Northern Coast Research Articles

Reproductive phenology and pollination biology of the wild pineapple Ananas bracteatus (Bromeliaceae): an analysis based on field and herbarium records

ABSTRACT Ananas Mill., notably known for pineapple cultivation, is one of the most recognized genera of the Bromeliaceae. Despite its agricultural significance, the phenology of wild Ananas species remains poorly understood, leading to a problematic issue because understanding their reproductive cycle is necessary to better predict the effects of climate change on their populations. This study investigated the reproductive phenology, pollination, and floral biology of Ananas bracteatus (Lindl.) Schult. & Schult.f., an endemic species from the eastern coast of South America, through observations in an Atlantic Forest fragment on Bahia’s northern coast. We estimated its flowering and fruiting periods by interpolation using Inverse Distance Weighting (IDW) based on herbarium collections, using the speciesLink database. Ananas bracteatus exhibited a highly seasonal flowering, and continuous fruiting throughout the year, primarily influenced by temperature, and related to the long maturation period of its infructescence. IDW proved highly effective showing a high probability of A. bracteatus blooming between August and December and fruiting throughout the year. The flowers remain viable throughout anthesis and pollination is conducted by two efficient pollinators: Chionomesa frimbriata Gmelin, 1788 and Eupetomena macroura Gmelin, 1788. The application of innovative methodologies, such as IDW, can address research gaps in biodiverse regions like Brazil’s Atlantic Forest, where long-term phenological studies, vital for the conservation and management of species, are often limited and scarce.

Impacts of Along-Strait Winds on Sea Level, Sea Surface Temperature, and Current in the Jeju Strait During Summer 2022

The along-strait wind in the Jeju Strait (JS) significantly impacts the sea level, surface temperature, and currents on its northern and southern coasts. During the summer of 2022, the winds in the JS were characterized by strong easterly winds that occurred before the approach of several typhoons. A strong correlation of 0.61 was found between the along-strait wind and the difference in sea level anomaly between the strait’s south and north coasts. A more robust correlation of 0.71 was estimated between the along-strait wind and the difference in sea surface temperature anomaly. When the positive (eastward) wind blows along the strait, it causes upwelling along the north coast, resulting in cold anomalies there and warm anomalies along the south coast, and vice versa. In addition, a positive correlation (r = 0.39–0.50) was estimated between the along-strait wind and along-strait surface current, with a negative correlation (r = −0.68 to −0.44) for the cross-strait current in most observation stations of the JS, except near the coast of Jeju Island. The positive along-strait wind causes the sea level to fall on the north coast and strengthens the eastward surface current. In contrast, the negative (westward) along-strait wind has the opposite effect, causing the sea level to rise near Wando, then slowing down or reversing the eastward surface current. Overall, these findings show that Ekman dynamics can explain wind-induced coastal upwelling and downwelling on both coasts of the JS, providing valuable insights into the environmental conditions surrounding marine organisms in this coastal region.

BDCN_UNet: Advanced shoreline extraction techniques integrating deep learning

The delineation of shorelines, marking the dynamic boundary between land and sea, is crucial for coastal management and ecological conservation. This research investigates various methods for automatic shoreline extraction from satellite images, utilizing cost-effective and regularly available remote sensing data. A deep learning framework is used for the comparison that combines semantic segmentation (UNEt) and edge detection (Bi-Directional Cascade Network, or BDCN) to make the results more accurate. The study focuses on the northern coast of Egypt, a region with diverse landscapes and significant human interventions. We’ve made progress in our methods by using advanced image processing, the CoastSat Toolkit, the BDCN_UNet framework, time series analysis, and deep learning networks to look at and keep an eye on Egypt’s North Coast’s future plans in more detail. This study captures the intricate interplay between natural and human factors in coastal environments, offering valuable insights for sustainable coastal development. The performance analysis of four models (UNet, Pyramid Scene Parsing Network, DeepLabV3, and BDCN_UNet) applied to three satellite datasets (Sentinel-2, PlanetScope, and Pleiades) showed that PlanetScope and Pleiades consistently yield higher accuracy (0.90–0.99), while Sentinel-2 proved more challenging, particularly for Pyramid Scene Parsing Network and DeepLabV3. UNet and BDCN_UNet exhibited robust performance across all datasets, especially with Pleiades delivering the best results overall.

From Dry to Temperate: How Climate Change Alters Growing Seasons?

ABSTRACTThe thermal growing season, which represents a plant's theoretical growth season, is a key indicator of phenology's response to climate change. Using thermal growing season indices (start, end and length) and their sensitivity to air temperature, this study examines how climate change impacts them. For various climate types of Iran, Mann–Kendall and Sen's slope tests were applied to examine trends in thermal growing season indices at two temperature thresholds: 5°C (for cold‐season plants) and 10°C (for tropical plants) between 1995 and 2020. Using a novel heuristic algorithm, multiple linear regressions were used to determine the most influential seasonal air temperature indices including mean, range and extreme on thermal growth indices as well. Plants in cold and temperate climates experienced significant early onset and lengthening of their growing seasons, with tropical plants on northern coasts experiencing the earliest onset (14.7 days/decade) and the lengthening growing season (16 days/decade). For plants in cold climates, the end of the growing season was also delayed (5 days/decade). The onset growth season was most sensitive to spring minimum and average temperatures in cold and temperate climates, while it was most sensitive to winter average temperatures in dry climates. In cold climates, changing spring and winter temperature ranges also affected the onset of the growing season, while in dry climates, changing autumn temperature ranges affected the end of the growing season. However, extreme temperatures only affect the end of the growing season in temperate climates. Furthermore, the early onset of the growing season is the primary factor contributing to the lengthening of the growing season in all climates. The findings of this study can assist in developing and implementing agriculture and water resource management strategies that mitigate climate change's adverse effects.

Recent progress in tsunami deposit investigations in Taiwan

Abstract Identifying deposits of modern/historical and prehistorical tsunamis in Taiwan has been successful in the past two decades and has substantially increased the extant tsunami catalogs, which have been limited in the past four centuries due to scarce and ambiguous historical accounts. In this review, the initiation of the investigation is briefly discussed, partly in response to the latest catastrophic tsunamis in the Indo-Pacific and the stimulated public concern in Taiwan. Major developments and results of the investigation include the onset of the first stage before 2010, with findings in Keelung, the eastern coast, and Lanyu Island, and the second/ongoing stage after 2013, with findings in the northern and eastern coasts and Penghu Islands. These findings contributed to validating the debated historical events, expanding the event number and time span of the tsunami catalog, and elaborating on tsunami processes, which collectively enabled the delineation of the recurrence time intervals between events. Limitations, uncertainty, further contributions, and feedback are discussed including insights into the regional western Pacific hazards of tsunamis, earthquakes, and volcanic eruptions; the principles of recognizing tsunami deposits and processes; and the propositions of future studies and hazard mitigations in Taiwan.

Surface exposure ages of middle–late Pleistocene marine and fluvial terraces along the northern and southern Sanriku coasts, Northeast Japan

To estimate long-term rates of coastal uplift along the northern Pacific coast of Northeast Japan, we determined the surface exposure ages of marine and fluvial terraces based on terrestrial in situ cosmogenic radionuclide dating of exposed bedrock surfaces. Based on reinterpretation of marine and fluvial terraces, we collected samples from the northern and southern Sanriku coast. The surface exposure ages from 10Be concentrations in quartz calculated from the measured 10Be/9Be ratios commonly suggest MIS 5 and MIS 7 for the marine and fluvial terraces and averaged coastal uplift rates of ca. 0.25 ± 0.15 and 0.4 mm/yr along the northern and southern Sanriku coast at intermediate timescales. The results may demonstrate different styles of crustal strain accommodation in the northern Northeast Japan arc above the subducting Pacific plate.

LENGTH-WEIGHT RELATIONSHIP OF 55 SPECIES OF FISH CAUGHT BY ARROWHEAD FIXED TRAPS “CURRAIS” IN THE COAST OF PERNAMBUCO (BRAZIL)

The length-weight relationship (LWR) of 55 species was estimated in captures conducted in arrowhead fixed traps off the northern coast of Pernambuco (Northeast, Brazil) using frequentist and Bayesian statistical approaches. The fish were obtained between the months of May 2014 and November 2020, with one or two days of sampling each month. The most diverse families were Carangidae and Haemulidae with 13 and 10 species, respectively. A new maximum length was recorded for Oligoplites saurus. Except for Odontoscion dentex, all other species exhibited condition factor values greater than 1.00. The species Chloroscombrus chrysurus, Diapterus auratus, Diapterus rhombeus, Harengula clupeola, O. saurus, and Opisthonema oglinum showed continuations of their estimates from previous Bayesian analyses, contributing to the improvement of data for these species. Keywords: Somatic growth, traditional fishing, tropical waters, condition factor, bayesiananalysis.

Distribution and Affecting Factors of Aragonite Saturation in the Northern South China Sea in Summer

Based on the carbonate and hydrological parameters of a survey made in August–September 2011, we investigated the distribution and affecting factors of aragonite saturation (Ωarag) in the northern South China Sea. The levels of Ωarag were found to gradually decrease with depth in the northern South China Sea. Surface-water Ωarag values ranged from 2.56 to 3.68, with the highest value occurring in the region of Pearl River-diluted water near the northern coast. The increase in Ωarag due to primary production, stimulated by the Pearl River freshwater input, exceeded the decrease in Ωarag due to the direct input of low-Ωarag fresh water, resulting in high Ωarag in that area. In contrast, Ωarag levels below 2 generally appeared in subsurface water below 50 m in depth. Intense community respiration was the main reason for the low Ωarag. By 2100, bottom-water Ωarag levels could be lower than 1.7, and even the undersaturation of aragonite could appear, due to the oceanic absorption of atmospheric CO2.

Vaucheria macounii comb. et stat. nov. (Vaucheriaceae, Xanthophyceae): first occurrence in Europe and notes on the species

The article provides data on the first occurrence of Vaucheria longicaulis var. macounii Blum (Vaucheriaceae, Xanthophyceae) from the White Sea, an internal sea in northern European Russia. Originally described from the Pacific coast of the USA (Washington), the variety was subsequently found only in British Columbia, Canada. In 2021, the alga was first found in three localities on the northern coast of the Onega Peninsula. In 2022, it was found throughout collections from the eastern coast of the Onega Bay, indicating its much wider distribution. These records are considered the first in Russia, Europe, and the Arctic Ocean. The observations allowed the expansion of the morphological range of the variety in terms of shape and dimensions of gametangia. Due to significant differences in the shape and length of antheridia from the nominate variety of V. longicaulis, the raising of the variety to species level, as V. macounii, is proposed here.

SPATIO-TEMPORAL VARIATION OF PROCHRISTIANELLA SP. (CESTODA: TRYPANORHYNCHA) IN THE HOST OCTOPUS MAYA (CEPHALOPODA: OCTOPODA) AND ITS RELATIONSHIP WITH THE REPRODUCTION.

Although harvest of Octopus maya (Mexican four-eyed octopus) is one of the most important fisheries in the Yucatan Peninsula, little is known about the parasites of these cephalopods and how they affect host physiological processes. We analyzed the spatio-temporal variation of infection of O. maya by the cestode larva Prochristianella sp. (found in the anterior salivary glands) and its relationship with the gonad development stages (GDSs) of the host. From August 2009 to May 2010, 439 specimens of O. maya were caught in 2 localities on the northern coast of the Yucatán Peninsula: Dzilam de Bravo (n = 239) and Ria Lagartos (n = 200). The mantle length, eviscerated body weight, reproductive complex weight, and gonad weight were recorded in each specimen. Portions of each gonad were used to identify the GDS based on histology for each individual to determine the periodicity of the reproductive cycle and the monthly variation in the reproductive complex weight. Temporal variation in the monthly mean abundance of cestodes but not in prevalence was evident. A permutational multivariate analysis of variance indicated that variation in the mean abundance of Prochristianella sp. was affected by host GDS, month of sampling, host sex, and sampling locality; however, the first-order interactions indicated that the most were important variables were GDS, month, and host sex. General linear model analyses also indicated that the size, reproductive status, and sex of the hosts were significantly related to the abundance of cestodes. Temporal variation was evident in the monthly mean abundance of Prochristianella sp. but not in its prevalence; the number of parasites increased in octopuses from September to December. Regarding the GDS, the mean abundance of the parasite increased as gonads developed, and gonad development was related to water temperature and time, which are linked to season and the upwelling that occurs in spring and summer. In the oral cavity of octopuses, variations in cestode abundance related to host sex, size, and reproductive status can have major implications for the production of saliva, an essential secretion for food acquisition and defense in this host, and could affect octopus reproduction and recruitment of this food resource so important for the Yucatán Peninsula.

Getting Scarce and Lure Shy: Impacts of Recreational Fishing on Coastal Northern Pike (Esox lucius) Abundance, Size Structure and Vulnerability to Angling

ABSTRACTControlled experiments have shown that northern pike (Esox lucius) is able to develop lure avoidance, but whether such patterns exist in the wild is unknown. We assessed the impact of recreational fishing on a natural population of pike in the southern Baltic Sea, from samples of three pairs of partially protected areas (pMPA) and nearby unprotected sites. Pike were 2–4 times more abundant inside pMPAs than outside in sites open to fishing. The mean size of pike was not greater in pMPAs, but protected sites hosted more exceptionally large fish than sites open to fishing. Pike in sites with reduced recreational fishing effort were more aggressive to artificial lures. About one‐third of the catch rate differences among pMPAs and open sites could be attributed to lure shyness. Collectively, our work shows that recreational fisheries exploitation of coastal pike reduced abundance, truncated the size structure of the largest individuals, and contributed to fisheries‐induced timidity through reduced reactivity to lures.

Северный морской путь: прошлое, настоящее, будущее. Итоги международного научного мегапроекта

The author characterizes the idea, concept, implementation process and results of the international scientific project devoted to the history, modernity and prospects of the Northern Sea Route devel-opment, which resulted in a collective monograph published in 2022. The content and structure of this publication are presented, its participants, scientists from four European countries, are indicated. The au-thor examines how this book reveals the most significant milestones of the historical past of this maritime communication, starting with the development of navigation in the European part of the Arctic and the emergence of the idea of the possibility of passage between Europe and Asia, from the Atlantic to the Pacific Ocean along the Eurasian northern coast of Russia, which was called the Northeast Passage. The research compares the results of scientific investigations and search for a through passage from Europe to Asia by this waterway, as well as exploration of its parts and organization of navigation. The author characterizes the transformation of the Northeast Passage into the Northern Sea Route and the organization of its permanent operation and through navigation in the 20th century. The article analyzes the contradictory trends in the development of the Northern Sea Route in the beginning of the 21st century, as well as possible scenarios for its future. The article also reveals the process of studying the history of the Northeast Passage/Northern Sea Route over several centuries and identifies the most significant studies published in Russia and abroad.

Viral niche-partitioning: comparative genomics of giant viruses across environmental gradients in a high Arctic freshwater-saltwater lake.

Giant viruses (GVs; Nucleocytoviricota) impact the biology and ecology of a wide range of eukaryotic hosts, with implications for global biogeochemical cycles. Here, we investigated GV niche separation in highly stratified Lake A at the northern coast of Ellesmere Island, Nunavut, Canada. This lake is composed of a layer of ice-covered freshwater that overlies saltwater derived from the ancient Arctic Ocean, and it therefore provides a broad gradient of environmental conditions and ecological habitats, each with a distinct protist community and rich assemblages of associated GVs. The upper layer (mixolimnion) had measurable light and oxygen, and contained diverse GVs linked to photosynthetic protists, indicating adaptation to surface biotic and abiotic conditions. In contrast, the saline lower layer (monimolimnion), lacking oxygen and light, hosted GVs associated with predicted heterotrophic protists, some of which are known for a predatory lifestyle, and with several viral genes suggesting adaptation to deep-water anaerobic conditions. Our observations underscore the coupling between physical and chemical gradients, microeukaryotes and their associated GVs in Lake A, and provide insight into the potential for GVs to directly and indirectly impact host metabolism. There were similarities between the genetic composition of GVs and the metabolic processes of their potential hosts, implying co-evolution and niche-adaptation within the lake habitats. Notably, we found a greater presence of viral rhodopsins in deeper water layers, suggesting an evolutionary relationship with potential hosts capable of supplementing their energetic needs to thrive in low energy, anoxic conditions.

Landscape changes caused by the 2024 Noto Peninsula earthquake in Japan.

Landscapes are shaped by tectonic, climatic, and surface processes over geological timescales, but we rarely witness the events of marked landscape change. The moment magnitude 7.5 Noto Peninsula earthquake in central Japan was caused by a large thrust faulting, up to nearly 10 meters of slip, that expanded more than 150 kilometers along the fault zone. The deformation field reconstructed from satellite data and field surveys reveals up to 4.4 meters of uplift and associated coastal advance along the entire northern coast of the peninsula, meter-scale systematic movement of the mountain slopes consistent with slip on flexural faults, and activation of secondary inland faults, suggesting synchronized ruptures. The findings show excellent consistency between the coseismic deformation and geomorphic features and provide a vivid example of the role of a major earthquake in landscape formation.

Thin‐Plate Spline Interpolation Spatial Modelling of GNSS Retrieved Water Vapour Over Northeast Japan

ABSTRACTThe study investigated precipitable water vapour (PWV) variation over Northeast Japan by using more than two decades (2000 to 2022) of measurements. These data have been extracted from 36 Global Navigation Satellite System (GNSS) networks and interpolated with thin‐plate spline interpolation to understand its spatial variation over the region. PWV annual and seasonal variation is studied and correlated with ERA5 reanalysis observations. These PWV variation shows that the northern part of Northeast Japan which is located at higher latitudes showed a smaller magnitude compared to PWV magnitude in the southern part of low latitudes. This is possible because the cold air is drier and the warm air holds more moisture in the lower southern part. The correlation coefficient variation based on geographical area is visible which quantifies the consistency between GNSS PWV and ERA5 and visualises the effects in sampling. The southern part, where the correlation coefficients are very high (more than 0.80), indicates good agreements between GNSS PWV and ERA5 values and can be considered well‐sampled observations. Moreover, the correlation coefficients drop the values to approximately 0.40–0.60 for poorly sampled observations on the northern coast, pointing out the interannual inconsistency of PWV measurements, which are loosely related to ERA5 observations. Finally, the correlation coefficient between PWV with surface temperature and atmospheric pressure over Northeast Japan is investigated. This is clear from the results that the correlation coefficient between PWV and temperature is around 0.98 for each site, indicating that PWV has a very high dependency on surface temperature. The correlation coefficient between PWV and pressure is highly negative around −0.80, indicating their inverse relationship. We believe the outcomes from this study will contribute to a better understanding of PWV over Japan and the future refinements of atmospheric models over the East Asian region.

Darazya at El Alamein: a Greco-Roman settlement against the backdrop of an important Second World War battle

Abstract Ancient geographers and travellers of the early nineteenth and twentieth centuries described localities on the northern coast of Egypt, including the Hellenistic-Roman town ruins known today as Darazya. Impressive Second World War structures are also scattered there. Research initiated in 2021 will broaden insights into the history of the region.

Comparing ERA5 reanalysis and in situ wind databases to characterize windstorms causing Tehuelche scallop beach strandings in San José gulf, Patagonia.

Windstorm patterns associated with beach strandings of the commercially important Tehuelche scallop, Aequipecten tehuelchus, in San José Gulf, Patagonia, were analyzed to understand the windstorms recurrence given their potential impact on the dynamics of the resource. Although the phenomenon of scallop strandings has been recognized for a long time, the lack of environmental records has made it difficult to thoroughly study the meteorological conditions that trigger these events. The availability of reanalysis data has the potential to address this data gap; however, its feasibility must first be validated. To address this, the first step was to characterize and compare hourly wind intensity (m/s) and direction (degrees) data from the fifth-generation global climate reanalysis (ERA5), provided by the European Centre for Medium-Range Weather Forecasts, with in situ wind data for the 2013-2020 period. The study focused on wind conditions during reported Tehuelche scallop strandings along the northern coast of the gulf. Subsequently, a historical search for southerly windstorms with characteristics similar to those responsible for past strandings was conducted using the ERA5 database, covering the period from 1950 to 2023. Overall, ERA5 accurately captured the dates, durations, intensities, and directions of southerly windstorms at high temporal resolution (hourly), though with a slight tendency to underestimate wind intensities of higher winds. The estimated mean annual frequency of ERA5-detected southerly windstorms with intensities higher than 11m/s was 5.4 storms per year, with durations ranging from 12 to 74h. These windstorms can occur throughout the year, with an increased frequency and duration during winter. ERA5 proved to be a valuable tool for characterizing windstorms, complementing in situ data and providing insight into past stranding events where no observational data were available.

Advance in the search for precursors of earthquakes associated with underwater methane seeps off the northern coast of Bulgaria

The aims of the publication are to provide a brief overview of research in Bulgaria to search for earthquake precursors related to gas/methane manifestations mainly in the water area in front of the Bulgarian coast and of known Bulgarian devices for monitoring gas emissions, as well as to propose a new monitoring site of underwater gas sources, and studying the relationship between earthquakes and gas emissions. As a result of conducted neotectonic studies, of Quaternary sediments, based on interpretation of seismoacoustic profiles and detailed seismostratigraphic interpretation of Quaternary sediments, attachment of registered gas sources to active faults was established. This allows the selection of a suitable monitoring site located around the intersection of two suspected fault lines “outlined” by recorded gas springs.

Utilization of SAR Data to Evaluate Industrial Locations on the North Coast of Central Java

Abstract Central Java province, located on the northern coast of Java Island, holds a strategic position as a busy land transportation route, connecting cities in southern Central Java and East Java with the capital city. The growth of industrial centers and industrial zones along the northern coast of Central Java is a positive effect of this position. However, the subsidence of land along the northern coast of Central Java is its negative impact. This can be detrimental to industrial areas and settlements along the northern coast of Central Java. Therefore, spatial planning must consider this land subsidence. The utilization of SAR data to periodically monitor land subsidence is crucial in formulating spatial arrangements that can accommodate the impact of land subsidence. In this study, to obtain land subsidence, the InSAR method was used. The data processed in this study consisted of Sentinel 1 from 2015 – 2023. It was found that land subsidence in the coastal areas of northern Central Java ranges from 0 to 25 cm per year. This data on land subsidence serves as an important basis for policymakers, planners, and stakeholders to develop more effective adaptation and mitigation strategies in spatial planning in the coastal areas of northern Central Java.

Wave Characteristics in the Northern Waters of Central Java Based on the Wavewatch III Numerical Model

The northern coast of Central Java is a strategic development area, but it has the potential for high wave disasters. Planning activities and mitigating maritime disaster risks requires an understanding of wave characteristics. This study analyzes wave characteristics in the northern waters of Central Java using the Wavewatch III numerical model. Significant wave height and wave direction were averaged from 2014 to 2023. The results showed that wave conditions in the northern waters of Central Java tend to be higher in December, January, February, July, August, and September. Meanwhile wave conditions tend to be lower in March, April, May, June, October, and November.