Central-southern Coast Research Articles

Carbon sequestration and geochronology in Southern England’s seagrass meadows

The aim of this study was to provide an evaluation of the current methods used to assess carbon sequestration (Cseq) rates from intertidal Zostera spp. meadows in central Southern England. This study evaluated the use of 210Pb dating methods to calculate sediment accretion rates from four intertidal seagrass meadows along the southern central coast of England. Results obtained were then used to determine Cseq rates, following different models. The mean rate of Cseq calculated in this study using the CRS model was 75.12 g m-2 year-1, comparable to other global regions and within the estimated global range. However, results revealed that other, conservative methods, provide much lower Cseq rates, highlighting the need for caution when choosing appropriate methods and reporting results related to seagrass carbon sequestration potential. Moreover, these results highlight the importance of local assessments of Cseq, and the need to create robust models that include the effects of mixing, erosion, and disturbance, to better understand the possible effects of extreme climate events and anthropogenic impacts on seagrass ecosystems' carbon sequestration potential.

Evaluating the long-term geomorphic process in-relation to hydrodynamics in the central coastal zone of Bangladesh

The central coast of Bangladesh is dynamic for its geographical location, hydrodynamic characteristics and residual flow. The research employed the Digital Shoreline Analysis System (DSAS), an ArcGIS extension tool, to conduct a historical trend analysis of shoreline. The study demonstrates that the central coast is eroding to the north and accreting to the south. The highest accretion value was found as 195.42 m/year, whereas the maximum value of erosion was estimated as −185.83 m/year, according to End Point Rate (EPR). The Linear Regression Rate (LRR) indicates that the average rate of erosion and accretion are −17.77 m/year and 17.88 m/year, respectively. Meanwhile, using Weighted Linear Regression (WLR), 0.48% of all transects demonstrated statistically significant erosion, while 0.43% showed statistically significant accretion. During the wet season, heavy river discharge leads to a low salt level in the ocean. Ocean currents hit central coast of Bangladesh from east to west, affecting the majority of the islands in the Meghna Estuary in the dry season. Changes in current directions can be seen during the wet seasons. Southern central coast areas are hit by south-east currents that split in two directions. The Sandwip Channel has a flow of 10,000 to 15,000 m³ s−1 northward. The Tetulia River, Shahbazpur Channel, and Hatia-Sandwip flow southward at rates ranging from 3000 to 17,000 m³ s−1, 14,000 to 60,000 m³ s−1, and 7000 to 39,000 m³ s−1, respectively. In the Meghna Estuary, the combined forces result in a counter-clockwise residual circulation, with the northward flow in the Sandwip channel and southbound flow in the Hatia and Shahbazpur channels. As a result of hydrodynamic, ocean currents, and residual flow, the Central Coast of Bangladesh is continually changing in appearance.

Scenario-based tsunami hazard assessment for the coast of Vietnam from the \(109^{o}\) Meridian fault zone

Located on the continental shelf and stretching approximately 1,000 km along the Central and Southern Central coasts of Vietnam, the 109o Meridian Fault system has long been recognized as seismically active. Empirical evidence of the seismic, volcanic, and submarine landslide activities also suggests that this fault might be capable of originating near-field tsunamis, which can harm the Vietnamese coastal zone. This paper investigates the possibility of the near-field tsunamis from the 109o Meridian Fault and their impact on the Vietnamese coasts. Location and segmentation of the 109o Meridian fault were determined using seismological, geophysical data, and geomorphologic evidence. The fault’s seismotectonic and geodynamic characteristics were used to model the tsunami source. The COMCOT model was used for simulating three worst-case tsunami scenarios excited by earthquakes with Mw = 8.0 originated in two different segments of the 109o Meridian Fault source. The relationship between tsunami wave height and the source-to-coast travel time is investigated in detail at the virtual sea-level stations distributed along the Vietnamese coastline. The simulation results are presented in the deep-ocean tsunami amplitude maps for the entire East Vietnam Sea region and the coastal tsunami amplitude maps for the Vietnamese coasts. The simulation results show the highest tsunami hazards concentrated along the Central and Southern Central Vietnam coastal zones (from Quang Nam province to Ba Ria-Vung Tau province), with the highest tsunami waves not exceeding 4 m observed off-shore the Quang Ngai, Phu Yen and Ninh Thuan provinces. The shortest tsunami travel time from the source to the Southern Central coast is 35 minutes. Due to its strike-slip mechanism, there is a low possibility of the 109o Meridian fault generating earthquake-triggered tsunamis. Moreover, even if they occurred, the near-field tsunamis generated from the 109o Meridian fault source can hardly cause severe damage and losses for the coastal zones of Vietnam, as shown by the simulation results. Nevertheless, the worst-case scenarios simulation results provide the highest risk that the near-field tsunamis from the 109o Meridian fault source might affect the Vietnamese coasts, which is helpful for the national tsunami warning and response purpose.

Assessment of water quality with emphasis on trophic status in bathing areas from the central-southern coast of Cuba

Bathing water quality has become a matter of concern due to health risks. This study sought to assess water quality in bathing areas from the southeastern coast of the Cienfuegos province, Cuba. Certain physical, chemical, and biological parameters (salinity, temperature, pH, oxygen saturation, N-NH4+, N-NO2-, N-NO3-, P-PO43-, COD, BOD5, fats and oils, chlorophyll-a, thermotolerant and total coliforms, and phytoplankton) were measured on five beaches during 2019-2020 in both rainy and dry seasons. A water quality index (WQI) was calculated using the the results of an eutrophication index (EI) and subsequently analyzed. Cluster analysis (CA) and principal components analysis (PCA) were conducted to interpret water quality variations. The WQI values ranged between fair and good, with significant differences between seasons. Multivariate analyses demonstrated the influence of river contributions on water quality indicators based on the results of the CA and the first principal component (PC1) correlated with Sal, DO, total and thermotolerant coliforms, and certain nutrients. PCA also reflected the increase in BOD5 levels during the summer based on PC2, while the PC3 correlated with COD and response parameters (chlorophyll-a and phytoplankton) were linked to the trophic status. The assessment of trophic status showed non-eutrophic conditions. The abundance and diversity of phytoplankton in these beaches was low (128.5 x 103 cells L-1, total mean value), following the normative definitions of the water framework directive. Harmful algal species occurred in low numbers (1.88 x 103 cells L-1, total mean value), but certain species could represent a risk of dermatitis to bathers. The application of different classification schemes allowed for a comprehensive assessment of water quality in this coastal zone, helping to identify the need for monitoring and further ecological study on harmful algae species.

Construction of fine resolution bioclimatic variables for Central Highlands and Southern Central Coast of Vietnam

In this study, 19 surface bioclimatic variables of high spatial resolution 0.00226o (~ 250 m) are generated in a Geographic Information System by the combination of (1) the raster dataset of monthly temperature and precipitation obtained from the global WorldClim database at 0.00833o spatial resolution for the period of 1960–2000; and (2) the climate data (temperature and precipitation) of the Central Highlands and Southern Central Coast collected from the 31 temperature and 97 precipitation recording sites for the period of 1991–2015. The statistical downscaling method is applied, using multiple linear regression analysis, in which elevation, geographic coordinates, and distance from the coast are treated as independent variables, to estimate the distribution of temperature; and the B-Spline interpolation method combined with multiple linear regression analysis is employed on precipitation over the study area. The outcomes of the two main analyses are computed to create 19 high spatial resolution bioclimatic variables. While using only local climate data on analyzing the regression models results in high fluctuation of estimated temperature, the combination of the two datasets is more informative. The spatial distribution of our interpolated precipitation is similar to the WorldClim data but has a smaller difference in the mean annual precipitation. The results, which shows higher spatial resolution and are closer to the observed data than those from the WorldClim, could be better applied for predicting species distribution in the region.

Decapod crustaceans associated with the shrimp fishery of the central-south portion of Veracruz, Mexico

The objective of this study was to analyze the brachyuran crab assemblages associated with shrimp fishing on the central-southern coast of Veracruz. Information was collected using 46 trawls organized within nine fishing quadrants. The total catch shrimp, bycatch, and discard were recorded and standardized (CPUE kg h-1). Value index by species, species richness, diversity using Shannon and Weaver index, and equitability were determined. A total of 3055 individuals were collected, which corresponded to nine families, 13 genera, and 14 species. Achelous spinicarpus species were identified at the greatest relative abundance (77.74%). Four new species records for the zone: Hepatus pudibundus, Iliacantha liodactylus, Leiolambrus punctatissimus, and Platylambrus granulatus. Species richness varied according to fishing quadrant and depth interval assessed. The highest value of species richness was eight, and observed Margalef species richness index values ranged from 0 to 2.23. The diversity values ranged from 0 to 2.41 bits ind-1; this may indicate that a few species share the greatest impact of trawling. The presence of lagoon systems was determined to define a portion of the composition of the assemblage. Understanding assemblage structure is important to improve knowledge on the impact of shrimp trawling activity on the ecosystem.

A Preliminary Petrologic and Provenance Analysis of Groundstone Artifacts from the Northern Channel Islands and Coastal Southern Alta California

ABSTRACT The Chumash of the southern Central Coast of Alta California have long been recognized for their complex sociopolitical systems and extensive exchange networks. This study employs petrologic geoarchaeological methods to examine groundstone bowl and mortar fragments from Chumash archaeological sites along the Northern Channel Islands and the Oxnard Plain region of the southern Central Coast. Through comparison of macroscopic and microscopic descriptions, our purpose is to establish the rock units from which the artifacts were likely produced to determine whether these tools were locally manufactured, or if non-local, the possible distances over which these artifacts were transported. The results of our preliminary study suggest that during the early late Holocene, the local Chumash obtained their groundstone mortars via both local production and intraregional exchange, with some finished tools found at least 80 km distant from probable raw material sources.

Natural resource use conflicts and priorities in small islands of Vietnam

Small islands of Vietnam witness increasing natural resource use conflicts among stakeholders resulting from their isolation from the mainland, combined with more recent pressures of urbanization, tourism, and socio-economic development. A challenge facing both residents and governments is identifying more appropriate inter-sector cooperation to minimize conflicts taking into account short-term economic feasibility and long-term sustainability. This study deals with conflicts and priorities in natural resource use as perceived by residents and local officials in the Ly Son Island of the Vietnamese Southern-Central Coast Region. A decision tree on conflict and priority analysis is structured at four hierarchical levels: sector, sub-sector, socio-economic activity, and objective. While a Likert 5 scale’s weighted mean (wMean) was applied to the survey data and to rank conflicts, the Analytic Hierarchy Process was used to estimate the weight values by priority. The results show that, although conflicts are limited, conflict hotspots exist in mountainous forested areas, farms, residential locations, and along coasts. Both residents and local officials shared the opinion that priorities help dealing with conflicts on the island. Over-all, perception analysis contributes to integrated spatial planning, marine spatial planning, and integrated coastal zone management for Ly Son Island with a consideration of improving inter-sector cooperation between agriculture, fishery, forestry and conservation, industry and service, tourism, and army.

Determinants of foreign direct investment in Southern Central Coast of Vietnam: a spatial econometric analysis

Determinants of foreign direct investment in Southern Central Coast of Vietnam: a spatial econometric analysis

Incorporation of Cochlodinium bloom-derived organic matter into a temperate subtidal macrobenthic food web as traced by stable isotopes

Harmful algal blooms involving the dinoflagellate Cochlodinium polykrikoides occur every summer off the Korean peninsula's central southern coast. To determine whether Cochlodinium bloom-derived organic carbon is incorporated into the subtidal macrobenthic food web, we compared the δ13C and δ15N values of suspended particulate organic matter (SPOM) and sedimentary organic matter, and macrobenthic consumers between bloom and non-bloom seasons. Chemotaxonomic analysis revealed the presence of Cochlodinium blooms in summer and a predominance of diatoms in autumn. Both the δ13C and δ15N values of SPOM were higher in the bloom than in the non-bloom seasons. Such temporal shifts in the δ13C and δ15N values were also observed for most macrobenthic consumers collected in both seasons. Consistent temporal isotopic shifts in SPOM and macrobenthos revealed that the Cochlodinium bloom-derived carbon was incorporated into the coastal benthic food web, resulting from its increasing availability during blooms.

Factors affecting offshore fishing households’ income in southern central coast of Vietnam

Factors affecting offshore fishing households’ income in southern central coast of Vietnam

Recent geodynamic characteristics of the Southern Central coast and the relations with geological hazards

Recent geodynamic characteristics of the Southern Central coast are analyzed on the basis of vertical and horizontal displacement velocities along active fault zones. The horizontal displacement velocity varies in magnitude from this fault system to another fault system, from 0.11–0.3 mm/year on the strike-slip - normal faults to 0–0.058 mm/year on the strike-slip faults and normal faults. The subsidence velocity changes complicatedly, different from one fault to another fault, depending on the mechanism of faults. On the continental shelf, most of the values of high subsidence’s velocity are related to the normal and strike-slip faults. Subsidence activities make the sea level increase highly, the subsidence activity makes the sea level rise at structures that fall close to the shore, reach about 0.2–0.48 mm/year in late Pleistocene - Holocene. The increase of sea level directly affects the intensity of erosion, flood, salinity and land loss events in coastal lowlands. Slippage of the seabed, earthquakes, volcanoes are geological hazards directly related to the geodynamic regime of the Southern Central coast.

Marine red algae from central-southern coast of Cuba

The aim of this study was to carry out a taxonomic survey of red marine benthic algae that occur in the littoral zone of central-southern Cuba. The samplings were performed in the period 2010–2012at 12 stations predominantly in reef environments. A total of 81 taxa were recorded and distributed in 9 orders and 24 families. Ceramiales was the most represented order with 38 taxa, followed by Corallinales with nine taxa. Hypoglossum caloglossoides represents a new record for Cuban benthic marine algae. Forty-nine species of macroalgae are new additions to the flora of reef environments from the central-southern region of Cuba. Sixty species of the region are provided in Figures (2–61). Dichotomaria obtusata was the most common species found. Some species such as Ceramium fujianum, Gloiocladia iyoensis, Griffithsia schousboei var. anastomosans and Dasya ocellata have been found in Cuba only in the central-southern region. Calcified crustose and articulated coralline algae were found to be common in the coral reef locations, while filamentous turfs and fleshy or frondose macroalgae were commonly found in the stations of shallow or intertidal waters. The floristic composition of red marine benthic algae indicates the central-southern coast of Cuban archipelago as a site of elevated species richness and that its coral reef environments are in a status of good health due to prevalence of calcareous coralline macroalgae.

Determinants of Offshore Fishing Vessel’s Output in Southern Central Coast Region: An Empirical Approach

This paper uses econometric models to estimate factors determining offshore fishing vessel’s output in Southern Central Coast region. The estimated findings indicates that factors namely the residential characteristics, types of fishery, engine power, vessel’s years, fishing technology, modern fish finder, number of days per trip, captains’s experience, participation in fishing teams have significant impacts on offshore fishing vessel’s output. Meanwhile, captains’s age and education level as well as fishing ground do not affect this factor. In addition, we find out that fishing stimulation, especially in the application of modern technologies to seafood exploitation and the elimination of empiricism is important to offshore fishing vessel’s output. The findings allow us to bring forward some policy recommendations for central and provincial governments to improve offshore fishing vessel’s output in Southern Central Coast region.

Evidence of positive tectonic inversion in the north-central sector of the Sicily Channel (Central Mediterranean)

In order to unravel the tectonic evolution of the north-central sector of the Sicily Channel (Central Mediterranean), a seismo-stratigraphic analysis of single- and multi-channel seismic reflection profiles has been carried out. This allowed to identify, between 20 and 50 km offshore the central-southern coast of Sicily, a ~80-km-long deformation belt, characterized by a set of WNW–ESE to NW–SE fault segments showing a poly-phasic activity. Within this belt, we observed: i) Miocene normal faults reactivated during Zanclean–Piacenzian time by dextral strike-slip motion, as a consequence of the Africa–Europe convergence; ii) releasing and restraining bend geometries forming well-developed pull-apart basins and compressive structures. In the central and western sectors of the belt, we identified local transpressional reactivations of Piacenzian time, attested by well-defined compressive features like push-up structures and fault-bend anticlines. The reconstruction of timing and style of tectonic deformation suggest a strike-slip reactivation of inherited normal faults and the local subsequent positive tectonic inversion, often documented along oblique thrust ramps. This pattern represents a key for an improved knowledge of the structural style of foreland fold-and-thrust belts propagating in a preexisting extensional domain. With regard to active tectonics and seismic hazards, recent GPS data and local seismicity events suggest that this deformation process could be still active and accomplished through deep-buried structures; moreover, several normal faults showing moderate displacements have been identified on top of the Madrepore Bank and Malta High, offsetting the Late Quaternary deposits. Finally, inside the northern part of the Gela Basin, multiple slope failures, originated during Pleistocene by the further advancing of the Gela Nappe, reveal tectonically induced potential instability processes.

Post-earthquake coastal evolution and recovery of an embayed beach in central-southern Chile

Earthquakes and tsunamis are significant factors for change along active margin shores, and influence coastal evolution. The Chilean coast was affected in 2010 by a subduction earthquake with a magnitude of Mw8.8 and also by a trans-Pacific tsunami, which generated violent geomorphologic changes and damaged homes. Following these events, the magnitude of the changes which affect Chile's central-southern coast (37°S) and the role of subduction earthquakes in coastal evolution on a historical scale were investigated.At Lebu bay (an embayed beach) data were generated for variations in time and space along the shoreline, topographical and bathymetric changes in the bay, and for morphodynamic littoral processes. Logarithmic and parabolic models were applied to the shoreline along with map overlays in order to determine changes. The shoreline processes were analyzed based on statistics for waves, tides and sediment transport for pre- and post-tsunami conditions.An average accretion rate of 2.80m/year (1984–2010) was established for the shoreline, with a strong trend towards accretion in the last 30years. A parabolic function best represented the general form of the shoreline, although the presence of a river in the concave zone affected the fit in this sector. Two factors controlled historical changes on the beach: one of anthropic origin in addition to the earthquake and tsunami on February 27th, 2010. The post-earthquake recovery was fast, and currently the beach is in a stable condition despite the inter-seismic subsidence process previous to the event. This coastal system showed a high resilience in the face of coastal geomorphological changes induced by high-impact natural disturbances. However, the opposite occurred in relation to changes induced by anthropogenic disturbances.

Heavy metals and TPH effects on microbial abundance and diversity in two estuarine areas of the southern-central coast of São Paulo State, Brazil

Coastal areas may be impacted by human and industrial activities, including contamination by wastewater, heavy metals and hydrocarbons. This study aimed to evaluate the impact of hydrocarbons (TPH) and metals on the microbiota composition and abundance in two estuarine systems in the coast of São Paulo: the Santos (SE) and Itanhaém (IE) estuaries. The SE was found to be chronically contaminated by heavy metals and highly contaminated by hydrocarbons. This finding was correlated with the increased density of cyanobacteria in sediments and suggests the possible use of cyanobacteria for bioremediation. These contaminants influence the density and composition of estuarine microbiota that respond to stress caused by human activity. The results are troubling because quantitative and qualitative changes in the microbiota of estuarine sediments may alter microbiological processes such as decomposition of organic matter. Moreover, this pollution can result in damage to the environment, biota and human health.

Tsunami Waveform Inversion of the 2007 Peru (Mw8.1) Earthquake

An earthquake shook the central-southern coast of Peru on August 15, 2007, as a coseismic effect a tsunami was generated, which flooded some villages and beach resorts and killed 3 people. From the analysis and signal processing of 10 tidal records, we obtained the parameters of the seismic source and the initial coseismic deformation through an inversion modeling, in which the synthetic signals are compared with the observed signals by a non-negative least square method. The maximum slip located on the southern part of the rupture geometry is 7.0 m. The calculated scalar seismic moment isM0= 1.99 × 1021Nm, equivalent to a magnitude ofMw8.1. We used these parameters to obtain a heterogeneous seismic source model, which was used as initial condition to simulate the tsunami propagation and inundation. We used the field survey observations to validate our source model.

Os sistemas de financiamento na pesca artesanal: um estudo de caso no litoral Centro-Sul Catarinense

Este artigo demonstra que o setor da pesca artesanal enfrenta dificuldades para acessar políticas públicas de crédito, o que colabora com a manutenção de mecanismos informais de financiamento. O estudo de caso realizado no Litoral Centro-Sul de Santa Catarina partiu de entrevistas semiestruturadas com pescadores e atravessadores, seguindo-se da análise de discurso e da mobilização de conceitos da sociologia econômica para entender as relações entre esses dois grupos de atores sociais. Os resultados evidenciaram que, embora a criação de uma linha de crédito específica para a pesca artesanal no quadro do Programa Nacional de Fortalecimento da Agricultura Familiar (Pronaf) tenha origem em uma reivindicação do setor, o acesso aos recursos dessa linha ainda é muito baixo. A análise apontou que os sistemas de financiamento formais e informais adotados pelos pescadores artesanais estão imbricados nas relações sociais. Os sistemas de financiamento informais têm se mantido mesmo após a criação de uma linha de crédito para a pesca artesanal. A associação de oferta de serviços financeiros com a comercialização do pescado fortalece laços assimétricos de poder entre pescadores e atravessadores. O crédito oficial é acessado por um pequeno número de pescadores artesanais, prevalecendo formas tradicionais e informais de financiamentos pouco favoráveis aos pescadores.

Revision and updating of the antiarch (Placodermi, Vertebrata) fauna from the Devonian of Belgium with palaeobiogeographical considerations

Anatomical, systematic, and paleobiogeographical data on the Devonian antiarchs from Belgium are reviewed, updated and completed thanks to new data from the field and re-examination of paleontological collections. The material of Bothriolepis lohesti is enhanced and the species redescribed in more detail. An undetermined species of Bothriolepis is recorded from the Famennian of Modave (Liege Province), one species of Asterolepis redescribed from the Givetian of Hingeon and another one described from the Givetian of Mazy (Namur Province). Grossilepis rikiki sp. nov. is recorded from the Famennian tetrapod-bearing locality of Strud (Namur Province) and from the Famennian of Moresnet (Liege Province). It is the first occurrence of Grossilepis after the Frasnian and on the central southern coast of the Euramerican continent. Its occurrence in the Famennian of Belgium may be the result of a late arrival from the Moscow Platform and the Baltic Depression, where the genus is known from Frasnian deposits. Remigol...