| 1. |
- Abessolo, Grégoire O., et al.
(författare)
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Modeling the Bight of Benin (Gulf of Guinea, West Africa) coastline response to natural and anthropogenic forcing
- 2021
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Ingår i: Regional Studies in Marine Science. - : Elsevier BV. - 2352-4855. ; 48
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Tidskriftsartikel (refereegranskat)abstract
- The 400-km long coast of the Bight of Benin, formed by sand barriers and lagoons, is bordered to the east by the Niger River Delta and to the west by the Volta River Delta and is characterized by several coastal infrastructures, of which the most important are the deep water harbors of Lomé, Cotonou, and Lagos. In this study, an enhanced version of the CASCADE coastal evolution model was implemented in order to reproduce the evolution of the coast over the period 2000-2015, considering the presence of coastal infrastructure, inlets, and the reduced sediment influx from rivers. The model results showed simulated coastal response around the main coastal infrastructure in agreement with observed data. In addition, the validated model was used to estimate the amount of sediment needed to control erosion through beach nourishment downstream of the harbors. The impact of reducing sediment input on coastal evolution was investigated through model parameterization of the influx at the boundary. Overall, the model may be a useful tool for improving regional coastal policies in the Bight of Benin.
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| 2. |
- Dahlgren, E., et al.
(författare)
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A screening study of relationships among concentrations of algal toxins, PFAS, thiamine deficiency and biomarkers in the European flounder from the southern Baltic Sea
- 2022
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Ingår i: Regional Studies in Marine Science. - : Elsevier BV. - 2352-4855. ; 53
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Tidskriftsartikel (refereegranskat)abstract
- In the disturbed Baltic Sea ecosystem, several animal species display failing health related to exposure to toxic compounds, reduced energy metabolism and immune system disorders. In order to investigate possible associations between fish health and exposure to chemicals affecting the energy metabolism and immune defence, the levels of algal toxins (bromophenols, hydroxylated polybrominated diphenyl ethers and nodularin), perfluorinated alkyl substances (PFAS) and thiamine (vitamin B1) were determined in European flounder (Platichthys flesus). Several biomarkers indicating health status were examined in the fish, including ethoxyresorufin-O-deethylase (EROD), and activities of glutathione reductase, glutathione S-transferase and catalase, in addition to a large set of blood variables. The fish were collected from Hanobukten in the south-western parts of the Baltic Sea in late August 2018. Regression analyses of algal toxins, PFAS and thiamine concentration displayed several significant associations with biomarkers associated with detoxification and liver function, immune system function and blood status of the fish. (c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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| 3. |
- de Brito, Almir Nunes, et al.
(författare)
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Tidal exchange in a choked coastal lagoon : A study of Mundaú Lagoon in northeastern Brazil
- 2018
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Ingår i: Regional Studies in Marine Science. - : Elsevier BV. - 2352-4855. ; 17, s. 133-142
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Tidskriftsartikel (refereegranskat)abstract
- Changes in the inlet morphology of choked coastal lagoons often restrict the water exchange with the sea, making them vulnerable to pollution events and eutrophication processes. In this study, the importance of tides for the water exchange was investigated in Mundaú Lagoon, which is a choked lagoon located in northeastern Brazil that has a very dynamic inlet and channel system. The analysis was carried out for critical scenarios during the dry season when the river flow to the lagoon decreases markedly. The concepts of integrated flushing time and spatially distributed residence time scales were applied using a Lagrangian particle tracking approach coupled with a hydrodynamic model. The flushing time of Mundaú Lagoon was estimated to be 12.6 days during neap tide and 5.7 days during spring tide, including a return flow factor. Employing an e-folding form, the corresponding value was calculated to be 64 and 54 days for particles allowed and not allowed to return to the lagoon, respectively. The spring tides were responsible for the most pronounced water exchange in the Mundaú Lagoon. Different particles release times displayed the effect of the initial tidal conditions on the flushing time; lower exchange times were estimated for releases during ebb tides and spring tides. The integrated estimation of the water exchange when imposing a scenario of most frequent wind conditions indicated a considerable delay caused by this forcing, increasing the flushing time up to 23 days. Another observed effect of the wind was a spatial redistribution of the tidal exchange in the lagoon into different zones with similar residence time.
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| 4. |
- Fetterplace, Lachlan
(författare)
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Temporal stability in a protected and isolated fish community within marine parks surrounding Lord Howe Island
- 2021
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Ingår i: Regional Studies in Marine Science. - : Elsevier BV. - 2352-4855. ; 48
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Tidskriftsartikel (refereegranskat)abstract
- Remote oceanic islands often display high levels of biodiversity and endemism, making them important locations for marine parks aimed at conserving biodiversity. To determine whether marine parks are reaching conservation objectives requires consistent assessments of their effectiveness through time. Lord Howe Island and Balls Pyramid are World Heritage listed remote oceanic islands in the Tasman Sea that support a diverse assemblage of fishes including many endemic and protected species. To conserve the region’s unique marine biodiversity, state and Commonwealth marine parks including no-take zones and partially protected zones open to line fishing were established. After approximately 5, 9 and 13 years of protection of shelf habitat we tested for changes in the marine park’s fish assemblage across management zones through time using baited remote underwater video systems (BRUVs). We detected no difference in total fish abundance, diversity, or assemblage composition between management zone types. The relative abundance of targeted carangids, yellowtail kingfish and silver trevally were 2 and 1.6 times greater in no-take zones than partially protected zones respectively, however, the substantial variation in their abundances among locations and sites meant that these differences were not statistically significant. No clear difference in the relative abundance of endemic, near-endemic and protected species were observed between management zone types. Generally, the abundance and diversity of fishes varied most among locations, sites and sampling years. The overall lack of difference in the fish assemblage between management zone types and its stability through time suggests current anthropogenic threats are relatively minor, and the marine park’s condition is reasonably healthy. Future surveys of the marine park’s fish assemblage will be valuable to test for body-size differences between zone types and to monitor trends in condition, particularly in response to possible changes in the number, frequency and intensity of anthropogenic threats.
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| 5. |
- Jolly, Yeasmin N., et al.
(författare)
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Evaluation of surface water quality near pollution sources in Buriganga River and deciphering their probable emergence, ecological, and health risk aspects
- 2023
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Ingår i: Regional Studies in Marine Science. - : Elsevier BV. - 2352-4855. ; 63
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Tidskriftsartikel (refereegranskat)abstract
- Potentially toxic elements (PTEs) contamination in Buriganga river water, provoked by the point and non-point sources, has recently become a major health concern. Concentration, pollution degree, drinking and irrigation water potentiality, and associated health risks are the factors considered for this study. This study ascertained a mean pH, EC, TDS, and salinity value of 6.96, 86.25 mu S/cm, 51.86 mg/L, and 86.56%, respectively, revealing that it is safe for drinking and agricultural purposes. Furthermore, the mean value of major anion (NO-23: 1.16, SO-24 : 13.40, PO-34 : 0.66, Cl-1 : 14.71 mg/L) and major cations (Na+1 : 16.95, K+1 : 4.26, Ca+2 : 17.63, and Mg+2 : 5.47 mg/L) also estimated safe for human consumption and agricultural use. Trace element evaluation index (TEI) value was found to vary among the sites and ranging from 4.40 to 10.50, indicating moderate pollution and risk imposed by the single PTEs can be ranked as Mn>Fe>Pb>As>Cu>Zn. Nemerow index and comprehensive pollution index value stipulated an insignificant to moderate pollution by the studied elements. Consequently, no ecological risk was posed via elements studied in the proposed sites. The emerging sources for PTEs are confined to both anthropogenic and lithogenic derivations. Non-carcinogenic risk assessment stipulated that the river water was safe for adults and children as the estimated Hazard Quotient (HQ) and Hazard Index (HI) value was found below the threshold value (HQ/HI<1). Total carcinogenic risk was calculated at 7.44E-08 and 1.60E-08 for adults and children, respectively, specifying no risk, and water from the sites was evaluated as suitable for agricultural irrigation purposes on the basis of estimated indices.
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| 6. |
- Kalogirou, S., et al.
(författare)
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Spatial and temporal distribution of narwal shrimp Plesionika narval (Decapoda, Pandalidae) in the Aegean Sea (eastern Mediterranean Sea)
- 2017
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Ingår i: Regional Studies in Marine Science. - : Elsevier BV. - 2352-4855. ; 16, s. 240-248
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Tidskriftsartikel (refereegranskat)abstract
- In the Aegean Sea the trap fishery for narwal shrimp, Plesionika narval, contributes to social and cultural cohesion of local fishery communities. Spatial and temporal distribution patterns of narwal shrimp was studied during an annual cycle, including catch per unit effort (CPUE), sex ratio and proportion of ovigerous females in the population. Shrimps were sampled at five localities within the depth range of 10 to 170 m. Catch per unit effort increased during the summer period at all depths, when seawater temperature increase. Differences in CPUE were observed between depths, with highest catches at depths below 70 m. The proportion of females decreased significantly with depth, a pattern especially evident during the summer period (May to August), indicating a migration of females to shallower waters. Significant higher abundance of ovigerous females was observed during the period May to October, concurrently with a vertical migration of females to warmer waters. To further support this pattern, the proportion of ovigerous individuals among females increased with decreased depth at all seasons. We suggest that the findings of our study have significant implications to current and future management of narwal shrimp in the Mediterranean Sea. © 2017 Elsevier B.V.
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| 7. |
- Khan, Md Nabiul Islam, et al.
(författare)
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Stand level carbon stocks in the soil-vegetation system of the coastal mangrove plantations in Bangladesh : Effect of stand age and choice of species
- 2023
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Ingår i: Regional Studies in Marine Science. - 2352-4855. ; 63
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Tidskriftsartikel (refereegranskat)abstract
- Mangrove plantations are crucial for carbon sequestration in global climate change mitigation efforts. However, the dynamics and partitioning of carbon stocks in the soil vegetation system in mangrove plantations are little understood. We assessed the carbon stocks across different plantation age groups, species, and sites. Our findings revealed that soil C concentration ranged from 0.4 to 1.5%, and soil carbon stocks varied from 30 to 90 Mg ha−1, with an average of 58 Mg ha−1 in 100 cm soil depth. The C concentration of top 30 cm layer was significantly higher than that of other layers up to 100 cm. The soil C stocks increased with increasing stand age up to a middle age of approximately 25 years, after which they reached a plateau at around 50 years. The biomass carbon stocks of Sonneratia apetala was 6.7 Mg ha−1 in young stands to 791.1 Mg ha−1 in the older stands, which ranged from 112.1 to 405.9 Mg ha−1 in Avicennia officinalis and 37.5 to 198.3 Mg ha−1 in Excoecaria agallocha. Although the coastal mangrove plantation projects in Bangladesh consists mainly of S. apetala, A. officinalis would also be planted considering its carbon stocks. We also developed allometric equations for stand-level C stocks in coastal mangrove plantations in Bangladesh based on basal area, tree height, and wood density of the mangrove species. Analyzing the C stocks partitioning in aboveground, belowground, and soil at different stand ages, we found that about 30% of C is stored in the soil of young stands, which declines to about 12% in older stands. This suggests that the relative growth in biomass C is much faster than soil C storage with the progress of stand age. The results of this study would support coastal afforestation and reforestation efforts to mitigate climate change.
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| 8. |
- Lam, V. W. Y., et al.
(författare)
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Dealing with the effects of ocean acidification on coral reefs in the Indian Ocean and Asia
- 2019
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Ingår i: Regional Studies in Marine Science. - : Elsevier BV. - 2352-4855. ; 28
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Tidskriftsartikel (refereegranskat)abstract
- Shallow coral reefs provide food, income, well-being and coastal protection to countries around the Indian Ocean and Asia. These reefs are under threat due to many anthropogenic stressors including pollution, sedimentation, overfishing, sea surface warming and habitat destruction. Ocean acidification interacts with these factors to exacerbate stress on coral reefs. Effective solutions in tackling the impact of ocean acidification require a thorough understanding of the current adaptive capacity of each nation to deal with the consequences. Here, we aim to help the decision-making process for policy makers in dealing with these future challenges at the regional and national levels. We recommend that a series of evaluations be made to understand the current status of each nation in this region in dealing with ocean acidification impacts by assessing the climate policy, education, policy coherence, related research activities, adaptive capacity of reef-dependent economic sectors and local management. Indonesia and Thailand, are selected as case studies. We also highlight general recommendations on mitigation and adaptation to ocean acidification impacts on coral reefs and propose well-designed research program would be necessary for developing a more targeted policy agenda in this region. (c) 2019 Elsevier B.V. All rights reserved.
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| 9. |
- Lund-Hansen, Lars Chresten, et al.
(författare)
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A fjord with a land-terminating glacier: Meltwater, bio-optics, particulate matter, nutrients, phytoplankton species, and primary production in west Greenland
- 2023
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Ingår i: Regional Studies in Marine Science. - 2352-4855. ; 64
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Tidskriftsartikel (refereegranskat)abstract
- Land-terminating glaciers and submarine melting of marine-terminating glaciers are significant features in Arctic regions and are foreseen to become more frequent as marine-terminating glaciers ultimately develop into a land-terminated state. A transition driven by the continuous rise in Arctic air temperatures, and emphasizes the importance of studies of land-terminating glaciers their bio-optical properties and biogeochemistry. Kangerlussuaq in west Greenland with a land-terminating glaciers and was selected for this study. During a research cruise we measured spectral and PAR attenuation, particulate matter concentrations, salinity, nutrient concentrations, Chla, and phytoplankton species composition, along a transect from river outlet to open marine waters. Results showed that surface waters in Kangerlussuaq were strongly influenced by meltwater with low salinities, high particulate matter concentrations, high PAR and spectral light attenuation coefficients, and low nutrient concentrations. Spectral composition was also affected by the particulate matter. PAR photic depths varied between 4 and 9 m dependent on particulate matter concentrations. There was a decrease with distance from outlet in silicate concentrations, and opposite for phosphate, which increased significantly from river outlet to the marine. Phytoplankton species number (42) and diversity were high at the marine station but low (3) in turbid waters dominated by the diatom Skeletonema costatum in high numbers. A meltwater plume covered about 50 % of the Kangerlussuaq at average discharges in early August. Primary production was quantified with a simple model based on light attenuation coefficients, and showed a near exponential decrease in production with increase in attenuation.
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| 10. |
- Mwevura, Haji, et al.
(författare)
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Dynamics of organochlorine and organophosphate pesticide residues in soil, water, and sediment from the Rufiji River Delta, Tanzania
- 2021
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Ingår i: Regional Studies in Marine Science. - : ELSEVIER. - 2352-4855. ; 41
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Tidskriftsartikel (refereegranskat)abstract
- The Rufiji River Delta (RRD) in Tanzania is an internationally important wetland. Subsistence mangrove rice farming (MRF) uses pesticides to combat crabs and herbicides to combat weeds. We undertook the first investigation of the dynamics of pesticide residues and hazard in farm soil, water, and sediment, during and following application. Twenty-one organochlorine and organophosphate insecticides, and the herbicide thiobencarb occurred at quantifiable concentrations. The residue profile indicated past use of organochlorine pesticides and current use of organophosphate pesticides (OPP). Residues of Sigma HCH4, Sigma DDT4, Sigma OPP5, and all residues combined (Sigma All(21)) in soils and sediments decreased significantly following application, but not for Sigma Cyclodienes(7). Sigma DDT4 and Sigma Cyclodienes(7) increased significantly in water following application, although this is likely related to legacy effects from upstream and not its use on MRFs. Sigma OPP5 made up 61% of Sigma All(21) in soils, 38% in sediments, and 45% in river water during application, dropping to 4.2%, 10%, and 19%, respectively, after application. Concentrations of compounds such as dieldrin, DDT, HCH, and OPPs exceeded various safety guidelines in all matrices. There were complicated dynamics of the residues between soils, sediments, and water, reflecting the complex interactions in a tidal riverine delta environment with the chronic presence of legacy pollutants and seasonal fluxes of current use pesticides. Multivariate analyses showed compound class specific differences in dynamics between matrixes and seasons. The predictions of pollutant concentrations and effects in highly biodiverse and productive tropical deltas with increasing human and extraction pressures, overlain with the spectre of climate change will be difficult. What seems certain though is that the stresses caused by chemicals will not lessen unless managed and calls for urgent interventions and further research. (c) 2020 Elsevier B.V. All rights reserved.
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