0.95 mean mmol C m?2 d?1), microbial respiration (0.52–0.61), microbial biomass dissolution (0.09–0.18) and the dissolution of refractory detritus (0.46–0.65). Moreover, the magnitude of carbon flows involved in the microbial loop changed in relation to POC input, with a decline in contribution during the high POC influxes, such as those recently experienced at Station M. Results indicate that during high POC episodic pulses the role of faunal mediated carbon cycling would increase. Semi-labile detritus dominates benthic faunal diets and the role of labile detritus declined with increased total POC input. Linear inverse modeling represents an effective framework to analyze high-resolution time-series data and demonstrate the impact of climate change on the deep ocean carbon cycle in a coastal upwelling system

lynx1 Supports Neuronal Health in the Mouse Dorsal Striatum During Aging: an Ultrastructural Investigation

Nicotinic acetylcholine receptors have been shown to participate in neuroprotection in the aging brain. Lynx protein modulators dampen the activity of the cholinergic system through direct interaction with nicotinic receptors. Although lynx1 null mutant mice exhibit augmented learning and plasticity, they also exhibit macroscopic vacuolation in the dorsal striatum as they age, detectable at the optical microscope level. Despite the relevance of the lynx1 gene to brain function, little is known about the cellular ultrastructure of these age-related changes. In this study, we assessed degeneration in the dorsal striatum in 1-, 3-, 7-, and 13-month-old mice, using optical and transmission electron microscopy. We observed a loss of nerve fibers, a breakdown in nerve fiber bundles, and a loss of neuronal nuclei in the 13-month-old lynx1 null striatum. At higher magnification, these nerve fibers displayed intracellular vacuoles and disordered myelin sheaths. Few or none of these morphological alterations were present in younger lynx1 null mutant mice or in heterozygous lynx1 null mutant mice at any age. These data indicate that neuronal health can be maintained by titrating lynx1 dosage and that the lynx1 gene may participate in a trade-off between neuroprotection and augmented learning

Neuropsychological, Behavioral, and Anatomical Evolution in Right Temporal Variant Frontotemporal Dementia: A Longitudinal Single Case Analysis

We examine longitudinal clinical and anatomical data for a patient with the right temporal variant of frontotemporal dementia. The patient received comprehensive clinical evaluations and structural MRI scans over three years. She presented with early behavioral deficits and ultimately developed semantic impairments consistent with the semantic variant of primary progressive aphasia. Imaging revealed early atrophy of the right temporal lobe, with later involvement of the left, and pathology confirmed bilateral temporal involvement. Findings support the view that right and left temporal variants reflect early asymmetry of atrophy that may become more bilateral over time, resulting in a mixed clinical picture

Integrating taphonomy into the practice of zooarchaeology in China

With the study of faunal remains (zooarchaeology) emerging as an increasingly prominent component of archaeological studies in China, the importance of studying processes of assemblage formation and preservation (taphonomy) is becoming evident. Remains of animals recovered from an archaeological site are a biased sample of the assemblage that was originally deposited because certain animal parts preserve better than others. Important characteristics of faunal assemblages, such as skeletal element representation and age profiles, can be affected by differential preservation caused by taphonomic agents, both cultural or natural. One primary goal of taphonomic studies is to provide an understanding of differential preservation of bone elements, allowing archaeologists to make more accurate assessments concerning the exploitation of different animal species by past peoples. Recent studies of the faunal assemblages from the Early Paleolithic site of Xujiayao and the Neolithic site of Taosi, both in Shanxi Province, provide examples of the effects that differential preservation can have on archaeological interpretations of skeletal element representation and age profiles, respectively. These examples illustrate how an understanding of taphonomy is critical to the future practice of zooarchaeology in China.Anthropolog

The consumption of protein-rich foods in older adults: An exploratory focus group study

Objective: Many older adults consume inadequate protein for their needs. This study explored the factors associated with the consumption of high-protein foods in older adults. Methods: Participants over the age of 65 years (n = 28) took part in 1 of 4 focus group discussions on meat, fish, eggs, dairy products, nuts, and pulses. Discussions were audio taped, transcribed, and analyzed using thematic analysis. Results: Numerous and various reasons for the consumption and non-consumption of high-protein foods were reported. Many of these reasons result from reductions in chemosensory, dental and physical abilities, and changes in living situation in the older population, and have impact specifically on high-protein foods because of their often hard, perishable and need-to-be-cooked nature, and high cost. Conclusions and Implications: Further work is required to establish the importance of each of thesereasons in relation to protein intakes, to prioritize those of likely greatest impact for increasing intakes. © 2013 Society for Nutrition Education and Behavior