Coastal Sites Research Articles

Evaluation of sediment contamination by macro and microplastics in coastal waters of Southern Mediterranean: a case study of Annaba, Algeria, before and after the COVID-19 pandemic

Plastic pollution in the hydrosphere ranks among the most pervasive environmental issues since the inception of the plastic industry and its widespread use in our daily lives. Nowadays, numerous countries worldwide suffer from this pollution not only along coastlines but also in deep-sea ecosystems. Our study carried out in the Gulf of Annaba aims to assess the prevalence and spatial distribution of plastic waste. Sampling was conducted at four coastal sites: El Battah, Seybousse, Rizzi Amor, and Ain Achir, both before and after the Covid-19 pandemic. The results reveal varying rates of macro and microplastic contamination, influenced by geographical differences, urban activities, and hydrodynamic factors. Moreover, the proportions of contamination depend on the types of waste. Furthermore, our study showed a clear divergence, particularly in two periods before and after the pandemic. Due to the lockdown, implemented in 2020, there was a marked decrease in the percentage of sediment plastic pollution, attributed to reduced human activity and partial cessation of industrial operations in these areas.

Atmospheric gaseous mercury and associated health risk assessment in the economic capital of India.

Mercury cycling in coastal metropolitan areas on the west coast of India becomes complex due to the combined effects of both intensive domestic anthropogenic emissions and marine air masses. The present study is based on yearlong data of continuous measurements of gaseous elemental mercury (GEM) concentration concurrent with meteorological parameters and some air pollutants at a coastal urban site in Mumbai, on the west coast of India, for the first time. The concentration of GEM was found in a range between 2.2 and 12.3ng/m3, with a mean of 3.1 ± 1.1ng/m3, which was significantly higher than the continental background values in the Northern Hemisphere (~ 1.5ng/m3). Unlike particulates, GEM starts increasing post-winter to peak during the monsoon and decrease towards winter. July had the highest concentration of GEM followed by October, and a minimum in January. GEM exhibited a distinct diurnal cycle, mainly with a broad peak in the early morning, a narrow one by nightfall, and a minimum in the afternoon. The peaks and their timing suggest the origin of urban mobility and the start of local activities. A positive correlation between SO2, PM2.5, temperature, relative humidity, and GEM indicates that emissions from local industrial plants in the Mumbai coastal area. Principal component analysis (PCA) and cluster analysis (CA) confirm this fact. Monthly back trajectory analysis showed that air mass flows are predominantly from the Arabian Sea and local human activities. Assessment of human health risks by USEPA model reveals that the hazardous quotient, HQ < 1, implies negligible carcinogenic risk. GEM observations in Mumbai during the study period are below the World Health Organization's (WHO) safe limit (200ng/m3) for long-term inhalation.

Ocean waves in the southwestern Atlantic Ocean: An evaluation of global wave models

AbstractIn situ wave observations are essential for implementing coastal management strategies, designing coastal and offshore structures and understanding many processes related to sedimentology and marine biology. Despite their importance, these observations are rather scarce in the coastal areas of southeastern South America. Moreover, the existing observations are discontinuous, with several gaps and no simultaneity. Today, global wave models have improved their performance by providing reliable wave parameters with high resolution and coverage even at near‐shore areas. In this work, wave parameters from five global models were compared with significant wave heights (HS), peak periods (T) and propagation direction at nine sites located at the Southwestern South Atlantic Ocean. The global products used were WAVERYS (Global Reanalysis Wav 001 032), IOWAGA (WAVEWATCH III Hindcast – WW3 – Global grid – CFSR), ERA5 (ECMWF reanalysis), NOAA WW3 – 30‐year Hindcast Phase 2 and NCEP/EMC Operational global wave model GFS – Wave. Mean arithmetic error (Bias), root mean square deviation, scatter index and the Pearson linear correlation coefficient (r) were assessed at each location where wave observations were available. The best agreements for HS were obtained at the deepest sites located farther from the coast. Lower statistical metrics were achieved at coastal sites where the bathymetry is roughly represented by the global models. The calculated correlation coefficients were found to be lower for T than for HS. Overall, T was slightly underestimated by global models. Wave propagation directions were excellently represented by global models at offshore sites. The WAVERYS model is the global product that best represents the wave parameters in the study area, probably due to its higher spatial resolution (0.2°) and more realistic atmospheric forcing (ERA5). In addition, it satisfactorily represents the temporal variability of HS in open water as well as swell characteristics at the outer the Río de la Plata.

New investigations in Gaza's heritage landscapes: the Gaza Maritime Archaeology Project (GAZAMAP)

Abstract Decades of conflict in the Gaza Strip have contributed to widely documented cultural heritage destruction, demonstrating a need to monitor vulnerable sites and enhance the empirical base. This article describes how the Gaza Maritime Archaeology Project (GAZAMAP 2022–2023) was developed to monitor coastal and near-coastal sites, collaboratively. Owing to the unprecedented destruction of heritage since October 2023, GAZAMAP's scope has fundamentally shifted.

The archaeology of shellfishing practices on Ua Huka, Marquesas Archipelago (French Polynesia)

AbstractShellfish remains are ubiquitous to coastal archaeological sites in the Marquesas but have seldom been the focus of dedicated investigations into their contribution to past diet and daily life. On the island of Ua Huka, in the northern group of the archipelago, people have consumed a variety of shellfish since their arrival on the island around the early 12th century AD. By analysing assemblages from five coastal sites spanning from the early settlement until the 18th century and using an archaeomalacological approach (precise taxonomic identification, coupled quantification methods, observation of taphonomic processes, biometry), we attempt to recount the exploitation processes of this resource, from the initial gathering stage to the final discarding of the shell. We further explore inter‐site and temporal variability in prey choice. Coupled with ethnographic accounts from European observers and insightful testimonies from current inhabitants of the island regarding present‐day practices, we highlight the persistence of choices regarding species selection, breakage patterns and cooking processes on an island that has seen major subsistence changes since European contact.

Tracking shifts in Society Islands marine subsistence through time: Intra‐site analysis of faunal remains and fishing gear

AbstractWe discuss new data from Colonization Phase and Early Expansion/Development Phase assemblages in the pre‐contact Society Islands. We focus on analysis of marine faunal remains and fishing gear to infer diachronic shifts in subsistence practices at two well‐dated coastal sites. Both Colonization Phase (AD 950–1200) and Early Expansion Phase (AD 1200–1450) faunal assemblages are dominated by fish and mollusks as opposed to animal domesticates. Colonization Phase assemblages see higher capture of Scombrids and higher capture of marine mammals and turtle. Early Expansion fishhook assemblages and faunal remains document a movement towards increased capture of reef fish as well as the adoption of local styles and locally specific fishing practices. Overall, the diachronic trend in the Society Island diets is towards a decrease in turtle, marine mammal, and wild bird remains and an increase in terrestrial domesticated species roughly two hundred years after colonization, similar to patterns seen elsewhere in Eastern Polynesia.

Doing landscape: sensorial and artistic approaches to Donkalnis and Spiginas Mesolithic–Neolithic ritual sites in western Lithuania

ABSTRACT During the Mesolithic and Neolithic, foragers dwelling in the Eastern Baltic, Scandinavia and Fennoscandia regions buried some of their dead on lake islands or other coastal sites. Based on ethnographic accounts, these sites are often understood as liminal places where water separates the lands of the dead and the living. In this paper, we take a more relational view of place and suggest that a particular combination of spatial perception of landscape and the dynamic nature of coastal sites might have contributed to the social agency of these places, resulting in their use as places for ritual activity. By exploring two Mesolithic–Neolithic burial places, Donkalnis and Spiginas (western Lithuania), with sensory archaeological and artistic approaches, we suggest that the ancient foragers of this region buried human bodies in these locations to be part of the place itself. Similar to other depositional acts, this could have been done to mark the location or communicate with the surrounding world.

An inverse model to correct for the effects of post-depositional processing on ice-core nitrate and its isotopes: model framework and applications at Summit, Greenland, and Dome C, Antarctica

Abstract. Comprehensive evaluation of the effects of post-depositional processing is a prerequisite for appropriately interpreting ice-core records of nitrate concentration and isotopes. In this study, we developed an inverse model that uses archived snow/ice-core nitrate signals to reconstruct primary nitrate flux (i.e., the deposition flux of nitrate to surface snow that originates from long-range transport or stratospheric input) and its isotopes (δ15N and Δ17O). The model was then applied to two polar sites, Summit, Greenland, and Dome C, Antarctica, using measured snowpack nitrate concentration and isotope profiles in the top few meters. At Summit, the model successfully reproduced the observed atmospheric δ15N(NO3-) and Δ17O(NO3-) and their seasonality. The model was also able to reasonably reproduce the observed snowpack nitrate profiles at Dome C as well as the skin layer and atmospheric δ15N(NO3-) and Δ17O(NO3-) at the annual scale. The calculated Fpri at Summit was 6.9 × 10−6 kgN m2 a−1, and the calculated Δ17O(NO3-) of Fpri is consistent with atmospheric observations in the Northern Hemisphere. However, the calculated δ15N(NO3-) of Fpri displays an opposite seasonal pattern to atmospheric observations in the northern mid-latitudes, but it is consistent with observations in two Arctic coastal sites. The calculated Fpri at Dome C varies from 1.5 to 2.2 × 10−6 kgN m−2 a−1, with δ15N(NO3-) of Fpri varying from 6.2 ‰ to 29.3 ‰ and Δ17O(NO3-) of Fpri varying from 48.8 ‰ to 52.6 ‰. The calculated Fpri at Dome C is close to the previous estimated stratospheric denitrification flux in Antarctica, and the high δ15N(NO3-) and Δ17O(NO3-) of Fpri at Dome C also point towards the dominant role of stratospheric origin of primary nitrate to Dome C.

Where the wild things aren’t: exploring the utility of rapid, small-scale translocations to improve site selection for shellfish restoration

The assessment of site suitability is a crucial step for informing future successful species reintroductions. It ensures that translocated species have the highest chance of survival in their new environment while minimising ecological risks. However, it can be challenging when risk factors are unknown, especially when working with sessile species that cannot easily relocate to more favourable conditions. Under these scenarios, rapid (1-2 week-long), small-scale (&amp;lt; 1 m2) experimental translocations can help reduce uncertainty and improve restoration outcomes. This study conducted small-scale experimental translocations of green-lipped mussels, Perna canaliculus, to 11 shallow coastal sites spread across Tīkapa Moana/the Hauraki Gulf, Aotearoa/New Zealand to investigate the relationship between predator abundance, environmental factors, and mussel loss to help refine existing site selection criteria. The total number of known mussel predators counted from timelapse images was used as a proxy for potential predator pressure. Translocated mussel survival ranged from 10 - 99% and was best predicted by current speed, wind direction, predator abundance, water clarity, and depth (adjusted R2 = 0.505). Predator abundance was best explained by site location (p = 0.001) and had weak correlations among environmental parameters (Rho = 0.067). These results suggest that small, short-term (1-2 week) experimental translocations can help to refine site selection criteria and reduce uncertainty in the site-selection process for larger-scale shellfish reintroduction efforts with unknown and/or hard-to-control risk factors.

SGD-OD: investigating the potential oxygen demand of submarine groundwater discharge in coastal systems

Submarine groundwater discharge (SGD) supplies nutrients, carbon, metals, and radionuclide tracers to estuarine and coastal waters. One aspect of SGD that is poorly recognized is its direct effect on dissolved oxygen (DO) demand in receiving waters, denoted here as SGD-OD. Sulfate-mediated oxidation of organic matter in salty coastal aquifers produces numerous reduced byproducts including sulfide, ammonia, dissolved organic carbon and nitrogen, methane, and reduced metals. When these byproducts are introduced to estuarine and coastal systems by SGD and are oxidized, they may substantially reduce the DO concentration in receiving waters and impact organisms living there. We consider six estuarine and coastal sites where SGD derived fluxes of reduced byproducts are well documented. Using data from these sites we present a semiquantitative model to estimate the effect of these byproducts on DO in the receiving waters. Without continued aeration with atmospheric oxygen, the study sites would have experienced periodic hypoxic conditions due to SGD-OD. The presence of H2S supplied by SGD could also impact organisms. This process is likely prevalent in other systems worldwide.

Tasmanian devil (Sarcophilus harrisii) gene flow and source-sink dynamics

Increased access to genetic data has substantially improved how we manage threatened species. The Tasmanian devil (Sarcophilus harrisii) is listed as endangered due to the ongoing threat of a highly contagious cancer, devil facial tumour disease (DFTD), causing more than 80% population reductions. To assist future management interventions (e.g. releases into wild sites) we expanded upon previous studies of gene flow for the devil by assessing more recent and broad-scale patterns. We use genome-wide single nucleotide polymorphisms generated via DArTSeq across 21 devil sites to delineate source-sink dynamics across the species’ range. Our findings revealed gene flow is stronger on the northeast and central regions of Tasmania, with high rates of bidirectional gene flow among central sites. The northwest exhibits weaker connectivity relative to other regions of Tasmania, while gene flow appears to be non-existent between the southwest and other areas. Northeast coastal sites tend to serve as ‘sources’ for inland central sites, whereas gene flow appears restricted to the coastline in the northwest. These results are consistent with genetic structure of devil sites and spatial spread of DFTD, which has yet to arrive in the southwest region of Tasmania. Southwest isolation is probably due to mountain ranges and lack of roadways. Interestingly, some waterbodies did not appear to restrict devil movement among sites. Conversely, areas of high elevation act as apparent barriers, as evidenced by limited gene flow observed between eastern and western sites. Integrating source-sink dynamics into conservation management planning will be crucial in developing effective strategies to safeguard the Tasmanian devil and other threatened species facing similar threats (i.e. disease, habitat loss).

Ethanol, acetaldehyde, and methanol in the gas phase and rainwater in different biomes and urban regions of Brazil

In the context of the increasing global use of ethanol biofuel, this work investigates the concentrations of ethanol, methanol, and acetaldehyde, in both the gaseous phase and rainwater, across six diverse urban regions and biomes in Brazil, a country where ethanol accounts for nearly half the light-duty vehicular fuel consumption. Atmospheric ethanol median concentrations in São Paulo (SP) (12.3 ± 12.1 ppbv) and Ribeirão Preto (RP) (12.1 ± 10.9 ppbv) were remarkably close, despite the SP vehicular fleet being ∼13 times larger. Likewise, the rainwater VWM ethanol concentration in SP (4.64 ± 0.38 μmol L−1) was only 26 % higher than in RP (3.42 ± 0.13 μmol L−1). This work demonstrated the importance of evaporative emissions, together with biomass burning, as sources of the compounds studied. The importance of biogenic emissions of methanol during forest flooding was identified in campaigns in the Amazon and Atlantic forests. Marine air masses arriving at a coastal site led to the lowest concentrations of ethanol measured in this work. Besides vehicular and biomass burning emissions, secondary formation of acetaldehyde by photochemical reactions may be relevant in urban and non-urban regions. The combined deposition flux of ethanol and methanol was 6.2 kg ha−1 year−1, avoiding oxidation to the corresponding and more toxic aldehydes. Considering the species determined here, the ozone formation potential (OFP) in RP was around two-fold higher than in SP, further evidencing the importance of emissions from regional distilleries and biomass burning, in addition to vehicles. At the forest and coastal sites, the OFP was approximately 5 times lower than at the urban sites. Our work evidenced that transition from gasoline to ethanol or ethanol blends brings the associated risk of increasing the concentrations of highly toxic aldehydes and ozone, potentially impacting the atmosphere and threatening air quality and human health in urban areas.

Marine Microorganisms as Potential Source of Quorum-Sensing Inhibitory Compounds

Antibiotics are extensively utilized globally, and the rate of antibiotic resistance is increasing more rapidly than ever. Since the introduction of antibiotics, the overuse of antibiotics caused selection pressure, and almost all pathogenic bacteria have developed resistance against commonly used antibiotics, which is particularly known as antimicrobial resistance (AMR). It has proven challenging to combat and resolve the issue of microbial resistance. A growing number of microorganisms have developed different resistance mechanisms and turned into "superbugs". The identification of quorum-sensing systems has given researchers a new hope for understanding drug resistance processes. The quorum-sensing system controls a number of cellular functions, including the expression of pathogenic genes, the synthesis of toxins, and the synthesis of extracellular polysaccharides. To targeting QS systems marine bacterial samples were collected by different coastal sites of Gujarat, like Mandvi, Dwarka and Diu. A total of 52 marine isolates were obtained, out of which 16 were associated with various marine macro-organisms like sponges and algae, whereas 36 were free-living. The study has done by screening those marine isolates shown potential to inhibiting the quorum sensing molecule by co culture study against Chromobacter violaceium, followed by growth inhibition assay. The G14 and G82 isolate shows highest degradation of N-acyl homoserine lactone by AHL study. The QSI compounds were extracted using ethyl acetate extraction method. Biofilm inhibition assay with Pseudomonas aeruginosa shows potent inhibitory effect of extract. These results prove that marine microorganism have potential to inhibits quorum sensing and virulence factors regulated by Quorum Sensing phenomenon.

Reference monopile designs for US East Coast sites supporting the IEA 15 MW reference turbine using a novel conceptual design methodology

A novel conceptual design methodology was developed and implemented to design twelve reference monopile foundations, compatible with the IEA 15 MW reference turbine. The designs are position-specific, corresponding to planned, US East Coast, wind energy development areas. The monopiles were designed considering the fatigue limit state (FLS), ultimate limit state (ULS), serviceability limit state (SLS), and natural frequency analysis (NFA), following an intentionally reduced subset of design load cases (DLCs) in IEC 61400-3-1. In 11 of 12 cases, the diameter and wall thicknesses of the monopile foundations were found to be determined by FLS criteria. The exception was one position subjected to a combination of breaking waves and a large significant wave height. For the 11 positions governed entirely by FLS, the maximum ULS utilization ratios varied between 0.63 and 0.81, indicating significant reserve capacity for the ultimate limit state. Fatigue damage during turbine idling was found to be an important contributor to lifetime fatigue damage, despite having a relatively small probability of occurrence. The novel design methodology described herein includes a preliminary FLS assessment step, which was found to be an efficient way to select an initial foundation geometry, while providing a 92% improvement in computational efficiency.

Phytochemical Composition, Antioxidant and Antifungal Activity of Essential Oils and Crude Extracts of &lt;em&gt;Dittrichia viscosa maritime&lt;/em&gt; (L.), an Aromatic and Medicinal Plant from Northern Morocco

Dittrichia viscosa, a perennial herb belonging to the Asteraceae family, was collected in a coastal site located in northern Morocco. This study focused on exploring the phytochemical composition and biological activities of essential oils (EOs) and solvents (methanol and acetone) extract of leaves, stems, and flowers. Total phenolic (TPC) and total flavonoid (TFC) contents were determined, and the result showed a high level of TPC and TFC in leaves with the values of 127.61 mg GAEs/g and 117.82 mg CEs/g, respectively. HPLC-MS analysis highlighted 18 phenolic acids and flavonoids, with notable quantities of apigenin 7-glucoside (2233 μg/g) and chlorogenic acid (1429 μg/g). GC‒MS analysis of EOs allowed the identification of 27 biologically active compounds, dominated by decanoic acid (20.98%) and toluene (19.66%). Regarding the biological activities, antioxidant activity was evaluated through the DPPH test, while antifungal activity was tested using the microdilution method. The most potent antioxidant effect was observed in the methanol extract of leaves, with a value of 0.18 mg/mL, while the weakest effect was noted in the acetone extract of flowers, registering a value of 1.63 mg/mL. Similarly, the antioxidant activity of methanolic extracts surpassed that of acetonic extracts in each part of D. viscosa. Concerning antifungal activity, the findings reveal that all extracts demonstrated important capacity against the tested pathogens. The methanolic extract displayed high efficacy compared to the acetonic one, with MFC values ranging between 1.94-3.38 mg/mL and 2.88-4.75 for Candida albicans, Aspergillus niger and Trichophyton rubrum, respectively. However, for Fusarium oxysporum f. sp. albedinis, the MFCs were higher (7.5-8.5 mg/mL). Regarding EOs, the MFCs were more favorable for the three human pathogenic fungi, ranging between 1.88 and 3.35 µL/mL, compared to F. oxysporum, which has an MFCs of 3.5 µL/mL. In summary, the findings demonstrated that D. viscosa could be considered a useful alternative and reliable source of bioactive compounds for the pharmaceutical and agricultural industries.

Large-Scale Re-Implantation Efforts for Posidonia oceanica Restoration in the Ligurian Sea: Progress and Challenges

The Ligurian Sea (NW Mediterranean) has been a focal point for numerous interventions aimed at restoring Posidonia oceanica meadows. The success of pioneer restoration actions in France during the 1970s stimulated similar initiatives across the Mediterranean Sea. Early attempts in the Ligurian Sea were implemented in 1993 and 1996 on limited seabed areas (i.e., tens of square meters) at the two coastal sites of Sori and Rapallo (Liguria, NW Italy). No further initiatives have been reported for the Ligurian Sea until 2022. In that year, a large-scale restoration project, which uses biodegradable mats coupled with metal mesh, began in Liguria. Different levels of anthropogenic pressure and wave exposure characterize the three investigated locations: (1) Portofino, on the eastern Liguria and on the border with the Portofino Marine Protected Area; (2) Bergeggi in the central Liguria and within the Isola di Bergeggi Marine Protected Area; and (3) Sanremo in the western Liguria, without any formal protection. Despite recent setbacks caused by severe storms in late 2023, which particularly damaged the Portofino site, ongoing monitoring revealed promising survival rates. Most notably, the site in Bergeggi displayed a 90% survival rate in September 2023. Although challenges to restore P. oceanica beds persist, such as mitigating damages caused by unpredictable events, this extensive re-implantation initiative offers the opportunity to evaluate the effectiveness of new basin-scale restoration strategies. This approach marks an important step in the conservation of Posidonia oceanica habitat.

A set of guidelines as support for the integrated geo-environmental characterization of highly contaminated coastal sites.

The knowledge of geomorphodynamic aspects is crucial for understanding marine and coastal processes/dynamics as well as for characterizing coastal environments heavily affected by anthropogenic activities. To provide a framework of analysis that can be applied in a consistent way for the geo-environmental characterization of highly contaminated coastal sites, in this paper a set of operational guidelines is proposed. Special attention is given to the role of geomorphological-based surveys and analyses in defining (i) the site-specific geological model of the investigated site, (ii) the anthropogenic impacts on marine and coastal sediments, (iii) the expected morphodynamic variations induced by climate change and anthropogenic interventions, (iv) tailored dissemination activities and community engagement plans. Then, an evaluation of the state of the art of activities already performed for the characterization of the coastal contaminated sites located in the Apulia region (southern Italy) is provided. The outcomes of this research are also provided in the form of infographics to favor their dissemination among communities and stakeholders.

French coastal network for carbonate system monitoring: the CocoriCO2 dataset

Abstract. Since the beginning of the industrial revolution, atmospheric carbon dioxide (CO2) concentrations have risen steadily and have induced a decrease of the averaged surface ocean pH by 0.1 units, corresponding to an increase in ocean acidity of about 30 %. In addition to ocean warming, ocean acidification poses a tremendous challenge to some marine organisms, especially calcifiers. The need for long-term oceanic observations of pH and temperature is a key element to assess the vulnerability of marine communities and ecosystems to these pressures. Nearshore productive environments, where a large majority of shellfish farming activities are conducted, are known to present pH levels as well as amplitudes of daily and seasonal variations that are much larger than those observed in the open ocean. Yet, to date, there are very few coastal observation sites where these parameters are measured simultaneously and at high frequency. To bridge this gap, an observation network was initiated in 2021 in the framework of the CocoriCO2 project. Six sites were selected along the French Atlantic and Mediterranean coastlines based on their importance in terms of shellfish production and the presence of high- and low-frequency monitoring activities. At each site, autonomous pH sensors were deployed, both inside and outside shellfish production areas, next to high-frequency CTD (conductivity–temperature–depth) probes operated through two operating monitoring networks. pH sensors were set to an acquisition rate of 15 min, and discrete seawater samples were collected biweekly in order to control the quality of pH data (laboratory spectrophotometric measurements) as well as to measure total alkalinity and dissolved inorganic carbon concentrations for full characterization of the carbonate system. While this network has been up and running for more than 2 years, the acquired dataset has already revealed important differences in terms of pH variations between monitored sites related to the influence of diverse processes (freshwater inputs, tides, temperature, biological processes). Data are available at https://doi.org/10.17882/96982 (Petton et al., 2023a).

Carbon fluxes of China's coastal wetlands and impacts of reclamation and restoration.

Coastal wetlands play an important role in regulating atmospheric carbon dioxide (CO2) concentrations and contribute significantly to climate change mitigation. However, climate change, reclamation, and restoration have been causing substantial changes in coastal wetland areas and carbon exchange in China during recent decades. Here we compiled a carbon flux database consisting of 15 coastal wetland sites to assess the magnitude, patterns, and drivers of carbon fluxes and to compare fluxes among contrasting natural, disturbed, and restored wetlands. The natural coastal wetlands have the average net ecosystem exchange of CO2 (NEE) of -577 g C m-2 year-1, with -821 g C m-2 year-1 for mangrove forests and -430 g C m-2 year-1 for salt marshes. There are pronounced latitudinal patterns for carbon dioxide exchange of natural coastal wetlands: NEE increased whereas gross primary production (GPP) and respiration of ecosystem decreased with increasing latitude. Distinct environmental factors drive annual variations of GPP between mangroves and salt marshes; temperature was the dominant controlling factor in salt marshes, while temperature, precipitation, and solar radiation were co-dominant in mangroves. Meanwhile, both anthropogenic reclamation and restoration had substantial effects on coastal wetland carbon fluxes, and the effect of the anthropogenic perturbation in mangroves was more extensive than that in salt marshes. Furthermore, from 1980 to 2020, anthropogenic reclamation of China's coastal wetlands caused a carbon loss of ~3720 Gg C, while the mangrove restoration project during the period of 2021-2025 may switch restored coastal wetlands from a carbon source to carbon sink with a net carbon gain of 73 Gg C. The comparison of carbon fluxes among these coastal wetlands can improve our understanding of how anthropogenic perturbation can affect the potentials of coastal blue carbon in China, which has implications for informing conservation and restoration strategies and efforts of coastal wetlands.

Kalba: research on trade networks of a prehistoric coastal community on the Gulf of Oman, United Arab Emirates

Kalba: research on trade networks of a prehistoric coastal community on the Gulf of Oman, United Arab Emirates