Mangrove Environment Research Articles

Neolyngbya tortuosa sp. nov. (Oscillatoriales, Microcoleaceae): a new corticolous cyanobacterium from a tropical mangrove environment in Phuket, west coast of Thailand

ABSTRACT The biodiversity and systematics of cyanobacteria in tropical mangroves are increasingly being explored, leading to the discovery of new taxa and their potential pharmacological applications. Nevertheless, knowledge of the diversity of mangrove associated cyanobacteria in Southeast Asia, especially in Thailand, remains limited compared to other regions due to the lack of comprehensive surveys. In this study, three Lyngbya like strains were isolated from environmental samples collected from the underexplored mangrove environment of Phuket Island on the west coast of Thailand. Strains were characterized by applying the polyphasic approach. Our results indicated that our isolates belonged to the genus Neolyngbya, distinct from other known Neolyngbya species both genetically and morphologically. Consequently, we proposed them as a new species, Neolyngbya tortuosa sp. nov. which was distinguished by its unique feature of trichome fragmentation occurring within its twisted and rigid sheath, and false branching. The 16S rRNA and 16S23S rRNA internal transcribed spacer (ITS) phylogeny revealed that this novel species formed a distinct, well supported clade within the monophyletic group of Neolyngbya. Additionally, the 16S rRNA genetic similarity, ITS dissimilarity values and secondary structures also provided comprehensive evidence for its description. The present study represents the first record of the genus Neolyngbya in Thailand, thereby expanding their biogeographical coverage in the tropics and enhancing our understanding of cyanobacterial diversity in tropical mangrove ecosystems.

Geospatial distribution and anthropogenic litter impact on coastal mangrove ecosystems from the Saudi Arabia coast of the Gulf

Mangrove ecosystems are significantly impacted by marine litter pollution, an increasingly important environmental problem. These ecosystems, situated at the interface between sea and land, serve as critical habitats and act as traps for plastic pollution. This study investigated the concentration, source, and composition of marine litter on both the mangrove bottom and canopy along the Saudi Arabia coast in the Gulf. The observed concentration of surface litter ranged from 0.98 ± 0.05 to 2.96 ± 0.25 items/m², with a mean concentration of 1.4 ± 0.61 items/m² (SD; N = 9). The mean trapped litter was 0.79 ± 0.45 items/tree, ranging from 0 to 7 items/tree. Plastic litter dominates the mangrove environment, accounting for 80% of debris items on the floor and 43% of those entangled in the canopy. Single-use plastics were the most prevalent type of litter detected across all surveyed locations. The sediments within the mangrove ecosystem serve as long-term repositories for plastic litter, evaluated through various indices, such as General Index, Clean Coast Index, Pollution Load Index, and Hazardous Litter Index, to assess the cleanliness of the mangrove floor. The Pollution Load Index shows a “Hazard level I,” indicating that the mangrove floor is less contaminated. A higher concentration of litter was observed in urban areas with greater population density, likely originating from terrestrial activities like urban runoff and marine activities, particularly fishing.

The challenge of establishing natural geochemical backgrounds in human-impacted mangrove soils of Northeastern Brazil.

The challenge of establishing natural geochemical backgrounds in human-impacted mangrove soils of Northeastern Brazil.

Hidden Microbial Diversity in Mangrove Depths: New Cyanobacterial Species of Picosynechococcus and Two New Records of Sirenicapillaria and Allocoleopsis from the Andaman Coast of Thailand

In Thailand, mangrove forests form a major component of the Andaman coastal ecosystems in the southern provinces. However, studies on their microbial assemblage largely revolved around groups of bacteria, fungi, and eukaryotic microalgae, while the diversity of cyanobacteria in these regions remains almost unknown. This taxonomic study applied the polyphasic approach to examine seven cyanobacterial strains collected from different mangrove environments (including soil crust, tree bark, wood, and rock surface) across Ranong, Phang-Nga, and Phuket provinces. The comprehensive analysis combining morphology, ecology, 16S rRNA phylogenetic relationships, genetic identity, ITS secondary structure, and ITS dissimilarity resulted in the first records of the genera Picosynechococcus, Allocoleopsis, and Sirenicapillaria in Thailand, and led to the description of a new species, Picosynechococcus mangrovensis sp. nov. This new species was differentiated from the type species P. fontinalis based on the distinct 16S rRNA gene phylogenetic position, low 16S rRNA genetic similarity, its slightly halophilic nature, and ability to form pseudo-filaments with up to 160 cells. Our research significantly expands the documented cyanobacterial diversity of Southeast Asian mangrove ecosystems, establishing a critical foundation for future ecological and biotechnological investigations in these understudied yet vital tropical habitats.

Development and Application of Human Health Risk-Based Screening Levels for Crude Oil Affected Soils and Sediments in the Niger Delta.

Management of oil impacted sites in Nigeria is regulated through the Environmental Guidelines and Standards for the Petroleum Industry in Nigeria (EGASPIN). This includes an intervention value for total petroleum hydrocarbons (TPH) of 5,000 mg/kg as a trigger for remedial action. This single intervention value does not differentiate between varied land uses or the specific chemical composition of spilled oil. The EGASPIN does allow development of refined screening levels based upon human health risk assessment methods. Following these requirements, we have applied the ASTM risk-based corrective action (RBCA) process to define Tier 1 Risk Based Screening Levels (RBSLs) and Tier 2 Site Specific Target Level (SSTLs). Both are derived using United States Environmental Protection Agency (USEPA) guidance supplemented by equations correcting for the properties of chemical mixtures, presence of a residual oil phase, and preferential depletion of volatile oil components. The RBSLs were calculated for five Nigerian crude oils and six exposure scenarios specific to the Niger Delta while SSTLs were calculated using sediment sampling results and four exposure scenarios from the Bodo oil spill area located in the eastern Niger Delta mangrove swamp area. Derived TPH RBSLs range between a factor of 2.5 lower (more stringent) for residential land use to > 10x higher for 'Commercial and Industrial Workers', when compared to the Nigerian EGASPIN intervention value. Derived SSTLs for TPH ranged between a value just above the intervention value for shoreline areas near Bodo Town to values ∼6x higher than the intervention value for most uninhabited mangrove areas. The derived RBSLs and SSTLs are protective of human health but other criteria (aesthetic, ecological) may be more stringent. Additional criteria are introduced, including oil mobility (potential spreading of existing impacts) and criteria for ensuring the viability of the mangrove environment.

New fungal genus, three novel species and one new record from mangroves, with reclassification of Melanconiella (Melanconiellaceae) species.

Mangrove ecosystems, located in the land-sea interface, host a diverse array of fungi. In this paper, we introduce a novel genus, three novel species and one new record of fungi collected from mangrove environments in Pranburi, Prachuap Khiri Khan, Thailand. We establish Pseudomelanconiella as a new genus in Melanconiellaceae, to accommodate Pseudomelanconiellamangrovei, a saprobe from submerged decomposing wood of Avicenniamarina. Phylogenetic analysis indicates its close relation with Septomelanconiella, but they differ in the morphology of the conidia. Additionally, our analysis of Melanconiellaceae led to the reclassification of Melanconiellaloropetali to Sinodisculaloropetali and synonymizing Sinodisculacamellicola and Melanconiellacamelliae. This paper also introduces two other novel species: Peroneutypahibisci, a saprobe found on Hibiscustiliaceus and Pseudochaetosphaeronemabruguierae from Bruguieracylindrica, the first species in this genus reported as a mangrove fungus. A new record of Rimoramangrovei from Ceriopstagal is also reported. These discoveries emphasize the rich fungal diversity in mangrove ecosystems supporting further exploration of this unique environment.

Benthic foraminifera as bioindicators of coral condition near mangrove environments.

Benthic foraminifera as bioindicators of coral condition near mangrove environments.

Metagenomic surveillance reveals different structure and function of microbial community associated with mangrove pneumatophores and their surrounding matrices.

Metagenomic surveillance reveals different structure and function of microbial community associated with mangrove pneumatophores and their surrounding matrices.

Bleaching and a Corallivore of the Coral Siderastrea radians in the Florida Keys

The tropical coral Siderasterea radians is typically found in mangrove areas, seagrass beds, and environments tolerated by few other scleractinians in the Caribbean and South Florida. Siderastrea radians experience bleaching stress in Buttonwood Sound in Florida Bay during April–May, a time when the seawater is below bleaching temperatures. Stress first appears as a pink coloration due to the presence of fluorescent pigments protecting the coral tissue and algal symbionts from exposure to excessive sunlight/UV light. Surveys of S. radians in areas frequented by parrotfish showed that up to 38.5% of the corals were pink, with about a quarter of all the corals having bite marks. In areas not frequented by parrotfish, only 3.2% of the corals were pink, and none had bite marks. A seasonal analysis in parrotfish-frequented seawater showed S. radians contained among the lowest tissue biomass and density of symbiotic algae during April–May 2010–2017, often looking pink. It is hypothesized that seawater temperature is not the cause of bleaching in Buttonwood Sound during April–May but rather predation by the rainbow parrotfish Scarus guacamaia.

Inter-annual changes and growth trends mapping of mangrove using Landsat time series imagery

ABSTRACT Mangroves, as the most prolific but vulnerable ecosystems, necessitate continuous monitoring for effective conservation. However, continuous mangrove mapping is challenging due to extensive land use changes and highly intertidal dynamics. In this study, a novel mangrove index, named the Composite Mangrove Index (CMI), was developed to map and assess the growth trends of mangroves, based on the truth that the spectral-temporal features of mangrove wetland environment related to greenness, moisture, and bare soil. To facilitate long-term mapping of mangroves, the Continuous Change Detection and Classification (CCDC) algorithm was utilized on the Google Earth Engine platform (GEE). The innovative mangrove mapping framework using the CMI based CCDC was applied in three diverse regions (i.e. Guangdong-Hong Kong-Macao Greater Bay Area (GBA) in southern China, Sundarbans in India and Bangladesh, and Gulf of Paria (GP) in northern Venezuela). The results showed that annual mangrove maps of these three typical regions from 2000 to 2020 achieved overall accuracy exceeding 92%, indicating the ability of CMI to capture the temporal inter-annual characteristics of mangroves. The area of mangroves represented a total increase of 700 ha in the GBA, while slightly decreasing in the Sundarbans and the GP. By comparing Fractional Vegetation Cover (FVC) and CMI with two mangrove types, CMI proved to be effective in not only assessing mangrove growth status but also monitoring recovery and degradation growth trends of mangroves, surpassing some existing indices (MI, EVI, TCA). Controlled experiments also demonstrated that CMI outperformed in mangrove classification compared to some mangrove indices (MI, MVI, CMRI). The distinctive CMI values can offer a rapid method to detect and quantify the growth trends for mangrove afforestation, restoration and even degradation. Therefore, the proposed CMI with CCDC provides new slight to monitor the ongoing efforts in mangrove conservation and shed light on understanding the mangrove dynamics.

Marketing of the Mud Crab (Scylla serrata) Cultivated in Mangrove Environment in Palampai Village, Kapuas Kuala District Central Kalimantan, Indonesia

Marketing of the Mud Crab (Scylla serrata) Cultivated in Mangrove Environment in Palampai Village, Kapuas Kuala District Central Kalimantan, Indonesia

Exploring microbial players for metagenomic profiling of carbon cycling bacteria in sundarban mangrove soils

The Sundarbans, the world’s largest tidal mangrove forest, acts as a crucial ecosystem for production, conservation, and the cycling of carbon and nitrogen. The study explored the hypothesis that microbial communities in mangrove ecosystems exhibit unique taxonomic and functional traits that play a vital part in carbon cycling and ecosystem resilience. Using metagenomic analysis to evaluate microbial communities in mangrove and non-mangrove environment, evaluating their composition, functional functions, and ecological relevance. The analysis revealed distinct microbial profiles, in mangrove and non-mangrove environments, with bacteria, proteobacteria, and viruses being the most prevalent groups, with varying abundances in each environment. Functional and taxonomical analysis identified genes involved in carbon regulation, including Triacylglycerol lipase, NarG, DsrB, DNA-binding transcriptional dual regulator CRP, Vanillate O-demethylase oxygenase, succinate-CoA ligase, Tetrahydrofolate ligase, Carboxylase, Ribulose-1,5-bisphosphate carboxylase/oxygenase, Glycine hydroxymethyltransferase, MAG: urease, Endosymbiont of Oligobrachia haakonmosbiensis, Ribulose bisphosphate carboxylase, Aconitate hydratase AcnA, and nitrous oxide reductase, suggesting the metabolic versatility of these microbial communities for carbon cycling. The findings emphasize the key role of microbial activity in preserving mangrove ecosystem health and resilience, highlighting the intricate interplay between microbial diversity, functional capabilities, and environmental factors.

Field assessment of wave attenuation by BESE-elements in a mangrove environment

Field assessment of wave attenuation by BESE-elements in a mangrove environment

Biogeomorphological inheritance: The legacy of past landforms constrains future tropical coastal landscapes

AbstractCoasts are some of the most dynamic environments on Earth. Coastal systems comprise physical environments together with a biological component, and, for much of the world, a human element, which in many cases imposes anthropogenic stresses. The biological component is especially prominent in the tropics, and the biogeomorphology of these coasts is dominated by the role played by key organisms: corals, which form impressive coral reefs, and mangroves, which fringe low‐energy shorelines. Whereas the present is the key to the past, the past also sets the stage on which future changes play out. Coral reefs have played a prominent role in deciphering the trajectory of past sea‐level change, and modern reefs are often founded on older Pleistocene reefs. Inheritance is apparent both at the scale of interglacial highstands and in terms of the Holocene landforms that characterise reef‐top habitats. The stratigraphy of mangrove environments reveals their more passive response to sea‐level rise, constrained by accommodation space provided by the prior topography. The suite of landforms that have developed during the past few millennia have resulted in a variable coastal landscape. Tidal incursion into low‐lying terrain enables mangrove establishment, re‐occupying former channel courses. The trajectory of past landform change has been contingent on biogeomorphological history, and the future response of these tropical systems will also reflect in part the legacy of their geomorphological evolution. The role of inheritance is investigated with respect to reef and wetland environments, illustrating how past coastal landforms predispose future response.

Impacts of Mangrove Loss on Greenhouse Gas Emissions in the Niger Delta, Nigeria

The mangrove vegetation within the Niger Delta region of Nigeria is ravaged by anthropogenic practices including but not limited to rapid urbanization, aquaculture expansion and oil exploration which penultimately distorts the biodiversity of both the mangrove and marine environments, culminating in the loss of structural and functional integrity of these ecosystems, specifically their role in climate change regulation. The study aimed at assessing the changes in mangrove covers from 1987 to 2022 in the study area as well as examining the changes in GHGs emissions resulting from the mangrove changes. The methodology adopted a remote sensing-based research design utilizing satellite imagery to analyze temporal changes in mangrove cover and evaluated their association with climate variables such as CO2 emissions and LST of the study area. Each satellite image geo-referenced in ArcGIS 10.8 & LULC changes calculated using geometry module of ArcGIS 10.8. NDIR spectroscopy was used in examining the variation in GHGs emissions. The data obtained revealed mangrove reduction from 12,991 km2 in 1987 to 9,089km2 in 2022 resulting in the loss of 3,904.00 km2 of mangrove forest. The reduction resulted in increased CO₂ emissions from 370.70 ppm to 403.29 ppm between 1987 and 2022. These results illustrate a clear link between mangrove cover change and CO₂ emissions, highlighting the critical role mangroves play in regulating climate change. The study was able to show that significant losses in mangrove cover have been closely associated with increased CO₂ emissions, thus reflecting the vital role these ecosystems play in carbon sequestration which underscores the importance of preserving these vital ecosystems to mitigate local and global climate impacts.

Taxonomical Characteristics and Biochemical Properties of Namalycastis abiuma: A Promising Nutritional Resource for Aquaculture

Namalycastis abiuma polychaete species is generally found in mangrove mud flats, whereas ten specimens were observed, with six being complete, ranging from 128 to 135 chaetigers. The species exhibits an elongated body with a convex dorsum and flat ventral surface. The prostomium is trapezoidal with a distinct anterior cleft, and the antennae are short and subconical. Moreover, the species has two pairs of eyes, tentacular cirri with smooth cirrostyles, and a button-shaped pygidium with two smooth anal cirri. The determination of proximate composition widely accepted standard methods were followed, whereas it revealed rich protein content with 54.24 ± 2.4%, and moderate lipid at 32.3 ± 1.2%, a lesser amount of carbohydrate with 17.2 ± 0.7%, and an ash percentage of 7.2 ± 0.5%. The fatty acid profile revealed that 30 numbers of fatty acids belong to SFA, MUFA, and PUFA; at the same time, omega-3 fatty acids, including EPA and DHA, are notable fatty acids that comprise 12.64 ± 1% of the total fatty acids. Unlike other polychaetes, the species of Namalycastis abiuma, generally found in mangrove environments, plays a significant role in nutrient cycling, giving crucial support to the coastal ecosystem's health, and the species has also shown great potential of biochemical profile, including protein, lipid, and carbohydrates, and specifically the presence of higher amounts of protein and omega-3 fatty acids, which collectively gives great attention to this species as a promising nutrient source that would support the aquaculture-adapted species like shrimp and fish in their immune system enhancement, reproduction, and growth. This study highlighted that this species is an alternative source for formulating feed, in contrast to reliance on traditional fishmeal, which may create more sustainable and affordable aquaculture practices.

Assessing the preservation potential of successive hurricane overwash deposits in Florida, USA mangroves

Geologic records of tropical cyclones (TCs) in low-energy, back-barrier environments are established by identifying marine sediments via their allochthonous biogeochemical signal. These records have the potential to reconstruct TC intensity and frequency through time. However, modern analog studies are needed to understand which biogeochemical indicators of overwash sediments are best preserved and how post-depositional changes may affect their preservation. Here, we examine the overwash sediments of two successive land-falling, high-intensity TCs: Hurricane Ian in 2022 and Hurricane Irma in 2017. Hurricane Ian’s overwash sediments at two mangrove sites, including one directly along (Matlacha Pass) and one other distal from (Blackwater Bay) Hurricane Ian’s path through southwest Florida, USA, were identified as a light gray very poorly to poorly sorted coarse silty sand with marine microfossils and geochemical marine signature. Hurricane Irma’s overwash sediments remained identifiable from post-Irma sediments at Blackwater Bay as a gray poorly sorted coarse silt with a marine microfossil signature but lacking a distinctive geochemical signature. The identification of overwash sediments left by TCs occurring in within five years demonstrates the high preservation potential of overwash sediments in low-energy, mangrove environments. Similar environments can be utilized to advance paleotempestology studies in southwest Florida.

Occurrence, distribution, and potential ecological risks of psychoactive substances in the mangrove environment, Hainan Island of South China

BackgroundAs a kind of emerging contaminant, psychoactive substances (PSs) have been detected in different types of freshwater ecosystems; however, their occurrence in coastal shore areas is seldom reported. In this study, surface water samples from the mangrove ecosystems across 6 cities and counties in Hainan Island, 68 water samples were collected from August to December 2022, for assessment of the occurrence, spatial distribution, and potential ecological risks of PSs in the mangrove ecosystem in Hainan Island, South China.ResultsA total of 13 PSs were determined by liquid chromatography–mass spectrometry (LC–MS), with 7 of them at high frequency (> 50%). Amphetamine (AMP) was detected with the highest concentration of 12.0 ng/L, followed by ephedrine (EPH) of 8.31 ng/L. The spatial distribution showed that PSs concentrations in mangroves in the Eastern Route were higher than those in the Western Route, similar to the level of regional development, which may be influenced by seasonal tourism. The risk quotients (RQs) of the PSs ranged from 0 to 0.0055, suggesting the low risk of PSs in Hainan mangrove ecosystems.ConclusionsGenerally, this study provided valuable insights into the environmental occurrence, spatial variations, and ecological risks of PSs in mangrove wetlands systems for the first time, serving as a foundation for understanding their influence on the mangrove ecosystem, which may aid in protection of those unique and vulnerable areas.

Reconstructing deltaic palaeoenvironments in southern South America: phytoliths in Miocene estuarine sediments (Paraná Formation)

Reconstructing deltaic palaeoenvironments in southern South America: phytoliths in Miocene estuarine sediments (Paraná Formation)

Palynostratigraphic Evaluation of Depositional Environment in Well E001 Niger Delta

Palynological investigation was carried out on E001 well to interpret the lithofacies and biostratigraphy with the aim of establishing the palynological zones and the consequent age, environment of deposition and paleoclimatic conditions of the rock sediments in the well, using visual microscopic observations to determine their lithological character and palynologic content of the sedimentary succession. E001 well is located on latitude 4° 31′ 16.58″N and longitude 8° 18′ 24.96″E onshore Niger Delta. The analysis of this study was carried out on 50 ditch cutting samples composite at 60ft interval ranging from a depth of 3480 to 6420ft. From the well logs, three lithofacies were delineated and stratified from shale to sandstone. The shale is fissile and dark brown, followed by the siltstone which are poorly sorted, and the sandstones are poorly to well sorted, rounded to well-rounded and fine to coarse grained, the presence of this lithofacies unit indicates that the well section penetrated the Agbada Formation. The Palynologic content recovered were fairly diverse as six (6) zones were erected from base to top which are Acrostichum aureum (Zone I), Zonocostites ramonae (Zone II), Pachydermites diederixi (Zone III), Granulatisporites spp. (Zone IV), Verrucatosporites alienus (Zone V), and Psilatricolporites crassus (Zone VI). These Miospore zones was compared with P820 palynological zones of Evamy et al. 1978 to assign a late Miocene age for the sediments. The paleoenvironmental conditions fluctuates between mangrove setting to freshwater conditions, based on the presence of continental-derived miospores such as Zonocostites ramonae, Psilatricolporites crassus, Acrostichum aureum, Retibrevitricolporites obodoensis, Pachydermites diedirixi, ctenolophonidities costatus. Analysis of the paleoclimatic conditions show that 60% of the total miospores are freshwater, 30% are mangrove, 1% Brackish water and 5% Marine environment. The Palynomorph Marine Index (PMI) also validates the depositional environment which transits from brackish water environment at the upper unit of the well to Fresh water and mangrove environment from the middle to the lower part of the well.