Components Of Ecosystems Research Articles

Divergent responses of forest canopy height to environmental conditions across China

As major components of terrestrial ecosystems, forest ecosystems play an important role in sequestering carbon and hence mitigating climate change. Canopy height is a crucial factor characterizing the structure and function of forest ecosystems, yet the driving mechanism of forest canopy height receives less attentions in China. Here, we utilize the satellite-based forest canopy height product with several environmental and climate factors (e.g. forest age, temperature, etc.) to delineate the spatial distributions of forest canopy height and its drivers in China at 1 km spatial resolution during the period of 2014 to 2018. The random forest is employed for identifying the dominant factors at province level, while Shapley additive explanations (SHAP) analysis is further incorporated at pixel-level to dig into the specific contributions of each driver. The results show that forest age primarily dominates the spatial distributions of forest canopy height across different forest ecosystems of China, followed by mean annual precipitation, soil type, and aspect. SHAP analysis further indicates that other factors, such as soil moisture and wind speed, also play critical roles to shape the spatial patterns of forest canopy height in China, which could not be revealed from province-level random forest analyses. Such results emphasize the priority of incorporating SHAP analysis with random forest to advance our understanding of forest canopy height distributions and benefit future projections. Our study highlights the necessity to characterize the spatial heterogeneity of forest canopy height, which is critical for accurate estimations of forest and even terrestrial carbon sink in China, facilitating the achievement of the goal of “carbon peak in 2030 and carbon neutrality in 2060”.

Towards the mechanical stability of biocrusts in drylands: Insights from inorganic ions and organic compounds and their interactions

Biocrusts are an important component of dryland ecosystems as they perform crucial ecological functions like stabilizing soils, mediating the hydrological cycle, and improving nutrient availability. The high mechanical stability of biocrusts is understood to be linked to exopolymeric substances (EPS), which in turn, are responsible for the adsorption of various ions and chemical compounds. This study aimed to investigate the chemical composition of biocrusts and assess potential correlations between their chemical composition and mechanical stability. Samples of three types of biocrusts (cyanobacteria, cyanobacteria and moss mixed, and moss crusts) and bare soil (as control) were collected from the northern Loess Plateau of China. The inorganic ions and organic compounds present in biocrusts were quantified using inductively coupled plasma-optic emission spectrometry, ion chromatography, and gas chromatography-mass spectrometry. Biocrust mechanical stability was assessed by penetration resistance (PR) and the mean weight diameter (MWD) of aggregates. Finally, the contribution of inorganic ions and organic compounds to the stability of the biocrusts was elucidated. The results indicated that all three types of biocrusts were more stable than bare soil, with moss crusts being the most stable. Chemical analyses revealed an enrichment of inorganic ions such as K+, Ca2+, Na+, Mg2+, SO42–, and halogen ions within the biocrusts, while they showed a depletion of Fe2+, Al3+, and NO3–. Ten types of organic compounds were identified in biocrusts and bare soil, with medium-chain alkanes and long-chain acids being the dominant compounds. In some cases, acids accounted for more than 40 % of the total organic compound content of the biocrusts. Redundancy analysis showed that the content of inorganic ions, such as Ca2+ and Mg2+, and organic compounds such as acids, amides, and alkenes, exhibited the closest association with the biocrust stability. Partial least squares path modeling indicated that both inorganic ions and organic compounds indirectly affected biocrust stability by influencing electric conductivity, bulk density, EPS, and fine particle (clay and silt) content. A strong association was found between the inorganic ions and PR or MWD (0.658 and 0.744, respectively), whilst the total effect of organic compounds on PR and MWD was 0.814 and 0.801, respectively. It is suggested that both the magnitude and types of chemicals associated with EPS indicate their capability to grant mechanical stability of the biocrusts, which in turn is conducive to maintaining the critical functions of biocrusts in global drylands.

Evolution mechanism of physical morphology of oxbow lake in the middle Yangtze River

Oxbow lakes, formed through river meandering cutoffs, are recognized as key components of river ecosystems, characterized by both fluvial and lacustrine features. The focus of previous research has been placed primarily on post-disconnection changes, leaving gaps in the understanding of their long-term morphological evolution. This gap is addressed through a comparative analysis of gate-controlled and naturally connected oxbow lakes over a 30-year period. In this study, Tian’ezhou Lake (gate-controlled) and Shangchewan Lake (naturally connected), located in the middle Yangtze River, are investigated. Key morphological parameters such as curvature, shoreline development index, and shrinkage rate were measured using Google Earth Engine (GEE). The influence of hydrological and meteorological factors on lake morphology was analyzed through Redundancy Analysis (RDA). Significant morphological changes were observed from 1990 to 2000. During this period, Tian’ezhou’s curvature was found to increase by 0.003/year, while Shangchewan’s curvature decreased by 0.011/year. After the construction of the Three Gorges Dam (TGD), a reduction in the rate of morphological evolution was detected, particularly between 2000 and 2010, when Tian’ezhou’s curvature decreased by 0.071/year and Shangchewan’s increased by 0.04/year. Post-2010, no significant changes in planar morphology were recorded in either lake. It was revealed by RDA that annual precipitation from 1990 to 1999 played a dominant role in influencing the morphological evolution of both lakes. From 2000 to 2020, water level fluctuations and hydrological connectivity emerged as the primary drivers. Gate control at Tian’ezhou Lake mitigated extreme water level fluctuations, contributing to a more stable environment and a slower rate of morphological evolution compared to Shangchewan. The findings underscore the importance of balanced water management strategies, integrating both natural and engineered hydrological interventions. Practical guidance is provided for ecological restoration and river management, with an emphasis on maintaining stable habitats and ensuring ecosystem resilience in response to hydrological changes.

A brief review on effect of heavy metals in fish fauna

The variety of fish species is essential for the well-being and stability of aquatic environments. Fishes are one of the most important aquatic creatures that are directly or indirectly related to human health and wealth. With thousands of different species inhabiting various water bodies around the world, each fish contributes to the overall biodiversity and sustainability of these environments. Humans have long relied on aquatic resources for food, medicines, and materials. Fish species are adapted to a variety of environments such as freshwater lakes, rivers, reservoirs, oceans, and estuaries. The diversity of habitats available allows a variety of fish species to thrive in different environments. Fish diversity is a vital component of aquatic ecosystems, supporting ecosystem stability, economic value, and cultural significance. India's inland water resources are abundant and diverse, including reservoirs that play an important role in the country's inland fisheries sector.Biodiversity and its conservation are considered one of the key issues to enable sustainable use of natural resources. Protecting ichthyophan diversity in its natural habitat is essential and the need of the hour. By understanding the factors that influence fish diversity and the importance of preserving biodiversity, we can work towards protecting and protecting these priceless resources for upcoming generations.

Socio-economic transformation follows environmental change on Svalbard

The European Arctic, which includes the Svalbard archipelago, is situated in one of the areas showing most notable changes due to global warming and associated cascade events and processes. The main driving factor, temperature rise, is continuing to cause a large-scale overall decline in ice, from glacier retreating, less coastal land-fast ice to thinning and shrinking of open-sea pack ice. This, together with increased inflow of Atlantic waters, is causing profound changes in the local fauna, food web and biodiversity. In parallel, changes in landscape are also notable, mainly due to increasing coastal erosion and glacial melt. Over the past decades, both the traditional hunting-trapping lifestyle and mining have declined almost to the point of non-existence. At the same time, destination tourism and scientific research have become the major industries, both associated with an increase in the size of the main settlement of Longyearbyen, and thus also service jobs and local administration. Along with the shrinking of the glaciated Arctic landscape, the archipelago exemplifies the broadest level of nature protection in Europe. Strict environmental regulations that restrict and even prohibit human activities in large areas contribute to Svalbard being one of the best formally protected wilderness environments in the entire Arctic. Thus, as Svalbard marine ecosystems continue to change, they also are becoming more accessible to humans, and so also anthropogenic pressures are both changing and increasing in extent. We provide a compilation of both ecosystem components and human activities, together with indications of how these are, in parallel, changing. This forms the basis for future ecosystem and societal valuation assessments.

Macrophyte Diversity and Ecosystem Services in Wetlands of Eastern Ranchi: A Multi-site Analysis of Abundance, Frequency, and Importance Value Index Patterns

Macrophytes, visible aquatic and semi-aquatic plants, are integral components of wetland ecosystems, playing crucial roles in maintaining biodiversity, providing ecosystem services, and ensuring ecological stability. This research examines the distribution, abundance, frequency, diversity, and ecosystem services of macrophytes in several wetlands (W1-W7) located in the eastern part of Ranchi district, Jharkhand, India. The study sites include Bundu Lake, Hindalco Pond, Choga Bada Talab, Raja Bandh, Kita Uparbandh, Tamar Bada Talab, and Rukka Dam. A quantitative assessment using quadrat sampling and phytosociological methods was conducted from September 2022 to March 2023 to ensure accurate data collection and analysis. The study documented 78 macrophyte species belonging to 33 families and 58 genera. Emergent macrophytes were found to be the dominant life form, constituting 69% of the recorded species. Several species demonstrated high frequency and abundance across multiple study sites, including Pontederia crassipes Mart., Alternanthera philoxeroides (Mart) Griseb., Hydrilla verticillata (L.f.) Royle, Ipomoea aquaticaForssk., and Nymphoides hydrophyllum (Lour.) kuntze. To assess the diversity and ecological characteristics of the macrophyte communities, various diversity indices were calculated. These included the Shannon-Wiener index, Simpson's index, Margalef index, and Pielou's Evenness index. The results of these analyses revealed high levels of macrophyte diversity and evenness within the studied wetlands. Twenty-one macrophytes were identified as key species and nine species as rare species based on their IVI (Importance Value Index) scores. The key species were found to provide essential ecosystem services, including erosion control, water quality improvement, nutrient cycling, carbon sequestration, and habitat provision for other organisms. This research contributes significantly to our understanding of macrophyte diversity patterns and traits-based ecosystem services in wetland ecosystems. The findings of this study have important implications for the development and implementation of effective conservation strategies for these vital wetland ecosystems in the eastern Ranchi (W1- W7).

Strengthening ecosystems

Abstract The mission of THCS activities with respect to strengthening ecosystems is based on the understanding that the actual transformation of health and care systems is dependent on the ability of numerous actors to align their goals and actions so that they are complementary. At the same time, it is also true that the transformation takes place at national, regional and local levels, making activities and support at these levels essential for the success of THCS. Therefore, the focus lies on connecting and supporting the broad community and other stakeholders in developing ecosystem-wide approaches and creating awareness and urgency among ecosystem layers and components, thus serving as a platform for transformation. One strand of activities for strengthening ecosystems aims at identifying, analysing, describing and disseminating key learnings from successful transformative ecosystems (TE’s). TE’s are broad constellations of interacting organisations and people who are committed, and through aligned actions, able to reach joint, explicitly defined goals in long-term. Making not only the most successful TE’s but also the dynamics explaining their achievements visible, value is being added through three main routes. Firstly, the experiences are distributed widely on European arenas and platforms as well as through national, regional and local channels to inspire ecosystem building processes in earlier stages of maturity. Secondly, collaboration between identified forerunner ecosystems is supported to enable mutual peer-learning. Thirdly, the examples are used to give guidance and inspiration to consortia that are applying for or receiving THCS project funding. As strategic partners of the ecosystem strengthening activities, other work packages of the THCS programme as well as the THCS National Mirror Groups are of great importance.

Expert elicitation of state shifts and divergent sensitivities to climate warming across northern ecosystems

Northern regions are warming faster than the rest of the globe. It is difficult to predict ecosystem responses to warming because the thermal sensitivity of their biophysical components varies. Here, we present an analysis of the authors’ expert judgment regarding the sensitivity of six ecosystem components – permafrost, peatlands, lakes, snowpack, vegetation, and endothermic vertebrates – across northern landscapes ranging from boreal to polar biomes. We identified 28 discontinuous component states across a 3700 km latitudinal gradient in northeastern North America and quantified sensitivity as the transition time from an initial to a contrasting state following a theoretical step change increase in mean annual air temperature of 5 °C. We infer that multiple interconnected state shifts are likely to occur within a narrow subarctic latitudinal band at timescales of 10 to more than 100 years, and response times decrease with latitude. Response times differ between components and across latitudes, which is likely to impair the integrity of ecosystems.

SNPs Analysis Indicates Non-Uniform Origins of Invasive Mussels (Mytilus galloprovincialis Lamarck, 1819) on the Southern African Coast

Understanding the origins of invasive species is necessary to manage them and predict their potential for spreading. The mussel genus Mytilus forms an important component of coastal ecosystems in the northern and southern hemispheres. M. galloprovincialis is an important invasive species globally, first appearing on the South African coast in the 1970s. Studies using nuclear and mitochondrial DNA indicated that the invasion probably originated from the north-east Atlantic. We used fifty-five polymorphic SNPs to genotype mussels from sites across the coast of South Africa with reference samples from the Mediterranean, the Atlantic, and New Zealand to test for possible introgression of the northern and southern taxa. Low levels of genetic differentiation were confirmed, and all samples grouped with reference samples of the Atlantic form of M. galloprovincialis, supporting previous studies. The SNP genotyping, however, allowed the detection of some individuals with genotypes typical of the Mediterranean, indicating that introduced populations in South Africa do not have a uniform origin. The initial population introduced to South Africa may have been genetically heterogenous from the start, coming from a region influenced by both the Atlantic and Mediterranean. Alternatively, multiple introductions may have taken place, originating from different regions, specifically North Africa, southern Europe, and the Mediterranean, building up the final heterogeneity.

Variation in species-specific responses to habitat fragmentation and land cover structure in urban small mammal communities

Abstract Urbanization is a key driver of habitat loss and fragmentation worldwide, yet many urban ecosystems contain vegetated habitat patches that support diverse wildlife communities. Managing urban systems to support robust wildlife communities requires us to understand the mechanisms that drive the response of species to the urban environment. Small mammals are key components of terrestrial ecosystems (e.g., seed predators, prey) and likely also carry out these roles in urban ecosystems; however, the effects of urbanization on small mammal communities are understudied. To identify how species-specific responses to urban environments shape community composition, we quantified both overall community and species-specific changes in small mammal abundance across an urbanization gradient in a Midwestern US metropolitan area. We combined small mammal trapping and land cover data to generate a hierarchical community abundance model. Species diversity increased with increasing proportional cover of human-modified land cover (i.e., impervious surfaces and turfgrass). This finding is driven by high species diversity on sites bordering streams in mowed parks and low diversity on sites with high tree canopy closure. Additionally, modeling results indicated that species responded differently to landscape attributes, leading to variation in small mammal community composition across the urbanization gradient: prairie-associated species tended to be more abundant in tall vegetation bordering mowed parks while habitat generalists tended to be more abundant on sites with greater canopy closure and shrub cover. Our results suggest that studies that focus on community-level responses (e.g., species richness) to urbanization may miss important species-specific responses. It may be particularly important to assess both species-specific and community-level responses in cities at ecotones (e.g., between forest and grassland) where species with different habitat requirements may replace one another in different types of green spaces, thereby changing community composition without affecting species diversity or richness. Our findings also indicate that vegetated urban patches, especially patches with tall vegetation cover and low canopy cover, are important habitat for prairie-associated small mammal communities, providing conservation options in heavily altered landscapes.

Measuring the ecological outcomes of fire: metrics to guide fire management

BackgroundChanges to fire regimes threaten biodiversity worldwide and emphasize the need to understand the ecological consequences of fire management. For fire management to effectively protect biodiversity, it is essential to have ecologicallyrelevant metrics to plan and evaluate management interventions. Here, we describe a suite of metrics to guide fire management for enhanced biodiversity outcomes.ResultsWe define five metrics that collectively provide comprehensive and complementary insights into the effect of fire regimes on ecosystem resilience and components of biodiversity. These include (1) Species Habitat Availability, a measure of the amount of suitable habitat for individual species; (2) Fire Indicator Species Index, population trends for species with clear fire responses; (3) Vegetation Resilience, a measure of plant maturity and the capability of vegetation communities to regenerate after fire; (4) Desirable Mix of Growth Stages, an indicator of the composition of post-fire age-classes across the landscape; and (5) Extent of High Severity Fire, a measure of the effect of severe fire on post-fire recovery of treed vegetation communities. Each metric can be quantified at multiple spatial and temporal scales relevant to evaluating fire management outcomes. We present a case study from Victoria, Australia, in which two metrics are applied across spatially-nested management areas. Results highlight four characteristics of metrics that enhance their value for management: (1) they quantify both status and trends through time; (2) they are scalable and can be applied consistently across management levels (from individual reserves to the whole state); (3) most can be mapped, essential for identifying where and when to implement fire management; and (4) their complementarity provides unique insights to guide fire management for ecological outcomes.ConclusionsThese metrics reflect common relationships between fire and biodiversity and are relevant to management in fire-prone ecosystems worldwide. They facilitate consistent translation of management responsibilities (planning, evaluation, reporting) across administrative levels and enable managers to strategically plan on-ground actions and transparently evaluate outcomes against strategic goals. A key next step for fire managers globally is to define “desirable” states for ecological metrics, to enable target-setting and the evaluation of management outcomes.

Impact of Climate and Vegetation Dynamics on the Ecosystem Services of Subtropical Forests—A Case Study of Baishanzu National Park Area, China

Forest ecosystems, as the primary component of terrestrial ecosystems, provide essential ecosystem services (ESs) critical for sustainable human development. However, changes in climate and vegetation can alter these forest ESs. Understanding the complex relationships between regional climate, vegetation, and ESs is key to ensuring the sustainable management of forest ESs. Therefore, this study, using Baishanzu National Park as a case example, analyzed the impacts of regional climate and vegetation dynamics (vegetation coverage, forest type, and forest structure) on forest ESs, specifically water yield (WY), soil conservation (SC), net primary productivity (NPP), and habitat quality (HQ). The results indicate that from 2000 to 2020, the forest Composite Index of Ecosystem Services (CIES) in Baishanzu National Park increased. Climate and vegetation dynamics have significant effects on forest ESs. Specifically, changes in WY and SC are primarily influenced by climate change, while changes in NPP and HQ are mainly affected by changes in forest type and structure. Complex trade-offs and synergies exist among different ESs, and the driving mechanisms of climate and vegetation changes on ES variations are also complex, involving both direct and indirect effects, with significant spatial heterogeneity. This study provides important references for the sustainable management and appropriate restoration of regional forest ESs.

Photoautotrophic picoplankton of the Kara Sea in the middle of summer: Effect of first-year ice retreat on carbon and chlorophyll biomass and primary production

The Arctic warming leads to a decline in sea-ice extent and thickness, rapid warming and freshening of the sea surface which impact the distribution of phytoplankton size composition. Picophytoplankton is an ecologically important component of Arctic pelagic marine ecosystems, and its role may be altered by global warming. In this study, the abundance and biomass, the chlorophyll a (Chl-a) and primary production (PP) of picophytoplankton, and its spatial and temporal distribution were investigated in the Kara Sea during the ice-melt season in July 2019. Picophytoplankton played a major role in the surface PP in the southern and western areas of the Kara Sea. In the surface layer, the contribution of picophytoplankton to total Chl-a increased insignificantly, and the contribution of picophytoplankton to total PP decreased significantly with the time of sea ice retreat. In the euphotic zone, the Chl-a concentration of picophytoplankton and its contribution to total Chl-a decreased with the time of sea ice retreat. The average picophytoplankton biomass determined in the present study (2.72 ± 5.10 mg C m−3) corresponded to the biomass estimates in the Arctic. The picophytoplankton community was strongly dominated by eukaryotes, cyanobacteria were only detected at 3 out of 11 stations, with maximum abundances (0.07 × 109 cells m−3) observed at depths below 15 m. The obtained results contribute significantly to the study of the picophytoplankton dynamics during the ice-melting season in the hard-to-reach Kara Sea.

Larval dispersal and physical connectivity of Pheronema carpenteri populations in the Azores

The study of larval dispersal and connectivity between deep-sea populations is essential for the effective conservation and management of deep-sea environments and the design and implementation of Marine Protected Areas. Dense sponge aggregations, known as “sponge grounds”, are a key component of marine benthic ecosystems, by increasing the structural complexity of the sea floor and providing structure and habitat for many other species. These aggregations are characteristic of the Azores deep-sea environment. These sessile organisms rely primarily on larval dispersal for their reproduction. Connectivity between specific Pheronema carpenteri sponge aggregations in the Azores was studied using a 3-D biophysical dispersal model. Different biological trait scenarios were analyzed, considering spawning seasonality and pelagic larval duration. Model results indicate that regional circulation patterns drive larval dispersion, shaping population connectivity of P. carpenteri sponge aggregations in the Azores, particularly among aggregations in the Central Group of Azorean islands. Some areas present high retention rates, receiving larvae from several sponge aggregations while also being important larval source aggregations. In contrast, aggregations from the Eastern Group may be isolated from the others. Larval dispersal and connectivity patterns were analyzed concerning the current configuration of Marine Protected Areas (MPAs) in the Azores. The results underscored the importance of maintaining protection efforts in existing MPAs and identified stepping-stone locations and specific sites where additional measures could enhance species connectivity in the Azores.

Biological soil crusts significantly improve soil fertility and change soil microbiomes in Qinghai-Tibetan alpine grasslands.

Biological soil crusts (BSCs), a vital component of ecosystems, are pivotal in carbon sequestration, nutrient enrichment, and microbial diversity conservation. However, their impact on soil microbiomes in alpine regions remains largely unexplored. Therefore, this study aimed to determine the influence of BSCs on alpine grassland soil microbiomes, by collecting 24 pairs of soils covered by biological and physical crusts along a transect on the Qinghai-Tibetan Plateau. We found that BSCs significantly increased the contents of soil moisture, organic carbon, total nitrogen, and many available nutrients. They also substantially altered the soil microbiomes. Specifically, BSCs significantly increased the relative abundance of Cyanobacteria, Verrucomicrobiota, and Ascomycota, while decreasing the proportions of Gemmatimonadota, Firmicutes, Nitrospirae, Mortierellomycota, and Glomeromycota. By contrast, microbial abundance and α-diversity demonstrated low sensitivity to BSCs across most study sites. Under the BSCs, the assembly of prokaryotic communities was more affected by homogeneous selection and drift, but less affected by dispersal limitation. Conversely, soil fungal community assembly mechanisms showed an inverse trend. Overall, this study provides a comprehensive understanding of the effects of BSCs on soil properties and microbial communities, offering vital insights into the ecological roles of BSCs.

Microplastic-Enhanced Cadmium Toxicity: A Growing Threat to the Sea Grape, Caulerpa lentillifera.

The escalating impact of human activities has led to the accumulation of microplastics (MPs) and heavy metals in marine environments, posing serious threats to marine ecosystems. As essential components of oceanic ecosystems, large seaweeds such as Caulerpa lentillifera play a crucial role in maintaining ecological balance. This study investigated the effects of MPs and cadmium (Cd) on the growth, physiology, biochemistry, and Cd accumulation in C. lentillifera while elucidating the underlying molecular regulatory mechanisms. The results demonstrated that exposure to MPs alone significantly promoted the growth. In contrast, exposure to Cd either alone or in combination with MPs significantly suppressed growth by reducing stem and stolon length, bud count, weight gain, and specific growth rates. Combined exposure to MPs and Cd exhibited the most pronounced inhibitory effect on growth. MPs had negligible impact while Cd exposure either alone or combined with MPs impaired antioxidant defenses and exacerbated oxidative damage; with combined exposure being the most detrimental. Analysis of Cd content revealed that MPs significantly increased Cd accumulation in algae intensifying its toxic effects. Gene expression analysis revealed that Cd exposure down-regulated key genes involved in photosynthesis, impairing both photosynthetic efficiency and energy conversion. The combined exposure of MPs and Cd further exacerbated these effects. In contrast, MPs alone activated the ribosome pathway, supporting ribosomal stability and protein synthesis. Additionally, both Cd exposure alone or in combination with MPs significantly reduced chlorophyll B and soluble sugar content, negatively impacting photosynthesis and nutrient accumulation. In summary, low concentrations of MPs promoted C. lentillifera growth, but the presence of Cd hindered it by disrupting photosynthesis and antioxidant mechanisms. Furthermore, the coexistence of MPs intensified the toxic effects of Cd. These findings enhance our understanding of how both MPs and Cd impact large seaweed ecosystems and provide crucial insights for assessing their ecological risks.

Temperature and ultraviolet radiation on a high mountain daphnid: When do interactions become lethal to highly adapted populations?

ABSTRACT Aquatic organisms from high mountain lakes experience extreme influences of climate and solar radiation, especially ultraviolet radiation (UVR), manifested through alterations in physiology, life history, and phenology. Zooplankton, a pivotal component of lake ecosystems, is particularly sensitive to changes in environmental conditions because of their short life cycles and diminished mobility. In the high mountains of the tropical Andes, zooplankton populations are adapted to low temperatures and high UVR because most of the Andean lakes are >4000 m a.s.l. This study focuses on Daphnia pulicaria populations originating from high-mountain Andean lakes, investigating their responses to different temperatures and UVR exposure by means of lab experiments. Key findings indicate that temperature is the most important factor impacting population variables, with high temperatures and UVR exposure leading to unfavorable population outcomes; however, physiological variables (cell viability and pigmentation, measured as melanin) are similarly influenced by temperature and UVR exposure. Pigmentation increases with temperature and is accentuated by solar radiation, indicating an adaptive response to mitigate UVR damage. Conversely, cellular viability declines with elevated temperatures and UVR exposure, showing that higher temperatures may offset the protective effects of pigmentation. Overall, these findings underscore the vulnerability of daphnid populations in high-mountain Andean systems to anticipated climate change impacts, with potential consequences for ecological dynamics in these critical ecosystems. More importantly, they show the importance of studying temperature and UVR (and probably other environmental conditions) as interacting variables because the results will dramatically differ if each factor is considered separately.

Alterations of the gut microbiome in HIV infection highlight human anelloviruses as potential predictors of immune recovery

BackgroundHIV-1 infection is characterized by a massive depletion of mucosal CD4 T cells that triggers a cascade of events ultimately linking gut microbial dysbiosis to HIV-1 disease progression and pathogenesis. The association between HIV infection and the enteric virome composition is less characterized, although viruses are an essential component of the gut ecosystem. Here, we performed a cross-sectional analysis of the fecal viral (eukaryotic viruses and bacteriophages) and bacterial microbiome in people with HIV (PWH) and in HIV-negative individuals. To gain further insight into the association between the gut microbiome composition, HIV-associated immunodeficiency, and immune recovery, we carried out a longitudinal study including 14 PWH who initiated antiretroviral therapy (ART) and were followed for 24 months with samplings performed at baseline (before ART) and at 2, 6, 12, and 24 months post-ART initiation.ResultsOur data revealed a striking expansion in the abundance and prevalence of several human virus genomic sequences (Anelloviridae, Adenoviridae, and Papillomaviridae) in stool samples of PWH with severe immunodeficiency (CD4 < 200). We also noted a decreased abundance of sequences belonging to two plant viruses from the Tobamovirus genus, a reduction in bacterial alpha diversity, and a decrease in Inoviridae bacteriophage sequences. Short-term ART (24 months) was linked to a significant decrease in human Anelloviridae sequences. Remarkably, the detection of Anellovirus sequences at baseline independently predicted poor immune recovery, as did low CD4 T cell counts. The bacterial and bacteriophage populations were unique to each PWH with individualized trajectories; we found no discernable pattern of clustering after 24 months on ART.ConclusionAdvanced HIV-1 infection was associated with marked alterations in the virome composition, in particular a remarkable expansion of human anelloviruses, with a gradual restoration after ART initiation. In addition to CD4 T cell counts, anellovirus sequence detection might be useful to predict and monitor immune recovery. This study confirms data on the bacteriome and expands our knowledge on the viral component of the gut microbiome in HIV-1 infection.3oR8qDfXoWY9s_P5ES648YVideo

A 30-m annual grassland dataset from 1991 to 2020 for Inner Mongolia, China

Grassland is a widely distributed land use type that provides essential resources for livestock production and serves as a crucial ecosystem component. Over the past decades, grassland has significantly degraded and shrunk due to climate change and human activities, with ongoing changes in its area. This study utilized the Google Earth Engine (GEE) and the Res-UNet++ model to analyze the phenological and spectral characteristics of grasslands in Landsat images for long-term annual monitoring. Additionally, the LandTrendr algorithm was utilized to correct long-term time series data for grasslands, yielding a map of grassland distribution in Inner Mongolia from 1991 to 2020. The results indicate that the overall spatial accuracy from 1991 to 2020 exceeded 96%, with a Kappa coefficient over 0.92, demonstrating high monitoring accuracy. In particular, the 2019 grassland monitoring area showed high consistency with data from the Third National Land Survey (TNLS), with a coefficient of determination (R^2) reaching 0.97, reflecting the high accuracy and reliability.

Blue-cloud DAB: developing a platform to harmonize, assess and disseminate marine metadata collections

AbstractThe integration and harmonization of marine data from diverse sources are vital for advancing global oceanographic research and ensuring seamless discovery and access of critical datasets. This paper presents a comprehensive analysis of the metadata harmonization efforts within the Blue-cloud 2026 project, which brokers data from numerous Blue Data Infrastructures (BDIs), leveraging the Discovery and Access Broker technology. The platform enables discovery and analysis of marine data collections while facilitating interoperability with other components of the marine digital ecosystem, such as virtual laboratories and the Semantic Analyzer. It also supports the flow of Blue-cloud information to other initiatives like the Global Earth Observations System of Systems. For data managers, the findings emphasize the importance of enhancing metadata quality, revealing discrepancies in core metadata elements, and the need for more consistent use of controlled vocabularies. For cyberinfrastructure developers, the study details the challenges of accommodating a wide array of interfaces from different data systems, highlighting the adoption of an extensible brokering architecture that harmonizes metadata models and protocols. The study also emphasizes the importance of metadata analysis in ensuring effective searches for end users, highlighting challenges in aggregating diverse sources, where data providers may have structured the content with different objectives compared to those of the system of systems. End users will gain insights into the current metadata content of Blue-cloud, enabling them to search and access data from multiple BDIs with an understanding of the technical complexities behind the scenes.