Evolution of the lagoon coast in northeastern Sakhalin exemplified by the Nyiskii Inlet‒Plastun Spit coastal system

The behavior of the coastal system represented by Nyiskii Inlet (lagoon) and Plastun Spit is investigated by modeling morphodynamic processes. The observable advance of Plastun Spit and displacement of the Anuchin Strait are explained by changes in the alongshore sediment flux transporting material to the end of the spit from the south. It is shown that severe storms combined with a surge and tide tend to deepen the lagoon bottom. The model of a tidal inlet system is proposed to describe the evolution of tidal flats under conditions of a relative rise in sea level. It is concluded that the volume of tidal flats can be reduced several times in the next 100 years. This trend should accelerate erosion of the inlet coasts due to decreased dissipation of the energy received from the open sea.     

Analysis of characteristics and mechanism of current system on the west coast of Guangdong of China in summer

On the basis of data of drifting bottles＇ tracks and the current measured in anchored stations, as well as temperature and salinity observed in cruise investigations and coastal stations, ADCP current data and AVHRR surface sea temperature （SST） data on the western coast of Guangdong, synthetic results of analysis showed that the coastal currents in the west of the mouth of the Zhujiang River were mainly westward in summer, which constituted the north branch of cyclonic gyre in the east of the Qiongzhou Straits. Part of its water flowed westward into the Beibu Gulf through the Qiongzhou Straits. The coastal current pattern was not identical with the traditional current system which flowed westward in the Qiongzhou Straits in winter and eastward in summer. The summertime＇s coastal current was always westward, maybe temporarily turning northeast only when the southwest wind was strong. The important characteristics of coastal current on the western coast of Guangdong, in the Qiongzhou Straits and in the north of the Beibu Gulf were analyzed and their mechanisms also were explained.     

Barnacle larval transport in the Mandovi–Zuari estuarine system, central west coast of India

A two-dimensional hydrodynamic and particle tracking model was used to estimate the dispersion and retention of barnacle larvae from their possible spawning sites in a tropical monsoon-influenced estuarine system (central west coast of India). Validation of the hydrodynamic simulations yielded a good match with field measurements. The pattern of larval dispersal in the region varied with the winds and currents. The seasonal changes in abundance could be attributed to physical forcing and weather conditions. The extent of barnacle larval dispersal from spawning sites varied from 10 to 78 km for different sites and seasons. During a 24-h cycle, the larval abundance showed one to two peaks in the estuarine area. The increased larval abundance is favored by the flood currents, pushing the larvae into the estuary. Physical forcing in the region helps in transport of the larvae from their spawning sites hugging to the coast and contributing to the population within the estuary. Field observations and numerical experiments suggest the occurrence of higher larval abundance in the estuary during post-monsoon. The dispersal pattern indicated that the barnacle population present in the estuary is well mixed, and with a seasonally changing pattern.     

A study on benthic community structure in west of the Taiwan Strait and near the Taiwan Shoals

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Mineral provinces and material provenance of the surficial sediments near the Zhongsha Islands in the South China Sea

1 IntroductionThe South China Sea is one of the northwesternPacific marginal basins, which is located atthe junc-tion region among Euro-Asia plate, Pacific plate andIndia plate. Owing to its unique geological charac-teristics, the South China Sea has beco…     

A study on chemical forms of heavy metals in the sediments of Zhujiang River and its estuary

The five chemical bound forms of Fe, Al and Mn in sediments in the main channel of the Zhujiang River.and its estuary, namely, exchangeable, carbonic, oxidative, organic and residual (in crystal) forms, were determined. The method of sequential extraction was used for separating the five bound forms.The main chemical form of the three elements in the sediments of the Zhujiang River and its estuarine zone is the residual one. The exchangeable form exists only in a small fraction.Correlationships between the concentration of a certain form of heavy metals and Eh. pH and salinity were discussed. The principles of geochemistry are used to explain the mechanism of heavy metal transport in the river.It was also found that the distribution rule of the chemical forms of Fe, Al and Mn in sediments in the lower reaches of the Zhujiang River was similar to the one in the lower reaches of the Yamaska River.     

Benthic foraminifera and their response to hydrography,periodic hypoxic conditions and primary production in the Koljö fjord on the Swedish west coast

The Koljö fjord on the Swedish west coast is a silled fjord characterised by strong stratification and stagnant bottom water, with periodically occurring hypoxic or anoxic conditions. In the Koljö fjord, renewal of the deep water generally occurs during winter. This study investigates how living benthic foraminifera react to hydrographic variations, periodic oxygen deficiency and variations in primary production. A series of monthly hydrographic measurements was made from August 1993 to December 1994, combined with sediment sampling along a (12–43 m) depth transect at five different sites. Monthly values of surface chlorophyll-a were available. Two periods of hypoxia to anoxia with one intervening period of oxic conditions, together with two autumn phytoplankton blooms and a spring phytoplankton bloom, made it possible to achieve the aims of this study. Below the pycnocline, three foraminiferal species: Elphidium excavatum clavatum, Elphidium incertum and Elphidium magellanicum represented more than 95% of the fauna. When oxygen content was very low, the foraminiferal fauna decreased but did not die out completely. A deep-water inflow in January 1994 caused the oxygen content to rise, but the foraminiferal population did not start to grow until three months later when the spring phytoplankton bloom sedimented out. Under oxic conditions, food availability seemed to limit the foraminiferal population. In itself, a very high organic content in the sediments does not seem to be a suitable food source; it is more likely that fresh phytoplankton is a potent food for these foraminifera. Reproduction of E. excavatum clavatum and E. incertum seems to have been triggered by increased food supply and sudden fluctuations in hydrographic variables. These foraminifera appear to grow from juvenile to adult in less than a month.     

Variability of the fields of concentration of microelements and strontium in seawater near the South Coast of the Crimea in 2002–2007

We study the space-and-time variability of the concentrations of 27 microelements (Sc, Cr, Mn, Fe, Ni, Co, Cu, Zn, As, Mo, Ag, Cd, Sn, Se, Sb, Ba, La, Ce, Sm, Eu, Tb, Hf, Hg, Pb, Au, Th, and U) and Sr in the sea, river, and waste waters of the South Coast of Crimea in 2002–2007. Parallel with the data about elements studied earlier, we present, for the first time, the data of investigations of the contents of rareearth elements (Lu, Nd and Yb) whose concentrations in the major part of the analyzed samples of seawater were lower than the limit of their quantitative determination. We present the ranges of the concentrations of elements and perform their comparison with the data of the previous period of monitoring.     

The redox profile of the bottom sediments in the Ob River’s mouth area

By the data of cruise 54 of the R/V Akademik Mstislav Keldysh (September 2007), the results of geochemical studies of the redox processes in the bottom sediments of the Ob River’s near-mouth area as applied to the redox indicator elements such as manganese, iron, and sulfur are presented. The characteristics of the bottom sediments and the distribution of these elements in them testify not only to the significant role of the mixing processes in the formation of the geochemical profile of the bottom sediments in the estuary but also to the role of the postsedimentation (diagenetic) processes.     

Air-sea heat flux exchange over the South China Sea under different weather conditions before and after southwest monsoon onset in 2000

With the data observed from the Second SCS Air-Sea Flux Experiment on the Xisha air-sea flux research tower, the radiation budget, latent, sensible heat fluxes and net oceanic heat budgets were caculated before and after summer monsoon onset. It is discovered that, after summer monsoon onset, there are considerable changes in air-sea fluxes, especially in latent heat fluxes and net oceanic heat budget. Furthermore, the analyzed results of five synoptic stages are compared. And the characteristics of the flux transfer during different stages around onset of South China Sea monsoon are discussed. The flux change shows that there is an oceanic heat accumulating process during the pre-onset and the break period, as same as oceanic heat losing process during the onset period. Moreover, latent fluxes, the water vapor moving to the continent, even the rainfall appearance in Chinese Mainland also can be influenced by southwester. Comparing Xisha fluxes with those obtained from the Indian Ocean and the western Pacific Ocean, their differences may be obeerved. It is the reason why SSTs can keep stableover the South China Sea while they decrease quickly over the Arabian Sea and the Bay of Bengal aftermonsoon onset.     

Sandy beach macrofaunal communities on the western coast of Portugal – Is there a steady structure under similar exposed conditions?

The structure of macrofaunal communities at two similar exposed sandy beaches on the western coast of Portugal was monitored for approximately 18 months by sampling all the beach area, from the shoreline to the base of the dunes. The beaches’ physical environment, as well as community density and composition, seasonal variations and the potential relationships between biological data and environmental parameters were studied. The two beaches had similar exposure to wave action, but differed in terms of sediment grain size, extent of the intertidal area, sediment moisture content and, especially, in the potential food availability in the form of allochthonous debris. Differences were observed with regard to the communities’ structure, namely regarding composition and relative contribution of the dominant species. Seasonality, especially temperature variations, and the interaction between seasons and the beach zones (supralittoral vs. intertidal) also had a strong influence on communities: controlling dominant species’ density and the horizontal distribution of the dominant species, and promoting a differential utilization of the beach by several resident macrofaunal animals. The present study allows the identification of key species in exposed sandy beaches of western Portugal and demonstrates that a steady community structure does not persist in the similarly exposed conditions observed, which may be mainly a response to distinct detritus subsidies, combined with differences in sediment grain size, sediment moisture content and extent of the intertidal area.     

Annual and spatial variation in the abundance length and condition of juvenile turbot (Psetta maxima L.) on nursery grounds on the west coast of Ireland: 2000–2007

Turbot (Psetta maxima Linnaeus) is a high value commercially exploited marine flatfish which occurs in European waters, from the Northeast Atlantic to the Arctic Circle, the Baltic and Mediterranean Sea. In Ireland, turbot are the most valuable commercial non-quota species. Very little is known about their population dynamics in the wild, in particular during the sandy beach nursery phase of the life history. In 2000, a survey was established to assess flatfish species on nursery grounds on the west coast of Ireland. Eleven sandy beaches were assessed for 0+ turbot by beach seining, over an eight year period (2000–2007) during the months of August and September. The objective of the study was to estimate juvenile turbot abundance and size structure to determine if any spatial and annual trends existed. Large scale variability in the recruitment of fish to nursery grounds may be indicative of fluctuations in the adult stock. Turbot were found to recruit to five beaches consistently over the eight year period. Temporal and spatial variability in the relative abundance and length of turbot was discerned, with no apparent overall trend. However, certain nursery grounds were shown in most of the years examined to support higher abundances of turbot in comparison to other areas over the eight year period. Turbot abundances on nursery grounds were significantly correlated with mean spring sea temperatures during the pelagic stage. The condition of turbot did not significantly differ on an annual or spatial scale. Mean densities of 0+ turbot along the Irish coast were found to be similar and at times higher than other areas in Europe, ranging from 0.1 (± 0.3) individuals 1000 m^− 2 to 18.5 (± 6.9) individuals 1000 m^− 2. Mean turbot total length on beaches ranged from 3.8 cm (± 0.6) to 6.6 cm (± 4.3). The observed spatial and temporal variability in abundance and length highlights the need for long-term studies when assessing juvenile flatfish populations. Results from the present study have provided much needed baseline data on wild juvenile turbot populations which is severely lacking for this species both on an Irish and on a European scale.     

The influence of the climate’s variability on the deep-water oxygen conditions in the east of the Gulf of Finland

Based on the long-term surveys in 1995?C2010, the influence of the variability of the winter conditions on the interannual dynamics of the content of dissolved oxygen was studied concerning the deep waters (the 40 m isobath line) of the eastern part of the Gulf of Finland. The content of oxygen varied within a wide range with a low-pronounced trend to a decrease during the considered period. All the processes affecting the aeration of deep waters, i.e., the advection of oxygen-depleted saline waters from the Baltic Sea and the intensity of the autumnal and winter mixing, correlated with the North Atlantic oscillation index, which determined the close positive correlation between this parameter and the oxygen content (r = +0.87). The hypoxic effects in the gulf were registered in the years of negative anomalies of the North Atlantic oscillation. The conclusion is reached that the deterioration of the oxygen conditions at the inner part of the Gulf of Finland during the late 20th-early 21st century is mainly caused by the large-scale variations in the atmospheric processes.     

Using fine‐scale catch predictions to examine spatial variation in growth and catchability of Panulirus cygnus along the west coast of Australia

Puerulus settlement has been monitored throughout the western rock lobster Panulirus cygnus fishery for nearly 40 years. These data, in combination with indices of effort and water temperature, were used to produce recruitment‐catch relationships for each 1° transect of latitude in the coastal part of this fishery from Kalbarri to Cape Leeuwin, as well as at the offshore Abrolhos Islands (total of eight transects). The fine spatial scales of these models provided estimates of certain life history traits that are known to affect lobster catches between adjacent fishing ports. This catch modelling showed that the proportions of 3‐ and 4‐year‐old post‐settlement lobsters contributing to the catches varied markedly from the southern to northern transects, suggesting that juvenile lobsters grow substantially faster in the warmer northern and offshore waters of this fishery. These proportions provide accurate estimates of juvenile growth rates, which are vital in the construction of location‐specific growth algorithms required by the age‐structured models used in the management of this fishery. Model estimates of density‐dependent mortality were greater in the more densely populated centre of the fishery and markedly lower at the northern and southern limits of this species distribution. Annual increases in fishing efficiency were also found to be lowest at the northern and southern extremes of the fishery and greatest in the centre of the fishery, where technology advances and increased fleet mobility have enabled the fleet to increase efficiency by 1–3% each year. Catchability (q) was found to be most influenced by water temperatures in the cooler southern transects, whereas at the Abrolhos Islands, changes in water temperature produced almost no discernable change in q. The catch modelling was also used to quantify the impact of management changes introduced in the 1993/94 fishing season. Increased protection of female lobsters and an 18% pot reduction resulted in a 3–4% permanent reduction in the catch rates of lobsters throughout most of the coastal fishery, whereas at the offshore Abrolhos Islands, catch rates increased by c. 20%, presumably owing to a reduction in the level of pot saturation.     

Hydrochemical conditions of the “Chistaya Banka” polygon in the Volga’s avant delta

Characteristics of different types of river drainage were obtained during studies of a polygon in the near-mouth part of the Volga River in 2000–2003: “fast” (flowing through deep channels) and “slow” (that which passes through the littoral parts of the delta (1–2 m)). The low current velocities (lower than in the channel waters by a factor of ten), the abundance of water vegetation, and the strong heating of the waters lead to the high intensity of the biochemical processes. Therefore, the chemical composition of the waters is subjected to significant transformation with intensity so high that it allows comparing these regions with some sort of “bioreactor.” These changes influence the dissolved oxygen and various forms of carbon content.     

Recent environmental changes and filamentous algal mats in shallow bays on the Swedish west coast — A result of climate change?

Over the last thirty years, many shallow estuarine bays, located in Scandinavian sheltered coastal environments, have been subject to the increased dominance of opportunistic species of filamentous green algae, oxygen deficiency in bottom waters and the alteration of flora and fauna. Human-induced eutrophication has been held responsible for these recent changes, but from this study the importance of climatic factors emerges. This research is based on the analysis of sediment cores from 8 shallow areas (d < 50 cm) along the Bohuslän archipelago, Swedish west coast, and focuses on their recent (< 100 years) sedimentary evolution. Evidence of hydrodynamic change was observed in the sediments, where modern fining-upward sequences contrast with the expected coarsening upward model due to ongoing land uplift. Heavy metal concentrations from modern pollution and ¹⁴C dating of mollusk shells and eelgrass roots provided the age control, and allowed to place these changes within the last three decades. Data were compared with historical meteorological records (seasonal warming, modification of dominant winds and upwelling and reduction of sea-ice), and a clear connection emerged between the environmental changes and variations in the North Atlantic Ocean weather pattern. The increase of winter temperature and reduction of reworking winter sea-ice in these sheltered bays increased the storing of nutrients in the sediments and the turnover of organic matter, favoring the early growth stage of opportunistic algae in the most sheltered areas of the archipelago. This, together with human-induced modifications (overfishing and eutrophication), increased the possibility of opportunistic explosions, which in turn determined a reduced water exchange, the increased deposition of fine sediments and organic matter and evolving hypoxic conditions.     

Dynamics of REE accumulation and fractionation in the subcolloidal fraction of bottom sediments in the Razdol’naya River–Amur Bay section,Sea of Japan

The REE contents (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) are determined by atomic emission spectroscopy in the subcolloidal fraction of bottom sediments in the Razdol’naya River–Amur Bay section. The mean contents of lanthanides in soils and river bottom sediments (before the mixing zone) are calculated. The increase in REE content and the fractioning in the series from light to middle and heavy REE in sediments of different estuary zones (river, water mixing, and marine), with the latter related to flocculation, sorption on iron and manganese hydroxides, clay minerals (hydromica, smectites), and lifetime accumulation of marine plankton, are dtermined. Via extraction of 0.5 N sodium hydroxide solution, the content of lanthanides associated with humic substances of subcolloidal fraction from the Amur Bay sediments are determined: 1.3 to 8.2% of La; 1.1 to 11% of Ce; and 0.3 to 1.5 of Gd.     

Effects of geomagnetic disturbances in the near Earth’s atmosphere and possible biophysical mechanism of their influence on the human cardiovascular system

We analyze the effect of geomagnetic activity on variations in quasi-static electric field strength and the horizontal geomagnetic field component in the band of periods of tidal and planetary waves. Variations in oscillation intensities and periods in the power spectra of these parameters synchronously with the K _p index are shown. Taking into account the relationship of these parameters with the air pressure, we suggest a possible biophysical mechanism of the relation between the state of the human cardiovascular system and geomagnetic activity by means of resonant interaction with the environment. In periods of high geomagnetic activity, the air pressure and temperature vary due to an increase in atmospheric transparency as a result of the Forbush decrease in the cosmic ray flux rate. It is these variations that directly affect humans.     

Influence of the sea surface temperature conditions in the Pacific subarctic frontal zone on the pink salmon’s winter survival ability

Similar to other high-latitude ocean basins, the subarctic Pacific exhibits strong seasonal and inter-annual variations in the abiotic factors of the environment, which, in turn, strongly influence biological objects. One of the principal factors of this kind is the temperature regime. For our research, we chose pink salmon because more than 90% of its natural mortality occurs precisely during the wintering period. The lifetime of pink salmon is only one year, and the conditions of their populations reflect the thermal regime of the given year. The main wintering area of Asian pink salmon is the part of the subarctic frontal zone located south of the Aleutian Islands (43°–46°N). This region features sufficiently high wintertime concentrations of chlorophyll a and temperature conditions favorable for pink salmon wintering. The interannual temperature variability in the frontal zone is close to zero, and the width of the frontal zone may significantly change depending on the winter severity. In “milder” winters, the area of wintering extends, while, in “severe” winters, it is rather narrow, the forage base for fish decreases, they become more accessible for predators, and their survival rates sharply drop.     

Impact of rapid urbanization on the modern sedimentary environments in a semienclosed embayment: Tong’an Bay,southeast China coast

Tong’an Bay (TAB) is a semienclosed embayment in the north of Xiamen Island. The sea area of TAB was mainly used for aquaculture in enclosed areas before 2003. Since 2003, the districts surrounding TAB have been undergoing a rapid urbanization process, and the scale of land used for urban construction in these districts has been continuously increasing. Under the backdrop of rapid urbanization, the coastline of TAB has largely been transformed into an artificial coastline. Due to the large scale of land reclamation and, dredging activities and the opening of the Gaoqi-Jimei (GJ) Seawall, there have been relatively significant changes in the coastal and submarine geomorphology in central northern, western, and southern TAB and Wuyuan Bay as well as a significant increase in the area where artificial submarine geomorphologies are distributed; the number of surface sediment types in the TAB has increased, and sediments in the sea area surrounding engineering projects have been coarsening; the sediment transport pattern has not significantly changed at the mouth of TAB and in central northern TAB, but the suspended sediment transport direction near the GJ Seawall has changed to a certain extent.