Northeastern Coast Research Articles

Characterization and classification of wave storm events and wave climate on the Sea of Marmara

This study aims to conduct a wave climate study and provide a detailed analysis of wave storm events on the Sea of Marmara based on a 40-year (1979–2018) hindcast dataset. The accuracy of the used dataset was initially investigated in terms of both climatic and storm conditions using five-year (2013–2017) measurements of significant wave height (Hm0) at the Silivri buoy station. For the wave climate, the measurements’ 5-year mean and maximum Hm0 values were compared with SWAN hindcasts. To detect wave storm events from a time series, a critical value was determined by using the mean and standard deviation of the measurements. After that, the corresponding hindcasted storms with the measurements were detected. This analysis showed that the hindcasts are compatible with the measurements not only for climatic conditions but also for storm conditions. Monthly and annual variations of mean and maximum Hm0 were examined based on a 40-year long-term wave dataset and different return period Hm0 values based on annual maximums were determined at various locations. Wave storm events in the long-term analysis have been characterized and classified based on the storm energy density (Es) in five storm categories according to their energy. Temporal analysis of wave storm events shows that there has been an increase in the number and severity of storm events in recent years. The middle regions of the sea and the northeastern coasts of Marmara Island and Kapıdağ Peninsula are the most affected regions by extreme sea conditions.

Effects of typhoon and upwelling on Chlorophyll-a distribution in the northeastern coast of Hainan during Summer.

Typhoons or upwelling are thought to promote higher phytoplankton chlorophyll-a (Chl-a) concentration in many previous studies. However, the combined effects of typhoons and upwelling have been less studied in the South China Sea. Based on satellite remote sensing data, we investigated potential contributions of temperature-characterizing upwelling and typhoon events to Chl-a changes in the Hainan northeast area. Results showed that the Chl-a concentration was 0.80 mg m-3 at the coastal upwelling index (CUI) of 1.7°C in the summer of 2020 when there were no typhoons crossing the area. The CUI (1.01°C) of typhoon-influenced period in 2019 was 0.21°C higher than that of typhoon-free period in 2019. And the Chl-a also increased from 0.70 mg m-3 to 0.99 mg m-3. In comparison, during the typhoon-free period, with the higher CUI, there was the higher concentration of Chl-a. In addition, the typhoon affected Chl-a concentration is significantly higher than that in the other two typhoon-free periods of 2019 and 2020. Though the typhoon has a limited effect on the upwelling intensity, the Chl-a concentration is much higher than when the upwelling acts alone. This is due to the combined effect of typhoon (vertical mixing and runoff) and upwelling. The above results indicate that upwelling dominated the changes in Chl-a concentration in the Hainan northeast upwelling area during the typhoon-free period. In contrast, strong vertical mixing and runoff dominated the changes of Chl-a concentration during the typhoon-influenced period in the above area.

A widespread Ponto-Caspian invader with a mistaken identity: integrative taxonomy elucidates the confusing taxonomy ofTrichogammarus trichiatus(=Echinogammarus) (Crustacea: Amphipoda)

AbstractAmphipods have diversified greatly in the Ponto-Caspian region. Although many of these species are prominent invaders their systematics remains unclear. Taking an integrative approach, we investigate the taxonomy of Trichogammarus trichiatus, a widespread invader in European inland waters. It was initially described from the north-eastern Black Sea coast as Chaetogammarus trichiatus by Martynov in 1932. A similar taxon, Chaetogammarus tenellus major, was described by Cărăușu from the western Black Sea in 1943 but later synonymized with C. trichiatus. Chaetogammarus trichiatus was itself shuffled between Chaetogammarus and the Atlanto-Mediterranean Echinogammarus, currently being assigned to Trichogammarus. Our analyses (six DNA markers, 60 measurements and scanning electron microscopic imaging) reveal that T. trichiatus and C. tenellus major are distinct species; the former is a Caucasian endemic, whereas the latter invaded Europe. Unexpectedly, T. trichiatus is an incipient species molecularly nested in Chaetogammarus ischnus, despite pronounced morphological and geographical differentiation. We also recover Chaetogammarus as polyphyletic, yet its member species are nested in the Ponto-Caspian radiation, thus distinct from Echinogammarus. Consequently, we reassign T. trichiatus to Chaetogammarus (Chaetogammarus trichiatus), synonymize Trichogammarus with Chaetogammarus and place C. tenellus major in the new genus Spirogammarus gen. nov. (Spirogammarus major comb. & stat. nov.). Chaetogammarus necessitates further systematic refinement.

An erosive neritic area of Shantou in coastal NE South China Sea since at least MIS 5 revealed by OSL dating of cores

The neritic region of the Chaoshan plain is located on the northeastern (NE) boundary of the South China Sea (SCS). Despite the extensive research on the stratigraphic architecture and sedimentary processes within the Chaoshan plain, the neighboring neritic area remains largely unexplored. In this study, we provide a new set of ages on seventeen quartz optically stimulated luminescence (OSL) dating results from four cores (SY2-2, SY3-1, SY3-2, and HS02) to investigate the regional chronostratigraphy and sedimentology of the area. The samples were collected at depths ranging from 0.6 to 73.5 m and yielded ages ranging from 4.9 ± 0.3 ka to >139 ± 28 ka. Sedimentation thickness from cores SY3-2, SY2-2, and HS02 is less than 4.2 m, 5.5 m, and 6.4 m, respectively, since at least Marine Isotope Stage (MIS) 5, and the Holocene sediments of core SY3-2 are less than 4.2 m thick. The preservation state of the sediments in the area is poor since at least 83.6 ka, indicating an intensified erosion in the neritic region of the northeastern South China Sea (NESCS) since at least MIS 5. This erosion may have been caused by fluvial incision resulting from sea-level decline during the last glacial period, as well as strong transportation caused by coastal currents.

Geo-History Notes for the Study of Production of the Beach Space in Northeastern, Brazil

The present work aims to present some geohistorical notes about the production of beach space in Northeast Brazil, based on bibliographic research. The Brazilian beach space results from different social practices, some of which emerged through the absorption of behaviors and lifestyles arising from modern westerns. The social appropriation of beaches on the coast of the Northeast took place in the mid-19th century, when local elites turned to the sea, in the context of the incorporation of the so-called "modern maritime practices" (therapeutic baths, vacations, etc.), colonizing an environment previously intended only for “traditional maritime practices” (fishing, defense, and port activity). The transformation and consumption of these spaces were based on the establishment of second homes and infrastructure aimed at the development of tourist activity. In the first part of this article, we characterize the environment and socially on the Northeastern coast, in order to demonstrate the predominance of the beach environment and its social and economic value. Then we seek to discuss the production of beach space in the Northeast, pointing out the geohistorical factors linked to its valorization. Finally, we briefly present the process of production of beach space in a large northeastern city, Recife, highlighting the historical process of appropriation and valorization of its beaches.

A new species of planthopper in the genus Jamaha (Hemiptera: Fulgoroidea: Nogodinidae) from the Northeastern coast of Jamaica

A new species of Jamaha Gnezdilov & O'Brien, 2008, is described from Jamaica and compared with other species in the genus. A key to the species of Jamaha is provided. Molecular data for the five-prime region of the cytochrome c oxidase subunit I (COI) gene and 18S rRNA gene is provided and compared to available Colpopterini, with other Nogodinidae as the outgroup, for a preliminary phylogenetic analysis. While the Colpopterini grouped with high support, these data remain too sparse to draw firm conclusions.

Bioassessment of environmental quality based on taxonomic and functional traits of marine nematodes in the Bohai Sea, China

Free-living marine nematodes are valuable biological indicators for different environmental disturbances. Their taxonomic composition and functional traits often respond to environmental changes. In this study, marine nematodes, collected from the Bohai sea on the northeastern coast of China in 2014, were investigated in terms of their taxonomic composition and functional traits. Furthermore, the environmental quality of the investigated area was assessed based on nematode metrics. The studied nematode community showed spatial variation in taxonomic and functional composition, in response to changes in environmental variables such as sediment chlorophyll-a, phaeophytin-a, organic matter content, silt-clay content etc. Overall, high percentage of tolerant marine nematodes species or colonizers predominated, suggesting a disturbed environmental condition of the study area. Further results from the environmental quality assessment based on nematode metrics indicated a moderate quality status at the most investigated stations.

A comparative study on antioxidant activity of propolis ethanolic extract and oil from different agroclimatic regions of Eastern India

Propolis is a honey bee product with a rich source of natural antioxidants due to its flavonoids and phenolic acids. Propolis has broad biological effects such as dysentery, eye diseases, wound healing, fever, ulcer, skin rashes, scorpion stings, oral infections, diarrhea, liver disorders, etc., and has been used as folk medicine since ancient times. The primary objective of this study was to determine the antioxidant potency of propolis oils from various agroclimatic regions. The in vitroantioxidant activity of different agroclimatic regions of propolis oils and the ethanolic extracts were studied using DPPH, hydroxyl radical, nitric oxide, and ABTS assay. This research found that propolis oil from South Eastern Ghat had a higher antioxidant activity with IC50 values for DPPH, ABTS, and hydroxyl radicals were 120.74 ± 2.83, 15.24 ± 0.74, and 34.30 ± 1.95 μg/mL, respectively. While propolis ethanolic extract from North Eastern Coastal Plain showed a higher radical scavenging effect with IC50 values for DPPH, nitric oxide, and hydroxyl radical were 123.12 ± 3.10, 28.07 ± 0.67, and 26.24 ± 0.79 μg/mL, respectively. According to the findings, the ABTS assay revealed more potent antioxidant activity in propolis than other methods. As a result, it was found that propolis oil has the highest antioxidant activity than the propolis ethanolic extract, and it can be used as a potent natural antioxidant source.

Population dynamics and reproduction of the ghost shrimp Fragillianassa fragilis (Biffar, 1970) (Axiidea: Callianassidae) in a sand-mud bank on the northeastern coast of Brazil

Population dynamics and reproduction of the ghost shrimp Fragillianassa fragilis (Biffar, 1970) (Axiidea: Callianassidae) in a sand-mud bank on the northeastern coast of Brazil

Masked diversity and contrasting soil processes in tropical seagrass meadows: the control of environmental settings

Abstract. Seagrass meadows are among the most valuable ecosystems on Earth. However, in tropical countries, there is a substantial knowledge gap in “seagrass science”. To address this gap, seagrass soils from three Brazilian coastal regions were investigated (the northeastern, southeastern, and southern coasts). Soil profiles from different geological and bioclimatic settings were sampled, described, and analyzed. Thus, detailed macromorphological descriptions, soil classification, physicochemical analysis (soil particle size, soil pH, pHoxidation, Eh, total organic carbon: TOC), Fe partitioning, and X-ray diffractometry were performed. Additionally, water samples were analyzed for pH, salinity, and ion concentrations. Different environmental settings in the coastal compartments produced contrasting geochemical conditions, which caused different intensities of pedogenetic processes. On the northeastern coast, the denser plant coverage favored higher TOC contents (2.5 ± 0.1 %) and an anaerobic environment (Eh = +134 ± 142 mV) prone to an intense sulfidization (i.e., pyrite formation: Py-Fe). Py-Fe contents in northeastern soils were 6- and 2-fold higher than in southeastern and southern coastal soils, respectively. Conversely, lower TOC contents (0.35 ± 0.15 %) and a suboxic environment (Eh + 203 ± 55 mV) in the southeastern soils, along with the Fe-rich geological surroundings, decreased the intensity of gleization. The contrasting intensities in the soil processes, related to the (seemingly subtle) differences in the geochemistry of each environment, ultimately caused relevant pedodiversity among the studied sites. Our findings contribute to a better understanding of the general functioning of tropical seagrass meadows but also have significant environmental implications for studies focused on carbon sequestration in these ecosystems.

Winter distribution and abundance of humpback whales (Megaptera novaeangliae) off Northeastern Brazil

The Brazilian coast is recognised as a Southern Hemisphere humpback whale (Megaptera novaeangliae) wintering ground (IWC breeding stock ‘A’). The northeastern coast of Brazil was an important whaling ground in the 20th century. Shipboard sighting surveys were conducted in this area to evaluate large whales’ distribution and density in 1999 and 2000. Humpback whale sightings (n = 81, 153 individuals) were recorded using line transect methodology. Data from the 2000 survey were used to estimate abundance over the continental shelf from 5 to 12°S (20,040km2 ). A total of 872.1km were surveyed on effort. Humpback whales were distributed from nearshore to the 800m isobath, but 93.5% of sightings were recorded shoreward of the 300m isobath. The relatively high density off northeastern Brazil suggests that the species is reoccupying historical areas of distribution and the presence of newborn individuals indicates that calving and nursing occur in the area. The hazard rate model best fit perpendicular distance data. Abundance was estimated at 628 individuals (CV = 0.335, 95% CI = 327-1,157). This estimate probably corresponds to only a portion of the breeding population. Therefore, additional studies must be conducted to estimate the total size of the humpback whale population wintering off Brazil.

Dynamics of particulate black carbon in the South China Sea: Magnitude, resident timescale, sinking speed, and flux

The dynamics of particulate black carbon (PBC) in marine environments are poorly understood. Here, radioactive 234Th was used to constrain the resident timescale, settling speed, and sinking flux of PBC (soot) in the coastal Northeastern South China Sea (NSCS). The PBC concentration varied from 0.013 μg-C L−1 to 4.340 μg-C L−1. Spatially, PBC showed an exponential decrease offshore, with a coefficient of 0.030 ± 0.004. Compiling available data, an empirical formula of PBC = a e−0.032x (x is the distance offshore) was proposed for predicting the descent of PBC offshore in coastal seas. Residence times of 0.8–13 d indicate that PBC is retained for days, implying its limited dispersal to the open sea. For the first time, the settling speed of PBC was evaluated in seawater, which averaged 8.8 ± 7.1 m d−1. These results highlight that bottle-sampled PBC falls mainly into the slow-sinking particle continuum in marine environments, due to its fine size. The sinking flux of PBC averaged 4.57 mg-C m−2 d−1 in the coastal NSCS. Using the sinking speed, the preliminarily estimated sinking rate of PBC was 23.8–1800 Tg-C yr−1 on global shelves. The crucial dynamic parameters of PBC provide insights into its internal cycling in coastal seas and can be used as model parameters for assessing global PBC.

The Role of Clay Minerals in the Petrophysical Properties of Carbonate Rocks from the Cotinguiba Formation (Sergipe-Alagoas Basin, Brazil)

The Cotinguiba Formation, of Cretaceous age, located in the Sergipe-Alagoas Basin, Brazilian Northeastern coast, comprises carbonate breccias and carbonate shales interlayered with fine to coarse clastic sediments (mudstones, marls), deposited in the maximum sea level episode during the Cenomanian-Coniacian transgressive event. Core sections were selected from the formation materials, from which 20 plugs were obtained, representing the main carbonate horizons present in Cotinguiba Formation. The selected samples were analyzed with petrophysical and physical methods (air porosimetry, mercury injection, and acoustic wave velocity) and mineralogical methods (optical microscopic analysis, x-ray diffraction (XRD) and scanning electron microscopy (SEM)). Results showed that the clay minerals’ content in the carbonates varies from 2% to 20%, with illites/micas and interstratified illite/smectite as the most abundant clay minerals, containing also traces of chlorite and kaolinite, and presence of palygorskite varying from trace to 8%. According to the percentages of calcite, dolomite, and siliciclastic + clay minerals obtained in the XRD analysis, the carbonates were lithologically identified as limestone, impure limestone, dolomitic limestone, impure dolomitic limestone, impure calcitic dolostone, and impure dolostone. The rocks have a good porosity, varying from 6% to 20% in the carbonates, predominantly related to microporosity. Clay minerals’ content influenced the grain density and acoustic properties, albeit not having the same role with porosity and permeability. SEM images, though, show that they have an important role in microporosity. Grain density variation related to phyllosilicate content was observed more significantly in impure limestones with a clay content higher than 8%, and a more pronounced decrease was observed in samples with palygorskite. Microporosity is the main factor for reducing Vp and Vs velocities in those carbonates, with values not exceeding 5341 m/s for Vp and 3026 m/s for Vs but, when clay content is higher than 4%, the Vp and Vs wave velocities do not exceed 4100 m/s and 2480 m/s, respectively. Therefore, the research allowed evaluating the influence of mineralogical and textural properties in the petrophysical properties of Cotinguiba Formation.

Comparative Morphometric Analysis of the Azov Anchovy (<i>Engraulis encrasicolus maeoticus</i> Pusanov, 1926) and the Black Sea Anchovy (<i>E. encrasicolus ponticus</i> Alexandrov, 1927) Based on the Body Shape

A comparative analysis of body shape was performed on 841 specimens of anchovy collected from 21 catches from the Sea of Azov, the Kerch Strait, and the Black Sea off the Crimea and the northeastern coast of the Caucasus in 2006–2007 and 2016–2017. Twenty-three measurements between 12 homologous landmarks of the body of each specimen according to the “Truss Network System” served as characters for analysis. Fifteen characters showed significant differences between the Azov anchovy Engraulis encrasicolus maeoticus Pusa-nov, 1926 and the Black Sea anchovy E. encrasicolus ponticus Alexandrov, 1927. Specimens of the Azov subspecies had larger relative values for all characters of the head region, the height of the trunk region, the re-lative length of the bases of the dorsal and anal fins, and the height of the base of the caudal fin. Specimens of the Black Sea subspecies had a greater postdorsal length and a larger distance from the end of the dorsal fin base to the end of the anal fin base. A multivariate principal component analysis revealed the highest variabi-lity of characters of body height, which depends on the fatness of the fish and demonstrates seasonal dyna-mics. The second group combines characters that do not have a seasonal component (dimensions of the head region, lengths of the bases of the dorsal and anal fins, and postdorsal distance) and can be used for distinguishing the shape of the Azov and Black Sea anchovies. The success rate of classification of Azov and Black Sea anchovies according to the body shape measurement characters using the discriminant analysis was 83.4%.

Een boom op Walcheren, meer dan een stip op de (Bonne)kaart

A tree on Walcheren, more than a dot on the (historical) map Topographical maps, even when consulted numerous times, can suddenly reveal a name, a number, an element never noticed before. The so-called Bonnekaart (page 616, edition 1926) shows the word ‘Boom’ (tree), halfway Vrouwenpolder and Veere, on the north-eastern coast of Walcheren (Zeeland). Which function can be attributed to this specific and marked tree to legitimate it being mentioned on the map? In this article we distinguish and judge several possibilities.

Spatiotemporal variations and the ecological risks of organophosphate esters in Laizhou Bay waters between 2019 and 2021: Implying the impacts of the COVID-19 pandemic

Organophosphate esters (OPEs) are a group of synthetic chemicals used in numerous consumer products such as plastics and furniture. The Coronavirus Disease 2019 (COVID-19) pandemic significantly slowed anthropogenic activities and reduced the emissions of pollutants. Meanwhile, the mismanagement of large quantities of disposable plastic facemasks intensified the problems of plastic pollution and leachable pollutants in coastal waters. In this study, the joint effects of the COVID-19 outbreak on the occurrence of 12 targeted OPEs in the waters of Laizhou Bay (LZB) were investigated. The results showed that the median total OPE concentrations were 725, 363, and 109 ng L−1 in the sewage treatment plant effluent, river water, and bay water in 2021, decreased significantly (p < 0.05) by 67%, 68%, and 70%, respectively, compared with those before the COVID-19 outbreak. The release potential of targeted OPEs from disposable surgical masks in the LZB area was ∼0.24 kg yr−1, which was insufficient to increase the OPE concentration in the LZB waters. The concentrations of most individual OPEs significantly decreased in LZB waters from 2019 to 2021, except for TBOEP and TNBP. Spatially, a lower concentration of OPEs was found in the Yellow River estuary area in 2021 compared with that before the COVID-19 pandemic due to the high content of suspended particulate matter in the YR. A higher total OPE concentration was observed along the northeastern coast of LZB, mainly owing to the construction of an artificial island since 2020. The ecological risks of the OPE mixture in LZB waters were lower than those before the COVID-19 outbreak. However, TCEP, TNBP, and BDP should receive continuous attention because of their potential ecological risks to aquatic organisms.

Observations of western gray whales by ship-based whalers in the 19th century

Animals belonging to the small, endangered population of western gray whales (Echrichtius robustus) are observed today primarily during the summer open-water season in feeding areas off the northeastern coast of Sakhalin Island, Russia. The migration route(s) and wintering area(s) used by this population are largely unknown. Gray whales once had a fairly extensive distribution in the Sea of Okhotsk but little detailed information has been published on when and where they occurred. Open-boat, ship-based whalers from the United States and a few other countries conducted an intensive hunt for bowhead whales (Balaena mysticetus) and North Pacific right whales (Eubalaena japonica) in the Sea of Okhotsk from the 1840s to 1870s. According to entries in voyage logbooks, the American whalers regularly encountered (and sometimes hunted) gray whales in the far northeastern corner of the Okhotsk Sea (Shelikhov Bay, Gizhiginskaya Bay and Penzhinskaya Gulf) between early May-late August. They also observed gray whales in summer along the northern coast of the sea (especially Tauskaya Bay), around the Shantar Islands, in Sakhalin Bay, off Cape Elizabeth at the northern tip of Sakhalin Island and along the west coast of the Kamchatka peninsula. No evidence was found in the logbooks studied of gray whales (and indeed of whaling effort) off northeastern Sakhalin Island where most observations of gray whales occur in the present day.

Baseline data on abundance, site fidelity and association patterns of common bottlenose dolphins (Tursiops truncatus) off the northeastern Tunisian coast (Mediterranean Sea)

The common bottlenose dolphin has been studied intensively in numerous locations around the world but very little is known about this species along the South Mediterranean Basin. In this study, the temporal distribution of dolphins, group dynamics, site fidelity and association patterns of common bottlenose dolphins along the northeastern coastal waters of Tunisia was assessed through mark-recapture photo-identification techniques. Prior to this study, no research has focused on bottlenose dolphins within these waters, despite the potential for human impacts on this species. A total of 718h of boat-based observations, spanning 284 days, were spent at sea between August 2008 and July 2010. During this period, 253h were spent in direct observation of 317 groups of common bottlenose dolphins. Bottlenose dolphins were observed in all seasons, although seasonality was evident, with more encounters during the summer. Photo-identification studies show that 43 individuals used the northeastern coast of Tunisia on a regular basis, while others were present less often. Based on a social structure analysis it was possible to discriminate different communities related with the spatial distribution of the sightings (Zembra island, Hammamet, Kelibia and Galite island).

New records of marine molluscs for the northeastern coast of Cuba

New records of marine molluscs for the northeastern coast of Cuba

Hydrogeophysical and Hydrochemical Assessment of the Northeastern Coastal Aquifer of Egypt for Desalination Suitability

Recently the limited freshwater resources have become one of the most significant challenges facing Egypt. Thus, new resources of drinkable water are required to meet the growing population demands and the national projects, to support the country’s economy. Saline groundwater desalination is an option that can support limited freshwater resources. This research represents a detailed analysis of hydrogeological and hydrochemical characteristics of a coastal aquifer in the West Port Said area, northeastern Egypt, to assess the desalination suitability of the aquifer, especially when the nearby seawater is contaminated. The hydrogeological characterization included various integrated approaches: geophysical survey, field investigations, wells drilling, well logging, pumping tests, and water sampling. The results show that: (1) The subsurface lithology consists of sandstone and clay, and three water bearing layers: A, B and C. (2) The average porosity values are 22%, 27.5%, and 25% for layers A, B, and C, respectively. The hydraulic conductivity values fall in the ranges of 5.8–12.7 m/day for layer A, 7.6–11.7 m/day for layer B, and 11.1–19.5 m/day for layer C, while the highest transmissivity values are in ranges of 5.8 × 102–12.7 × 102 m2/day for layer A, 7.6 × 102–11.7 × 102 m2/day for layer B and 11.1 × 102–19.5 × 102 m2/day for layer C. (3) The average storage values are 2.1 × 10−3, 1.8 × 10−3 and 5.3 × 10−3 in layers A, B and C, respectively. (4) Layers A and B showed Na-Cl-type, similar to seawater, but free from oil pollution. These results show layer B’s higher productivity and better quality. Despite the salinity, desalination technology can improve.