Ecological Linkages Research Articles

Climate change injustice and school attendance and absenteeism: proximal and distal ecological links

Climate change has been linked to a myriad of problems related to human functioning, with a particular scientific emphasis on economic, physical damage, and health sectors. Less attention, however, has been given to the links between climate change and problems in the educational sector, such as school attendance problems, which represent practical and everyday manifestations of the effects of climate change. This is unfortunate given that children, and particularly those in Black and Brown communities and in the majority world, are expected to bear the greatest burden from climate change now and in the future. One fundamental right of children is the right to an education and to attend school, and this right is threatened particularly for vulnerable populations in different ways by climate change. Narrative synthesis of key terms (e.g., climate change, school absenteeism) for literature review was conducted to identify key patterns that produced the primary themes represented in this article: physical health, mental health, violence, school environment, school displacement and migration, and economic challenges. These themes were organized along a general proximal-to-distal spectrum. The descriptions of each theme also illustrate mechanisms connecting these issues that may help inform future mitigation efforts.

Ecological resilience of three major urban agglomerations in China from the “environment–society” coupling perspective

Three major urban agglomerations in China are considered to construct a framework for measuring ecological resilience from the perspective of the “environment–society” coupling; the spatial and temporal characteristics of ecological resilience are clarified, and the spatial associations of ecological resilience within urban agglomerations are deconstructed. The following conclusions are obtained: (1) The Beijing–Tianjin–Hebei (BTH) region lags behind the other two in terms of ecological resilience, and cities within it are highly polarized. However, the opposite is true for the Pearl River Delta (PRD) region. The rates of change in ecological resilience in BTH and the Yangtze River Delta (YRD) exhibit clearly uneven spatial distributions describable as “low in the middle and high in the north and the south” and “lower on the coast than inland”, respectively. (2) The differences in ecological resilience among urban agglomerations characterize the largest portion of the total area. The values of the differences within urban agglomerations are observed, in descending order, in BTH, YRD, and PRD. (3) Regarding the structure of spatial linkages, that in BTH is more dependent on bilateral factors, whereas the importance of core cities in the PRD is clearly greater. (4) In BTH, there is an urgent need to relieve the ecological pressure on the central cities. To increase the level of ecological resilience in the YRD, controlling the landscape pattern of water systems and the ecological quality of water sources should be prioritized. The ecological linkage effect between small city circles in the PRD region should not be ignored.

Predicting freshwater biological quality using macrophytes: A comparison of empirical modelling approaches

Difficulties have hampered bioassessment in southern European rivers due to limited reference data and the unclear impact of multiple interacting stressors on plant communities. Predictive modelling may help overcome this limitation by aggregating different pressures affecting aquatic organisms and showing the most influential factors. We assembled a dataset of 292 Mediterranean sampling locations on perennial rivers and streams (mainland Portugal) with macrophyte and environmental data. We compared models based on multiple linear regression (MLR), boosted regression trees (BRT) and artificial neural networks (ANNs). Secondarily, we investigated the relationship between two macrophyte indices grounded in distinct conceptual premises (the Riparian Vegetation Index — RVI, and the Macrophyte Biological Index for Rivers — IBMR) and a set of environmental variables, including climatic conditions, geographical characteristics, land use, water chemistry and habitat quality of rivers. The quality of models for the IBMR was superior to those for the RVI in all cases, which indicates a better ecological linkage of IBMR with the stressor and abiotic variables. The IBMR using ANN outperformed the BRT models, for which the r-Pearson correlation coefficients were 0.877 and 0.801, and the normalised root mean square errors were 10.0 and 11.3, respectively. Variable importance analysis revealed that longitude and geology, hydrological/climatic conditions, water body size and land use had the highest impact on the IBMR model predictions. Despite the differences in the quality of the models, all showed similar importance to individual input variables, although in a different order. Despite some difficulties in model training for ANNs, our findings suggest that BRT and ANNs can be used to assess ecological quality, and for decision-making on the environmental management of rivers.

Seasonal dynamics of the phage-bacterium linkage and associated antibiotic resistome in airborne PM2.5 of urban areas

Inhalable microorganisms in airborne fine particulate matter (PM2.5), including bacteria and phage, are major carriers of antibiotic resistance genes (ARGs) with strong ecological linkages and potential health implications for urban populations. A full-spectrum study on ARG carriers and phage-bacterium linkages will shed light on the environmental processes of antibiotic resistance from airborne dissemination to the human lung microbiome. Our metagenomic study reveals the seasonal dynamics of phage communities in PM2.5, their impacts on clinically important ARGs, and potential implications for the human respiratory microbiome in selected cities of China. Gene-sharing network comparisons show that air harbours a distinct phage community connected to human- and water-associated viromes, with 57 % of the predicted hosts being potential bacterial pathogens. The ARGs of common antibiotics, e.g., peptide and tetracycline, dominate both the antibiotic resistome associated with bacteria and phages in PM2.5. Over 60 % of the predicted hosts of vARG-carrying phages are potential bacterial pathogens, and about 67 % of these hosts have not been discovered as direct carriers of the same ARGs. The profiles of ARG-carrying phages are distinct among urban sites, but show a significant enrichment in abundance, diversity, temperate lifestyle, and matches of CRISPR (short for ‘clustered regularly interspaced short palindromic repeats’) to identified bacterial genomes in winter and spring. Moreover, phages putatively carry 52 % of the total mobile genetic element (MGE)-ARG pairs with a unique ‘flu season’ pattern in urban areas. This study highlights the role that phages play in the airborne dissemination of ARGs and their delivery of ARGs to specific opportunistic pathogens in human lungs, independent of other pathways of horizontal gene transfer. Natural and anthropogenic stressors, particularly wind speed, UV index, and level of ozone, potentially explained over 80 % of the seasonal dynamics of phage-bacterial pathogen linkages on antibiotic resistance. Therefore, understanding the phage-host linkages in airborne PM2.5, the full-spectrum of antibiotic resistomes, and the potential human pathogens involved, will be of benefit to protect human health in urban areas.

Ecological linkages between top-down designed benzothiazole-degrading consortia and selection strength: From performance to community structure and functional genes

The inefficient biodegradation and incomplete mineralization of nitrogenous heterocyclic compounds (NHCs) have emerged as a pressing environmental concern. The top-down design offers potential solutions to this issue by targeting improvements in community function, but the ecological linkages between selection strength and the structure and function of desired microbiomes remain elusive. Herein, the integration of metagenomics, culture-based approach, non-targeted metabolite screening and enzymatic verification experiments revealed the effect of enrichment concentration on the top-down designed benzothiazole (BTH, a typical NHC)-degrading consortia. Significant differences were observed for the degradation efficiency and community structure under varying BTH selections. Notably, the enriched consortia at high concentrations of BTH were dominated by genus Rhodococcus, possessing higher degradation rates. Moreover, the isolate Rhodococcus pyridinivorans Rho48 displayed excellent efficiencies in BTH removal (98 %) and mineralization (∼ 60 %) through the hydroxylation and cleavage of thiazole and benzene rings, where cytochrome P450 enzyme was firstly reported to participate in BTH conversion. The functional annotation of 460 recovered genomes from the enriched consortia revealed diverse interspecific cooperation patterns that accounted for the BTH mineralization, particularly Nakamurella and Micropruina under low selection strength, and Rhodococcus and Marmoricola under high selection strength. This study highlights the significance of selection strength in top-down design of synthetic microbiomes for degrading refractory organic pollutants, providing valuable guidance for designing functionally optimized microbiomes used in environmental engineering.

Forest floor nematode communities and associated tree canopies: Is there an ecological linkage?

We searched for patterns supporting the hypothesis of compositional and functional linkage between forest floor nematode communities and dominant tree canopies, while controlling for some relevant soil and climate variables. Twenty-one forest sampling sites scattered throughout the South-Eastern Carpathian basin were selected under spruce, beech, and hornbeam-oak canopies. The relative contribution of forest canopy type to nematode assemblage differentiation was estimated through nematode taxonomic composition and feeding guild structure. The forest canopy type had a significant effect on nematode taxon/feeding guild composition and diversity at stand level. Several (diagnostic) nematode taxa and feeding guilds were positively associated with and accurately predicted the forest canopy types considered. Apart from the herbivorous nematodes, all the other trophic guilds were significantly related, in terms of their relative abundance, to the forest canopy type. Both nematode taxonomic and trophic diversity were significantly higher under beech canopy compared with its two counterparts. The highest total nematode beta diversity, either taxonomic or trophic, was attained between hornbeam-oak and spruce canopies. Nematode taxonomic and trophic beta diversity between forest canopy types were largely determined by taxon replacement and respectively, by a nested trophic structure. Overall, four concordant and two discordant patterns were revealed between nematode taxon and feeding guild composition with respect to overlying forest canopy, all underpinning the addressed ecological linkage. The present results bring evidence regarding the important contribution of the forest canopy, along with climatic variables, in driving the taxonomic and functional composition/diversity of nematode communities from the soil organic horizon.

Studies on the influence of water quality on community assemblage of immature mosquitoes in different ecosystems along the Vaigai river, Tamil Nadu, South India

BackgroundOver the last few decades, river ecosystem is highly modified through various anthropogenic activities which are resulted to alter ecosystem functions and services. This modified ecosystem rendering conducive environment to mosquitoes through various ecological links for the self-sustaining populations. However, deciphering the community assemblage of immature mosquitoes with reference to water quality at modified ecosystem is very essential to make suitable control measure to curtail mosquito populations. In order to understand how the water quality influences the larval density, habitat specificity and community assemblage of immature mosquito populations, a study was conducted at different ecosystems (urban, semi-urban and rural) along the Vaigai river. The physicochemical parameters such as pH, TDS, salinity, conductivity, turbidity, DO, were analyzed at each study site.ResultsOur results clearly revealed that Anopheline species were highly preferred to breed less polluted habitat than Culicine species. Community assemblage by Anopheline and Culicine mosquitoes were found to be higher at all the studies whilst community assemblage by Anopheline were maximum at rural and semi-urban sites. Among the Anopheline species, Anopheles subpictus able to breed at high polluted habitat, particularly higher turbid level (28.49 ± 2.18 NTU) than other Anopheles species. Cx. gelidus mostly breed at sewage disposal habitats with high salinity level (1.01 ± 0.08) whilst Cx. bitaeniorhynchus bred in only fresh water bodies particularly low turbid habitats (3.97 ± 0.40 NTU). Grouping of immature mosquitoes based on the habitat similarity, An. subpictus, Cx. vishnui, An. vagus, Cx. tritaeniorhynchus, Cx. gelidus and Cx. quinquefasciatus were able to breed in highly polluted habitats which are resulted fell in group A than group B mosquitoes. Cx. vishnui and An. subpictus have strong habitat similarity (0.96) and can able to share their habitats with more number of Anopheline and Culicine mosquitoes.ConclusionsFrom the study we concluded that, Cx. vishnui and An. subpictus were most prevalent species and strong habitats similarity along the Vaigai river basin. An. subpictus and An. vagus can adapt to breed in polluted habitats and this may be adequate to extend the vectorial capacity and disease outbreak along the Vaigai river basin.

Microeukaryotes Associated with Freshwater Mussels in Rivers of the Southeastern United States.

Microeukaryotes are a diverse and often overlooked group of microbes that are important in food webs and other ecological linkages. Little is known about microeukaryotes associated with aquatic invertebrates, although filter feeders such as mussels are likely to take in and potentially retain microeukaryotes in their gut while feeding. Microeukaryotes such as apicomplexans have been reported in marine mussel species, but no studies have examined the presence of these microorganisms in freshwater mussels or how they relate to mussel host species or environmental conditions. In this study, microbial community DNA was extracted from the gut tissue of over 300 freshwater mussels, representing 22 species collected from rivers in the southeastern USA. Microeukaryote DNA was detected using PCR amplification, followed by the sequencing of positive amplicons. Microeukaryotes were found in 167 individual mussels (53%) of those tested. Amplicons included dinoflagellates/algae that differed between mussel species and are likely food sources that were distinct from those found in water and sediment samples analyzed concurrently. A total of 5% of the positive amplicons were non-photosynthetic alveolates that could represent parasitic microeukaryotes. Understanding the distribution of microeukaryotes in the freshwater mussel gut microbiome could further our understanding of the ongoing decline of mussel populations.

Peanut–cotton intercropping to enhance soil ecosystem multifunctionality: Roles of microbial keystone taxa, assembly processes, and C-cycling profiles

Legume-based intercropping, such as the peanut–cotton system, stands out as a promising strategy for enhancing soil ecosystem multifunctionality (EMF); however, the underlying microbial mechanisms driving these enhancements remain inadequately explored. In this study, after implementing peanut–cotton intercropping for six consecutive years, a data set of 13 ecosystem functional indicators including 41 soil variables, was obtained and used to quantify the average EMF index. We investigated changes in microbial keystone taxa in co-occurrence networks, community assembly processes, carbon (C) cycling profiles, and their collective impacts on soil EMF. Soil EMF increased by an average of 140.0 % in the peanut–cotton intercropping system, compared with monoculture systems of both peanut and cotton, driven by significant increases in C-cycling (159.9 %), nutrient provisioning (91.2 %), and microbial growth efficiency functions (53.9 %). The peanut–cotton intercropping system significantly increased the average well-color developments (AWCD), abundance of C-fixation and C-degradation genes, and related pathways, resulting in a highly vigorous microbial C-cycling profile. The microbial community assembly processes shifted from a balance of stochastic and deterministic processes in monocultures to predominantly deterministic processes (> 70 %) in the intercropping system. Additionally, the peanut–cotton intercropping system fostered a more efficient and stable bacterial–fungal cross-kingdom network than the monocultures, characterized by a higher average clustering coefficient, higher robustness, and shorter average path length. This intercropping system also recruited a group of keystone taxa affiliated with Proteobacteria, Actinobacteria, and Ascomycota phyla. The enhancement of EMF in the peanut–cotton intercropping system resulted from the positive impact of key microbial community members and their assembly, C/N ratios, AWCD, and C-fixation and C-degradation genes. Our study provides insights into the complex ecological linkages between microbial communities, C-cycling profiles, and soil ecosystem functions, providing valuable insights into the microbial mechanisms underlying the benefits of intercropping systems.

Microbial assessment of the ecological linkage between a red tide of Karenia brevis and bottom water anoxia off the coast of Fort Myers and Sanibel Island, Florida

Coastal ecosystem management necessitates a comprehensive understanding of the physical, chemical, and biological components and their interplay with socio-economic activities. Red tides of Karenia brevis reoccur almost annually on the West Florida Shelf and cause significant human and environmental health problems that often result in negative economic impacts. It is crucial that we understand the processes and dynamics of both phytoplankton and microbial communities as conditions necessary for the formation of hypoxia and anoxia in the coastal ecosystem. With the aim of identifying key microbial communities responsible for anoxia, we investigated the 2017–2018 Karenia bloom. Various water quality parameters, phytoplankton, and microbial community compositions were studied at eight sites on the West Florida Shelf. K. brevis densities were highest at the site of the plume of the Caloosahatchee River. At the site with the highest K. brevis abundance (6.3 ×106 cells/L), dissolved oxygen (DO) was supersaturated (303 %) at the surface, and the chlorophyll a concentration was 118 µg/L. The highest bacterial cell count (9.0 ×106 cells/mL) and the lowest bacterial diversity were also observed at this site. The bacterial community determined by high-throughput amplicon sequencing at this bloom site was unique and dominated by Bacteroidetes, which occupied 65 % of the relative abundance of the microbial community. The bottom water was generally hypoxic (mean ± SD: 0.98 ± 1.13 mg/L), with select stations having DO as low as 0.06 mg/L (anoxic). The anoxic bottom water harbored unique microbial taxa that were associated with the low oxygen conditions. Significant negative correlations were found between DO and the relative abundance of Deltaproteobacteria, Firmicutes, Spirochaetes, and unclassified Proteobacteria. Our investigation lays the groundwork for subsequent studies delving into the responses of phytoplankton and microbial communities to disturbances caused by Karenia blooms, as well as future strategies for mitigation and ecosystem restoration.

Global biogeographic regions for ants have complex relationships with those for plants and tetrapods

On a global scale, biodiversity is geographically structured into regions of biotic similarity. Delineating these regions has been mostly targeted for tetrapods and plants, but those for hyperdiverse groups such as insects are relatively unknown. Insects may have higher biogeographic congruence with plants than tetrapods due to their tight ecological and evolutionary links with the former, but it remains untested. Here, we develop a global regionalization for a major and widespread insect group, ants, based on the most comprehensive distributional and phylogenetic information to date, and examine its similarity to regionalizations for tetrapods and vascular plants. Our ant regionalization supports the newly proposed Madagascan and Sino-Japanese realms based on tetrapod delineations, and it recovers clusters observed in plants but not in tetrapods, such as the Holarctic and Indo-Pacific realms. Quantitative comparison suggests strong associations among different groups—plants showed a higher congruence with ants than with tetrapods. These results underscore the wide congruence of diverse distribution patterns across the tree of life and the similarities shared by insects and plants that are not captured by tetrapod groups. Our analysis highlights the importance of developing global biogeographic maps for insect groups to obtain a more comprehensive geographic picture of life on Earth.

PROTECTION AND RESTORATION OF BIODIVERSITY AND ECOSYSTEMS OF THE DREVLYANSKY RESERVE

Biodiversity loss is one of the most important environmental issues of our time with far-reaching consequences. Species extinction can disrupt existing ecological linkages and degrade natural communities, potentially leading to their collapse. Declining biodiversity can also destabilise biotic communities, leading to a loss of ecosystem integrity and impairing the ability of the ecosystem to support critical ecological functions. [1-2].

Affective Entanglements: Human-Nonhuman Relations in Buddhist Ecologies of Feeling

This article reflects on key concepts in early South Asian Buddhism and their potential for creative dialogue with current concepts of research at the philosophical forefront of ecological thinking. It explores the role of feelings---that is, both bodily affects and culturally formed emotions---as crucial in negotiating the relations between humans and nonhumans and their environments. To this end, the concept of affective entanglement is proposed as a way of describing and analysing the condition of constitutive ecological linkage articulated through feelings and based in the fundamental interdependence of all phenomena in the world. Through careful analysis of a series of important early Buddhist Pali texts dealing with forested environments, this article explores how the early Buddhist teaching can challenge and enrich how we think of persons and bodies in relation to other beings and environments. Through a discussion of the powerful emotion of fear and the importance of vulnerability, the article develops thoughts on how Buddhist emotional practices as practices of care can inspire new approaches in today's times of escalating ecological crisis and acute vulnerability in coexisting and intersecting human and nonhuman pluriworlds.

Dynamic patterns of carbohydrate metabolism genes in bacterioplankton during marine algal blooms

Carbohydrates play a pivotal role in nutrient recycling and regulation of algal–bacterial interactions. Despite their ecological significance, the intricate molecular mechanisms governing regulation of phycosphere carbohydrates by bacterial taxa linked with natural algal bloom have yet to be fully elucidated. Here, a comprehensive temporal metagenomic analysis was conducted to explore the carbohydrate-active enzyme (CAZyme) genes in two discrete algal bloom microorganisms (Gymnodinium catenatum and Phaeocystis globosa) across three distinct bloom stages: pre-bloom, peak bloom, and post-bloom. Elevated levels of extracellular carbohydrates, primarily rhamnose, galactose, glucose, and arabinose, were observed during the initial and post-peak stages. The prominent CAZyme families identified—glycoside hydrolases (GH) and carbohydrate-binding modules (CBMs)—were present in both algal bloom occurrences. In the G. catenatum bloom, GH23/24 and CBM13/14 were prevalent during the pre-bloom and peak bloom stages, whereas GH2/3/30 and CBM12/24 exhibited increased prevalence during the post-bloom phase. In contrast, the P. globosa bloom had a dominance of GH13/23 and CBM19 in the initial phase, and this was succeeded by GH3/19/24/30 and CBM54 in the later stages. This gene pool variation—observed distinctly in specific genera—highlighted the dynamic structural shifts in functional resources driven by temporal alterations in available substrates. Additionally, ecological linkage analysis underscored a correlation between carbohydrates (or their related genes) and phycospheric bacteria, hinting at a pattern of bottom-up control. These findings contribute to understanding of the dynamic nature of CAZymes, emphasizing the substantial influence of substrate availability on the metabolic capabilities of algal symbiotic bacteria, especially in terms of carbohydrates.

Community Diversity of Fungi Carried by Four Common Woodpeckers in Heilongjiang Province, China.

Woodpeckers exhibit selectivity when choosing tree cavities for nest development in forest ecosystems, and fungi play a significant and important role in this ecological process. Therefore, there is a complex and intricate relationship between the various behaviors of woodpeckers and the occurrence of fungal species. Research into the complex bond between fungi and woodpeckers was undertaken to provide more information about this remarkable ecological relationship. Through the process of line transect sampling, woodpecker traces were searched for, and mist nets were set up to capture them. A total of 21 woodpeckers belonging to four species were captured. High-throughput sequencing of the ITS region was performed on fungal-conserved samples to enable an in-depth analysis of the fungal communities linked to the woodpeckers' nests. Members of Ascomycota were the most abundant in the samples, accounting for 91.96% of the total, demonstrating the importance of this group in the forest ecosystem of this station. The statistical results indicate significant differences in the fungal diversity carried by woodpeckers among the different groups. Species of Cladosporium were found to be the most prevalent of all the detected fungal genera, accounting for 49.3%. The top 15 most abundant genera were Cladosporium, Trichoderma, Beauveria, Epicococcum, Hypoxylon, Penicillium, Nigrospora, Aspergillus, Oidiodendron, Cercospora, Talaromyces, Phialemo-nium, Petriella, Cordyceps, and Sistotrema. The standard Bray-Curtis statistical technique was used in a hierarchical clustering analysis to compute inter-sample distances, allowing for the identification of patterns and correlations within the dataset. We discovered that in the grouped samples from woodpeckers, there were differences in the diversity of fungal communities carried by four woodpecker species, but the less dominant fungal species were still similar. The findings highlight the need to consider these diverse ecological linkages in woodpecker research and conservation efforts.

Ecosystem-based management approaches for watershed conservation and geosustainability

When contributors' goals and legislative and political structures vary, as they often do in the case of worldwide fish populations, it becomes more challenging to implement ethical fishing tactics. Canada, the United States, and Mexico all fish from Pacific regions anchovies in the California Modern. Climate-driven numbers and geographic dynamics may pollute the waters of collaborative aquaculture and lead to overloading. This research expands upon prior works using a game theoretic model of Tran's boundary sardine fisheries in different climatic conditions to account for ecological links. More significant economic advantages accrue from cooperation fishing tactics that consider the mackerel's role as feed for other species in the natural system, as opposed to plans that merely take note of the worth of mackerel harvests to a particular fishing nation. The maximum environmental benefit is obtained at a fishery rate for sardines barely less than the sardine Fishery Management Safe Yield. Ecological-based control of fisheries can increase sustainability and profits, but only if investors and policy makers consider the ecology in business-applicable models. Understanding and adapting to the fast alterations in habitat distributions due to climate change and designing ways to achieve viable and lucrative fishery amidst altering environments will necessitate an increased emphasis on ecosystem-based governance.

Analysis of land cover change in Sagara Anakan Cilacap, Central Java using principal component analysis (PCA)

Land cover in area Mangrove, an ecosystem with high productivity, is an ecological link that is very important for life in the waters. This study aims to identify land cover vegetation, water bodies, and soil using Principal Component Analysis (PCA) method with imagery using Landsat imagery for 1997 and 2021 carried out by processing Landsat 7 and Landsat 8 OLI images consisting of pre-processing processes and image classification. The results showed that in the mangrove area in Sagara Anakan, there was a significant change in land cover; for the lagoon area, the land cover was overgrown with mangrove forests, but areas far from the lagoon had changed to settlements or sparse vegetation.

The Last Glacial Maximum climate at Boomplaas Cave, South Africa

With a rich sequence of floral and faunal remains spanning the past >65,000 years, Boomplaas Cave is among the more important paleoenvironmental archives from South Africa's southern Cape. However, over the last several decades, its paleoenvironmental records have been the subject of conflicting interpretations, fueling uncertainty over fundamental aspects of Quaternary climate change in the region. Most significantly, researchers have variably interpreted the fossil plant and animal assemblages dating to the Last Glacial Maximum (LGM) as indicating harsh and arid or humid and productive conditions. This review critically examines the paleoenvironmental evidence from Boomplaas Cave, focusing on its LGM deposits and how they relate to the contentious problem of moisture availability through time. We show that interpretations of aridity during the LGM either (i) lack robust ecological links between the evidence and the paleoenvironmental interpretation, or (ii) are based on spurious patterns arising from sampling effects. In contrast, interpretations of relatively humid conditions during the LGM are grounded in present-day ecological observations and are consistent with both local and regional paleoenvironmental datasets. Overall, the evidence strongly supports the characterization of the LGM as a time of relatively humid conditions, with the transition to the Holocene characterized by increasing aridity. Several lines of evidence from Boomplaas Cave further suggest that this phase of increased humidity was associated with a dominance of winter rainfall, in contrast to the aseasonal rainfall regime that characterizes the southern Cape today.

A type III polyketide synthase cluster in the phylum Planctomycetota is involved in alkylresorcinol biosynthesis

Members of the bacterial phylum Planctomycetota have recently emerged as promising and for the most part untapped sources of novel bioactive compounds. The characterization of more than 100 novel species in the last decade stimulated recent bioprospection studies that start to unveil the chemical repertoire of the phylum. In this study, we performed systematic bioinformatic analyses based on the genomes of all 131 described members of the current phylum focusing on the identification of type III polyketide synthase (PKS) genes. Type III PKSs are versatile enzymes involved in the biosynthesis of a wide array of structurally diverse natural products with potent biological activities. We identified 96 putative type III PKS genes of which 58 are encoded in an operon with genes encoding a putative oxidoreductase and a methyltransferase. Sequence similarities on protein level and the genetic organization of the operon point towards a functional link to the structurally related hierridins recently discovered in picocyanobacteria. The heterologous expression of planctomycetal type III PKS genes from strains belonging to different families in an engineered Corynebacterium glutamicum strain led to the biosynthesis of pentadecyl- and heptadecylresorcinols. Phenotypic assays performed with the heterologous producer strains and a constructed type III PKS gene deletion mutant suggest that the natural function of the identified compounds differs from that confirmed in other bacterial alkylresorcinol producers.Key points• Planctomycetal type III polyketide synthases synthesize long-chain alkylresorcinols.• Phylogenetic analyses suggest an ecological link to picocyanobacterial hierridins.• Engineered C. glutamicum is suitable for an expression of planctomycete-derived genes.

The seahills and seahills ecosystems in the nearshore of Thua Thien-Hue province (Central Vietnam)

At the seabed in the nearshore, Vietnam has sandbars, shoals, bedrock knobs, rock reefs, and other landforms with elevations a few to several tens of meters higher than the seabed, which is always under the lowest astronomical tide (chart datum) and material structure of diverse compositions such as sands, gravel, boulders, blocks, etc. They have determined and warned on the chart map for the safety of navigation and the navy. These areas are significant fishing grounds due to abundant fish, shrimp, and benthic organisms. However, until now, investigation, research, and knowledge regarding these landforms’ environment, biomes, and naturals have yet to be explored. This paper presents some initial results of natural features (morphology, genetic terrain, material compositions, and types), environmental features, ecological community features (diversity, major groups of organisms, marine fish resources), and their significance in marine biomes (distribution of organisms, ecological linkage, habitats of endemic species) of a sandbar, bedrock in the nearshore in Thuan An, Tu Hien - Chan May and Lang Co - Hai Van - Son Cha of Thua Thien Hue province in the framework project of Thua Thien Hue province and National Independent Project belongs to the National Program 562 with Code Number is ĐTĐLCN.78/22. Based on these findings, the authors proposed naming this terrain “seahill” and the accompanying ecosystem “seahill ecosystems” in the nearshore of Vietnam while continuing to investigation, survey, and research.