Anthropogenic Activities Research Articles

Exploring the Role of Tools and Technologies in Enhancing Human Knowledge Acquisition: The Flora of Cambodia as a Pilot Project.

The globalization of the world profoundly impacts the academic and scientific domains. Technological advances have enabled an immeasurable progress in many scientific fields, for example structural or functional genomics, bioinformatics or even the development of artificial intelligence, which is becoming a catalyst for disciplines such as taxonomy. However, we are witnessing an unprecedented paradox. We have entered a period described as the 6th mass extinction (e.g., Ceballos et al. 2015, Ceballos et al. 2020, Cowie et al. 2022), where biodiversity has been in decline for many years because of anthropogenic activity (Myers et al. 2000, Sachs et al. 2009, Butchart et al. 2010) and yet, techniques have never been so advanced (e.g., online databases, metabarcording and eDNA identification methods). They produce a deluge of results and data that must be managed to facilitate their access and re-use and benefit to all users, i.e., scientists and stake-holders or policy makers on a global scale. Currently, the flora of Cambodia is part of the Flora of Cambodia, Laos and Viêt-nam*1 and is jointly edited by the Royal Botanic Garden of Edinburgh and the Muséum national d’Histoire naturelle in Paris since 2013. Given Cambodia's historical ties to French Indochina, France's long-term presence has significantly contributed to the documentation of Cambodia's biodiversity. The largest collection of Cambodian specimens is housed at the Paris Herbarium. The Flora of Cambodia project (Ung 2023) started in 2023 as a pilot project for testing the effectiveness of different open tools developped for taxonomists, e.g., the echinopscis platform*2 developped at the Royal Botanical Garden Kew; Bionomia*3; data made available online through platforms such as the Global Biodiversity Information Facility, Atlas of Living Australia, and World Flora Online. Other sources will also be used, like publications (Joyce et al. 2020) and "les herbonautes"*4, a citizen science platform. The short-term result is to produce a checklist of the vascular plants of Cambodia in multiple languages including Khmer. This project aligns with the FAIR (Findable, Accessible, Interoperable, Reusable) (Wilkinson et al. 2016) and CARE (Collective benefit, Authority to control, Responsability, Ethics) (Carroll et al. 2020) principles.

Geographic Information System and Contamination Indices for Environmental Risk Assessment of Landfill Disposal Sites in Central Saudi Arabia

Landfills pollute air, soil, and surface and groundwater worldwide. The present work aims to assess the environmental risks of three landfills in southern Riyadh using GIS, soil quality guidelines, and contamination indices. GIS tools indicated an increase in the area of the landfill sites with time. The concentration of heavy metals (HMs) in the investigated landfills had the following descending order: Fe (11,532 mg/kg) ˃ Al (5405 mg/kg) ˃ Pb (561.7 mg/kg) ˃ Zn (356.8 mg/kg) ˃ Mn (165 mg/kg) ˃ Cr (74.8 mg/kg) ˃ Cu (42.7 mg/kg) ˃ Ni (22.4 mg/kg) ˃ V (21.8 mg/kg) ˃ As (5.16 mg/kg) ˃ Co (4.08 mg/kg). The highest values of Al, As, Co, Ni, Pb, V, and Zn were recorded from Al Kharj road landfill (RL3). However, the average values of all HMs were lower than those from most worldwide soils and backgrounds, except for Zn, Cu, Cr, and Pb. Results of enrichment factor and statistical analysis indicated deficiency to minimal enrichment and geogenic sources for Al, Co, Mn, and V, while those of As, Cr, Pb, Zn, and Cu showed EF ˃ 2, which might be indicative of anthropogenic activities, especially in RL3. Additionally, very high contamination and a high effects range—median were reported in individual samples, especially for Pb, As, and Zn, indicating frequent adverse effects for these HMs. The difference in contamination for the HMs in the studied landfill sites might be attributed to the difference in the magnitude of input for each metal into the landfill site and/or the difference in the removal rate of each metal from it.

DRONES4BLUECARBONSEAGRASS: A Capacity-Building Program for Mapping Seagrasses using Unmanned Aerial System (UAS) Technology in the Philippines

Abstract. Coastal blue carbon ecosystems, such as mangrove forests and seagrass meadows, are important for various environmental functions, serving as habitats, food sources, and carbon sinks. Despite their importance, seagrass ecosystems are experiencing global decline due to numerous stressors, including anthropogenic activities. To address this, effective monitoring and management strategies are crucial. Traditional in situ surveys for seagrass monitoring are labor-intensive and time-consuming. Alternatively, remote sensing technologies, particularly satellite imagery, offer a more efficient means of mapping seagrass distribution over large areas. However, accurately assessing seagrass cover at a local scale remains challenging with satellite data alone. Recently, unmanned aerial system (UAS) technology has emerged as a promising approach for seagrass mapping. With its fine resolution and flexibility for image acquisition, UAS can provide more precise estimates of seagrass cover, complementing satellite data. This integration enhances accuracy assessments and expands data availability for training and validation purposes. Under the BlueCARES Project, a drone training program was developed to equip stakeholders with the skills needed for cost-effective UAS-based seagrass mapping. The drone training program encompasses lectures on UAS basics, flight planning, and image processing. Beyond training, collected data are used to create seagrass maps and assess seagrass density. This initiative not only advances seagrass conservation but also fosters collaboration between government agencies, academia, and local communities to achieve sustainable management of blue carbon ecosystems.

Accumulation of Heavy Metals in the Leaves of Some Woody Plants in Osh City

Pollution of the environment with harmful substances occupies a leading place among global environmental problems. This phenomenon is closely related to anthropogenic activity, especially in cities. The origin and chemical nature of harmful substances are different, but heavy metals occupy a special place among them. Over the past ten years, research aimed at studying the distribution of heavy metals in the environment and their accumulation in plants has significantly developed. Because the Sustainable Development Goals adopted by the UN in 2015 provide for by 2030, to reduce the negative environmental impact of cities per capita, including by paying special attention to air quality and the removal of urban and other waste. The purpose of our research was to determine the characteristics of the accumulation of heavy metals in the leaves of trees and shrubs growing in the park areas of Osh. The trees selected as objects were Salix babylonica L., Acer pseudoplatanus L., Populus ×canescens (Aiton) Sm., Platanus orientalis L., Juniperus virginiana L., planted in park areas near highways. The concentration of heavy metals was determined by the atomic absorption method in the Central Laboratory State Enterprise under the Ministry of Natural Resources, Ecology and Technical Control of the Kyrgyz Republic. Quantitative analysis revealed the presence of some heavy metals: manganese, copper, lead, strontium and zinc in all plant samples. Laboratory tests showed a high concentration of copper, exceeding the MAC. Based on the research results, we note the need to continue studying the influence of heavy metals on the physiological processes of various tree species in Osh and expanding the geography of research in the city’s microdistricts.

Advances in Global Oyster Reef Restoration: Innovations and Sustainable Ecological Approaches

Oysters have been recognized as ecological engineers for aquatic ecosystems, as oyster reefs provide critical habitats and foraging locations for other marine species. In the past few decades, anthropogenic activities have negatively impacted oyster reef ecosystems across the globe, resulting in a significant decline in their population. This review critically examines the causes and extent of oyster reef degradation, as well as the effectiveness of restoration initiatives employed to reverse this decline. Furthermore, this review evaluates the effectiveness of restoration strategies employed to rehabilitate oyster reefs. Different approaches, such as genetic improvement, suitable site selection, and oyster seeding to enhance oyster reef restorations, are critically reviewed in this paper. Furthermore, some advanced restoration approaches such as 3D printing, shell recycling, and acoustics technologies are also discussed in this paper, which opens the new doors for researchers in the field of restoration ecology. Challenges and barriers hindering successful restoration are also addressed, including financial constraints, regulatory complexities, and public engagement. The findings and insights presented herein contribute to the growing body of knowledge on oyster reef ecology and serve as a valuable resource for policymakers, scientists, and conservation practitioners seeking effective strategies for restoring these vital coastal ecosystems.

Long-Term Ground Deformation Monitoring and Quantitative Interpretation in Shanghai Using Multi-Platform TS-InSAR, PCA, and K-Means Clustering

Ground subsidence in urban areas is mainly due to natural or anthropogenic activities, and it seriously threatens the healthy and sustainable development of the city and the security of individuals’ lives and assets. Shanghai is a megacity of China, and it has a long history of ground subsidence due to the overexploitation of groundwater and urban expansion. Time Series Synthetic Aperture Radar Interferometry (TS-InSAR) is a highly effective and widely used approach for monitoring urban ground deformation. However, it is difficult to obtain long-term (such as over 10 years) deformation results using single-platform SAR satellite in general. To acquire long-term surface deformation monitoring results, it is necessary to integrate data from multi-platform SAR satellites. Furthermore, the deformations are the result of multiple factors that are superimposed, and relevant studies that quantitatively separate the contributions from different driving factors to subsidence are rare. Moreover, the time series cumulative deformation results of massive measurement points also bring difficulties to the deformation interpretation. In this study, we have proposed a long-term surface deformation monitoring and quantitative interpretation method that integrates multi-platform TS-InSAR, PCA, and K-means clustering. SAR images from three SAR datasets, i.e., 19 L-band ALOS-1 PALSAR, 22 C-band ENVISAT ASAR, and 20 C-band Sentinel-1A, were used to retrieve annual deformation rates and time series deformations in Shanghai from 2007 to 2018. The monitoring results indicate that there is serious uneven settlement in Shanghai, with a spatial pattern of stability in the northwest and settlement in the southeast of the study area. Then, we selected Pudong International Airport as the area of interest and quantitatively analyzed the driving factors of land subsidence in this area by using PCA results, combining groundwater exploitation and groundwater level change, precipitation, temperature, and engineering geological and human activities. Finally, the study area was divided into four sub-regions with similar time series deformation patterns using the K-means clustering. This study helps to understand the spatiotemporal evolution of surface deformation and its driving factors in Shanghai, and provides a scientific basis for the formulation and implementation of precise prevention and control strategies for land subsidence disasters, and it can also provide reference for monitoring in other urban areas.

Ecological Risk of Heavy Metals in an Eco-Industrial Park in China

ABSTRACT To ascertain whether rapid industrialization has affected the accumulation of heavy metals (HMs) in Suzhou Industrial Park (SIP), China, the occurrence and ecological risk of HMs, including Cu, Zn, Pb, Cr, Cd, Ni, As and Hg in sediments were analyzed. The results indicated that total concentrations of HMs (mg kg−1) were in the descending sequence of Zn (235.28) > Cr (95.71) > Cu (78.91) > Ni (55.51) > Pb (23.96) > As (22.12) > Cd (0.38) > Hg (0.14). The concentrations of HMs, except for Ni and Cd, were found to be below the probable effect level (PEL). Correlation analysis (CA) and principal component analysis (PCA) showed that HMs in SIP mainly originated from anthropogenic activities. HMs were mainly in residual fractions (55.5 ~ 95.1%), and the exchangeable fractions of Zn and Cd were relatively high. The risk assessment results indicated that Hg and Cd significantly contributed to ecological risks, whereas Cr and Pb made relatively minor contributions. Our findings indicated that intense anthropogenic activities promote HMs accumulations in streams in SIP during rapid industrialization.

How do trade-offs between ecological construction and urbanization affect regional carbon balance? A case study from China’s Yellow River Basin

Anthropogenic activities, including trade-offs between ecological construction and urbanization, alter land use by either adding or subtracting from the carbon balance. Therefore, it is unknown how the trade-offs between ecological construction and urbanization impact the regional carbon balance. We selected the Yellow River Basin for this study to shed light on how human activity affects the carbon balance and promote the advancement of the objective of becoming carbon–neutral. Using panel data, soil respiration data, and GEM-CO2 models, carbon emissions and sinks in multiple fields were quantified on a raster scale based on multi-source remote sensing data. The trade-offs between urbanization and ecological construction were then spatially illustrated through changes in ground cover. Finally, a raster-scale study was conducted to investigate the ways in which trade-offs between urbanization and ecological construction impact the regional carbon balance. The basin was able to maintain a carbon balance in 2001; however, by 2019, it experienced a severe carbon imbalance. The primary causes of this were rapid growth in energy consumption and direct household waste incineration. By 2019, 84.79% of rasters had a trade-off connection, indicating an increasing trend in the degree of trade-off between ecological construction and urbanization. This affected the pattern of land use in the basin, which in turn affected the carbon balance. Rapid urbanization has exacerbated the carbon imbalance, but ecological construction can reverse this trend. The carbon balance was negatively correlated with the trade-off between ecological construction and urbanization, and the conversion of natural resources by human activity hastened the spread of regional carbon imbalances.

Advocating for planetary health is an essential part of advocating for children's health.

Burning of fossil fuels along with deforestation and ecological disruption have led to the warming of the Earth and climate change. Children are especially vulnerable to adverse health effects of climate change associated changes in the air, soil, and water as their organs are still developing, have a faster breathing rate, higher per pound ingested and inhaled exposures, and greater relative body surface area. To protect this vulnerable population, health care professionals need to play a leading role. In 2015, the American Academy of Pediatrics (AAP) updated their original 2007 Global Climate Change and Children's Health policy statement (again updated in 2024) stating that, "failure to take prompt, substantive action would be an act of injustice to all children." Health care professionals need to educate themselves and their patients of the health risks posed by climate change and incorporate climate change counseling into their practice. They also need to go beyond the framework of the healthcare system and work collaboratively with communities, corporations, and governments to advocate for policies and solutions to mitigate and adapt to climate change. The health and wellbeing of future generations rests upon the actions we take today. IMPACT: Summarizes the adverse effects of increased anthropogenic activity and burning of fossil fuels on planetary and human health Details the increased vulnerability of children to environmental assaults and their long-term effects Provides guidance and resources to health care professionals to empower them to act as advocates for systemic and structural changes that protect children's health.

Flight initiation distance differs among eumelanin‐based color morphs in feral pigeons

AbstractOrganisms facing anthropogenic activities usually exhibit phenotypic responses assumed to enhance coping with disturbance. These responses include a decreasing degree of reaction toward potentially risky situations (“behavioral tolerance”) with increasing disturbance. Though melanin is associated with many phenotypic traits, including pigmentation and behavior, the potential relationship between behavioral tolerance and melanin has never been explored. Such relationship may potentially result from either direct association between melanin and behavior (e.g., genetic correlation) or indirectly through a coloration‐dependent behavior‐modulating factor (e.g., differential predation or human preferences in cities toward color morphs). Feral pigeons (Columba livia) represent an ideal biological system to test for these hypotheses, due to their presence in cities worldwide, their considerable variation in eumelanin‐based coloration, ranging from white to black plumage, and their close proximity to humans. We measured Flight Initiation Distance (FID, classically used for behavioral tolerance assessment) of feral pigeons of 4 different eumelanin‐based color morphs in sites differing in their urbanization rate and pedestrian traffic within the restricted scale of a city center (Paris). Urbanization rate and pedestrian traffic had no effect on FID, maybe because of the small spatial scale considered. FID varied with eumelanin‐based coloration: white pigeons had lower FID (104.6 cm; i.e., higher behavioral tolerance) than darker morphs (232.3 cm for Blue bar, 184.4 cm for T‐pattern & Checker, and 181.8 cm for Spread color morphs). Though the exact underlying causes remain to be identified, we propose different possible mechanisms for this relationship that remain to be investigated in future work.

Determination of Nanoparticles and Elements in Blue Mussels (Mytilus edulis) along the Norwegian Coastline.

Our work aimed to examine nanoparticle levels in 69 distinct pooled mussel samples along the Norwegian coastline, considering samples from different environmental contexts, including natural locations, potentially polluted hotspots, and mussel farms. Single-particle ICP-MS was utilized to determine particle mass and number concentrations at environmentally relevant levels in addition to the total content of 11 elements: aluminum, barium, cerium, copper, iron, manganese, lead, silicon, silver, titanium, and zirconium. Results showed nanoparticle mass concentrations of few ng/g up to tens of μg/g and number concentrations of 106 to 109 particles/g (wet weight). Certain urban and industrially impacted locations were linked to increased levels of, e.g., silver, lead, cerium, zirconium, and titanium NPs. Farmed mussels exhibited lower concentrations. However, natural variations were considerable, and impacted locations mostly did not differ from the highest levels in pristine areas. The study presents the first extensive survey of NPs of 11 different elements in marine biota and provides evidence of increased levels of NPs in areas with anthropogenic activities.

Distribution and sources of polycyclic aromatic hydrocarbons in cascade reservoir sediments: influence of anthropogenic activities and reservoir hydrology.

The construction of dams has caused disruptions to river connectivity, leading to alterations in the deposition of hydrophobic organic contaminants in reservoir sediments. Further investigation is warranted to explore the impact of cascade reservoirs with differing hydrological characteristics on polycyclic aromatic hydrocarbons (PAHs) distribution in sediment. This study examines the presence of 30PAHs in the sediments collected from six cascade reservoirs situated in the Wujiang River basin during January and July 2017. The results showed that Σ30PAHs ranged from 455-3000ng/g dw (mean 1030ng/g dw). Anthropogenic activities and reservoir hydrology determined the distribution trend of PAHs in sediments, with an overall increase from upstream to midstream and then a decrease downstream. The PAH levels were highly linked to the secondary industry (P < 0.05). This was further supported by the relationship between the PAH emissions from coal combustion and traffic sources analyzed by the positive matrix factorization model and economic parameters in the wet season (P < 0.01). At the same time, reservoir age (RA) showed a positive correlation with PAH concentrations (P < 0.05), while hydraulic retention time (HRT) exhibited a negative correlation with PAH levels (P = 0.03). The relationship between total organic carbon (TOC) and PAHs in stream sediments worldwide was nonlinear (P < 0.01), with PAH concentrations initially rising and then falling as TOC levels increased. Concerns regarding carcinogenic risk were raised due to contributions from coal and vehicular sources, with the risk increasing with RA.

Risk assessment and sources associated with potentially toxic elements in suspended particulate matter: A karst river perspective in active mining area

Study regionDaiyang River Basin, a typical karst river basin impacted by mining activities in Guizhou, Southwest China. Study focusRivers are fundamental components of regional water security, but they are facing potentially toxic elements (PTEs) pollution caused by mining activities. This study investigated the concentration, behavior, risks and sources of nine PTEs in suspended particulate matter (SPM) from mining-impacted karst rivers, which are essential for the safety and management of karst water environments. New hydrological insights for the regionThe contents of Cr, Ni, Cu, Zn, As, Cd, Sb and Hg exceeded the corresponding local soil background values, with Zn and Cu being the most important pollutants. These elements caused a very high potential toxicity risk to the basin and unacceptable carcinogenic and non-carcinogenic risks to the local residents. Correlation analysis and the positive matrix factorization (PMF) model indicated that Ni, Cd, Zn and Cu were mainly derived from mixed sources of geological background and anthropogenic activities (30.95 %), Hg, Sb, and As were related to coal mining and combustion sources (28.91 %), while Pb, As, Cr and Sb were mainly contributed by natural sources (40.15 %). Furthermore, mixed sources, mining-related sources and As were identified as priority control factors in the study area. These insights can provide powerful support for decision-makers to develop control policies and reduce PTEs pollution in karst areas.

The Effects of Model Insoluble Copper Compounds in a Sedimentary Environment on Denitrifying Anaerobic Methane Oxidation (DAMO) Enrichment.

The contribution of denitrifying anaerobic methane oxidation (DAMO) as a methane sink across different habitats, especially those affected by anthropogenic activities, remains unclear. Mining and industrial and domestic use of metals/metal-containing compounds can all cause metal contamination in freshwater ecosystems. Precipitation of metal ions often limits their toxicity to local microorganisms, yet microbial activity may also cause the redissolution of various precipitates. In contrast to most other studies that apply soluble metal compounds, this study investigated the responses of enriched DAMO culture to model insoluble copper compounds, malachite and covellite, in simulated sedimentary environments. Copper ≤ 0.22 µm from covellite appeared to cause immediate inhibition in 10 h. Long-term tests (54 days) showed that apparent methane consumption was less impacted by various levels of malachite and covellite than soluble copper. However, the medium-/high-level malachite and covellite caused a 46.6-77.4% decline in denitrification and also induced significant death of the representative DAMO microorganisms. Some enriched species, such as Methylobacter tundripaludum, may have conducted DAMO or they may have oxidized methane aerobically using oxygen released by DAMO bacteria. Quantitative polymerase chain reaction analysis suggests that Candidatus Methanoperedens spp. were less affected by covellite as compared to malachite while Candidatus Methylomirabilis spp. responded similarly to the two compounds. Under the stress induced by copper, DAMO archaea, Planctomycetes spp. or Phenylobacterium spp. synthesized PHA/PHB-like compounds, rendering incomplete methane oxidation. Overall, the findings suggest that while DAMO activity may persist in ecosystems previously exposed to copper pollution, long-term methane abatement capability may be impaired due to a shift of the microbial community or the inhibition of representative DAMO microorganisms.

Ecological Vulnerability of Aquatic Ecosystems-A Review.

The continuous increase of anthropogenic activities reinforces their stress on aquatic ecosystems (from continental to marine ecosystems) that are the most altered ecosystems on Earth. To evaluate the risk of ecosystem decline toward human alterations, the concept of "ecological vulnerability" was developed to help managers to prioritize conservation actions. Various definitions of vulnerability and its components were used, but this concept is often centered on the intersection of three components: sensitivity, exposition, and adaptive capacity. The aim of this study was through a review of the scientific literature of the last 10 years, first to assess the goals of the use of the concept of vulnerability in aquatic ecology: for which pressure (e.g., climate change, predation) and organism, on which level of organization (individuals, species, …). The second objective, was to address the methods developed to assess vulnerability: which components were considered, which metrics were used, the scoring process… Fish were the organisms the most frequently concerned and the number of publications decreased with the increasing complexity of biodiversity studied (from populations to multitrophic organizations). Climate change was the main stressor for which vulnerability was assessed. Vulnerability was commonly defined as being highly sensitive, highly exposed and lowly adaptable even if adaptive capacity was rarely addressed. This study showed an interest in the concept of vulnerability to protect aquatic ecosystems. Nonetheless, to better evaluate their risk of biodiversity loss, we should consider vulnerability at a higher level of organization and encompass the adaptive capacity of the biota.

Pseudomonas putida triggers phosphorus bioavailability and P-transporters under different phosphate regimes to enhance maize growth

The decline of available phosphorus in soil due to anthropogenic activities necessitates utilizing soil microorganisms that influence soil phosphorus levels. However, the specific mechanisms governing their interaction in Zea mays under diverse phosphate regimes remain largely unknown. The present study investigated the dynamics of phosphorus solubilization and the impact of organic acid supplementation in combination with the beneficial rhizobacterium Pseudomonas putida (RA) on maize growth under phosphorus-limiting and unavailable conditions. HPLC analysis revealed gluconic acid as the primary organic acid (OA) produced by P. putida across all three conditions (P-sufficient, P-limiting, and P-unavailable), with the highest production occurring under P-limiting conditions. The study evaluates the effects of RA, OA, and OA + RA on plant growth parameters under P-limiting and insufficient conditions, revealing significant alterations in growth and biochemical parameters (P = 0.05) compared to their respective untreated controls. Additionally, plants treated with organic acids and bacterial inoculation show increased phosphorus concentrations in both roots and shoots. Gene expression analysis of key phosphorus transporter genes (PHT1, PHO1, PTF, PHF1) further supports the role of organic acids and bacterial inoculation in enhancing phosphorus uptake. In conclusion, our study affirms that the secretion of gluconic acid by RA and its plant growth-promoting properties boost phosphorus uptake and maize growth by increasing phosphorus availability and influencing the expression of phosphorus transport-related genes.

Channel breakdown and avulsion in arroyos feeding the Little Colorado River, Arizona, USA

Improved knowledge regarding dryland river character and behaviour is important as the increasing threats of climate change and anthropogenic activities exacerbate water security issues in channels prone to discontinuity and termination. Dryland river character and behaviour is determined by a complex and dynamic interplay between extrinsic controls and intrinsic processes. Polacca and Oraibi Wash are two discontinuous dryland rivers, tributaries of the Little Colorado River in semi-arid, north-eastern Arizona, USA. Valley-scale morphometrics and downstream longitudinal trends were derived from remote sensing and geospatial analyses, hydraulic modelling, and field measurements, to assess the key controls, patterns, and processes driving channel diminution and discontinuity. Both rivers are entrenched along most of their valleys and experience downstream hydro-geomorphic changes as valley confinement eases in their low gradient floodplains. The rivers exhibit non-equilibrium responses to a concomitant decline in calculated discharge (from ∼82 to <4 m3 s−1), stream power (from ∼334 to <5 W m−2), and channel cross-sectional area (from ∼82 to <3 m2), which are the principal factors contributing to channel breakdown and the development of broad floodouts. Small distributary channels and avulsions are evident in the lowland reaches where channel discontinuity occurs, with a dominance of knickpoints in distal floodout reaches as they attempt to re-establish channel continuity. Using historical aerial imagery we show that knickpoint headcut retreat rates have ranged from ∼1.7 to 53 m a−1. Channel breakdown patterns and processes in the Polacca and Oraibi Washes are similar to other dryland rivers around the world, and reveal common underlying factors that are central to river termination and reformation. This study reveals a combination of intrinsic erosion and sedimentation processes and avulsion threshold responses that trigger channel adjustment resulting from downstream fluvial decline. However, key extrinsic controls, such as valley confinement and hydroclimate, influence and limit the rate and nature of these adjustments. Early recognition of these geomorphic changes can inform river, land, and water management strategies across the American southwest.

Coupling of anthropogenic activities and natural factors on dissolved organic matter: Insights from coastal urban rivers in southern China

Accelerated urbanization has reshaped the biogeochemistry of dissolved organic matter (DOM) in urban rivers, yet the interplay between anthropogenic and natural influences on riverine DOM remains unclear. This study utilized absorbance and fluorescence spectroscopy coupled with parallel factor analysis (PARAFAC), to explore the spatiotemporal distribution of DOM in twenty coastal rivers located in a highly urbanized area. Findings highlight increased DOM abundance, especially the protein-like component (C2: 1.48 RU in urban areas and 0.24 RU in suburban areas), in the rivers of urban areas, contrasted by seasonal shifts of chromophoric DOM (CDOM) and humic-like DOM in the rivers of suburban areas (a350: 3.18 m−1 in the wet season and 1.23 m−1 in the dry season). Tidal mixing’s role in DOM distribution is evidenced by diurnal salinity changes and its inverse relationship with DOM abundance. Notably, the Shenzhen River’s unique DOM composition (a higher abundance of humic-like DOM and a lower abundance of protein-like DOM) suggests agricultural impacts. Strong correlations (R2 values reaching up to 0.87) between spectral DOM indicators and chemical oxygen demand (COD) underscore the great potential of spectral methods for water quality monitoring. Overall, this study illuminates the coupled effects of urbanization and natural factors on riverine DOM, offering insights for the biogeochemical cycling of DOM and water quality management in urban rivers, with implications for similar urbanized regions globally.

Assessing indicators and preferences of cultural ecosystem services in urban areas: a case study of Murcia, Spain

ContextThe degradation of the environment due to anthropogenic action underscores the need to demonstrate the benefits that natural areas provide to society. Continuously growing urbanisation trends and high demand on urban green infrastructure requires the inclusion of cultural ecosystem services (CESs) in strategic urban planning. To achieve this, understanding the population's preferences regarding the various CESs provided by urban green spaces is extremely useful for their management and long-term planning strategies. Nevertheless, the complexity of urban environment and urban CESs and inclusion of participatory-oriented and demand-based planning poses challenges in conducting solution-oriented assessments.ObjectivesTo address this issue, we aim to define and validate spatial indicators that are applicable in any urban area. We employ them to quantify the provision of CESs considering that such approach can contribute to better urban planning strategies.MethodsA survey, aiming to validate five proposed CESs indicators and evaluate the population’s perception regarding the importance of CESs in urban green areas in the city of Murcia (Spain) was conducted. In total, 733 answers were collected. The survey results underwent through statistical and geospatial analysis at the neighbourhood level, which facilitated the creation of CESs maps, considering socio-demographic characteristics of the respondents.ResultsAll five proposed CESs indicators were highly accepted by the respondents across all demographic groups. Conversely, differences in the perception of importance of CESs are noted based on the age of the respondents. Disparities in CESs provision are observed between different city neighbourhoods and socio-demographic groups.ConclusionsWe identified significant differences in CESs perception by age group. We also detected the areas where action is needed to improve the CESs provision. Through this study, we emphasize the significance of participatory-based, demand-oriented, and territorially tailored planning approaches to ensure the high provision of CESs and enhance urban well-being.

Tolerance of free-living larval stage of a parasite from coastal mining areas in northern Humboldt Current to copper pollution at low and high temperatures.

Metal pollution is a worldwide problem and one of the greatest threats to ecosystem integrity due to its toxicity, persistence, and bioaccumulation in biological systems. Anthropogenic pollution impacts marine organisms and host-parasite dynamics, with the northern Chilean coast experiencing elevated copper levels in marine waters and sediments due to mining activities. In this study, we assessed the effects of exposure to copper concentrations at low and high-water temperatures on the survival and longevity of the marine parasite Himasthla sp. cercariae (Trematoda: Digenea) using the snail Echinolittorina peruviana as its first intermediate host. Snails were collected from intertidal rocky pools in northern Chile (23°S). To assess parasite survival and longevity, cercariae were collected from a pool of infected snails, and their mortality was recorded every 6 hours until all cercariae were dead. In a preliminary experiment conducted at 19°C, cercariae were exposed to different copper concentrations (0.2, 1.5, 3.0, and 6.0 mg/L) for 78 hours. Cercariae showed tolerance to copper. However, at the higher copper concentration (6 mg/L), survival was negatively impacted (50%) at 54 hours. In contrast, at the lower concentration (0.2 mg/L) and in the control group, cercariae sustained a 73-90% survival rate even after 54 hours. Based on these findings, we conducted subsequent experiments involving two copper treatments (0.2 and 3.0 mg/L) and two temperatures (14 and 22°C). Survival and longevity were significantly higher at lower temperature and copper concentration (14°C and 0.2 mg/L). Conversely, at higher temperature and copper concentration (22°C and 3 mg/L), survival and longevity decreased to only 66 hours. Our results show that Himasthla sp. cercariae tolerated most copper concentrations, with vulnerability observed primarily in high water temperatures, indicating an adverse effect on cercariae performance. This study contributes valuable insights into how parasites respond to environmental pollution, in marine ecosystems influenced by anthropogenic activities.