Tidal Sea Research Articles

THE INFLUENCE OF ENVIRONMENTAL VARIABLES ON ALGAL PIGMENT IN THE WESTERN LAGOS LAGOON, NIGERIA

Algal pigments areuseful in the estimation of primary production and phytoplankton biomass. Chlorophyll a, chlorophyll b and phaeophytina are notable algal pigments in this regard. Open lagoon are coastal environments known to exhibit continuous environmental gradients daily and seasonally. Algal pigments and environmental variables of the western parts of the Lagos Lagoon were investigated for six month at seven stations (November, 2015 April, 2016). The environmental indices reflected seasonal changes related to rainfall distribution pattern and tidal sea water incursion. Air temperature (25 35?C), water temperature (26 32.5?C), total dissolved total (656 19611.31 mg/L), dissolved oxygen (4.15 6.83 mg/L), transparency (22.5and 135cm), pH (6.73 7.59), salinity (23.24‰) and calcium (4.69258.17mg/L) recorded increased values in the dry than wet season. On the other hand biological oxygen demand (1 4mg/L), chemical oxygen demand (4 18mg/L), total suspended solids (1 38mg/L), nitrate (0.19 12.85mg/L),copper (0.0020.004mg/L), zinc (0.01 and 0.057) and cadmium (0.0006 0.0018mg/L) recorded higher values in the wet season. Chlorophyll a, chlorophyll b and pheophytinavalues were higher in the dry season. Notable correlation coefficient (r) was recorded between chlorophyll a and nitrate (r = 0.73, p< 0.05), phosphate (r = 0.82, p< 0.01), chemical oxygen demand (r = 0.35, p< 0.01), biochemical oxygen demand (r = 0.22, p<0.01)and copper (r = --.387, p<0.01). On another hand correlation between chlorophyll b and rainfall (r = 0.62, p< 0.01), pH (r = 0.31, p< 0.05), zinc (r = 0.44, p<0.05), manganese (r = 0.36, p< 0.05) and cadmium (r = 0.33, p< 0.05)were noteworthy.Furthermore phaeophytina showed a correlated relationship with rainfall (r = 0.39, p<0.01), dissolved oxygen (r = 0.31, p<0.05) and cadmium(r= 0.36, p<0.05). Recorded chlorophyll a values place the western Lagos Lagoon between the mesotrophic and eutrophic status. Increasing nitrate (nutrient) levels coupled with the reduced rainfall events led to the development of more algal cells (phytoplankton) thus higher algal pigments level within the western Lagos lagoon ecosystem.

Signature of Tidal Sea Level in Geomagnetic Field Variations at Island Lampedusa (Italy) Observatory

In this work, we analyze the geomagnetic field measurements collected from 2017 to 2020 at the Italian observatories of Lampedusa and Duronia (an island and inland site, respectively) for investigating a possible signature of the tidal sea water level changes on the local magnetic variations. We obtain the following main results: (a) evidence of the geomagnetic power spectral peaks at the solar and lunar tidal main frequencies at both sites is found; (b) by using a robust fit procedure, we find that the geomagnetic field variations at Lampedusa are strongly influenced by the lunar tidal variations in the sea level, while at Duronia, the main effects on the geomagnetic field variations are associated with diurnal solar ionospheric tides; (c) a single-station induction arrows (SSIAs) investigation reveals different behaviors between Lampedusa and Duronia. Specifically, Lampedusa shows that the induction arrows in different frequency ranges point toward different directions with different amplitudes, probably related to the surrounding regions with different water depths, while Duronia shows a persistent coast effect, with the induction arrows pointing toward the Adriatic sea; and (d) a Superposed Epoch Analysis reveals, only for Lampedusa, a close relationship between SSIAs with a frequency of >2 mHz (<1.3 mHz) and the sea level variations driven by the astronomical O1 tide, indicating an amplitude intensification of ∼4×10−3 (∼5×10−3) and an azimuthal angle increment of ∼3∘ ( ∼9∘), in correspondence to a 1 cm sea level increase.

The Effect of Asphalt Baths Wearing Coarse (AC–WC) on the Tide

The phenomenon of high tide that occurs in the coastal areas of Indonesia, especially on the island of Java which often results in floods or often called tidal floods. Tidal flooding is a flood event caused by the overflow of sea tides into coastal land. Often the overflow reaches on some roads located in coastal areas so that roads located in those coastal areas are damaged. Therefore, it is necessary to conduct research to investigate the effects caused by stagnant water on road pavement. The study used two standard methods of immersion in high tide and water in the laboratory. This study aims to determine the durability performance of the soaking mixture continuously (continuously) and periodically (intermittently). Soaking specimens (test objects) in a tide with a time variation of 12 hours; 24 hours; 48 hours; and 72 hours. While periodic soaking is carried out by soaking the specimen (test object) for 12 hours, then removed and allowed to stand for the next 12 hours for 3 days. Soaking the asphalt concrete wearing course (AC-WC) mixture either continuously or periodically in the tide has a greater influence compared to the use of laboratory water. This is indicated by the value of the Stability of the asphalt mixture in a bath with a tide smaller than the asphalt mixture soaked with laboratory standard water.

Tidal Sea Level Oscillations in the Sea of Azov

Tidal Sea Level Oscillations in the Sea of Azov

Spatiotemporal optical properties of dissolved organic matter in a sluice-controlled coastal plain river with both salinity and trophic gradients

Due to the combined effect of sluices and sea tide, the sluice-controlled coastal plain river would be characterized by both trophic state and salinity gradients, affecting the spatiotemporal optical properties of dissolved organic matter (DOM). In this study, we investigated the spatiotemporal variation of water quality parameters and optical properties of DOM in the Haihe River, a representative sluice-controlled coastal plain river in Tianjin, China. A significant salinity gradient and four trophic states were observed in the water body of the Haihe River. Two humic- and one protein-like substances were identified from the DOM by the three-dimensional fluorescence spectra combined with the parallel factor (PARAFAC) analysis. Pearson's correlation analysis and redundancy analysis (RDA) showed that the salinity significantly affected the abundance of chromophoric DOM (CDOM) but did not cause significant changes in the fluorescence optical characteristics. In addition, the effect of Trophic state index (TSI) on the CDOM abundance was greater than that on the fluorescence intensity of fluorescent dissolved organic matter (FDOM). In the water body with both salinity and trophic state gradients, TSI posed a greater influence than salinity on the CDOM abundance. Our results fill the research gap in spatiotemporal DOM characteristics and water quality variation in water bodies with both salinity and trophic state gradients. These results are beneficial for clarifying the joint influence of saline intrusion and sluices on the DOM characteristics and water quality in sluice-controlled coastal plain rivers.

Role of Non-Orthogonal Hydrodynamic and Sedimentation Model for Port Facilities Analysis on Port of Kuala Tanjung

The port-channel and the availability of piers are strongly influenced by physical environmental conditions such as sea current, sea tide, sediment transport, and wave. The best size of vessel and pier length depends on the location’s demand and sea environment. The uncertainty of these environmental factors results in the low efficiency of port infrastructure, the load factor for back cargo, and the reliability level of port users. This paper presents the role of MuHydro3D and MuSed3D software, a three-dimensional hydrodynamic, and sedimentation models to determine the best vessel size. Using a non-orthogonal curvilinear coordinate technique, also known as the boundary-fitted technique, MuHydro3D and MuSed3D can accurately and quickly simulate the environmental conditions at the port. Knowledge of environmental conditions is expected to be an accurate basis in determining the depth and dredging duration, pier length, ship size, or the need of breakwater. The Port of Kuala Tanjung is one of Indonesia’s designated international hubs and was chosen as the case study in this paper. The result shows that the sedimentation rate of dredging for a vessel with up to 3,000 TEUs capacity is not too sensitive. Moreover, a vessel design with an approximate capacity of 3,000 TEUs is the optimum size from the pier length aspect.

Education of Fish Detection Tools (Fish Finder) to Fishermen in Dusun XI Percut Sei Tuan Village, Deli Serdang Regency

Traditional fishermen in Dusun XI, Percut Village, Deli Serdang Regency, North Sumatra Province, using rawai fishing gear, nets, and hand line instead of other technological gear. Sea tides also influence fisherman's ability to get out of sea; when the river mouth reaches high tides, fishermen will go to sea; when the river mouth recedes, fishermen can not go to sea. Fishermen are frequently returned to sea with little results, especially in the absence of technological application. Education is important, and advances in fish finder technology can help fishermen catch more fish by making it easier to use. The implementation method is theoretical and practical, with the formation of an actually trying to implement committee team occurrence through educational methods with theoretical media attention, as well as practical activities such as fisherman group discussions and joint operation demonstration activities in the field. Fishermen in Dusun XI, Percut Village, Deli Serdang Regency benefit significantly from using a fishfinder tool and helping in increasing fish catches, according to data monitoring and assessment.

Digitising historical sea level records in the Thames Estuary, UK

London is one of the world’s most important coastal cities and is located around the Thames Estuary, United Kingdom (UK). Quantifying changes in sea levels in the Thames Estuary over the 20th century and early part of the 21st century is vital to inform future management of flood risk in London. However, there are currently relatively few long, digital records of sea level available in the Thames. Here we present a new extensive sea level dataset that we have digitised from historical hand-written tabulated ledgers of high and low water, from the Port of London Authority (PLA). We captured 463 years of data, from across 15 tide gauge sites, for the period 1911 to 1995. When these historical datasets are combined with digital records available from the PLA since 1995, the sea level time-series span the 111-year period from 1911 to 2021. This new dataset will be of great importance for ongoing monitoring of mean sea-level rise, and changes in tidal range and extreme sea levels in the Thames Estuary.

Tidal Range and Sea Level Changes at The Area in front of Umm Qasr Port South of Iraq

The high maximum and low for sea level in north west of Arabian Gulf in the area next to Umm Qasr port were studied for a nodal lunar cycle that equal nineteen years (1999 – 2017). It was found that the sea level is rising. Depending on, the sea level monitoring of the nineteen years’ interval, the essential characteristics of Umm Qasr's tidal range have been identified. This study addressed the problems of the collective impact of tides and meteorological elements at sea level, more precise characterization is given to this phenomenon through defining the frequency division for the tidal sea level, where it was found that the prevailing range within the two values are (3.0 - 4.0m), while the actual average tide is (3.908m). In addition, was comparing the calculated and registered range of the tide through the study period was found that the recorded range exceeded the calculated range and this increase due to meteorological elements which increases the effectiveness in the summer months in the study area.

The analysis of coastline changes of maruni beach in Manokwari during 1995-2021 period

The coastal area of Maruni at Manokwari Regency is known for its potential as a fish-producing area, industry, settlements, ports, and others. However, some parts of Maruni coastal areas have been damaged due to the development. The coastal area experienced changes caused by both natural processes and human activities. The presence of natural and artificial processes in coastal areas results in accretion and abrasion. The dynamics of oceanographic pressures such as sea tidal, sea waves, ocean currents, and tides occurring in the Maruni Beach area cause changes in the movement of sediments affecting the coastal area. Continuous changes can be a threat to Maruni coastal line as the Trans Papua Barat Road passed this route. This research was conducted with the aim to quantify the rate of coastline changes and oceanographic dynamics of Maruni coastal line at the south part of Manokwari Regency, Papua Barat Province from 1995 to 2021. The utilization of remote sensing interpretation method from Landsat 5 TM, Landsat 8 OLI, and oceanographic data providers (BIG, ECMWF) accommodated data source. The analysis result concluded that changes in the coastline at Maruni Coastal line during the 1995-2021 period predominantly encountered abrasion. The magnitude rate of change experienced a very small accretion, but was replaced by a very high abrasion event that occurred during two observation periods between 1995-2021.

Situs Problematika Pariwisata Situs Kota Cina Medan

The research was conducted to find out the problems of Kota Cina Sites tourism as educational and cultural tourism. The technique used in this research is the technique of interview, observation, and documentation. Qualitative data whose sources consist of primary and secondary sources. The data collection technique is using purposive sampling technique, while the data analysis technique is in the form of qualitative descriptive data. The results of this study indicate a complex problem in Kota Cina Site tourism which includes three things, including (a) Community; (b) Government; and (3) Natural and Non-Natural Disasters. The problem is the lack of attention from the community and government in preserving and managing the Kota Cina Site to develop it as a historic site that has the potential for educational and cultural tourism. As well as sea tides that caused the Kota Cina site to experience sea intrusion and also the problem of conflict of interest. However, attention is still getting from the private sector, archaeologists, and academics

Декарбонізація та енергетична криза

The purpose of the study is to identify new directions for reducing the share of fossil fuels in the energy balance of industrial production for the possibility of overcoming the energy crisis. Humanity has been living in conditions of an unprecedented energy crisis for the past few years. First, the coronavirus pandemic, then the sharp rise in energy prices and the war in Ukraine unleashed by Russia exacerbated energy consumption problems and increased the need for wider development of alternative energy sources and the latest industrial technologies. In the crisis conditions of 2022 the European Union not only maintained the course for decarbonization, but also accelerates the transformation of the economy and industry, because this contributes to energy independence and security. Two way strategies are being developed in the energy sector - diversification through the distribution and balance of energy sources, which guarantee the security of the entire energy system, and decarbonization as a course to gradually abandon traditional energy sources (natural gas, oil, coal, peat), reducing carbon dioxide emissions and transition to renewable sources (solar radiation, wind, sea tides, biomass). Environmentally friendly hydrogen is considered one of the key components of the future energy system. The main directions of the European Strategy in the field of hydrogen are analyzed, and a number of fundamental documents of the EU energy policy adopted in 2022 are presented. Today, ferrous metallurgy is one of the largest sources of emissions, so the task of changing the course to production with a low level of emissions and a carbon-neutral sector is for it one of the most relevant. The potential of hydrogen as a fuel and reducing agent has been known for a long time, but now its role in decarbonization at all stages of metallurgical production is becoming more and more significant. Several large research programs on hydrogen production and reduction of iron oxides have been launched in the world. Based on the deep modernization of production capacities and energy systems, as well as the introduction of new innovative methods, the amount of current annual emissions during steel production can be reduced by 15-20%. Further reductions to 1.0 t CO2/t steel are possible with new technologies such as blast furnace gas recirculation, oxygen blast furnace, maximum replacement of coke with biomass and by replacing carbon with hydrogen in reductants and fuels such as natural gas and coke gas. The energy crisis can become a "window of opportunity", developing new directions for reducing the share of fossil fuels in the energy balance.

Electricity Generation from Sea Tides

Electricity Generation from Sea Tides

Characteristics and Long-Term Variability of Occurrences of Storm Surges in the Baltic Sea

Understanding the characteristics of storm surges is especially important in the context of ongoing climate changes, which often lead to catastrophic events in the coastal zones of seas and oceans. For this reason, this paper presents the characteristics of the Baltic Sea storm surges and trends in their occurrences through the past 60 years. The study material was based on hourly sea level readings, spanning the years 1961–2020, retrieved from 45 Baltic Sea tide gauges, as well as air pressure and wind field data. Owing to the analysis and visualization of storm situations, two main types of storm surges were identified and characterized: a surge driven by wind and a surge driven by subpressure associated with an active low pressure area. This paper also discusses a third, mixed type of storm surge. Further analyses have indicated that through the past 60 years in the Baltic Sea, the duration of high sea level has increased by 1/3, the average number of storm surges has increased from 3.1 to 5.5 per year, and the maximum annual sea levels have increased—with a trend value of 0.28 cm/year. These processes, also observed in other marine basins, provide strong evidence for contemporary climate change.

Tensile strength behaviour of steel plates with corrosion-induced geometrical deteriorations

ABSTRACT Mechanical properties of constructional steel are negatively affected by a corrosive environment which is of special importance for marine structures. This study deals with the change of mechanical properties of butt-welded specimens made of shipbuilding steel when they are exposed to the real marine environment (fresh water, sea water, sea tide) for prolonged periods (6, 12, 24 and 36 months). Results of the study include engineering stress–strain diagrams obtained using uniaxial tensile tests, and give insight into the change of material strength due to the length of exposure and the type of environment. The values of measured Charpy impact energy illustrate the change in material toughness. It can be concluded that the sea tide has the most negative impact on the mechanical properties of the considered steel, while most of the deterioration of properties happens during the first six months in a corrosive environment.

Influence of Storm Tidal Current Field and Sea Bottom Slope on Coastal Ocean Waves during Typhoon Malakas

Wave–current interaction in coastal regions is significant and complicated. Most wave models consider the influence of ocean current and water depth on waves, while the influence of the gradient of the sea bottom slope is not taken into account in most research. This study aimed to analyze and quantify the contribution of storm tidal currents to coastal ocean waves in a case where sea bottom slope was not ignored. Fourier analysis was applied to solve the governing equation and boundary conditions, and an analytic model for the calculation of the variation of amplitude of wave orbital motion was proposed. Ocean currents affect ocean waves through resonance. In this paper, an implemented instance of this analytic model was given, using the Shengsi area during Typhoon Malakas as an example. The results suggest that vertical variation in the amplitude of wave orbital motion is remarkable. The impact of wave–current interaction is noticeable where the gradient of the sea bottom slope is relatively large.

Link and stability-aware adaptive cooperative routing with restricted packets transmission and void-avoidance for underwater acoustic wireless sensor networks

In underwater acoustic wireless sensor networks (UAWSNs), the conventional routing protocols continuously transmit data packets containing the same information when a source node detects an event of interest. This approach, however, leads to high energy consumption, high interference and challenges the stability of the network due to heavy data load on the nodes close to water surface. To overcome these challenges, this article proposes two routing protocols for UAWSNs. They are, SRRPV: stability-aware routing with restricted packets transmission and void-avoidance and LS-ACRPV: link and stability-aware adaptive cooperative routing with restricted packets transmission and void-avoidance. In SRRPV, a source node detects the event of interest, generates and routes packets. Subsequent packets routing is performed only when a change in intensity of the event is detected. Due to restricted packets transmission, three-hop connected paths with suitable neighbors are chosen to overcome the existence of a void (non-availability of a suitable forwarder) and, therefore, control packets loss. Moreover, the defined packet holding time ensures that nodes with the highest available energy transfer the most packets by holding the packets for the shortest interval of time. This strategy, in combination with restricted packets transmission, achieves network stability. Since limited number of packets are routed, the LS-ACRPV protocol is designed that adds reliability to the SRRPV protocol by selecting a routing link with the highest probability of successfully delivering packets to the destination or using adaptive cooperative routing to combat severe link conditions. Unlike the conventional protocols, the proposed protocols do not require the geographical position coordinates of nodes, which is challenging in underwater environment as nodes change their positions with sea tides and currents. Extensive simulation results reveal promising performance of the proposed schemes in terms of energy expenditure, delay and network stability at the expense of low packets delivery due to restricted packets transmission.

Hydrodynamic Climate of Port Phillip Bay

This study is dedicated to the hydrodynamic climate of Port Phillip Bay (PPB)—a largest coastal lagoon system in Victoria, Australia. Novelty of the present study includes long-term hydrodynamic hindcast simulations integrated with a spectral wave model. Specifically, a coupled unstructured grid wave–current modelling system (SCHISM + WWM) was built upon a high resolution and advanced wave physics (ST6). This coupling system was thoroughly calibrated and validated against field observations prior to applying for 27-year hindcast and case scenarios. Data from these simulations were then used to investigate the hydrodynamic climate of PPB focusing on three main aspects: water levels, waves and currents. For sea levels, this study shows that tidal and extreme sea levels (storm tides) across a large part of PPB have a similar magnitude. The highest storm tide level is found along eastern coasts of the bay in line with the wind pattern. In the vicinity of the entrance, the extreme sea level slightly reduced, in line with wave decay due to coupling effects. This extreme level is lower than results reported by previous studies, which were not built on a wave–current coupled system. For the wave field, the mean wave direction inside PPB is strongly affected by seasonality, in line with wind patterns. The 100-year return significant wave height is above 2 m along the eastern coasts. At PPH, waves get refracted after passing the narrow entrance. For currents, this study shows that both mean variations and high percentile currents are not affected by seasonality. This highlights the fact that tidal currents dominate flow movements in PPB. However, in extreme conditions, the circulation in PPB is also driven by wind patterns, forming two gyre systems. Based on case scenarios simulations, the strongest magnitude of wind-driven currents is above 0.5 m/s and found in the confined shallow region in the southern portion of PPB.

Small-Scale and Long-Term Variability in Population Dynamics of the Cockle Cerastoderma edule in a Southern North Sea Tidal Flat System

The cockle Cerastoderma edule is one of the most common macrofauna species in the Wadden Sea areas of the North Sea. Cockle population dynamics are influenced by various abiotic and biotic factors such as temperature, food availability, and inter- and intraspecific competition. Cockles play an important role in the food web of the Wadden Sea, for instance, large shellfish-eating birds, such as oystercatchers and common eiders, use the cockle C. edule and the blue mussel Mytilus edulis as a main diet component. However, the populations of shellfish-eating bird species have been declining dramatically across the Wadden Sea since the beginning of the 21st century. While there are detailed monitoring programs in blue mussels due to commercial interests, little information is known about the stocks and long-term dynamics of cockles in the German Wadden Sea. To fill this gap, in 2005 a local conservation society (“Der Mellumrat e.V.”) initiated a study to sample cockles at one transect per year south of the island of Mellum, which was extended by 5 more transects in 2011. In addition to the spatial analysis, we analyzed the long-term variability in cockle population dynamics. Min/max autocorrelation factor analysis (MAFA) revealed a decline in cockle abundance, while no clear length trends were found. Canonical and spearman correlation analyses exposed significant correlations between cockle abundance and length and chlorophyll a, mussel bank area as well as oystercatcher and common eider populations. This study clearly shows that there is an urgent need for comprehensive time series of cockle data to analyze and explain ecological long-term changes in cockle population dynamics in relation to environmental changes and to point out how parts of the Wadden Sea food web, such as shellfish-eating birds are affected by these changes.

Haline Convection within a Fresh-Saline Water Interface in a Stratified Coastal Aquifer Induced by Tide

Sea-tide effects on the fresh-saline water interface (FSI) in a stratified coastal aquifer are examined through laboratory experiments. The physical model, a two-dimensional rectangular flow tank, is filled with layered aquifers and aquitards. The aquifers serve as the main entrances/exits of water to/from the system through significant horizontal flows, creating unstable conditions of heavier saline water above lighter freshwater for short periods of time. Several processes create mixing; this instability results in haline convection, creating downward fingering, stable rising of horizontal saltwater front, and unstable upward fingerings of flushing freshwater. The time lag between the sea tide fluctuations and the emergence of adequate fresh- and saltwater is higher in a stratified system compared to a homogeneous system. Furthermore, longer tide cycles lead to the enlargement of the FSI’s toe horizontal movement range. The combination of tidal forcing with a layering aquifer structure leads to a wider FSI by creating a significant salt- and freshwater mixing inside each layer, vertical flows between the layers, and saltwater bodies at isolated areas. Haline convection within the FSI might be the reason for the wider fresh-saline interfaces that are found in field studies.