Climate change is a pervasive and growing global threat to biodiversity and ecosystems. Here, we present the most up-to-date assessment of climate change impacts on biodiversity, ecosystems, and ...ecosystem services in the U.S. and implications for natural resource management. We draw from the 4th National Climate Assessment to summarize observed and projected changes to ecosystems and biodiversity, explore linkages to important ecosystem services, and discuss associated challenges and opportunities for natural resource management. We find that species are responding to climate change through changes in morphology and behavior, phenology, and geographic range shifts, and these changes are mediated by plastic and evolutionary responses. Responses by species and populations, combined with direct effects of climate change on ecosystems (including more extreme events), are resulting in widespread changes in productivity, species interactions, vulnerability to biological invasions, and other emergent properties. Collectively, these impacts alter the benefits and services that natural ecosystems can provide to society. Although not all impacts are negative, even positive changes can require costly societal adjustments. Natural resource managers need proactive, flexible adaptation strategies that consider historical and future outlooks to minimize costs over the long term. Many organizations are beginning to explore these approaches, but implementation is not yet prevalent or systematic across the nation.
•Climate change is affecting ecosystems at multiple scales.•Individual/species: changes in morphology and behavior, phenology, and range shifts observed•Ecosystems: shifts in productivity, species interactions, and emergent properties observed•Together, these changes are impacting ecosystem services and human well-being.•Natural resource managers need proactive, flexible approaches to deal with changes.
Despite the impressive photovoltaic performances with power conversion efficiency beyond 22%, perovskite solar cells are poorly stable under operation, failing by far the market requirements. Various ...technological approaches have been proposed to overcome the instability problem, which, while delivering appreciable incremental improvements, are still far from a market-proof solution. Here we show one-year stable perovskite devices by engineering an ultra-stable 2D/3D (HOOC(CH
)
NH
)
PbI
/CH
NH
PbI
perovskite junction. The 2D/3D forms an exceptional gradually-organized multi-dimensional interface that yields up to 12.9% efficiency in a carbon-based architecture, and 14.6% in standard mesoporous solar cells. To demonstrate the up-scale potential of our technology, we fabricate 10 × 10 cm
solar modules by a fully printable industrial-scale process, delivering 11.2% efficiency stable for >10,000 h with zero loss in performances measured under controlled standard conditions. This innovative stable and low-cost architecture will enable the timely commercialization of perovskite solar cells.
The dynamics of fish communities at tropical and sub-tropical rocky reefs are influenced in many cases by predation activity and predator-prey interactions. These processes usually follow specific ...diel patterns in reef areas with higher rates of these interactions occurring during the crepuscular periods. However, other factors such as habitat complexity and species-specific behavior may alter these patterns, increasing variability in species interactions. A better understanding of the dynamics of these patterns and processes would allow us to manage and monitor fish communities in these productive and vulnerable areas more efficiently. We investigated behavioral changes of predators and prey fish in sub-tropical "live-bottom" (sandstone) reefs at Gray's Reef National Marine Sanctuary (GRNMS), located 20 nautical miles off the coast of Georgia, USA, using fisheries acoustic methods in association with visual census and direct observation using SCUBA. Changes in co-location and habitat preferences of predators and prey over time throughout the diel cycle were investigated using species distribution models (MAXENT) based on habitat predictors and by means of spatial statistics. The results indicate that predator and prey distribution patterns changed considerably throughout the day. Prey and predator species exhibited complex spatial dynamics and behavior over diel periods, with prey modifying patterns of habitat use and spatial distribution, likely as a response of their interactions with predators. Crepuscular periods were confirmed to be the most active phases in terms of predator-prey interactions and consequently the most variable. The combination of tools and approaches used in this study provided valuable sources of information that support the inferences of predation risk-driven habitat selection of prey in this sub-tropical reef system.
The world's coral reefs appear to be in a global decline, yet most previous research on coral reefs has taken place at depths shallower than 30 m. Mesophotic coral ecosystem (depths deeper than ~30 ...m) studies have revealed extensive, productive habitats and rich communities. Despite recent advances, mesophotic coral ecosystems remain understudied due to challenges with sampling at deeper depths. The few previous studies of mesophotic coral ecosystems have shown variation across locations in depth-specific species composition and assemblage shifts, potentially a response to differences in habitat or light availability/water clarity. This study utilized scuba to examine fish and benthic communities from shallow and upper mesophotic (to 45 m) zones of Flower Garden Banks National Marine Sanctuary (FGBNMS, 28°0'N; 93°50'W) from 2010-2012. Dominant planktivores were ubiquitous in shallow and upper mesophotic habitats, and comparisons with previous shallow research suggest this community distribution has persisted for over 30 years. Planktivores were abundant in shallow low-relief habitats on the periphery of the coral reef, and some of these sites that contained habitat transitioning from high to low relief supported high biomass of benthic predators. These peripheral sites at FGBNMS may be important for the trophic transfer of oceanic energy to the benthic coral reef. Distinct differences between upper mesophotic and shallow communities were also observed. These included greater overall fish (as well as apex predator) biomass in the upper mesophotic, differences in apex predator community composition between depth zones, and greater percent cover of algae, rubble, sand, and sponges in the upper mesophotic. Greater fish biomass in the upper mesophotic and similar fish community composition between depth zones provide preliminary support that upper mesophotic habitats at FGBNMS have the capacity to serve as refugia for the shallow-water reefs. Diving surveys of the upper mesophotic and shallow-water coral reef have revealed valuable information concerning the reef fish community in the northern Gulf of Mexico, with implications for the conservation of apex predators, oceanic coral reefs, and the future management of FGBNMS.
Less than a decade after being observed off Florida, the invasive Indo-Pacific lionfish is now widely distributed off the southeast coast of the United States. As a step towards measuring invasion ...impacts to native communities, we examine the magnitude and extent of this invasion by first, compiling reports of lionfish to provide range information and second, estimate lionfish abundance from two separate studies. We also estimate native grouper (epinepheline serranids) abundance to better assess and compare lionfish abundances. In the first study we conducted SCUBA diver visual transect surveys at 17 different locations off the North Carolina coast in water depths of 35-50 m. In the second study, we conducted 27 Remote Operated Vehicle (ROV) transect surveys at five locations from Florida to North Carolina in water depths of 50-100 m. In both studies, lionfish were found to be second in abundance only to scamp (Mycteroperca phenax). Lionfish were found in higher abundance in the shallower North Carolina SCUBA surveys (graphic removed ha-¹) than in the deep water ROV surveys (graphic removed ha-¹). Lionfish reports continue to expand most recently into the Bahamas, raising the specter of further spread into the Caribbean and Gulf of Mexico. The potential impacts of lionfish to native communities are likely to be through direct predation, competition and overcrowding. The high number of lionfish present in the ecosystem increases the potential for cascading impacts throughout the food chain. Within the southeast region the combined effects of climate change, overfishing and invasive species may have irreversible consequences to native communities in this region.
We assessed the utility of an alternative method of video analysis for generating data for sharks and compared observations of sharks from the use of baited remote underwater video stations (BRUVS) ...with observations made by scuba divers during surveys conducted simultaneously with BRUVS video recordings. Videos were made off east-central Florida as part of a fishery-independent trap-video survey of fish species in hard-bottom reef habitats. In videos from 25 of 72 sites, we observed sharks, including the nurse (Ginglymostoma cirratum), tiger (Galeocerdo cuvier), spinner (Carcharhinus brevipinna), sandbar (C. plumbeus), Atlantic sharpnose (Rhizoprionodon terraenovae), bull (C. leucas), and lemon (Negaprion brevirostris) sharks. In contrast, divers observed 3 species of sharks at 5 sites. We conclude that video observations are superior to diver observations for detecting sharks. Rapidly viewing an entire video (the alternative method), rather than viewing only a 20-min segment (the standard protocol), has the potential to increase the number of sites where sharks are observed and the number of shark species that are observed in video analysis (as it did, by 400% and 40%, respectively, in this study). This method holds promise for providing critical information without extraction of specimens and for aiding stock assessments and essential fish habitat delineation for these important predators.
This work revises the essentials of electrocatalytic electrochemical measurement done in alkaline electrolytes. The hydrogen oxidation reaction (HOR) and the oxygen reduction reaction (ORR) were ...considered as a baseline to understand some key critical factors in a half-cell system. The material considered herein was essentially the carbon supported platinum nanoparticles as benchmark material. The main electrochemical techniques considered were cyclic voltammetry (CV) and the rotating disk electrode (RDE). The critical factors considered were the electrochemical cell vessel, reference electrode, nature of the cation in the alkaline electrolyte, and ohmic drop correction.
Numerous location-based diet studies have been published describing different aspects of invasive lionfish (
Pterois volitans and Pterois miles
) feeding ecology, but there has been no synthesis of ...their diet composition and feeding patterns across regional gradients. 8125 lionfish stomachs collected from 10 locations were analyzed to provide a generalized description of their feeding ecology at a regional scale and to compare their diet among locations. Our regional data indicate lionfish in the western Atlantic are opportunistic generalist carnivores that consume at least 167 vertebrate and invertebrate prey species across multiple trophic guilds, and carnivorous fish and shrimp prey that are not managed fishery species and not considered at risk of extinction by the International Union for Conservation of Nature disproportionately dominate their diet. Correlations between lionfish size and their diet composition indicate lionfish in the western Atlantic transition from a shrimp-dominated diet to a fish-dominated diet through ontogeny. Lionfish total length (TL) (mm) was found to predict mean prey mass per stomach (g) by the following equation
mean prey mass
=0.0002*
TL
1.6391
, which can be used to estimate prey biomass consumption from lionfish length-frequency data. Our locational comparisons indicate lionfish diet varies considerably among locations, even at the group (e.g., crab) and trophic guild levels. The Modified Index of Relative Importance developed specifically for this study, calculated as the frequency of prey
a
× the number of prey
a,
can be used in other diet studies to assess prey importance when prey mass data are not available. Researchers and managers can use the diet data presented in this study to make inference about lionfish feeding ecology in areas where their diet has yet to be described. These data can be used to guide research and monitoring efforts, and can be used in modeling exercises to simulate the potential effects of lionfish on marine food webs. Given the large variability in lionfish diet composition among locations, this study highlights the importance of continued location-based diet assessments to better inform local management activities.
We quantified native fish densities along a depth-temperature gradient within a temperate-tropical marine transition zone (North Carolina continental shelf) to examine the role of depth and ...temperature in structuring these communities. We also examined the distribution of invasive lionfish (Pterois volitans, P. miles) to evaluate a laboratory-derived thermal minimum for lionfish. We collected year-round continuous bottom water temperature data from 2000 to 2010 and surveyed lionfish (2004 to 2010), conspicuous fishes (2006 to 2010) and cryptic smaller-bodied fishes (2007 to 2010) at depths from 5 to 46 m using SCUBA. Bottom water temperatures were constant across the depth gradient during summer and increased from inshore to offshore during winter. The conspicuous fish community was structured by 3 depth zones, 5–14, 15–37 and 38–46 m, that corresponded with winter mean temperatures of 13.9, 17.9 and 20.9°C, respectively. The cryptic fish community was structured by 4 depth zones, 5–15, 18–24, 27–38.5 and 39.5–46 m, with corresponding winter mean bottom temperatures of 13.8, 15.6, 18.7 and 20.9°C. In contrast, summer temperatures were not important in structuring either the conspicuous or the cryptic fish community. Thus, fish communities in the spring/summer appear to be structured by the pattern of bottom water temperature experienced the previous winter, supporting previous studies that indicate winter minimum temperature is important for determining fish distribution and abundance in temperate marine ecosystems. In addition, the deeper fish communities were dominated by tropical species. Lionfish, a tropical species, was found in the highest densities from 38 to 46 m and present in locations with a winter mean of 15.3°C and higher. Increasing temperatures could favor a potential expansion of invasive lionfish and native tropical species into the nearshore waters on the North Carolina shelf, resulting in unforeseen community structure and trophic disruptions.
In recent times, coupled, tripled and quadruple fixed point theorems have been intensively studied by many authors in the context of partially ordered complete metric spaces using different ...contractivity conditions. Roldán et al. showed a unified version of these results for nonlinear mappings in any number of variables (which were not necessarily permuted or ordered) introducing the notion of multidimensional coincidence point. Very recently, Choudhury et al. proved coupled coincidence point results in the context of fuzzy metric spaces in the sense of George and Veeramani. In this paper, using the idea of coincidence point for nonlinear mappings in any number of variables, we study a fuzzy contractivity condition to ensure the existence of coincidence points in the framework of fuzzy metric spaces provided with Hadžić type t-norms. Then, we present an illustrative example in which our methodology leads to the existence of coincidence points but previous theorems cannot be applied.
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