Lagoon Water Research Articles

Surviving in a warming and crowded world: a review of Irrawaddy dolphin in Asia’s largest brackish water lagoon

Surviving in a warming and crowded world: a review of Irrawaddy dolphin in Asia’s largest brackish water lagoon

Is the Plant Bolboschoenus maritimus an Adequate Biomonitor for Trace Metal Contamination in Saltmarshes? A Field Study from the Óbidos Lagoon (Portugal)

Monitoring the negative impacts of trace metals is crucial to assess the health and stability of ecosystems. In salt marshes, halophyte plants were reported as possible bioaccumulators of these elements. The aim of this work was to explore the bioaccumulation potential of Bolboschoenus maritimus as a tool for monitoring the presence of metals in coastal environments. Bolboschoenus maritimus were collected from a brackish water lagoon, and the presence of the trace metals lead, cadmium, and nickel were seasonally evaluated in distinct parts of the plants, and in water and sediment samples. Lead was the trace metal with the highest concentration detected in water and sediments of the sampling site. The highest lead concentrations in B. maritimus were recorded in the spring season. The transport index indicated an accumulation of lead in the leaves of around 70% in the spring of 2009. Cadmium in leaves in spring and summer of 2009 reached values above 5 mg Cd. kg−1. Nickel was not detected in most samples collected. Bolboschoenus maritimus was considered an adequate biomonitor for lead and cadmium, since it bioaccumulates both metals with seasonally distinct results, as the bioaccumulation factor results indicated.

Microplastics in Indian Brackish Water Lagoon: Occurrence and Distribution in the Chilika Lake

Microplastics in Indian Brackish Water Lagoon: Occurrence and Distribution in the Chilika Lake

Wind-modulated groundwater discharge along a microtidal Arctic coastline

Groundwater discharge transports dissolved constituents to the ocean, affecting coastal carbon budgets and water quality. However, the magnitude and mechanisms of groundwater exchange along rapidly transitioning Arctic coastlines are largely unknown due to limited observations. Here, using first-of-its-kind coastal Arctic groundwater timeseries data, we evaluate the magnitude and drivers of groundwater discharge to Alaska’s Beaufort Sea coast. Darcy flux calculations reveal temporally variable groundwater fluxes, ranging from −6.5 cm d−1 (recharge) to 14.1 cm d−1 (discharge), with fluctuations in groundwater discharge or aquifer recharge over diurnal and multiday timescales during the open-water season. The average flux during the monitoring period of 4.9 cm d−1 is in line with previous estimates, but the maximum discharge exceeds previous estimates by over an order-of-magnitude. While the diurnal fluctuations are small due to the microtidal conditions, multiday variability is large and drives sustained periods of aquifer recharge and groundwater discharge. Results show that wind-driven lagoon water level changes are the dominant mechanism of fluctuations in land–sea hydraulic head gradients and, in turn, groundwater discharge. Given the microtidal conditions, low topographic relief, and limited rainfall along the Beaufort Sea coast, we identify wind as an important forcing mechanism of coastal groundwater discharge and aquifer recharge with implications for nearshore biogeochemistry. This study provides insights into groundwater flux dynamics along this coastline over time and highlights an oft overlooked discharge and circulation mechanism with implications towards refining solute export estimates to coastal Arctic waters.

NUMERICAL MODELING OF BAR-BUILT ESTUARIES AND IMPLICATIONS FOR THE MANAGEMENT OF INTERMITTENT INLETS

Bar-built estuaries are common in tropical and temperate regions, accounting for nearly 3 percent of the estuaries throughout the world (McSweeney et al. 2017). Bar-built estuaries tend to have intermittent inlets that can open from the estuary side outward in regions with seasonal changes in river discharge (Kraus et al., 2008; Orescanin and Scooler 2018). It is well known that intermittent inlet dynamics primarily depend on the interplay between wave energy and inlet discharge driven by lagoon water levels (Rich and Keller, 2013). Forcing processes are generally understood, however, less is known about their interaction or thresholds, which is ultimately what drives the closure of intermittent inlets. The aim of this study is to explore numerical modeling techniques and parameters to simulate the hydrodynamics and closure of intermittent inlets in bar-built estuaries. Increasing the understanding of the conditions that lead to closing of intermittent inlets would allow for improved flood, sediment, and water quality management in the communities surrounding bar-built estuaries.

ON-REEF CYCLONIC WAVE CLIMATE THROUGHOUT THE GREAT BARRIER REEF

The Great Barrier Reef is an iconic ecosystem that is collapsing under low lagoon water quality from terrestrial runoff and resulting overly productive crown-of-thorns starfish, coral bleaching from thermal stress and physical destruction from tropical cyclones, to name the top four stresses. This collapsing is mostly seen in coral coverage declining over time from water quality and starfish stresses combined with episodic large scale drops from thermal stress and tropical cyclones. Action on improved land use would decrease the impact from water quality and starfish and action on climate change would reduce thermal stresses and hence, the frequency of bleaching events. Tropical cyclone impacts, while they may be getting more intense or larger under climate change, their destructive power is significant either way (i.e., before and after climate changes). These stresses have led to the administrative body, the Great Barrier Reef Marine Park Authority, to shift from passive management to active interventions, which are generally extremely costly compared to the income generated by the Great Barrier Reef. Consequently, to ensure the limited resources are deployed to obtained maximum benefit, interventions are being tested across all stresses including cyclonic stresses. This requires fine scale determination of cyclonic wave climates across the entire Great Barrier Reef.

Pollution status determination using trace metals and organic contaminants of the water column in coastal areas of the Red Sea and the Gulf of Aqaba: A baseline assessment

Herein, we aim to provide a baseline assessment of the pollution status of the water column in coastal areas of Saudi Arabia (Red Sea and the Gulf of Aqaba), using trace metals (Cd, Co, Cr, Cu, Ni, Pb and Zn), total petroleum hydrocarbons (TPHs) and polycyclic aromatic hydrocarbons (PAHs), in seawater samples obtained from 71 sampling stations in June–July 2021. Concerning trace metals, the maximum concentrations for Co, Cu and Ni were detected in Al-Shuqaiq, whereas the highest Pb and Zn concentrations were found in the Jeddah lagoon waters. Elevated concentrations of TPHs and the highest sum of PAHs were recorded in surface waters of Al Lith, Jeddah lagoon and Jeddah Mena. Overall, the concentrations of all trace metals, TPHs and individual PAHs for which environmental standards have been stipulated for the Kingdom of Saudi Arabia fall well below the threshold values.

Assessment of benthic habitats of highly threatened oyster reefs of Pulicat Lake, India

The present study was aimed at demarcating the distribution of oyster habitats along the Pulicat Lake, the second largest brackish water lagoon in India, and investigating their benthic faunal assemblages and functional feeding groups. This study delineated three major reefs (6.70 ha, 5.50 ha, and 2.39 ha areas), and two minor beds (1.10 ha and 0.68 ha areas). Four species of oysters, namely, Magallana bilineata, Saccostrea cuccullata, Isognomon ephippium and Pinctada imbricata fucata were found in the oyster habitats, with M. bilineata being a major reef-forming/ecosystem forming species. Macrofaunal assemblages in the oyster habitats comprised 71 species representing five major phyla belonging to 66 genera under 48 families. Macrofauna were grouped into five Functional Feeding Groups (FFG) considering oyster habitats as a primary food provider. The FFG analysis revealed that the oyster reef/bed in Pulicat Lake is in moderate Ecological Quality Status (EQS). This study is considered very important to know the current extent of oyster reefs and gain a better understanding of the community interactions within oyster habitats and their ecological value to the dwelling species.

Winter spring assemblage pattern of harpacticoid copepods from lagoon waters of Agatti and Kavaratti, Lakshadweep islands, southeastern Arabian Sea

Winter spring assemblage pattern of harpacticoid copepods from lagoon waters of Agatti and Kavaratti, Lakshadweep islands, southeastern Arabian Sea

Benthic fluxes and mineralization processes at the scale of a coastal lagoon: Permeable versus fine-grained sediment contribution

Benthic fluxes of biogenic compounds play a major role in the biogeochemistry of shallow aquatic environments. Quantifying these fluxes at the scale of a lagoon is a challenge, especially when sediments are heterogeneous and fluxes at the sediment-water interface combine diffusive and advective transport processes. Diagenetic processes and associated benthic fluxes were quantified across different seasons in a lagoon of the French Mediterranean coast (La Palme lagoon) from vertical profiles of pore water and sedimentary solid fraction carried out at many representative stations of the lagoon. The northwestern part of the lagoon is covered with fine-grained sediment with low permeability and the rest of the lagoon contains permeable sandy sediment. We obtained vertical profiles with centimetre-scale resolution of water content, salinity, and major particulate and dissolved biogenic compounds of C, N, P, Si, S, Fe and Mn. This study allowed us to refine the sedimentary mapping of the lagoon, to specify the spatio-temporal evolution of biogeochemical processes, and to determine more precisely the part of the diffusive fluxes of nutrient compared to advective fluxes. Comparison of the vertical profiles with a molecular diffusion transport model shows that molecular diffusion is the dominant process in fine-grained sediments, while sandy sediments are dominated by advection due to circulation of lagoon water in shallow sediments. Benthic respiration renders fine-grained and sandy sediments anoxic from the first few mm below the sediment-water interface, particularly due to the availability of labile organic matter. Benthic dissolved inorganic nitrogen fluxes are of the same order of magnitude in both sediment types, despite the different flux mechanisms. This suggests that the intensity of organic matter mineralization processes is the same in fine and sandy sediments. Benthic phosphate fluxes are greater in sandy than in fine sediments because phosphorus is more efficiently retained in the solid fraction of fine sediments. Thus, sandy sediments play a dominant role in the pelagic-benthic coupling of the lagoon.

Degradation of crude oil by the microbial populations of Lagos and Ologe lagoon waters

Introduction: hydrocarbon contamination of surface waters as a result of anthropogenic activity poses threat to ecosystems and counter their beneficial uses. Some indigenous microbial communities have the potential to purify such waters unaided. Aims: To show the biodegradative potential of microbial communities in Lagos and Ologe Lagoons during minimal pollution with crude oil. Materials and Methods: The total heterotrophic bacteria and hydrocarbon utilising bacterial and fungal populations were estimated from Lagos and Ologe lagoon water samples contaminated with 1% crude oil over 42-day incubation period by plate count and vapour-phase transfer techniques. Residual hydrocarbons were determined by Gas chromatography. Results: The predominant bacterial genera identified from the lagoons include Enterobacter, Klebsiella and Proteus, while Escherichia, and Morganella. Aspergillus and Mucor were the predominant fungal genera in both waters. The hydrocarbon degradation rate in the Lagos Island microcosm was 65.391±0.370 mg/l/d, degradation rate constant 0.05±0.01 /d, half-life 9.559±0.093 /d and percentage degradation of 95.315 ± 0.134. Corresponding values in the Ologe water were 61.190± 8.542 mg/l/d, 8.725 ±0.389 /d, 0.055±0.003/d and 96.345±0.488 respectively. There was almost complete disappearance of the various fractions of the oil in the two samples. The microbial communities from both lagoons effectively utilised majority of the hydrocarbon fractions after 42 days where 66.890±1.075 and 100±000 were recorded for benzene, toluene had 100±000 percent degradation, anthracene 96.755±0.119 and 99.726±0.026, and pristane had 91.674±0.222 and 99.943±0.015 while phytane had 96.44±0.058 and 99.670±0.104 respectively. Conclusion: Efficient biodegradation of moderate contamination crude oil could be achieved by indigenous microbial flora present in Lagos and Ologe lagoon waters.

Fishing methods, catches composition and exploited biomass in the Aby lagoon (Adiaké, Côte d’Ivoire)

Ivorian lagoon water bodies contribute to the fight against food insecurity through fisheries. They provide fresh and competitive products to the local population. Thereby, strategies for their rational and sustainable exploitation must be put in place. This study aimed at contributing to the improvement of fishing activities in the Aby lagoon. It is the result of three months of surveys (from January to March 2020) with the fishermen and the fisheries administration. It appears that fishing is practiced by indigenous peoples. The most represented were aged over 45 years old (71.30%). Gillnets (65.59%) and nailed plank canoes (67%) were the most used. However, Aly nets (5.63% of fishing gears types) remain the most productive providing 80% of catches. The main fish species recorded were Ethmalosa fimbriata (Clupeidae), Elops lacerta (Elopidae) and Sarotherodon melanotheron (Cichlidae). However, the effective management of the water body still remains a major concern. Indeed, constraints were mainly: the non-submission of individual fishermen to the fisheries administration, the struggle for space reserved for fishing between individual and collective fishermen, the use of non-selective gears such as the Aly net. Thus, it seems necessary to train and sensitize the actors on the concept of sustainable development and to apply the management rules for a rational exploitation of this fishery.

Estimation of nitrogen and phosphorus fluxes into a Barrier Island lagoon via meteoric groundwater discharge

Meteoric groundwater discharge (MGD) to coastal regions transports terrestrial freshwater and nutrients that may alter coastal ecosystems by supporting harmful algal blooms. Estimation of MGD-driven nutrients is crucial to assess potential effects on coastal zones. These estimates require a reliable assessment of MGD rates and pore water nutrient concentrations below subterranean estuaries. To estimate nutrient delivery into a subterranean estuary in the Indian River Lagoon, FL., pore water and surface water samples were collected from nested piezometers along a selected transect on five sampling episodes. Groundwater hydraulic head and salinity were measured in thirteen onshore and offshore piezometers. Numerical models were developed, calibrated, and validated using SEAWAT to simulate MGD flow rates. Lagoon surface water salinity exhibits no spatial but mild temporal variation between 21 and 31. Pore water salinity shows tremendous variation in time and space throughout the transect except in the middle region of the lagoon which exhibits uniform but elevated salinities up to 40. Pore water salinity as low as that of freshwater happens to occur in the shoreline regions during most of the sampling episodes. Both pore water and surface water show remarkably higher total nitrogen TN than total phosphorus TP concentrations and most TN is exported as NH4, reflecting the effect of mangroves on the geochemical reactions that reduce NO3 into NH4. Nutrient contributions of pore water and lagoon water exceed the Redfield TN/TP molar ratio in all sampling trips by up to a factor of 48 and 4, respectively. Estimated TP and TN fluxes receives by the lagoon via MGD are 41–106 and 113–1478 mg/d/m of shoreline. The molar TN/TP ratio of nutrient fluxes exceeds the Redfield ratio by a factor of up to 3.5 which indicates the potential of MGD-driven nutrients to alter the lagoon water quality and support harmful algal blooms.

Irrawaddy dolphin in Asia's largest brackish water lagoon: A perspective from SWOT and sentiment analysis for sustainable ecotourism

Chilika, the largest brackish water lagoon in Asia, is a habitat of the Irrawaddy Dolphin (IRD) and a popular tourist destination for dolphin watching. However, this dolphin-based tourism has turned unsustainable due to the adverse impacts of tourism on IRD. This study uses SWOT (strengths, weaknesses, opportunities, threats) to analyze various internal and external factors that control IRD-based tourism in Chilika. Content analysis and sentiment analysis are also used to know the tourists' views regarding dolphin tourism in Chilika lagoon, and telephonic interviews with boat owners to determine the impact of tourism on local communities before and after the COVID-19 pandemic. SWOT analysis highlights existing opportunities and strengths of IRD tourism in Chilika, such as prevalent ‘positive’ perception (48%) among the tourists and stable IRD population. 38% of tourists' perceptions were ‘negative,’ corroborating inherent weaknesses and threats of IRD tourism, such as faulty marketing strategy, excessive tourist pressure, and the ongoing COVID-19 pandemic. Interviews with boat operators reveal that the pandemic lockdown laid the financial situation of local tourist boat operators down. This study suggests multipronged solution approaches, for example ensuring the integrity of IRD habitat, optimal resource utilization, high service quality, and necessary infrastructure development to facilitate a sustainable ecotourism model in the lagoon.

Quantification of groundwater discharge into a shallow coastal lagoon applying a multi-tracer approach

In many cases, shallow coastal lagoons are, on the one hand, vulnerable habitats for birds and marine ecosystems and, on the other hand, threatened by discharging nutrient-laden surface waters and groundwater. In particular, the localization and quantification of submarine groundwater discharge (SGD) is of key concern in this regard. The presented study aimed at investigating SGD into a vulnerable coastal lagoon that is strongly impacted by evaporation applying a multi-tracer approach. The joint application of radionuclides (222Rn, 223Ra, 224Ra), stable water isotopes (δ18O, δ2H) and the water salinity as environmental water tracers allowed evaluating the suitability of the individual parameters in this specific type of environment. Whilst stable isotope and salinity data were difficult to construe in terms of SGD occurrence due to the intense impact of evaporation, a radon mass balance allowed localising SGD areas within the lagoon and quantifying the related SGD flux rates. In addition, a 224Ra/223Ra ratio analysis revealed information on the apparent age of the discharged groundwater, and hence on the flushing intensity of the lagoon. Besides these site-specific results, the study allowed the following general conclusions regarding the suitability of the applied tracers: (i) we verified the suitability of a radon mass balance approach for proving/disproving SGD occurrence and quantifying SGD fluxes in shallow coastal lagoons strongly impacted by evaporation; (ii) we showed that the impact of evaporation may impede the use of water stable isotope and salinity data as SGD indicators in such specific environments; (iii) we demonstrated that the tidal impact on a lagoon water body during a sampling campaign can be compensated by adapting sampling schedule and cruise track to the tidal cycle.

Application of water quality index (WQI) and geographic information system (GIS) to assess water quality during rainy season 2020 in O Loan Lagoon, Phu Yen Province, Vietnam

The research studies the water quality of O Loan Lagoon, which has been active in aquaculture in recent years. Based on the water quality index (WQI) calculations of 15 water samples collected in 3 periods from September 2020 to October 2020, spatial and temporary polluted distribution maps were established using ArcGIS software. The results indicate that the WQI value ranges from 1 to 80, reaching an average of 58. This estimation shows that the water quality of O Loan Lagoon is only average during the rainy season in 2020. Water quality distribution maps show that the southern region's water quality is poorer than the rest. This result demonstrates the negative impacts of aquaculture activities on the coastal lagoon's water environment, and local authorities need appropriate solutions for sustainable aquaculture activities in this area.

Reappraisal of lagoon specific local marine reservoir effects in Tongatapu, the Kingdom of Tonga, over the last 3000 years

Lagoon-specific local marine reservoir effects (ΔRlagoon) were defined as a new proxy to estimate the radiocarbon (14C) activity change in the lagoon freshwater proportion [1]. In Tongatapu island, previous research showed that ΔRlagoon values increased linearly between ∼2.6 and 0.4 ka, which suggested that ΔRlagoon value increase was caused by the near-closure of the Fanga ‘Uta Lagoon [1]. However, the calculated values contained large errors. Here, we refine those study results and present 26 new 14C values from G. tumidum combined with the previously published values and a ΔRlagoon value recalculated using Marine20. Moreover, we investigated whether the 14C value of G. tumidum reflected that of the dissolved inorganic carbon in the lagoon water. Although the new ΔRlagoon values were similar between 0.4 ka and 1.2 ka, the values increased from 2.6 ka to 1.2 ka. This timing was consistent with geophysical comparisons reported in our previous study and archaeological studies.

Development of polypropylene membranes grafted with nanocellulose to analyze organic pollutants in environmental waters using miniaturized passive samplers based on liquid-phase microextraction

Reinforcing hollow polypropylene fibers with nanocellulose is a viable alternative for implementing miniaturized passive sampling devices (MPSDs) based on liquid-phase microextraction (LPME). This modification improves the extractive properties of microporous membranes, including the sensitivity to fluctuations in the uptake steps. The new material, polypropylene hollow fiber grafted with nanocellulose, was developed and characterized using X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) coupled with Energy Dispersive System (EDS) and Thermogravimetric (TGA) and Differential Thermal (DTA) analysis. The morphology type of the crystallite of cellulose most abundant after chemical regeneration was the CII (Celulose II) allomorphic. Sorption studies were carried out and revealed that the modified membrane could absorb 177% more water than its untreated commercial counterpart, making it suitable for long-term sampling. Miniaturized passive sampling devices were equipped with the new material, and the devices were deployed in situ for passive sampling of organic pollutants in environmental waters of marginal lagoons. Fingerprint analysis of samples was performed by comprehensive two-dimensional gas chromatography coupled with mass spectrometry and identified a variety of pollutants such as pesticides, plasticizers and prescription and illegal drugs and their metabolites. Therefore, these MPSDs can be employed for the sampling and long-term monitoring of water contaminants with a wide range of polarities.

Assessing the Influence of Anthropogenic Land-Use Changes on Bird Diversity and Feeding Guilds—A Case Study of Kalametiya Lagoon (Southern Sri Lanka)

Kalametiya Lagoon, a highly threatened Sri Lankan wetland, has undergone drastic hydrological changes in recent decades, due to an upstream irrigation project. These changes led to the invasion of the lagoon water by monospecific Sonneratia caseolaris mangrove stands and Typha angustifolia reedbeds. As Kalametiya has been a nationally recognized bird sanctuary since 1984, this invasion is expected to have brought significant changes upon local avifauna. Therefore, this study aimed at determining the lagoon’s current bird diversity and distribution in relation with habitat types and environmental variables. Thirty-seven point-count stations were studied, between January and April 2022. Seventy-nine bird species, including four endemic and ten nationally threatened species, were encountered during the study period. Invertebrate feeders and polyphages were the richest and most diverse guilds. Bird communities were also found richer and more diverse in T. angustifolia reedbeds than in S. caseolaris mangroves. As feeding guild composition was significantly influenced by several environmental variables (i.e., water nitrate content, water TDS, water pH, soil pH), guilds could have great potential as bioindicators of the ecosystem if further studies are done to explore these relationships. Considering the important bird diversity found in the new habitats, this research brings additional proof that a management aiming at restoring the lagoon to its past state would bring significant changes to its avifaunal community. These changes could, in the future, be more precisely defined by a thorough comparison with past inventories of the lagoon’s bird community.

THE PUBLIC’S PERCEPTIONS TOWARD THEME PARKS AS A RECREATIONAL ACTIVITY

A theme park is an attraction that the public enjoys. A theme park provides amusement and creates a leisure time for the public to spend time with family, friends and other relatives. Therefore, it is critical to determine the public's expectations and perceptions of theme park recreation. The purpose of this study is to determine the level of public participation in a theme park recreational activity. The theme parks selected are Sunway Lagoon Water Park, iCity Water World, and Wet World Water Park. All of the selected theme parks are located in the state of Selangor. The objective of the study is to investigate the influence factor of public perception on theme park attendance based on social demographics. Due to the Covid-19 situation, the survey was conducted through an online form using a Google form. A total of 437 people from the selected theme parks were surveyed. The study found that most theme park visitors are students and are between 18 and 30 years old. The result shows that public participation in theme park recreational activities is significant. It was found that people who do their leisure activities in amusement parks have higher expectations. On the other hand, the influence factor of public perception of participation in theme park leisure activities was significant. The iCity Water World has the highest influence. The influence factor of public perception of participation is statistically significant in theme parks. Nevertheless, the management should cooperate and communicate with the government and private organizations to improve the country's economy due to the Covid-19 situation.