ALBERT

Description: We study the distribution of projected ellipticity n () for galaxies in a sample of 20 rich (Richness ≥ 2) nearby ( z 〈 0.1) clusters of galaxies. We find no evidence of differences in n (), although the nearest cluster in the sample (the Coma Cluster) is the largest outlier ( P (same) 〈 0.05). We then study n () within the clusters, and find that increases with projected cluster-centric radius R (hereafter the -R relation). This trend is preserved at fixed magnitude, showing that this relation exists over and above the trend of more luminous galaxies to be both rounder and more common in the centres of clusters. The -R relation is particularly strong in the subsample of intrinsically flattened galaxies ( 〉 0.4), therefore it is not a consequence of the increasing fraction of round slow rotator galaxies near cluster centers. Furthermore, the -R relation persists for just smooth flattened galaxies and for galaxies with de Vaucouleurs-like light profiles, suggesting that the variation of the spiral fraction with radius is not the underlying cause of the trend. We interpret our findings in light of the classification of early type galaxies (ETGs) as fast and slow rotators. We conclude that the observed trend of decreasing towards the centres of clusters is evidence for physical effects in clusters causing fast rotator ETGs to have a lower average intrinsic ellipticity near the centres of rich clusters.

Description: F1Fo-ATP synthases are universal energy-converting membrane protein complexes that synthesize ATP from ADP and inorganic phosphate. In mitochondria of yeast and mammals, the ATP synthase forms V-shaped dimers, which assemble into rows along the highly curved ridges of lamellar cristae. Using electron cryotomography and subtomogram averaging, we have determined the...

Description: Developing land-use practices that lead to sustainable net primary productivity in rangelands are important, but understanding their consequences to population and community processes is not often accounted for in basic ecosystem studies. Grazed and ungrazed upland ecosystems generally do not differ in net ecosystem CO 2 exchange (NEE), but the underlying mechanisms and the concurrent effects of defoliation to vegetative and reproductive biomass allocation are unclear. To address this, we measured evapotranspiration (ET), NEE, and its constituent fluxes of ecosystem respiration (R eco ) and gross ecosystem photosynthesis (GEP) with live canopy leaf area index (LAI live ; m 2 live leaf area/m 2 ground area) and aboveground leaf, culm, and reproductive biomass in plots of clipped and unclipped squirreltail ( Elymus elymoides ) and bluebunch wheatgrass ( Pseudoroegneria spicata ) growing in intact sagebrush steppe. Clipping reduced LAI live by 75%, but subsequent re-growth rates in clipped plots was similar to LAI live accumulation in unclipped plots. Concurrently, ET and NEE was similar between clipped and unclipped plots, with NEE primarily determined by GEP. GEP was initially lower in clipped plots, but then converged with unclipped GEP even as LAI live continued to increase in both treatments. GEP convergence was driven by higher whole-plant photosynthesis (GEP live  = GEP/LAI live ) in clipped plots. Ecosystem water use efficiency (GEP/ET) was reduced by 16% with clipping, due to low GEP/ET 2 weeks following defoliation, but GEP/ET converged before GEP levels did. Proportional reproductive biomass was higher in E. elymoides (21.4% total biomass) than in P. spicata (0.5% total biomass) due to lower allocation to specific leaf and culm mass. Clipping reduced reproductive effort in E. elymoides , in terms of total reproductive biomass (−56%), seed mass per unit leaf area (−64%), and seed mass per flowering head (−77%). We concluded defoliation increased canopy-level light penetration, facilitating rapid recovery of ecosystem fluxes, but that allocation to vegetative regrowth supporting this led to lower reproductive effort in these range grasses. Insights from studies such as this will be useful in formulating systems-based land management strategies aimed at maintaining annual productivity and long-term population and community goals in semiarid rangeland ecosystems.

Description: We characterized century‐scale growth records of inner and outer reef corals across ~200 km of the Florida Keys Reef Tract (FKRT) using skeletal cores extracted from two ubiquitous reef‐building species. We find that corals across the FKRT have sustained extension and calcification rates over the past century but have experienced a long‐term reduction in skeletal density, regardless of reef zone. We argue that the subtropical climate of the FKRT may buffer corals from chronic growth declines associated with climate warming, though the significant reduction in skeletal density may indicate underlying vulnerability to present and future trends in ocean acidification. Abstract Through the continuous growth of their carbonate skeletons, corals record information about past environmental conditions and their effect on colony fitness. Here, we characterize century‐scale growth records of inner and outer reef corals across ~200 km of the Florida Keys Reef Tract (FKRT) using skeletal cores extracted from two ubiquitous reef‐building species, Siderastrea siderea and Pseudodiploria strigosa. We find that corals across the FKRT have sustained extension and calcification rates over the past century but have experienced a long‐term reduction in skeletal density, regardless of reef zone. Notably, P. strigosa colonies exhibit temporary reef zone‐dependent reductions in extension rate corresponding to two known extreme temperature events in 1969–1970 and 1997–1998. We propose that the subtropical climate of the FKRT may buffer corals from chronic growth declines associated with climate warming, though the significant reduction in skeletal density may indicate underlying vulnerability to present and future trends in ocean acidification.

Description: Anthropogenic increases in atmospheric carbon dioxide concentration have caused global average sea surface temperature (SST) to increase by approximately 0.11°C per decade between 1971 and 2010 – a trend that is projected to continue through the 21st century. A multitude of research studies have demonstrated that increased SSTs compromise the coral holobiont (cnidarian host and its symbiotic algae) by reducing both host calcification and symbiont density, among other variables. However, we still do not fully understand the role of heterotrophy in the response of the coral holobiont to elevated temperature, particularly for temperate corals. Here, we conducted a pair of independent experiments to investigate the influence of heterotrophy on the response of the temperate scleractinian coral Oculina arbuscula to thermal stress. Colonies of O. arbuscula from Radio Island, North Carolina, were exposed to four feeding treatments (zero, low, moderate, and high concentrations of newly hatched Artemia sp. nauplii) across two independent temperature experiments (average annual SST (20°C) and average summer temperature (28°C) for the interval 2005–2012) to quantify the effects of heterotrophy on coral skeletal growth and symbiont density. Results suggest that heterotrophy mitigated both reduced skeletal growth and decreased symbiont density observed for unfed corals reared at 28°C. This study highlights the importance of heterotrophy in maintaining coral holobiont fitness under thermal stress and has important implications for the interpretation of coral response to climate change. Anthropogenic increases in atmospheric carbon dioxide concentration since the Industrial Revolution have caused global average sea surface temperature to increase, resulting in reduced fitness of the coral holobiont (cnidarian host and its symbiotic algae) including reductions in host calcification and symbiont density. We are only beginning to understand the role of heterotrophy in the coral holobiont response to elevated temperature, particularly for temperate corals. Here, we conducted two common garden experiments and the results suggest that heterotrophy mitigated the negative effects of thermal stress for the temperate coral Oculina arbuscula , highlighting the importance of heterotrophy in maintaining coral holobiont fitness under thermal stress and revealing implications for the interpretation of the coral thermal stress response to climate change.

Description: Organic Letters DOI: 10.1021/acs.orglett.5b01648

Description: Despite constituting a widespread and significant environmental change, understanding of artificial nighttime skyglow is extremely limited. Until now, published monitoring studies have been local or regional in scope, and typically of short duration. In this first major international compilation of monitoring data we answer several key questions about skyglow properties. Skyglow is observed to vary over four orders of magnitude, a range hundreds of times larger than was the case before artificial light. Nearly all of the study sites were polluted by artificial light. A non-linear relationship is observed between the sky brightness on clear and overcast nights, with a change in behavior near the rural to urban landuse transition. Overcast skies ranged from a third darker to almost 18 times brighter than clear. Clear sky radiances estimated by the World Atlas of Artificial Night Sky Brightness were found to be overestimated by ~25%; our dataset will play an important role in the calibration and ground truthing of future skyglow models. Most of the brightly lit sites darkened as the night progressed, typically by ~5% per hour. The great variation in skyglow radiance observed from site-to-site and with changing meteorological conditions underlines the need for a long-term international monitoring program. Scientific Reports 5 doi: 10.1038/srep08409

Description: Technological developments in municipal lighting are altering the spectral characteristics of artificially lit habitats. Little is yet known of the biological consequences of such changes, although a variety of animal behaviours are dependent on detecting the spectral signature of light reflected from objects. Using previously published wavelengths of peak visual pigment absorbance, we compared how four alternative street lamp technologies affect the visual abilities of 213 species of arachnid, insect, bird, reptile and mammal by producing different wavelength ranges of light to which they are visually sensitive. The proportion of the visually detectable region of the light spectrum emitted by each lamp was compared to provide an indication of how different technologies are likely to facilitate visually guided behaviours such as detecting objects in the environment. Compared to narrow spectrum lamps, broad spectrum technologies enable animals to detect objects that reflect light over more of the spectrum to which they are sensitive and, importantly, create greater disparities in this ability between major taxonomic groups. The introduction of broad spectrum street lamps could therefore alter the balance of species interactions in the artificially lit environment. © 2013 Blackwell Publishing Ltd