Abundance Of Organisms Research Articles

Warming promotes expansion of a key demersal fishing resource of the western Mediterranean

Climate change is affecting marine ecosystems altering the distribution and abundance of organisms, with implications for fisheries and food security. This warming-induced reshuffle in species abundance could bring threats and opportunities to the fisheries, but needs to be assessed to promote effective actions and to foster resilience. We analyzed the density and distribution patterns of deep-sea rose shrimp (Parapenaeus longirostris), as well as identified the main environmental have identified the environmental drivers shaping its habitat along the western Mediterranean (Iberian Peninsula) during the period 2001–2020. Using spatial distribution models developed concurrently with an ensemble of four Regional Climate Models (RCMs), we have projected the density of this species during the next century under two climate scenarios (RCP4.5 and RCP8.5). Bathymetry and sea bottom temperature drove the density of the species, leading to a marked northward expansion during the last two decades. Our results projected an increase in its distribution and especially in density throughout the area along the 21st century, mirroring the effect of global warming. Consequently, the most distant period (i.e. 2100s) and the warmest scenario (RCP8.5) presented also the highest densities and low internal variability of the ensemble. We discussed the power of assessing uncertainties using a RCM ensemble, particularly under complex oceanographic features, to bring robust information for an effective scientific advice to fisheries management.

Biotics and bacterial function: impact on gut and host health.

The human gut microbiota, the vast community of microbes inhabiting the gastrointestinal tract, plays a pivotal role in maintaining health. Bacteria are the most abundant organism, and the composition of bacterial communities is strongly influenced by diet. Gut bacteria can degrade complex dietary carbohydrates to produce bioactive compounds such as short-chain fatty acids. Such products influence health, by acting on systemic metabolism, or by virtue of anti-inflammatory or anti-carcinogenic properties. The composition of gut bacteria can be altered through overgrowth of enteropathogens (e.g., Campylobacter, Salmonella spp.), leading to dysbiosis of the gut ecosystem, with some species thriving under the altered conditions whereas others decline. Various "biotics" strategies, including prebiotics, probiotics, synbiotics, and postbiotics, contribute to re-establishing balance within the gut microbial ecosystem conferring health benefits. Prebiotics enhance growth of beneficial members of the resident microbial community and can thus prevent pathogen growth by competitive exclusion. Specific probiotics can actively inhibit the growth of pathogens, either through the production of bacteriocins or simply by reducing the gastrointestinal pH making conditions less favorable for pathogen growth. This review discusses the importance of a balanced gut ecosystem, and strategies to maintain it that contribute to human health.

Streptococcus dysgalactiae subsp.-equisimilis as an emerging secondary pathogen in leprosy foot ulcers

Background and Objectives: Leprosy foot ulcers (LFU) tend to become chronic due to secondary bacterial infections, leading to subsequent disfigurement and disability. Treatment modality for infected plantar ulcers thus so far is majorly based on conventional approach of empirical antibacterial therapy. However, this approach tends to overlook unconventional pathogens which are likely to be present in the LFU. Materials and Methods: Twenty-six leprosy patients (17 males and 9 females) who had completed multidrug therapy (MDT) and those are suffering from foot ulcer were included. Using sterile cotton swabs, two wound swabs were collected, of these; one for bacterial culture and another for NGS (Next Generation Sequencing). Results: Out of 26 samples tested on conventional bacterial culture, Streptococcus spp. (50%) was predominant organism. On NGS, 09/26 (34.61%) showed Streptococcus-dysgalactiae-subsp.-equisimilis-GGS 12 as the most abundant single organism, along with some unknown and unclassified organisms; 03/26 (11.5%) were Arcanobacterium-haemolyticum-DSM-20595 alone and 02/26 (7.69%) were Streptococcus-pyogenes alone.Acombination of Arcanobacterium-haemolyticum-DSM-20595 and Streptococcus-dysgalactiae-subsp.-equisimilis-GGS 124 was found in nine (34.61%) specimens. Conclusion: Polymicrobial infection with conventional and unconventional pathogenic bacteria is another notable finding suggesting appropriate interventions. The study findings also reiterate the need for understanding the polymicrobial infec- tions and their role in the clinical progression of the LFU.

Species- and subspecies-level characterization of health-associated bacterial consortia that colonize the human gut during infancy

ABSTRACT Background The human gut microbiome develops rapidly during infancy, a key window of development coinciding with the maturation of the adaptive immune system. However, little is known about the microbiome growth dynamics over the first few months of life and whether there are any generalizable patterns across human populations. We performed metagenomic sequencing on stool samples (n = 94) from a cohort of infants (n = 15) at monthly intervals in the first 6 months of life, augmenting our dataset with seven published studies for a total of 4,441 metagenomes from 1,162 infants. Results Strain-level de novo analysis was used to identify 592 of the most abundant organisms in the infant gut microbiome. Previously unrecognized consortia were identified which exhibited highly correlated abundances across samples and were composed of diverse species spanning multiple genera. Analysis of a published cohort of infants with cystic fibrosis identified one such novel consortium of diverse Enterobacterales which was positively correlated with weight gain. While all studies showed an increased community stability during the first year of life, microbial dynamics varied widely in the first few months of life, both by study and by individual. Conclusion By augmenting published metagenomic datasets with data from a newly established cohort, we were able to identify novel groups of organisms that are correlated with measures of robust human development. We hypothesize that the presence of these groups may impact human health in aggregate in ways that individual species may not in isolation.

Novel isolates expand the physiological diversity of Prochlorococcus and illuminate its macroevolution.

Prochlorococcus is a diverse picocyanobacterial genus and the most abundant phototroph on Earth. Its photosynthetic diversity divides it into high-light (HL)- or low-light (LL)-adapted groups representing broad phylogenetic grades-each composed of several monophyletic clades. Here, we physiologically characterize four new Prochlorococcus strains isolated from below the deep chlorophyll maximum in the North Pacific Ocean. We combine these physiological properties with genomic analyses to explore the evolution of photosynthetic antennae and discuss potential macroevolutionary implications. The isolates belong to deeply branching low-light-adapted clades that have no other cultivated representatives and display some unusual characteristics. For example, despite its otherwise low-light-adapted physiological characteristics, strain MIT1223 has low chl b2 content similar to high-light-adapted strains. Isolate genomes revealed that each strain contains a unique arsenal of pigment biosynthesis and binding alleles that have been horizontally acquired, contributing to the observed physiological diversity. Comparative genomic analysis of all picocyanobacteria reveals that Pcb, the major pigment carrying protein in Prochlorococcus, greatly increased in copy number and diversity per genome along a branch that coincides with the loss of facultative particle attachment. Collectively, these observations support a recently developed macroevolutionary model, in which niche-constructing radiations allowed ancestral lineages of picocyanobacteria to transition from a particle-attached to planktonic lifestyle and broadly colonize the euphotic zone.IMPORTANCEThe marine cyanobacterium, Prochlorococcus, is among the Earth's most abundant organisms, and much of its genetic and physiological diversity remains uncharacterized. Although field studies help reveal the scope of diversity, cultured isolates allow us to link genomic potential to physiological processes, illuminate eco-evolutionary feedbacks, and test theories arising from comparative genomics of wild cells. Here, we report the isolation and characterization of novel low-light (LL)-adapted Prochlorococcus strains that fill in multiple evolutionary gaps. These new strains are the first cultivated representatives of the LLVII and LLVIII paraphyletic grades of Prochlorococcus, which are broadly distributed in the lower regions of the ocean euphotic zone. Each of these grades is a unique, highly diverse section of the Prochlorococcus tree that separates distinct ecological groups: the LLVII grade branches between monophyletic clades that have facultatively particle-associated and constitutively planktonic lifestyles, whereas the LLVIII grade lies along the branch that leads to all high-light (HL)-adapted clades. Characterizing strains and genomes from these grades yields insights into the large-scale evolution of Prochlorococcus. The new LLVII and LLVIII strains are adapted to growth at very low irradiance levels and possess unique light-harvesting gene signatures and pigmentation. The LLVII strains represent the most basal Prochlorococcus group with a major expansion in photosynthetic antenna genes. Furthermore, a strain from the LLVIII grade challenges the paradigm that all LL-adapted Prochlorococcus exhibit high ratios of chl b:a2. These findings provide insights into the photophysiological evolution of Prochlorococcus and redefine what it means to be a low- vs high-light-adapted Prochlorococcus cell.

Performance of Gram Stain Characteristics for Predicting Culture Growth in Lower Respiratory Specimens Across Multiple Institutions

Abstract Data from Gram stains performed on clinical specimens can guide clinical decision-making and downstream laboratory workflows. However, the extent to which Gram stain results predict gold-standard culture results, and the generalizability of this performance across sites, warrants additional exploration. We sought to discover which Gram stain features would be associated with clinically significant culture growth (“growth”). To do so, 574 remnant specimens from the lower respiratory tract collected from four institutions were analyzed. A standardized Gram stain and culture protocol was performed across all study sites. Final reference organism identification was assigned using MALDI-ToF MS, and clinically significant growth was defined as any organism reported to the medical record. Gram stains with mixed microorganisms detected were considered concordant if ≥2 organisms of different Gram stain appearances were identified in culture. Growth was observed in 53% of specimens, including 25% of specimens in which Gram stain demonstrated no organisms. The 95% confidence intervals (CI) of the site-wise growth rates were 30-42%, 42-52%, 51-67%, and 60-77% (p < 0.001 by Chi-squared). By Gram stain morphology, 53-69% of specimens with Gram-positive cocci grew any clinically significant bacteria, while 31-49% grew a concordant Gram-positive cocci. 65-85% of specimens with Gram-negative bacilli grew any clinically significant bacteria, while 59-74% grew a concordant Gram-negative bacilli. 63-83% of specimens with mixed microorganisms grew 2 or more clinically relevant bacteria of differing Gram stain morphologies. Specimens from bronchoalveolar lavages (BALs) were less likely to have growth (30-42%) than endotracheal aspirates (66-77%). Polymorphonuclear leukocyte (PMNs) abundance was associated with culture growth, with Gram stains showing no, rare, few, moderate, or abundant PMNs demonstrating growth 28, 44, 52, 60, and 67% of the time (p < 0.001). Specimens with None and few squamous epithelial cells on Gram stain demonstrated growth 38-52% and 59-68% of the time (p < 0.001). No significant difference in growth was observed for red blood cells. Organism abundance on Gram stain was significantly associated with culture growth, with growth rate CIs being 20-32% for no organisms, 44-62% for rare, 58-77% for few, 70-93% for moderate, and 81-95% for abundant organisms seen. The extent to which these associations could guide the development of decision rules or machine learning models that demonstrate acceptable negative predictive value for pathogen growth to alleviate the operational burden of low-utility cultures is an exciting future direction to explore.

Effects of Dietary Quality on Vaginal Microbiome Composition Throughout Pregnancy in a Multi-Ethnic Cohort.

Background: Vaginal Lactobacillus predominance is associated with improved vaginal health and reduced pregnancy complications. Little is known about how dietary quality may improve vaginal microbial composition or about dietary interventions that may promote Lactobacillus abundance. To understand the host factors affecting vaginal microbiota during pregnancy in a multi-ethnic cohort in Hawai`i. We hypothesize that better diet quality improves vaginal microbial composition, as represented by Lactobacillus abundance and depletion of anaerobic organisms. Methods: We compared comprehensive diet quality, as measured by the Healthy Eating Index-2015 (HEI-2015), to taxonomic classifications of bacteria present within the vagina. Participants of the four predominant ethnic groups in Hawai'i (Japanese, Filipino, Non-Hispanic White and Native Hawaiian) completed Quantitative Food Frequency Questionnaires (QFFQs) and collected vaginal swabs during each trimester. 16s rRNA amplicon sequencing (V2-V9 regions) was performed on vaginal samples. HEI-2015 scores and macro- and micronutrient intake were compared with the predominant species present using the Mann-Whitney-U test, PERMANOVA, and the Pearson correlation coefficient. A mixed-effects logistics regression model was used to predict the depletion of Lactobacillus species while accounting for confounding demographic factors. Results: Matched, longitudinal data for 40 participants demonstrated three predominant Lactobacillus species: L. crispatus, L. iners, and L. gasseri, with another subset of samples with anaerobic abundance. (Primarily, Atopobium vaginae, Prevotella, and Gardnerella vaginalis.) Non-Hispanic White participants had lower amounts of Lactobacillus iners compared to other racial and ethnic groups. HEI scores correlated with the chao index and observed species number primarily in the first trimester (r = 0.25, p < 0.05). Greater carbohydrate intake was associated with a higher abundance of L. crispatus, while lower carbohydrate intake trended towards more L. iners (0.056) and anaerobic species. Conclusions: Increased carbohydrate consumption and improved diet quality may be associated with beneficial vaginal microbial composition in pregnancy.

Forest fragmentation effects on plant-animal interaction do not always show consistent patterns – Evidence from a seed removal experiment of 31 woody species

Forest fragmentation often leads to changes in the abundance and composition of various organisms, thereby affecting biotic interactions. Currently, many studies lack consensus on the magnitude or direction of the impact of forest fragmentation on plant-animal interactions. Here, we employed seed-rodent interaction as a case study and assessed the removal by rodents of 66,960 seeds belonging to 31 woody species in 18 fragmented forests with areas of 1.05–14,517.63 ha, in a seriously fragmented tropical area in Southwest China for two consecutive years. Our study provided strong evidence that forest fragmentation affected seed-rodent interactions but did not follow a consistent pattern between years. Forest size and edge effects on seed removal were mainly due to variations in seed availability but not rodent activity. Interestingly, the effect of fragment size on seed removal was species-specific with monotonic decreases as well as U-shaped and humped-shaped patterns. These remarkable spatiotemporal and interspecific variations pertaining to forest fragmentation impact on seed removal may translate into subsequent seed germination and seedling regeneration processes, which may further influence the species composition in different fragmented forests. This complexity in responses among plant species reiterates the need to consider the interspecies specificity in conservation and management initiatives of fragmented forests. Additionally, we recommend that multiple field surveys involving multiple species be conducted in future studies focusing on forest fragmentation to help us better understand fragmentation effects on ecological processes.

Correlations between the increase in atmospheric CO2 and temperature, and the subsequent increase in silica, and groundwater organisms

Rising atmospheric temperature and CO2 impact all freshwater systems. In groundwater, one such impact is CO2- and temperature-induced weathering, which leads to more intense weathering of silicate rocks. Here, we tested whether the increased CO2 levels, the weathering, or rather the increasing temperature, impacted on fauna and prokaryotes in the groundwater ecosystem. We also conducted the analyses separately for two groups of wells, one of which contained wells that were secluded from the surface (and often rather deep), and wells tapping the quaternary aquifers (often rather shallow) which exchange with the surface more intensely. Organism abundances and relative composition did not correlate with temperature or CO2 levels. While many organisms rely on silica, in contrast, we found negative correlations between silica concentrations and fauna. The increases in silica concentrations over time, i.e. temporal trends, also partly correlated negatively with organisms. We hypothesize that the unexpected negative correlations are not direct effects, but indirectly indicate that groundwater communities do not adapt rapidly enough to changes in silica concentrations, but also more generally to changes for which silica might only be a proxy. Groundwater fauna take part in the ecosystem service of water self-cleaning and are thus considered beneficial for sustainable raw water for drinking water production. The propensity of groundwater fauna to decrease with increases in silica, jeopardizes future drinking water production.

In situ imaging of a kleptoplastidic ciliate thin layer indicates traditional sampling underestimates oceanic mixotroph biomass

Planktonic mixotrophs, including ciliates, are abundant, yet understudied, mediators of primary and secondary production in aquatic food webs. Here, we report high-resolution in situ observations of a thin layer—a vertically limited patch of high organism abundance—of the ciliate, Laboea strobila. Within the thin layer, peak L. strobila abundances were as high as 62,000 cells/L, six times higher than previously reported, and were strongly positively correlated with co-measured chlorophyll a concentrations, indicating that the organism indulged in kleptoplasty, retaining plastids from ingested algae. Estimates indicated L. strobila contributed to ~63–78% of chlorophyll a within the layer, in sharp contrast to conventional expectations that phytoplankton dominate this signature, suggesting that mixotroph biomass, and consequently, their contribution to marine ecosystems is widely underestimated. These observations also highlight the importance of pairing traditional approaches such as chlorophyll a measurements with high-resolution imaging for proper attribution of biomass proxies.

The Genome Architecture of the Copepod Eurytemora carolleeae, the Highly Invasive Atlantic Clade of the E. affinis Species Complex.

Copepods are among the most abundant organisms on the planet and play critical functions in aquatic ecosystems. Among copepods, populations of the Eurytemora affinis species complex are numerically dominant in many coastal habitats and are food sources for major fisheries. Intriguingly, certain populations possess the unusual capacity to invade novel salinities on rapid time scales. Despite their ecological importance, high-quality genomic resources have been absent for calanoid copepods, limiting our ability to comprehensively dissect the genome architecture underlying the highly invasive and adaptive capacity of certain populations. Here, we presented the first chromosome-level genome of a calanoid copepod, from the Atlantic clade (Eurytemora carolleeae) of the E. affinis species complex. This genome was assembled using high-coverage long-read and high-throughput chromosome conformation capture sequences of an inbred line, generated through 30 generations of full-sib mating. This genome, consisting of 529.3 megabase (Mb) (contig N50 = 4.2 Mb, scaffold N50 = 140.6 Mb), was anchored onto four chromosomes. Genome annotation predicted 20,262 protein-coding genes, of which ion transporter gene families were substantially expanded based on comparative analyses of 12 additional arthropod genomes. Also, we found genome-wide signatures of historical gene body methylation of the ion transporter genes and the significant clustering of these genes on each chromosome. This genome represents one of the most contiguous copepod genomes to date and among the highest quality marine invertebrate genomes. As such, this genome provides an invaluable resource to help yield fundamental insights into the ability of this copepod to adapt to rapidly changing environments.

Niche breadth specialisation impacts ecological and evolutionary adaptation following environmental change.

None declared.Conflicts of interestEcological theory predicts that organismal distribution and abundance depend on the ability to adapt to environmental change. It also predicts that eukaryotic specialists and generalists will dominate in extreme environments or following environmental change, respectively. This theory has attracted little attention in prokaryotes, especially in archaea, which drive major global biogeochemical cycles. We tested this concept in Thaumarchaeota using pH niche breadth as a specialisation factor. Responses of archaeal growth and activity to pH disturbance were determined empirically in manipulated, long-term, pH-maintained soil plots. The distribution of specialists and generalists was uneven over the pH range, with specialists being more limited to the extreme range. Nonetheless, adaptation of generalists to environmental change was greater than that of specialists, except for environmental changes leading to more extreme conditions. The balance of generalism and specialism over longer timescales was further investigated across evolutionary history. Specialists and generalists diversified at similar rates, reflecting balanced benefits of each strategy, but a higher transition rate from generalists to specialists than the reverse was demonstrated, suggesting that metabolic specialism is more easily gained than metabolic versatility. This study provides evidence for a crucial ecological concept in prokaryotes, significantly extending our understanding of archaeal adaptation to environmental change.

Cryptosporidium andersoni-associated proliferative abomasitis in a roan antelope.

A 2-y-old, intact male roan antelope (Hippotragus equinus) was submitted for routine postmortem investigation after a prolonged history of diarrhea and weight loss. The abomasal mucosa was diffusely thickened and corrugated. Abomasal gland hyperplasia was associated with abundant apical organisms consistent with Cryptosporidium spp. Genomic DNA was extracted from abomasal and intestinal contents and subjected to PCR using primers specific for the 18S rRNA gene of Cryptosporidium spp., followed by Sanger sequencing. The sequence was >99% homologous to Cryptosporidium andersoni. C. andersoni-associated proliferative abomasitis has not been reported previously in a captive hippotraginid, to our knowledge.

Vertical distribution of mesopelagic fishes deepens during marine heatwave in the California Current

Abstract Marine heatwaves can impact the distribution and abundance of epipelagic organisms, but their effect on deep pelagic communities is unclear. Using fisheries acoustics data collected in the Central California current from 2013 to 2018, we found that during the warmest years of a large marine heatwave (2015–2016), the estimated center of mass depth of mesopelagic fishes deepened by up to 100 m compared to preheatwave conditions. Using a generalized additive model, we evaluated which biophysical factors may have driven these changes and found that light, dynamic height anomaly, and acoustic backscatter explained 81% of the variability in depth. We attribute the vertical shift by mesopelagic fishes into deeper waters to heatwave-driven compression of upwelling habitat that indirectly increased the amount of light reaching mesopelagic depths. Our results suggest that mesopelagic fishes are interconnected with, and thus sensitive to changes in near-surface oceanographic conditions, which could lead to cascading effects on vertical carbon export and the availability of mesopelagic fishes as prey for top predators under future climate conditions.

Paleoenvironmental Transition during the Rhuddanian–Aeronian and Its Implications for Lithofacies Evolution and Shale Gas Exploration: Insights from the Changning Area, Southern Sichuan Basin, South-West China

During the Rhuddanian–Aeronian interglacial period, global geological events such as glacial melting, synsedimentary volcanic activity, biological resurgence, and large-scale marine transgressions caused frequent fluctuations in paleoproductivity, climate changes, and sea level variations. These paleoenvironmental transitions directly influenced the development characteristics of shale lithofacies. This study investigates the Longmaxi Formation shale in the Changning area in the Southern Sichuan basin, focusing on 28 core samples from Well N1. Using scanning electron microscopy, QEMSCAN, TOC, XRD, and major and trace element analyses, we reconstructed the paleoenvironmental transitions of this period and explored their control over shale lithofacies types and mineral compositions. Four shale lithofacies were identified: carbonate rich lithofacies (CRF), biogenic quartz-rich lithofacies (BQRF), detrital clay-rich lithofacies (CRDF), and detrital quartz-rich lithofacies (DQRF). During the Rhuddanian period, rising global temperatures caused glacial melting and rapid marine transgressions. The low oxygen levels in bottom waters, combined with upwelling and abundant volcanic material, led to high paleoproductivity. This period primarily developed BQRF and CRF. Rich nutrients and abundant siliceous organisms, along with anoxic to anaerobic conditions, provided the material basis and preservation conditions for high biogenic quartz and organic matter content. High paleoproductivity and anoxic conditions also facilitated the precipitation of synsedimentary calcite and supplied Mg2+ and SO42− for the formation of iron-poor dolomite via sulfate reduction. From the Late Rhuddanian to the Mid-Aeronian, the Guangxi orogeny caused sea levels to fall, increasing water oxidation and reducing upwelling and volcanic activity, which lowered paleoproductivity. Rapid sedimentation rates, stepwise global temperature increases, and the intermittent intensification of weathering affected terrigenous clastic input, resulting in the alternating deposition of CRF, CRDF, and DQRF. Two favorable shale gas reservoirs were identified from the Rhuddanian–Aeronian period: Type I (BQRF) in the L1–L3 Layers, characterized by high TOC and brittleness, and Type II (DQRF) in the L4 Layer, with significant detrital quartz content. The Type I-favorable reservoir supports ongoing gas production, and the Type II-favorable reservoir offers potential as a future exploration target.

Depositional Environment and Ecological Response of Bioconstructions: A Case Study of Southern China (Guizhou Province) in Moscovian-Gzhelian.

From the late Carboniferous to the early Permian, multiple pulses of glaciation and deglaciation have been caused by the LPIA. The Pennsylvanian period experienced phases of recovery, proliferation, and decline, ultimately forming a reef system distinctly different from that of the Mississippian period. During the late Bashkirian to Moscovian, the metazoan reef experienced a limited resurgence, with reef predominantly formed by chaetetid developing in the United States, northern China, and Japan. During the Kasimovian to Gzhelian, the phylloid algal reef dominated the global reef systems. In the late Pennsylvanian, bioconstruction cases and paleoenvironmental proxies in southern Guizhou Province were studied to investigate the composition, recovery, and evolutionary processes of the bioconstructions as well as their response to environmental variations during this period. Several bioconstructions have been reported in the Lumazhai section of Houchang Town, Guizhou Province, southern China, from the Moscovian to the Gzhelian. The upper Carboniferous strata are well-preserved and continuously exposed. The continuous strata, abundant fossils, and diverse bioconstructions provide excellent research materials for exploring the mutual constraints between organisms and their environment. This study identified ten microfacies, whose vertical evolution indicated significant changes in the depositional environment related to relative sea-level fluctuations. Skeletal grains are widely present in these facies. Among them, foraminifera, algae, bryozoans, crinoids, and Tubiphytes are the most common and exhibit distinct distribution characteristics in various environments. Quantitative statistics, CCA and theoretical ecospace have been utilized to examine and interpret environmental impact factors. Quantitative analysis of their relative abundance and distribution patterns provides insights into the complex interactions between organisms and environmental factors. The relative abundances of different organisms and factors controlling their bioconstructions are influenced by relative sea-level changes. CCA analysis reveal that hydrodynamic conditions are the primary influencing factor. Variation trends in average tiering and motility reveal the characteristics of biological communities during environmental changes in phylloid algae and microbial bioconstructions. These bioconstructions are not directly correlated with changes in environmental factors, and the biological communities in phylloid algae mounds and biostromes exhibit similar organism compositions and ecological niches across different environments.

Unveiling Arthropod Responses to Climate Change: A Functional Trait Analysis in Intensive Pastures.

This study investigates the impact of elevated temperatures on arthropod communities in intensively managed pastures on the volcanic island of Terceira, Azores (Portugal), using a functional trait approach. Open Top Chambers (OTCs) were employed to simulate increased temperatures, and the functional traits of ground dwelling arthropods were analyzed along a small elevation gradient (180-400 m) during winter and summer. Key findings include lower abundances of herbivores, coprophagous organisms, detritivores, and fungivores at high elevations in summer, with predators showing a peak at middle elevations. Larger-bodied arthropods were more prevalent at higher elevations during winter, while beetles exhibited distinct ecological traits, with larger species peaking at middle elevations. The OTCs significantly affected the arthropod communities, increasing the abundance of herbivores, predators, coprophagous organisms, and fungivores during winter by alleviating environmental stressors. Notably, iridescent beetles decreased with elevation and were more common inside OTCs at lower elevations, suggesting a thermoregulatory advantage. The study underscores the importance of considering functional traits in assessing the impacts of climate change on arthropod communities and highlights the complex, species-specific nature of their responses to environmental changes.

Machine learning for potential anti-cancer discovery from black sea cucumbers

&lt;p&gt;Despite being an abundant marine organism in Indonesia, black sea cucumbers &lt;em&gt;(Holothuria atra)&lt;/em&gt; is still underutilised due to its slightly bitter taste. This study aims to identify potential anti-cancer compounds from black sea cucumbers using machine learning (ML) to perform drug discovery. ML models were used to predict interactions between compounds from the organism with cancer-related proteins. Following prediction, all compounds were computationally validated through molecular docking. The validated compounds were then screened using absorption, distribution, metabolism, excretion, and toxicity (ADMET) Lab 2.0 to assess their druglike properties. The results showed that ML predicted seven out of 86 compounds were interacted with cancer-related proteins. Computational validation from the results showed that four out of seven compounds demonstrated stable interaction with proteins where only one compound meet the criteria of drug-like compound. The framework of ML and computational validation highlighted in this study shows a great promise in the future of drug discovery specifically for marine organisms. Since computational method only works in prediction realms, wet lab validation and clinical trials are imperative before the drug candidate can be produced as actual anti-cancer drug.&lt;/p&gt;

Deciphering macrobenthic biological traits in response to long-term eutrophication in Xiangshan Bay, China

As an emerging global issue in coastal marine ecosystems, eutrophication may lead to profound ecological consequences or disasters. Six locations in Xiangshan Bay were sampled during 2012–2022 along the eutrophication gradient from the innermost bay with the most eutrophication to the outer bay with the least eutrophication. A trait-based method was adopted to explore the ecological effects of eutrophication on macrobenthic communities. The results showed that the community composition is mostly characterized by deposit feeders and predators with small (1–3 cm) and large (> 10 cm) body sizes, classified as indifferent and tolerant species (AMBI ecological groups), deposit feeders and predators (feeding mode), and a preference for a free living lifestyle. The RLQ and fourth-corner analyses further confirmed that there was a negative correlation between the abundance of small macrobenthic organisms (< 1 cm) and nitrate concentration. Phosphorus was a crucial influencing factor for macrobenthic spatial patterns and was strongly affected by the activities of deposit feeders and the decomposition of macrobenthos. Due to mass organic deposition resulting from increased primary production, long-term eutrophication had led to an increase in the proportion of detritus feeders. In addition, the significant negative correlation between the concentration of dissolved oxygen and first-order opportunistic species represented by the polychaete Capitella capitata indicated tolerance to hypoxia. The macrobenthic community in Xiangshan Bay had been negatively affected but maintains considerable stability in functional diversity and functional redundancy under the influence of long-term eutrophication.

Population Size and Spatial Distribution of the Mexican Blind Cavefish (Astyanax) within the Caves

The most studied cavefish in the world is Astyanax mexicanus, and the most frequently used specimens in research come from the Pachón cave in Northeast Mexico. A recent study using the capture–mark–recapture technique revealed that the Pachón population size is only in the hundreds of individuals, not in the thousands. This result raises serious concerns about their long-term survival and highlights the need to accurately estimate the population size of other Astyanax caves. In our study, we used a well-established, non-invasive method for estimating population size: the transect sampling method, which counts the abundance of organisms along a line at regular intervals. We used the 310 m long Sabinos Cave’s Pool #1 for measurements and estimated a population of 1142 individuals. Most importantly, we found that cavefish are not distributed uniformly: 68% of the individuals were clustered under a bat roost. To corroborate this observation, we used drones to explore submerged galleries inaccessible to scientists. Results from the Toro/Calera Cave system confirmed that most galleries were essentially void of cavefish, except for in those few areas with high amounts of nutrients. Scientists visiting the most studied Astyanax localities (Pachón, Sabinos, Tinaja, and Chica) experience what appear to be high-density populations of about 10 fish/m2, possibly because the pool they visit happens to be under bat roosts. Our study shows that one cannot extrapolate the density at these localities to the rest of the habitat, where densities might be two orders of magnitude lower. Future studies should consider that the apparent high density at visited sites is overrepresenting the total population size when calculating the number of fish specimens to be captured.