Mangrove Sediments Research Articles

210Pb dating and neutron activation analysis of the Sundarban mangrove sediments: sedimentation rate and metal contamination history

Abstract In this study, alpha spectrometry and neutron activation analysis were applied to assess the mass accumulation rate, contamination history, and ecological risk of the Sundarban mangrove sediments. The mass accumulation rates of sediments using 210Pb dating determined for the first time in this area ranged from 0.068 to 3.20 kg m−2 y−1, with an average of 0.61 kg m−2 y−1. The contamination history of 11 metal(loid)s (Al, Ca, V, Cr, Fe, Ni, Cu, Zn, As, Hg, and Pb) was assessed. Different environmental contamination indices suggested that Sundarban mangrove sediments were contaminated by As. Considering different sediment quality guidelines, it was observed that Cr, Ni, and As posed occasional adverse biological effects on marine organisms. Multivariate statistical approaches were applied to elucidate the origin and transport behavior of the studied metal(loid)s in the mangrove ecosystem which suggested that sources of metal(loid) pollution were both anthropogenic and geogenic. The results from this study should improve the knowledge of metal contamination and ecological risk to biota to develop new strategies and enlarge management practices to save sensitive mangrove ecosystems.

Organophosphate Triesters and Their Transformation Products in Sediments of Mangrove Wetlands in the Beibu Gulf, South China Sea

As emerging pollutants, organophosphate esters (OPEs) have been reported in coastal environments worldwide. Nevertheless, information on the occurrence and ecological risks of OPEs, especially the related transformation products, in mangrove wetlands is scarce. For the first time, the coexistence and distribution of OP triesters and their transformation products in three mangrove wetlands in the Beibu Gulf were investigated using ultrasonication and solid-phase extraction, followed by UHPLC-MS/MS detection. The studied OPEs widely existed in all the sampling sites, with the total concentrations ranging from 6.43 ng/g dry weight (dw) to 39.96 ng/g dw and from 3.33 ng/g dw to 22.50 ng/g dw for the OP triesters and transformation products, respectively. Mangrove wetlands tend to retain more OPEs than the surrounding coastal environment. Pearson correlation analysis revealed that the TOC was not the sole factor in determining the OPEs’ distribution, and degradation was not the main source of the transformation products in mangrove sediments in the Beibu Gulf. The ecological risks of selected OPEs for different organisms were also assessed, revealing a medium to high risk posed by OP diesters to organisms. The levels or coexistence of OPEs and their metabolites in mangroves need constant monitoring, and more toxicity data should be further studied to assess the effect on normal aquatic organisms.

Characteristics and Antibacterial Activities of Bacteriocin Produced by Lactid Acid Bacteria Isolate LG-50 and LG-90

Biopreservative agents is natural food preservative agent derived from microbes such as bacteriocin produced by lactic acid bacteria (LAB). Bacteriocin is a protein compound that has a small molecular weight and has antibacterial activity because it is effective in preventing the growth of pathogenic bacteria in food and beverages. Escherichia coli and Staphylococcus aureus are pathogenic bacteria that can contaminate seafood products because they can cause infection and food toxication. Isolates LG-50 and LG-90 are LAB, bacterial collection of the Microbiology Laboratory, Faculty of Biology, Isolate from mangrove sediment in Logending beach. Both isolates are not yet known for their potencies to synthesize bacteriocin and its inhibitory capability to the growth E. coli and S. aureus. The research aimed to determine the ability of LG-50 and LG-90 isolates to produce bacteriocin, to determine the ability of LG-50 and LG-90 isolates to inhibit the growth of E. coli and S. aureus bacteria invitro, to identity the characteristics of isolate LG-50 and LG-90 from Logending beach mangrove sediment. The results of this research show that the bacteriocins LG-50 and LG-90 were able to inhibit the growth of E.coli with inhibition zone diameters of 13.5 mm and 13 mm, in S. aureus with inhibition zone diameters of 15 mm and 15.5 mm.

Mangrove sediments are environmental hotspots for pathogenic protists

Mangrove sediments are unique ecosystems providing habitats for diverse organisms, especially microbial communities. However, little is known about the diversity and environmental risk of a critical group of microorganisms, the protists. To address this gap, we employed metagenome sequencing technologies to provide the first comprehensive view of the protistan community in the mangrove sediment. Our results surprisingly showed that parasitic protists dominated the protistan community in mangrove sediments, with an average abundance of 59.67%, one of the highest in all ecosystems on Earth. We also found that the relative abundance of protists decreased significantly (R = −0.21, p = 0.045) with latitude but increased with depths (R = 0.7099, p < 0.001). The parasitic communities were positively influenced by microbial (bacteria, fungi, and archaea) communities, including horizontal-scale and vertical-scale. In addition, sulfate and salinity had the most significant influence on the protistan community. Our findings provide new insights into our understanding of protistan variation in mangrove sediments, including abundance, composition, and possible functions, and indicate that mangrove sediments are hotspots for environmental pathogens, posing a potential risk to human health.

Regulatory role of sesarmid crabs in nutrient dynamics and implications for the productivity of mangroves

The ecological role of brachyuran crabs in mangroves has been extensively studied, but their role as mediators of biogeochemical processes of essential nutrients remains unclear. We hypothesized that speciose sesarmid crabs in tropical mangroves can improve nutrient transfer rate (NTR) and enhance primary productivity by reducing nutrient recycling bottlenecks. Using stable isotope labels and tidal mesocosms simulating the mangrove environment (with and without crabs), we traced the transfer of carbon (C) and nitrogen (N) across the system (from mangrove leaf litter to mangrove seedlings, the microphytobenthos (MPB), and sediment). We compared NTR between the two treatments by measuring the 13C and 15N enrichment levels (as a proxy for NTR) of mangrove seedlings, MPB, and sediment. The significantly higher enrichment level of sediment, MPB and seedlings (for N) in mesocosms with crabs indicated higher NTR driven by these animals. Such increased NTR also led to higher primary productivity, supporting our hypothesis. A consumer-driven nutrient dynamics (CND) framework was established to provide a comprehensive understanding of the role of sesarmid crabs in mediating biogeochemical processes. It is clear that the reciprocal nutrient flow between MPB and sesarmid crabs, and the biogeochemical hotspots created in surface sediment underpin this CND effect. A system picture emerges whereby nutrient flow is strongly regulated by sesarmid crabs promoting the productivity of mangroves by (1) enhancing nutrient remineralization; (2) retaining nutrients; (3) creating biogeochemical hotspots; and (4) improving overall nutrient transfer rate.

Stochastic processes drive the diversity and composition of methanogenic community in a natural mangrove ecosystem

Methanogens are considered to be crucial components of mangrove ecosystems with ecological significance. However, understanding the assembly processes of methanogenic communities in mangrove ecosystems is relatively insufficient. In the current study, a natural mangrove in a protection zone was employed to investigate the diversity and assembly processes of methanogenic community by using amplicon high-throughput sequencing, a null model as well as a neutral community model. The results showed that methanogenic community in mangrove sediments were highly diverse, with the predominance of methylotrophic Methanolobus, and hydrogenotrophic Methanogenium, Methanospirillum. The diversity, composition, and gene abundance varied obviously across the mangrove sampling sites, whereas the measured environmental variables exhibited a negligible effect. Null model showed that the values of beta nearest-taxon index were mostly between −2 and 2, indicating that stochastic processes contributed more than deterministic processes driving the methanogenic community assembly in mangrove sediments. Neutral community model revealed a high estimated migration rate of methanogenic community, further substantiating the significance of stochastic processes. Among the keystone species identified in network analysis, methanogens affiliated to hydrogenotrophic Methanospirillum may have a crucial role in maintaining the structure and function of methanogenic community. Notably, these keystone species were almost unaffected by measured environmental factors, indicating that the methanogenic community in mangrove sediments is more likely to be affected by stochastic processes. This study deepens the understanding of the diversity and assembly of methanogenic community in mangrove sediments, and provides clues to maintain mangrove ecosystem functioning.

Antibiotic resistance profile in sediments and bacterial isolates from a human-impacted mangrove from Bahía Magdalena, Mexico

Abstract Antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs) in the environment are considered emerging contaminants. One of the ecosystems that can harbor resistant bacteria and genes is mangroves. This report aims to assess ARB and ARG's presence at two mangrove locations in Bahia Magdalena, Mexico. Bacterial isolates were selected based on their phenotypic profiles of antibiotic resistance. DNA from mangrove sediments and bacterial isolates was tested for int1 and antibiotic resistance genes by final point PCR. From 90 ARB isolates, the phenotypic profile showed resistance to ciprofloxacin (90%), cefotaxime (85.7%), and ampicillin (78.6%), while the beta-lactamase gene (blaCTX-M) was present in 72.9% of the isolates. Antibiotic resistance genes identified in sediments were found even at 30–50 cm depth, but the integron Class gen (int1) was found mainly in shallow samples. Principal component analysis showed a close relationship between the integron gene, vancomycin, and sulfonamides resistance genes. No correlation was found between the phenotypic and genotypic profiles of the bacterial isolates. Also, no differences were observed between the two mangrove ecosystems studied. The impact of anthropogenic activities was equally significant on both sites. The role of mangrove ecosystems in the dispersion of antibiotic resistance needs to be further explored.

SCREENING OF MICROBIAL BIOPESTICIDES AGAINST POST-HARVEST FUNGAL PATHOGEN COLLETOTRICHUM SPP A PRELIMINARY STUDY

Most common fungal pathogens are found in Colletotrichum genus which cause economically significant anthracnose or blight disease in a variety of tropical and subtropical fruit and vegetables. Despite that, the excessive application of chemical pesticides in agriculture has caused many problems such as poor soil fertility, pollution and risk to human health due to the toxic accumulation of the pesticides in the soil. This study was carried out to isolate potential bacterial colonies from five different soil sources around Universiti Malaysia Terengganu and to the screen isolated bacteria for antagonistic effect against Colletotrichum species. In total, 50 bacterial strains were isolated and subjected to selective screening to distinguish bacterial strains capable of inhibiting Colletotrichum sp. Based on the selective screening, nine bacterial strains with different morphology were selected and tested further in quantitative screening by calculating their percentage of inhibition of radial growth (PIRG). The results showed that S5-H strain demonstrated the highest inhibition effect at (75.67 ±2.86)%, followed by S5-I strain (68.89 ±5.93)%, S5-D strain (66.89 ±6.15)%, S3-C strain (60.33 ±3.19)%, S5-F strain (57.89 ±4.66)%, S5-G strain (53 ±5.79)%, S2-I strain (41.33 ±7.26)%, S4-B strain (40 ±7.07)% and S3-D strain (38.33 ±8.90)%. Based on the results, bacterial isolate S5-H with yellow, round, convex and entire colony from mangrove muddy sediment was shown to have a potential to be utilized as biopesticides against Colletotrichum sp. Nevertheless, this study requires further work in the future focusing on species identification by 16S rRNA phylogeny and mechanism of action exhibited by S5-H strain.

EFFECTS OF Avicennia marina MANGROVE SEDIMENTATION ON WAVE ATTENUATION

Mangrove ecosystems protect coastlines from abrasion and erosion, dampen strong winds against oceans, and bind sediment periodically. The purpose of the study was to determine the effects of Avicennia marina sedimentation on wave attenuation. The employed methods in this research were spot-check, transect-squared, and laboratory test methods. The measurement of the wave data involved SBE 26 and RBRDuo T.D. They were carried out at 5 stations with thicknesses of 3 m, 5 m, 10 m, 20 m, and 50 m respectively. The percentages of the wave energy attenuation were 49.5%, 53.8%, 82.9%, 91.4%, and 92.3%, with grain diameter percentages of 19.36%, 19.75%, 19.87%, and 21.27%. The higher the percentage of wave attenuation, the smaller the percentage of grains, and vice versa. When a wave arrives, the energy is so large that each large particle of the sediment in the sea is brought back to the mangrove ecosystem. When the wave disappears, the released energy gets so smaller that only small particles are taken back to the sea. The conclusion of this study is that the diameter percentage of mangrove sediment was related to the percentage of wave attenuation. The greater the percentage of wave attenuation, the smaller the percentage of grains.

Outwelling of reduced porewater drives the biogeochemistry of dissolved organic matter and trace metals in a major mangrove‐fringed estuary in Amazonia

AbstractMangrove‐fringed estuaries are intertidal ecosystems discharging significant amounts of dissolved organic matter (DOM) into coastal oceans. DOM in these ecosystems is derived from autochthonous production, fluvial input, and mangrove porewater outwelling; however, differentiating between these sources remains challenging. Our incomplete understanding of the biogeochemical factors controlling DOM dynamics and its relationship with nutrient and trace metal cycling still hinders the formulation of elemental budgets in coastal environments. Here, we relate the DOM composition in a mangrove‐fringed estuary in North Brazil (Amazonia) to the redox conditions at the formation sites. We combined molecular DOM analyses via ultrahigh‐resolution mass spectrometry (FT‐ICR‐MS) with parallel factor analysis of excitation–emission fluorescence matrices (EEM‐PARAFAC), nutrient and redox‐sensitive trace metal analyses. During low tide, the influx of oxygen‐depleted porewater carried terrigenous DOM, inorganic nutrients, and trace metals into the mangrove‐fringed creeks. Precipitation of metal(hydr)oxides and microbial turnover controlled nutrient and trace metal dynamics in the estuary. The highest inorganic nitrogen concentrations within the upper mangrove‐fringed estuary indicated outwelling from mangrove sediments as an essential source. Phosphate concentrations were highest within the lower mangrove‐fringed estuary, where available phosphate likely exceeded precipitation with iron(hydr)oxides. We tracked the DOM transport to the coastal ocean using a novel molecular index derived from sulfidic porewater (ISuP). Outwelling of recalcitrant DOM from mangrove habitats is relevant in the context of blue carbon storage. Therefore, applying our molecular proxy (ISuP), together with trace‐metal and optical DOM analyses, is a powerful approach for differentiating contributions of diverse DOM sources in highly complex coastal ecosystems.

Chemolithoautotrophic diazotrophs dominate dark nitrogen fixation in mangrove sediments.

Diazotrophic microorganisms regulate marine productivity by alleviating nitrogen limitation. So far chemolithoautotrophic bacteria are widely recognized as the principal diazotrophs in oligotrophic marine and terrestrial ecosystems. However, the contribution of chemolithoautotrophs to nitrogen fixation in organic-rich habitats remains unclear. Here, we utilized metagenomic and metatranscriptomic approaches integrated with cultivation assays to investigate the diversity, distribution, and activity of diazotrophs residing in Zhangzhou mangrove sediments. Physicochemical assays show that the studied mangrove sediments are typical carbon-rich, sulfur-rich, nitrogen-limited, and low-redox marine ecosystems. These sediments host a wide phylogenetic variety of nitrogenase genes, including groups I-III and VII-VIII. Unexpectedly diverse chemolithoautotrophic taxa including Campylobacteria, Gammaproteobacteria, Zetaproteobacteria, and Thermodesulfovibrionia are the predominant and active nitrogen fixers in the 0-18cm sediment layer. In contrast, the 18-20cm layer is dominated by active diazotrophs from the chemolithoautotrophic taxa Desulfobacterota and Halobacteriota. Further analysis of MAGs shows that the main chemolithoautotrophs can fix nitrogen by coupling the oxidation of hydrogen, reduced sulfur, and iron, with the reduction of oxygen, nitrate, and sulfur. Culture experiments further demonstrate that members of chemolithoautotrophic Campylobacteria have the nitrogen-fixing capacity driven by hydrogen and sulfur oxidation. Activity measurements confirm that the diazotrophs inhabiting mangrove sediments preferentially drain energy from diverse reduced inorganic compounds other than from organics. Overall, our results suggest that chemolithoautotrophs rather than heterotrophs are dominant nitrogen fixers in mangrove sediments. This study underscores the significance of chemolithoautotrophs in carbon-dominant ecosystems.

Assessment of heavy metals at mangrove ecosystem, applying multiple approaches using in-situ and remote sensing techniques, Red Sea, Egypt.

Mangrove areas are considered the most retention zone for heavy metal pollution as it work as an edge that aggregates land and sea sediments. This study aims to examine if the heavy metals' existence in the mangrove sediment is related to contamination or natural resources. In addition, it gives an interpretation of the origin of these metals along the Egyptian Red Sea coast. Twenty-two samples of mangrove sediments were collected and then, analyzed for metals (Mn, Ni, Cu, Fe, Cd, Ag, and Pb) using inductively coupled plasma mass spectroscopy (ICP-MS). Integration between the in-situ data, contamination indices, and remote sensing and geographical information science (GIS), and multivariate statistical analysis techniques (PCA) were analyzed to assess and clarify the spatial origin of heavy metals in sediment at a regional scale. The average concentration of heavy metals from mangrove sediments were shown to be substantially lower than the referenced value, ranging from moderate to significant except the levels of Ag were very high. The heavy metals concentrations were expected to be naturally origin rather than anthropogenic and that be confirmed by mapping of Red Sea alteration zones spots. These alteration zones are parallel to mangrove sites and rich by several mineralization types including heavy metals that are carried by flooding to the coastline. Remote sensing and GIS techniques successfully contributed to interpreting the pattern of the origin of heavy metals and discharging systems that control the heavy metals concentration along the Red Sea coast.

Contributions of plant‐ and microbial‐derived residuals to mangrove soil carbon stocks: Implications for blue carbon sequestration

Abstract Coastal blue carbon ecosystems, particularly mangroves, are becoming increasingly recognised for their importance in mitigating climate change. Still, the specific patterns and drivers of plant lignin components and microbial necromass accumulation in these ecosystems are unclear. In response, we carried out a study along a 40‐year mangrove restoration chronosequence, measuring lignin phenol and amino sugar concentrations in soil profiles (0–100 cm) as indicators of plant‐based and microbial‐derived residues, respectively. Our results showed that restoration significantly increased plant lignin phenol and amino sugar concentrations, with mature mangroves having much higher concentrations than tidal flats. During restoration, the fungal necromass was greater than the bacterial necromass. The factors influencing the lignin phenols were tree biomass, total nitrogen, pH and salinity, while those influencing the formation of amino sugars were total biomass, soil C: N ratio and pH. While the amino sugars decreased, the lignin phenols increased with the content of SOC, providing evidence of the important role lignin phenol components play in the formation of SOC in mangrove. Synthesis: By separating soil carbon into plant‐based and microbial‐derived components, our results demonstrate that the carbon stock in mangrove sediments is vulnerable to disturbances and that changes from anaerobic to aerobic conditions cause significant carbon mineralisation. The precise identification of soil carbon sources in blue carbon ecosystems could aid in elucidating the mechanisms of soil carbon sequestration and their responses to environmental changes. Read the free Plain Language Summary for this article on the Journal blog.

Isolation and Characterization Morphology of Nitrogen-Fixing Bacteria from Mangrove Sediment

Mangrove ecosystems are coastal areas with ecological and socioeconomic functions. This area has a function as a nutrient provider for aquatic biota. The mangrove ecosystem also plays important role in nutrient cycling in coastal areas. The process of converting nitrogen into nutrients needed by plants (ammonium (NH4+) or nitrate (NO3+)) is called nitrogen fixation. The agents that play a role in this process are bacteria. The mangrove sediment has an abundant microbial communities which responsibility to this process. Sampling was carried out in the mangrove area of Tirang Beach, Semarang using the purposive sampling method. There are three sampling points, such as in the estuary, residential areas, and ponds. The isolation process was carried out using the spread plate method on solid NFB (Nitrogen Free Bromthymol) selective media, and purification using the quadrant streak plate method on the media. There are the most bacterial colonies in mangrove locations next to settlements, range from 2-11 bacterial colonies, and the least in mangrove locations near water bodies is 6 bacterial colonies. After purification, eight pure bacterial colonies have been identified and have similar morphological characteristics, white color, circular shape, entire margin, and flat elevation.

Estimation of carbon stocks in mangrove sediments in Ruyung Village, Mesjid Raya District, Aceh Besar Regency

Exploration related to blue carbon has increased recently. As one of the blue carbon ecosystems, the mangrove ecosystem is one of the coastal ecosystems that can absorb and store carbon. This research aims to calculate mangrove density and estimate carbon stocks in sediments in the mangrove ecosystem in Ruyung Village, Mesjid Raya District, Aceh Besar Regency. Mangrove density was calculated at three stations within 10 x 10 m transects. Sediment samples were also taken compositely, and carbon analysis was carried out in the sediment using the LOI (loss on ignition) method. There were two species of mangroves found at the research location, namely Rhizophora apiculata and Avicennia officionalis. The research results show that the average mangrove density at the research location is 0.20 ind/m2. The average soil density and sediment carbon stock at all research stations is 1.24 g/cm3 and 271.66 MgC/ha respectively. The mangrove ecosystem, both biomass and surrounding sediment, can store carbon, which is one of the ways to mitigate global warming.

Isolation screening and optimization of Laccase enzyme producing fungi from Mangrove sediment, Parangipettai

Isolation screening and optimization of Laccase enzyme producing fungi from Mangrove sediment, Parangipettai

Antibacterial, Antiaging, and Antiangiogenic Activity of Streptomyces sp. SAE4034 Extract from Mangrove Sediment

Antibacterial, Antiaging, and Antiangiogenic Activity of Streptomyces sp. SAE4034 Extract from Mangrove Sediment

First evidence of microplastic pollution in mangrove sediments and its ingestion by coral reef fish: Case study in Biawak Island, Indonesia

First evidence of microplastic pollution in mangrove sediments and its ingestion by coral reef fish: Case study in Biawak Island, Indonesia

Wonorejo mangrove indigenous bacteria: An insight into their potential as plastic-degrading agents

The use of bioplastic, such as polycaprolactone, to substitute conventional plastic remains a problem to solve. The bioplastic degradation time is still relatively low when compared to the rate of plastic consumption by the public. Therefore, exploration of indigenous bacteria with plastic-degrading potential is needed. This study aims to reveal the potential of indigenous bacteria isolated from Wonorejo Mangrove as plastic-degrading bacteria based on their growth in selective media and biofilm formation. Bacterial isolates obtained from water bodies and sediments of Wonorejo’s mangrove were inoculated on minimum salt media with the addition of 0.25% polycaprolactone as the sole carbon source and then incubated for four weeks to determine the bacterial growth based on its total number. The total number of bacteria was calculated by the direct counting method using a hemocytometer. The results indicated a slight decrease in the number of cells for each isolate. Isolate T1A.1 obtained from mangrove water samples encountered a decrease in the total number of bacteria by 2 times the initial number. Meanwhile, isolate T2.1, which was isolated from mangrove sediments, was decreased by 1.4 times from the initial number. However, the enumeration did not cover the cells that formed the biofilm, which was observed in this study. Based on the ability of the isolates to live in the minimum media and the biofilm formation indicated their potential as plastic-degrading agents, specifically for polycaprolactone. Identification and further studies of both isolates are needed to get a better insight into their potential as polycaprolactone-degrading agents.

A novel fibrinolytic enzyme producer from mangrove soil sediments: Screening, isolation, strain improvement, and fermentation

A novel fibrinolytic enzyme producer from mangrove soil sediments: Screening, isolation, strain improvement, and fermentation