Trends In Abundance Research Articles

Multi-omics insights implicate the remodeling of the intestinal structure and microbiome in aging

BackgroundAging can impair the ability of elderly individuals to fight infections and trigger persistent systemic inflammation, a condition known as inflammaging. However, the mechanisms underlying the development of inflammaging remain unknown.MethodsWe conducted 16S rRNA sequencing of intestinal contents from young and old C57BL/6J mice to elucidate changes in gut microbiota diversity and microbial community composition after aging. Aging-related differential bacterial taxa were then identified, and their abundance trends were validated in human samples. The variances in intestinal barrier function and circulating endotoxin between groups were also assessed. Furthermore, widely targeted metabolomics was conducted to characterize metabolic profiles after aging and to investigate the key metabolic pathways enriched by the differential metabolites.ResultsOur findings demonstrated an increase in relative proportion of pathogenic bacteria with age, a trend also revealed in healthy populations of different age groups. Additionally, aging individuals exhibited reduced intestinal barrier function and increased circulating endotoxin levels. Widely targeted metabolomics revealed a significant increase in various secondary bile acid metabolites after aging, positively correlated with the relative abundance of several aging-related bacterial taxa. Furthermore, old group had lower levels of various anti-inflammatory or beneficial metabolites. Enrichment analysis identified the starch and sucrose metabolism pathway as potentially the most significantly impacted signaling pathway during aging.ConclusionThis study aimed to provide insights into the complex interactions involved in organismal inflammaging through microbial multi-omics. These findings lay a solid foundation for future research aimed at identifying novel biomarkers for the clinical diagnosis of aging-related diseases or potential therapeutic targets.

Stable detection frequency of the threatened Christmas Island Boobook Ninox natalis, 2012–2022

ABSTRACT Both island species and raptors are at particularly high risk of extinction but few island raptor populations have been the subject of long-term monitoring. To determine trends in abundance in the Christmas Island Boobook, surveys were conducted annually from 2012–2017, in 2019 and in 2022. Across the survey period the population appears to have been either stable or to have increased slightly. Almost no part of the island lacked owls during the most recent survey. The detection rate averaged 1.56 (out of four surveys at a site); it was lowest in 2013 (1.22) and highest in 2022 (2.38). Detection was more likely on nights with low wind, at wetter sites and in closed vegetation, rather than in open or very low vegetation. In a separate analysis on the same data, the top-ranked dynamic occupancy-detection model found that occupancy increased with increasing elevation and vegetation height. No effect of a suspected threat, the presence of invasive yellow crazy ants Anoplolepis gracilipes at a site, could be detected. We recommend ongoing monitoring and research, potentially using automated recording devices and the tracking of individual owls to understand and refine the assumptions underpinning the interpretation of survey results.

In Situ Enrichment of Anammox Bacteria from Pig Farm Anoxic Sludge Through Co-Cultivation with a Quorum-Sensing Functional Strain Pseudomonas aeruginosa

Anaerobic ammonium oxidation (anammox), as an efficient and low-carbon method for nitrogen removal from wastewater, faces the challenge of slow enrichment of functional bacteria. In this study, the enrichment of anammox bacteria Candidatus Brocadia was successfully accelerated by co-culturing with the quorum-sensing strain Pseudomonas aeruginosa and anoxic sludge from a pig farm. Experimental results showed that the R2, which had Pseudomonas aeruginosa added, exhibited chemical reaction ratios RS (NO2−-N consumption/NH4+-N consumption) and RP (NO3−-N production/NH4+-N consumption) closer to the theoretical values of the anammox reaction since Phase Ⅱ. Bacterial community analysis indicated that the abundance of Candidatus Brocadia in R2 reached 1.63% in cycle 20, significantly higher than the 0.45% in R1. More quorum-sensing signaling molecules, primarily C6-HSL, were detected in R2. C6-HSL was positively correlated with processes such as the secretion of anammox extracellular polymers (EPS) and the regulation of nitric oxide reductase (Nir), which may explain the reason behind the accelerated increase in the abundance of Candidatus Brocadia through co-culturing. Moreover, the metabolism of the dominant genus Paracoccus within the two groups of reactors also showed positive regulation by C6-HSL, with its abundance trend similar to that of Candidatus Brocadia, jointly completing the nitrogen removal process in the reactors. However, it is still unknown which genera secrete large amounts of C6-HSL after inoculation with Pseudomonas aeruginosa. This research provides a novel and low-cost method for the enrichment of anammox bacteria.

Long-term trends in abundance and potential drivers for eight species of coastal birds in the U.S. South Atlantic

The U.S. South Atlantic coastal region is used by many marine birds for foraging, reproduction, and migration. We developed standardized indices of relative abundance from long–term (1980–2016), semi-structured monitoring data (eBird) for eight species: Brown Pelican (Pelecanus occidentalis), Double-Crested Cormorant (Nannopterum auritum), White Ibis (Eudocimus albus), Wood Stork (Mycteria americana), Piping Plover (Charadrius melodus), American Oystercatcher (Haematopus palliatus), Clapper Rail (Rallus crepitans), and Northern Gannet (Morus bassanus). Following a period of stable or declining abundance from the 1980s through the 1990s, most species have shown stable or slightly upward trends through the late 2000s; Brown Pelican and Piping Plover have shown some evidence of recent declines. Species–specific correlations between abundance indices developed from presence/absence data and those developed from count data were positive for all species and ranged from 0.53 to 0.86. Dynamic factor analysis identified common trends in abundance among several species, in particular, Brown Pelican, Double–Crested Cormorant, and White Ibis. Model performance was improved with inclusion of an indicator of sea level rise, but not forage fish abundance or temperature, indicating habitat availability mediated by changing water levels may explain some of the underlying abundance trends. Our results provide baseline information on long–term trends for several important coastal birds that can help inform research, monitoring and conservation efforts in the U.S. South Atlantic region.

Differential responses to weather and land‐cover conditions explain spatial variation in winter abundance trends in a migratory bird of conservation concern

Abstract Effective conservation strategies for animal populations require knowledge of relationships between population dynamics and their environmental drivers. However, these processes often vary within animal populations, requiring site‐specific conservation planning. Given limited financial resources, identifying groups of sites with similar population dynamics can help practitioners efficiently implement conservation programs to larger areas. We evaluated spatial patterns and environmental drivers of wintering site trends in a migratory bird of conservation concern, the Greenland white‐fronted goose (Anser albifrons flavirostris). We used latent class analysis to identify trend patterns in 35 years of abundance data among 59 geographically discrete Greenland white‐fronted goose wintering sites. We developed a state‐space abundance model in a Bayesian framework to quantify the effects of weather and land‐cover conditions experienced throughout spring migration, summer breeding, autumn migration and wintering periods on variation in wintering site abundance. We identified two main patterns in Greenland white‐fronted goose abundance trends: northeastern wintering sites declined on average by 3% per year, while southwestern wintering sites declined on average by 14% per year. Differential responses to weather and habitat conditions likely explained variation among groups, as geese at southwestern wintering sites were more negatively affected by harsh weather conditions (e.g. low temperatures and high precipitation on breeding areas) and poor habitat conditions (i.e. low‐quality grasslands and croplands) on wintering areas. Future conservation efforts to improve the suitability and nutritional quality of agricultural areas, especially cereal croplands in autumn and early winter and grasslands in late winter and early spring, could potentially improve local habitat conditions, especially in the southwestern wintering sites where abundance declines were steepest. Synthesis and applications. We demonstrate the potential to delineate animal populations based on spatial patterns in population dynamics using long‐term abundance monitoring data, which are commonly the only available data for conservation practitioners. By grouping sites based on spatial patterns in local abundance trends, we can further test hypotheses about how these groups are differentially affected by changing environmental conditions. This information is important for informing efficient conservation planning over large areas when financial resources are limited.

Monitoring spatiotemporal patterns in the genetic diversity of a European butterfly species

Abstract The importance of genetic diversity has been recognised by the Convention on Biological Diversity but attempts at monitoring or improving the genetic diversity of populations have been minimal. Here, we investigate changes over time in the genetic diversity of a wild insect species, Maniola jurtina (Lepidoptera: Nymphalidae) and present a large‐scale investigation into contemporary spatial genetic diversity. Using microsatellite markers, we calculate multiple measures of genetic diversity and divergence for M. jurtina populations over 8 years in the UK and compare these findings with long‐term abundance trends. We also conduct a large‐scale spatial analysis into the genetic diversity and population structuring of M. jurtina across Europe. All UK populations sampled have high levels of gene flow and genetic diversity, with genetic diversity stable over time. Across Europe, we find some population structuring between populations in the UK and the European mainland, suggesting restricted geneflow between the two regions. The monitoring of a wild species' genetic diversity is an achievable aim, and one that could be carried out for many species, particularly Lepidoptera. Future approaches may aim to develop higher resolution genetic markers and cover a wider range of species. The use of abundance data offers additional insight, and we find that concurrent, dedicated genetic monitoring can provide effective tracking of biodiversity trends.

Multidecadal underwater surveys reveal declines in marine turtles

AbstractMarine turtles are a group of imperiled marine megafauna particularly vulnerable to anthropogenic stressors. Most long‐term studies of marine turtles are based on nesting surveys which focus on numbers of eggs, hatchlings, and nesting females. However, we know less about long‐term abundance trends of immature and adult turtles in the marine environment. To address this data gap, we examined records from 35,000 underwater visual census (UVC) dives (1993–2019) and short‐term in‐water turtle survey data (2009–2014) at Cocos Island, Costa Rica. During UVCs, trained divemasters from UnderSea Hunter recorded observations of two species of marine turtles—green Chelonia mydas and hawksbill Eretmochelys imbricata. Our short‐term in‐water surveys revealed that most turtles at Cocos are greens, but both immature and mature greens occur at Cocos. We analyzed long‐term UVC data using a hierarchical modeling approach and we modeled a 26% decrease in the relative abundance of turtles observed on dives each year. Our model also revealed potential interactions between tiger sharks and turtles, finding that for each additional tiger shark present during a dive, the predicted relative abundance of turtles decreased by 43%. Lastly, our model suggested the influence of environmental variation on marine turtle relative abundance; a 1°C increase in sea surface temperature (SST) decreased the predicted relative abundance of turtles by 7%. Our results suggest that marine turtles are sensitive to long‐term environmental and oceanographic changes, and potentially avoid certain areas to reduce exposure to tiger sharks. Given our study area is already protected, there needs to be more focus on protecting adult turtles during their movements across the Eastern Tropical Pacific. Our work also highlights the importance of long‐term underwater surveys to monitor adult turtles.

Abundance Trends of Immature Stages of Ticks at Different Distances from Hiking Trails from a Natural Park in North-Western Italy.

Hiking trails may act as hotspots at the wildlife-human interface, posing an acarological risk for people and their pets. Ticks that are maintained in the environment by wild animals may quest on people walking along the trails. Assessing the risk of tick bites for people involved in outdoor activities is a further step in mitigating the risk of tick-borne diseases. This work describes the variation of tick abundance along a gradient of distances from hiking trails, where wildlife passage is favored by higher accessibility. Hiking trails with dense vegetation on the sides were sampled for ticks along a 100 m dragging transect, located in a natural park in North-Western Italy. Additional transects were replicated at 1, 2 and 4 m away from the trail on both sides. After morphological identification, descriptive statistics and modeling were applied to determine the abundance patterns across distances. Larvae were most abundant near the trail, peaking at 1 m and dropping sharply at further distances. Nymphs showed a more gradual and consistent decrease at progressing distance from the trail. Few adults were collected, preventing the identification of a clear trend. With higher tick abundance, the immediate vicinity of hiking trails may represent a source of acarological risk for humans and pets.

Interaction between marine and terrestrial biogenic volatile organic compounds: Non-linear effect on secondary organic aerosol formation

Biogenic volatile organic compounds (BVOCs) are the largest source of secondary organic aerosols (SOA) globally. However, the complex interactions between marine and terrestrial BVOCs remain unclear, inhibiting our in-depth understanding of the SOA formation in the coastal areas and its environmental impacts. Here, we performed smog chamber experiments with mixed α-pinene (a typical monoterpene) and dimethyl sulfide (DMS, a typical marine emission BVOC) to investigate their possible interactions and subsequent SOA formation. It is found that DMS has a non-linear effect on SOA generation: The mass concentration and yield of SOA show increasing and then decreasing trends with the increase of the initial concentration of DMS. The increasing trend can be attributed to OH regeneration from isomerization of the CH3SCH2OO radical together with acid-catalyzed heterogeneous reactions by the oxidation of DMS, while the decreasing trend is explained by the less contribution of isomerization reaction and the high OH reactivity that inhibits the formation of low volatility products. The results from infrared spectra and mass spectra together reveal the contribution of sulfur-containing molecules in the mixed system. Moreover, the mass spectra results indicate that acidic products generated by DMS photooxidation enhance the O:C ratio, while organosulfates are produced to contribute to the formation of mixed SOA. In addition, the trends in relative abundance of highly oxygenated organic molecules (HOMs) with C8 - C10 multiple functional groups in different mixed systems agree well with the turning point of the SOA yield. The findings of this study have significant implications for understanding binary or more complex systems in the atmosphere in the coastal areas.

Ptačí diverzita v historickém zámeckém parku – implikace pro ochranu biodiverzity v hospodářských lesích

Long-term trends of abundance and diversity of forest birds have been very stable over past decades in European managed forests. It can be caused by high heterogeneity on habitat scale. In European cultural landscapes, there is another habitat very similar to managed forests, and that is a historic manor park. The parks can even show higher bird diversity than managed forests. However, there is an evident knowledge gap related to long-term changes of bird abundance and diversity in the habitats of manor parks. In this study we observed long-term changes of bird community in the historic manor park Čechy pod Kosířem (Czech Republic) using comparison of bird territory mapping in 2022–2023 with older bird studies in this locality. We gained an overview of bird community changes in the manor park for the period of 1997–2023. Results show that the bird community in historic manor park was remarkably unvarying in abundance and diversity. Historic manor parks can be considered as important refuges for forest bird diversity in cultural landscapes. We discuss the research implications for conserving bird diversity in managed forests especially in connection with large old trees preservation providing heterogeneity of nest habitats.

The R-process Alliance: Fifth Data Release from the Search for R-process-enhanced Metal-poor Stars in the Galactic Halo with the GTC* * This paper includes data gathered with the 10.4 m Gran Telescopio Canarias located at La Palma, Canary Islands, Spain.

Understanding the abundance pattern of metal-poor stars and the production of heavy elements through various nucleosynthesis processes offers crucial insights into the chemical evolution of the Milky Way, revealing primary sites and major sources of rapid neutron-capture process (r-process) material in the Universe. In this fifth data release from the R-Process Alliance (RPA), we present the detailed chemical abundances of 41 faint (down to V = 15.8) and extremely metal-poor (down to [Fe/H] = −3.3) halo stars selected from the RPA. We obtained high-resolution spectra for these objects with the HORuS spectrograph on the Gran Telescopio Canarias. We measure the abundances of light, α, Fe-peak, and neutron-capture elements. We report the discovery of five carbon-enhanced metal-poor, one limited-r, three r-I, and four r-II stars, and six Mg-poor stars. We also identify one star of a possible globular cluster origin at an extremely low metallicity at [Fe/H] = −3.0. This adds to the growing evidence of a lower-limit metallicity floor for globular cluster abundances. We use the abundances of Fe-peak elements and the α-elements to investigate the contributions from different nucleosynthesis channels in the progenitor supernovae. We find the distribution of [Mg/Eu] as a function of [Fe/H] to have different enrichment levels, indicating different possible pathways and sites of their production. We also reveal differences in the trends of the neutron-capture element abundances of Sr, Ba, and Eu of various r-I and r-II stars from the RPA data releases, which provide constraints on their nucleosynthesis sites and subsequent evolution.

Long-term monitoring of a population of greater horseshoe bat emphasises the importance of a pest beetle prey on demographic trends.

The global decline in insect biomass has far-reaching implications for terrestrial and freshwater food webs, impacting species reliant on insects as a crucial component of their diet. This issue extends to species traditionally considered agricultural pests, such as the common cockchafer Melolontha melolontha. In the race to combat cockchafers through collection, insecticide use, and other control methods, the repercussions of their numerical fluctuations on predators, including species of high conservation importance like bats, have been largely overlooked. Drawing on 31-years of monitoring data for a greater horseshoe bat Rhinolophus ferrumequinum population in the Aosta Valley (Western Italian Alps), we investigated whether annual fluctuations in bat counts are influenced by cockchafer availability and weather conditions. Despite an overall positive trend in bat abundance, we observed pronounced annual fluctuations, mostly driven by cockchafer availability rather than variations in temperature and precipitation. Furthermore, we found a significant association between cockchafer availability and the median date of birth and birth rate of bats. Births occurred approximately 5 days earlier in cockchafer flight years, with earlier births also linked to warmer spring temperatures and higher numbers of warm days in April. Moreover, the ratio pups/older bats was 0.56 in cockchafer flight years, compared to 0.47 in other years. Our results underscore the importance of considering predator-prey dynamics when examining the long-term population trends of species of conservation concern. We recommend implementing restrictions on the use of chemicals and other potentially harmful practices that may diminish prey abundance or quality, including that of species considered as agricultural pests. In designing conservation strategies, a delicate balance should be struck between the current interests of farmers and the overarching goal of preserving biodiversity against potential future threats.

Anthropogenic and environmental risk factors of salmonid predation in a tidal freshwater delta

Abstract Water diversions that support agricultural and municipal use result in fish mortality through entrainment and impingement. Additionally, this infrastructure may attract both predators and prey fishes, thereby increasing predation rates and prey mortality near these anthropogenic contact points. The Sacramento–San Joaquin Delta (the Delta) in California's Central Valley is a tidal freshwater ecosystem that exports large volumes of water for municipal and agricultural use while at the same time providing valuable migratory and rearing habitat for imperilled fishes. Emigrating juvenile salmonids experience high mortality in the Delta, with predation by non‐native fishes contributing substantially. Therefore, this study had three main objectives. First, we determined if small water diversions aggregated piscivorous fishes like other similar structures in freshwater ecosystems. Second, we determined how small diversions may influence juvenile salmon predation risk in conjunction with other known predation risk factors (e.g. predator abundance, temperature and depth). Third, we assessed the predator assemblage, abundance and distribution to determine the likely predator composition in objectives one and two. Throughout the spring of 2021, we used ARIS (adaptive resolution imaging sonar; Sound Metrics) sonars to compare piscivore abundance at 30 water diversions in the north Delta to shorelines adjacent to diversions that did not contain these structures. We used predation event recorders (PERs) to assess the predation risk juvenile salmonids were exposed to, with linear distance (m) from diversions, and other predation risk factors in the north Delta. Finally, we used a boat electrofishing survey to determine the piscivore assemblage and compare spatial trends in black bass (Micropterus spp.) CPUE and relative abundance throughout these waterways. Piscivore abundance was greater near small water diversions than at adjacent shorelines and the predation risk of juvenile salmonids increased with diversion proximity. Additionally, predation risk increased with increasing piscivore abundance and decreasing water depth. The north Delta predator assemblage was dominated by black basses (Micropterus spp.), which likely drove the negative relationship of predation risk with water depth, given habitat requirements of these species. Furthermore, increasing smallmouth (Micropterus dolomieu) and spotted bass (Micropterus punctulatus) abundance in our northern study sites may have weakened temperature effects on predation, given metabolic requirements of these species. Our work demonstrated that small water diversions are likely to increase mortality of endangered salmonids, and that the north Delta predator assemblage was different than recorded by previous work in this system, changing predation risk factors. Although more work is needed to determine the population level impacts of diversions, the ubiquitous distribution of these structures warrants management solutions to reduce mortality from this source. These results indicate that in addition to entrainment and impingement, water diversions may increase mortality of small‐bodied fishes by attracting predators and elevating predation risk. Given the continual human demand for freshwater, predator–prey interactions should be considered along with entrainment and impingement when assessing intake infrastructure mitigation, especially when diversions co‐occur along migratory routes and essential habitat of imperilled fishes.

Spatial and seasonal foraging patterns drive diet differences among north Pacific resident killer whale populations.

Highly social top marine predators, including many cetaceans, exhibit culturally learned ecological behaviours such as diet preference and foraging strategy that can affect their resilience to competition or anthropogenic impacts. When these species are also endangered, conservation efforts require management strategies based on a comprehensive understanding of the variability in these behaviours. In the northeast Pacific Ocean, three partially sympatric populations of resident killer whales occupy coastal ecosystems from California to Alaska. One population (southern resident killer whales) is endangered, while another (southern Alaska resident killer whales) has exhibited positive abundance trends for the last several decades. Using 185 faecal samples collected from both populations between 2011 and 2021, we compare variability in diet preference to provide insight into differences in foraging patterns that may be linked with the relative success and decline of these populations. We find broad similarities in the diet of the two populations, with differences arising from spatiotemporal and social variability in resource use patterns, especially in the timing of shifts between target prey species. The results described here highlight the importance of comprehensive longitudinal monitoring of foraging ecology to inform management strategies for endangered, highly social top marine predators.

Element abundances of galactic RGB stars in the APO-K2 catalogue

Aims. We conducted an investigation on the chemical abundances of 4316 stars in the red giant branch (RGB) phase from the recently released APO-K2 catalogue. Our aim was to characterize the abundance trends of the single elements with [α/Fe], mainly focusing on C, N, and O, which are the most relevant for the estimation of stellar ages. Methods. The chemical analysis of the RGB sample involved cross-matching data from the APO-K2 catalogue with individual element abundances from APOGEE DR17. Results. The analysis detected a statistically significant difference in the [(C+N+O)/Fe]–[α/Fe] trend with respect to the simple α-enhancement scenario. This difference remained robust across different choices for the reference solar mixture and potential zero-point calibrations of C and N abundances. The primary discrepancy was a steeper increase in [O/Fe] with [α/Fe], reaching a 0.1 dex difference at [α/Fe] = 0.3. Notably, the impact on the evolutionary timescale of such oxygen over-abundance with respect to the commonly adopted uniform α-enhancement is rather limited. We verified that stellar models computed using an ad hoc O-rich mixture sped up the evolution by only 1% at [α/Fe] = 0.3, due to the counterbalancing effects of O enrichment on both the evolutionary timescale and the Z-to-[Fe/H] relationship.

Effects of Yellow Sea Warm Current on zooplankton community composition and functional groups in winter

The Yellow Sea Warm Current (YSWC) constitutes a significant hydrological feature in the Yellow Sea, particularly prominent during winter, facilitating the transport of warm, saline waters and warm-water species from the open sea to the Bohai and Yellow Seas. The YSWC induces alterations in the community structure and function of zooplankton. However, the effects of the YSWC on the functional trait compositions and functional groups of zooplankton remain unclear. This study aimed to elucidate the influence of the YSWC on the community structure, functional trait composition, and functional groups of zooplankton during winter of 2016. The YSWC significantly impacted the zooplankton assemblage in the central Yellow Sea (CYSA), resulting in notable distinctions from the Shandong coastal assemblage (SCA) and Jiangsu coastal assemblage (JCA). Compared to the SCA and JCA (comprising 45 and 34 taxa, with abundances of 119.4 ± 114.6 ind·m-3 and 82.8 ± 62.1 ind·m-3, respectively), the CYSA exhibited higher species richness and abundance (with 51 taxa and 144.4 ± 103.4 ind·m-3, respectively). This study documented a total of 11 warm-water species, showing a decreasing trend in both species richness and abundance from south to north. The CYSA was characterized by the predominance of medium‒sized, current‒feeding, omnivorous‒herbivorous broadcast spawners, whereas the SCA and the JCA were predominantly dominated by giant‒sized, ambush‒feeding carnivores. The Qingdao-Shidao anticyclonic eddy in the southern of Shandong Province led to a significant increase in the abundance of zooplankton, potentially impacting Yellow Sea fishery resource. This research contributed to a deeper understanding of how YSWC influence the zooplankton community and offered fresh insights into the effects of YSWC on zooplankton function traits and functional groups.

Microplastic removal and risk assessment framework in a constructed wetland for the treatment of combined sewer overflows

Combined sewer overflows (CSOs) release a significant amount of pollutants, including microplastics (MPs), due to the discharge of untreated water into receiving water bodies. Constructed Wetlands (CWs) offer a promising strategy for CSO treatment and have recently attracted attention as a potential solution for MP mitigation. Nevertheless, limited research on MP dynamics within CSO events and MP removal performance in full-scale CW systems poses a barrier to this frontier of application. This research aims to address both these knowledge gaps, representing the first investigation of a multi-stage CSO-CW for MP removal. The study presents one year of seasonal data from the CSO-CW upstream of the WWTP in Carimate (Italy), evaluating the correlation of MP abundance with different water quality/quantity parameters and associated ecological risks. The results show a clear trend in MP abundance, which increases with rainfall intensity. The strong correlation between MP concentration, flow rate, and total suspended solids (TSS) validates the first flush phenomenon hypothesis and its impact on MP release during CSOs. Chemical characterization identifies acrylonitrile-butadiene-styrene (ABS), polyethylene (PE), and polypropylene (PP) as predominant polymers. The first vertical subsurface flow (VF) stage showed removal rates ranging from 40 % to 77 %. However, the unexpected increase in MP concentrations after the second free water surface (FWS) stage suggests the stochasticity of CSO events and the different hydraulic characteristics of the CW units have diverse effects on MP retention. These data confirm filtration as the main retention mechanism for MP within CW systems. The MP ecological risk assessment indicates a high-risk category for most of the water samples, mainly related to the frequent presence of ABS fragments. The results contribute to the current understanding of MPs released by CSOs and provide insights into the performance of different treatment units within a large-scale CSO-CW system, suggesting the requirement for further attention.

Arthropod traits as proxies for abundance trends in the Azorean Islands

Human activities drive ecological transformation, impacting island ecosystems from species diversity to ecological traits, mainly through habitat degradation and invasive species. Using two unique long‐term datasets we aim to evaluate whether species traits (body size, trophic level, dispersal capacity and habitat occupancy) can predict temporal variations in the abundance of endemic, indigenous (endemic and native non‐endemic) and exotic arthropods in the Azores Islands. We found that body size is crucial to predict arthropod abundance trends. Small‐bodied herbivorous arthropods showed a decrease in abundance, while large‐bodied indigenous arthropods increased in abundance, mainly in well‐preserved areas. Also, large‐bodied exotic arthropods increased in abundance across the entire archipelago. Moreover, endemic canopy dwellers increased in abundance, while endemic ground‐dwellers decreased in abundance. Simultaneously, exotic arthropods showed the opposite result, increasing in abundance in the ground while decreasing in abundance in the canopy. Finally, habitat influenced both endemic and exotic spider abundance trends. Endemic spiders that occupy solely natural habitats experienced a decline in abundance, while exotic spiders in the same habitats increased in abundance. Our study underscores the significance of arthropod species traits in predicting abundance changes in island ecosystems over time, as well as the importance of monitoring species communities. Conservation efforts must extend beyond endangered species to protect non‐threatened ones, given the increased extinction risk faced by even common species on islands. Monitoring and restoration programs are essential for preserving island ecosystems and safeguarding endemic arthropod populations.

Long-term measurements reveal a 100-day lag between peaks in phytoplankton chlorophyll and benthic bacterial abundance in the Fram Strait

Abstract Repeated measurements of benthic and pelagic parameters in the rapidly changing Arctic Ocean provide a unique insight into spatial and interannual trends and changes in the ecosystem. Here, we compiled biogenic and biogeochemical measurements collected from sediment cores at the Long-Term Ecological Research Observatory HAUSGARTEN located in the Fram Strait. A total of 21 stations were visited yearly over a period of 18 years (2002–2019). The time series highlighted an increase in bacterial numbers for samples collected 50 days after the peak phytoplankton bloom. Although bacterial abundances were not bathymetric depth-dependent when viewed across all years, we observed a seasonal trend in benthic microbial abundance closely related to the timing of the phytoplankton bloom with a time-lag of 100 days between the surface phytoplankton peak and the peak in bacterial abundance in the sediment. Considering the residence time of phytoplankton in the upper ocean and the water depth, we estimated an average settling velocity for phytodetritus of 30 m.d−1, which is similar to previous observations from Fram Strait. This suggests that settling organic matter promotes vertical microbial connectivity and benthic bacterial abundance in the deep ocean, shaping the microbial biogeography, diversity, and biogeochemical processes.

Metagenomics analysis of sewage for surveillance of antimicrobial resistance in South Africa.

Our 24-month study used metagenomics to investigate antimicrobial resistance (AMR) abundance in raw sewage from wastewater treatment works (WWTWs) in two municipalities in Gauteng Province, South Africa. At the AMR class level, data showed similar trends at all WWTWs, showing that aminoglycoside, beta-lactam, sulfonamide and tetracycline resistance was most abundant. AMR abundance differences were shown between municipalities, where Tshwane Metropolitan Municipality (TMM) WWTWs showed overall higher abundance of AMR compared to Ekurhuleni Metropolitan Municipality (EMM) WWTWs. Also, within each municipality, there were differing trends in AMR abundance. Notably, within TMM, certain AMR classes (macrolides and macrolides_streptogramin B) were in higher abundance at a WWTW serving an urban high-income area, while other AMR classes (aminoglycosides) were in higher abundance at a WWTW serving a semi-urban low income area. At the AMR gene level, all WWTWs samples showed the most abundance for the sul1 gene (encoding sulfonamide resistance). Following this, the next 14 most abundant genes encoded resistance to sulfonamides, aminoglycosides, macrolides, tetracyclines and beta-lactams. Notably, within TMM, some macrolide-encoding resistance genes (mefC, msrE, mphG and mphE) were in highest abundance at a WWTW serving an urban high-income area; while sul1, sul2 and tetC genes were in highest abundance at a WWTW serving a semi-urban low income area. Differential abundance analysis of AMR genes at WWTWs, following stratification of data by season, showed some notable variance in six AMR genes, of which blaKPC-2 and blaKPC-34 genes showed the highest prevalence of seasonal abundance differences when comparing data within a WWTW. The general trend was to see higher abundances of AMR genes in colder seasons, when comparing seasonal data within a WWTW. Our study investigated wastewater samples in only one province of South Africa, from WWTWs located within close proximity to one another. We would require a more widespread investigation at WWTWs distributed across all regions/provinces of South Africa, in order to describe a more comprehensive profile of AMR abundance across the country.