The carbonate system in the central South China Sea

The Clements of the carbonate system (HCO3- , CO32-, CO2, ·CO2 and Pco2) in the central South China Sea have been calculated by determining the pH values and total alkalinity of the seawater samples collected at 42 stations, combining simultaneously with the data of the temperatures, salinity and depths. The distributions of their characteristics have been briefly described and discussed. The saturation degrees (Ω) of calcite and aragonite in the studied area have also been evaluated. The ΩcaIc- and Ωarag. in the surface waters are about 5.8 and 3.9, respectively. The saturation depth is about 2200m for calcite and 1200m for aragonite. The lysocline in the studied area probably lies between 3000 m and 4000 m where the saturation degree of calcite is approximately 0.78.     

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.     

Characterizing air–sea CO2 exchange dynamics during winter in the coastal water off the Hugli-Matla estuarine system in the northern Bay of Bengal, India

The distribution of the fugacity of CO₂ ( $ f_{{{\text{CO}}_{ 2} }} $ ) and air–sea CO₂ exchange were comprehensively investigated in the outer estuary to offshore shallow water region (lying adjacent to the Sundarban mangrove forest) covering an area of ~2,000 km² in the northern Bay of Bengal during the winter. A total of ten sampling surveys were conducted between 1 December, 2011 and 21 February, 2012. Physico-chemical variables like sea surface temperature (SST), salinity, pH, total alkalinity (TAlk), dissolved inorganic carbon (DIC) and in vivo chlorophyll-a along with atmospheric variables were measured in order to study their role in controlling the CO₂ flux. Surface water $ f_{{{\text{CO}}_{ 2} }} $ ranged between 111 and 459 μatm which correlated significantly with the SST (r = 0.71, p < 0.001, n = 62). Neither DIC nor TAlk showed any linear relationship with varying salinity in the estuarine mixing zone, demonstrating the significant presence of non-carbonate alkalinity. An overall net biological control on the surface $ f_{{{\text{CO}}_{ 2} }} $ distribution was established during the study, although no significant correlation was found between chlorophyll-a and $ f_{{{\text{CO}}_{ 2} }} $ (water). The shallow water region studied was mostly under-saturated with CO₂ and acted as a sink for atmospheric CO₂. The difference between surface water and atmospheric $ f_{{{\text{CO}}_{ 2} }} $ ( $ \Updelta f_{{{\text{CO}}_{ 2} }} $ ) ranged from ?274 to 69 μatm, with an average seaward flux of ?10.5 ± 12.6 μmol m^?2 h^?1. The $ \Updelta f_{{{\text{CO}}_{ 2} }} $ and hence the air–sea CO₂ exchange was primarily regulated by the variation in sea surface $ f_{{{\text{CO}}_{ 2} }} $ , since atmospheric $ f_{{{\text{CO}}_{ 2} }} $ varied over a comparatively narrow range of 361.23–399.05 μatm.     

Formation of methane-related authigenic carbonates in a highly dynamic biogeochemical system in the Krishna–Godavari Basin,Bay of Bengal

We report the abundant occurrence of authigenic Fe-rich carbonate, high Mg-calcite (HMC) and low Mg-calcite from 11 cores recovered from the Krishna–Godavari Basin (K–G Basin), Bay of Bengal. The cores were collected as part of the Indian gas hydrate exploration program on board R/V Marion Dufresne (MD-161: May, 2007) in different environments, including mounds (mud diapirs), mass flows, and hemipelagic sediments over a range of water depths from 647 to 2079 m. Authigenic carbonates range in size from 1 mm to 12 cm and display various morphologies like roundish or platy (micro-) nodules and tube-like forms. From the cores, 173 carbonate samples have been investigated for their depth distribution, mineralogy, geochemical and stable isotopic composition. The stable carbon isotopic composition of 46 out of 88 measured carbonate samples are around −50‰ which allows the differentiation into methane-related carbonates (HMC), especially at Sites 8 and 15, but also in low abundance at Sites 1, 5, 9 and 12. Results indicate that the carbonates at Site 8 and 15 represent paleo methane seepage locations. The Fe-rich carbonates occur abundantly at many sites in the K–G Basin. Their varying carbon isotopic composition indicates that probably not only sulfate reduction through organic matter degradation but also methanogenesis are the responsible processes for their formation.     

Particulate n-alkanes and fatty acids in the Changjiang river system

Particulate samples were collected from the Changjiang river system during a flood period, in May 1997, and POC, stable isotope and lipids associated with particles were examined. Results showed the decrease (0.84% ～ 1.88%) of organic carbon content from the upper reaches to the estuary.δ13C values of particulate organic carbon was in the range of -24.9×10-3 to -26.6×10-3, which were close to the isotopic signature of continental C3 vegetation. Total particulate n-alkanes concentrations varied from 1.4 to 10.1μg/dm3,or from 23.7 to 107μg/g of total suspended matter. Fatty acids were present in all the samples, from 1.4 to 5.4μg/dm3, with saturated and unsaturated straight-chain and branched compounds in the carbon number range from C12 to C30. Both δ13C and the ratio of carbon content to nitrogen content indicate the predominance of terrestrial inputs (soil organic matter) among the particles. The biomarker approach has been used to identify the relative portion of terrigenous and autochthonous fraction in the particulate samples. The distribution of fatty acids suggests a striking phytoplanktonic and microbial signal in most particle samples. The terrestrial alkanes are used to estimate the contribution of terrestrial inputs along the mainstream.     

Influence of processes in the ocean–atmosphere system in the North Atlantic on the intraannual variation of climatic characteristics on the territory of Ukraine

We make an attempt to study specific features of weather- and climate-forming processes developing due to the energy and mass transfer between the ocean and the atmosphere in the North Atlantic, as well as responses of the climate of Ukraine to the main climate-forming factors. These studies are based on a statistical model in the form of a system of third-order regression equations with feedback. We deduce a system of generating functions that allow us to estimate the regression coefficients. Within the developed model, we applied the factor analysis to compress the input information about the affecting factors in the region where the weather ships were located. This allowed us to reveal the tendencies of variations in the characteristics participating in the energy and mass transfer. The response of the climate in various regions of Ukraine to the processes running in the North Atlantic was determined using the cluster analysis whose algorithm was developed by the authors. We performed a number of experiments for various situations in the region of the North Atlantic that are possible due to the global warming of the climate and studied the response of climatic characteristics on the territory of Ukraine under similar processes. The adequacy of the developed model was verified on the basis of data on the real situation in February 2006. It is shown that the model satisfactorily describes the responses of climatic characteristics in regions of Ukraine to variations of the affecting factors in the North Atlantic.     

Phytoplankton distribution in the Agulhas system from a coupled physical–biological model

The greater Agulhas Current system has several components with high mesoscale turbulence. The phytoplankton distribution in the southwest Indian Ocean reflects this activity. We have used a regional eddy-permitting, coupled physical–biological model to study the physical–biological interactions and to address the main processes responsible for phytoplankton distribution in three different biogeochemical provinces: the southwest Subtropical Indian Gyre (SWSIG), the subtropical convergence zone (SCZ) and the subantarctic waters (SAW) south of South Africa. The biological model with four compartments (Nitrate–Phytoplankton–Zooplankton–Detritus) adequately reproduces the observed field of chlorophyll a. The phase of the strong modelled seasonality in the SWSIG is opposite to that of the SCZ that forms the southern boundary of the subtropical gyre. Phytoplankton concentrations are governed by the source-minus-sink terms, which are one order of magnitude greater than the dynamical diffusion and advection terms.North of 35°S, in the SWSIG, phytoplankton growth is limited by nutrients supply throughout the year. However, deeper stratification, enhanced cross-frontal transport and higher detritus remineralization explain the simulated higher concentrations of phytoplankton found in winter in the SWSIG. The region between 35° and 40°S constitutes a transition zone between the SCZ and the oligotrophic subtropical province. Horizontal advection is the main process bringing nutrients for phytoplankton growth. The front at 34°S represents a dynamical barrier to an extension further to the north of this advection of nutrients.Within the SCZ, primary production is high during spring and summer. This high productivity depletes the nutrient standing stock built up during winter time. In winter, nutrients supply in the convergence zone is indeed large, but the deep mixing removes phytoplankton from the euphotic zone and inhibits photosynthesis, yielding lower surface chlorophyll a concentrations.Waters south of the Subantarctic Front have a summer biomass close to that of frontal waters and higher than for subtropical waters. However, these simulated concentrations are slightly higher than the observed ones suggesting that limitation by iron and/or silica may play a role.     

Alternatives to ITQs in equity–efficiency–effectiveness trade-offs: How the lay-up system spread effort in the BC halibut fishery

Individual Transferable Quotas (ITQs), also called “catch shares”, have been broadly adopted in the last two decades, at the same time that concerns about their equity and effectiveness in delivering the predicted outcomes have increased. This paper documents how an alternative fishermen-designed and operated system of spreading fishing effort to avoid the race for fish—called the lay-up system—worked effectively and equitably for four decades in the British Columbia halibut fishery before ITQs were introduced in this fishery. Why the lay-up system was allowed to collapse and its history ignored illustrates important roles played by conflicting ideologies, bureaucratic rationality, and the inability to imagine an alternative way of solving fisheries management problems. Trade-offs between the efficiency, equity, and effectiveness of halibut and other management systems are considered.     

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.     

Simulation and prediction of climate changes in the 19th to 21st centuries with the Institute of Numerical Mathematics, Russian Academy of Sciences, model of the Earth’s climate system

This paper presents results from a simulation of climate changes in the 19th–21st centuries with the Institute of Numerical Mathematics Climate Model Version 4 (INMCM4) in the framework of the Coupled Model Intercomparison Project, phase 5 (CMIP5). Like the previous INMCM3 version, this model has a low sensitivity of 4.0 K to a quadrupling of CO₂ concentration. Global warming in the model by the end of the 21st century is 1.9 K for the RCP4.5 scenario and 3.4 K for RCP8.5. The spatial distribution of temperature and precipitation changes driven by the enhanced greenhouse effect is similar to that derived from the INMCM3 model data. In the INMCM4 model, however, the heat flux to the ocean and sea-level rise caused by thermal expansion are roughly 1.5 times as large as those in the INMCM3 model under the same scenario. A decrease in sea-ice extent and a change in heat fluxes and meridional circulation in the ocean under global warming, as well as some aspects of natural climate variability in the model, are considered.     

Monitoring of seabirds in the Benguela upwelling system: can seabirds be used as indicators and predictors of change in the marine environment?

Historical and contemporary data on Benguela seabirds assumed to be responsive to changes in food availability are reviewed as potential indicators and predictors of change in the ecosystem. Cyclic variations in the annual yields of seabird products evident at decadal long time-scales may reflect fluctuations in prey populations at similar periods. However, no such relationship has been demonstrated and consequently the value of such annual yields as indicators is not proved. More recently, interannual variation in diets, foraging effort, breeding success and chick growth of two of the three most abundant species of seabird in the ecosystem have been examined in relation to changes in prey abundance. Although the relative abundance of important forage species in the diets of both species of seabird have reflected regional changes in the absolute abundance of these prey, changes in the values of other parameters thought to reflect food availability were not consistently correlated between and within species. This indicates poor potential for their use as indicators of change at least over the range of abundances experienced in this study. Under present management protocol, data from seabirds do not nor are likely to provide abundance indices that may be used directly in stock assessment of commercially important species. To date, insights into distribution and migration of pelagic fish provided by seabird-derived data probably represent the most valuable contribution of birds to fisheries scientists studying the Benguela system.     

Biomass of meiobenthic in the Bohai Sea, China

IorasMeiOfauna is a vmp imprtant pep in benthic small bo web energetica1ly duo to theirarell aize and high turnovr rates. A nde Of meMauna op be the recireulaton of nutrient8*Marine nemathe mey keep the bacterial chnies on sand grains in active phase Of gorth byfeding on bacteria, thus enhancing the recirculation Of nutrients (McIntyre, l969; Feller andWrmick, l988; MOntagna et al., l995). But energetics studie8, no matter tfor conductedon the energybudgt level for individua sPeCies or a…     

Dramatic changes in the horizontal structure of mangrove forests in the largest delta of the northern Beibu Gulf,China

The horizontal structure of mangrove forests is an important characteristic that reflects a significant signal for coupling between mangroves and external drivers. While the loss and gain of mangroves has received much attention, little information about how the horizontal structure of mangrove forests develops from the seedling stage to maturity has been presented. Here, remote sensing images taken over approximately 15 years, UVA images, nutrient elements, sediments, and Aegiceras corniculatum...     

Analysis of state of the carbonate system of waters and variations of the content of organic carbon in bottom sediments of the Sevastopol bay in 1998–2005

On the basis of the experimental data accumulated in 1998–2005, we analyzed the space and time variations of the carbonate system of waters and the content of organic carbon in bottom sediments of the Sevastopol Bay. The intensity of gas exchange through the water-atmosphere interface was quantitatively estimated. It was shown that the partial pressure of carbon dioxide pCO₂ in waters of the bay became much higher for the period of observations. The maximum changes were observed in summer. They were especially pronounced for the bottom layer of waters. For the entire period of observations, the invasion of carbon dioxide CO₂ was predominant in the major part of the bay, and the content of organic carbon in the bottom sediments increased. The ability of waters in the bay to absorb CO₂ is explained by the synthesis of organic substances, which becomes possible due to the presence of the equivalent load of nutrients. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 2, pp. 57–67, March–April, 2008.     

From community-based to co-management: Improvement or deterioration in fisheries governance in the Cherai Poyil fishery in the Cochin Estuary,Kerala, India?

During the last 50 years, several different forms of fisheries governance have been tried and failed in the Cochin Estuary, Kerala, India. The latest shift has been from a community-based system to a co-management system, and this paper evaluates the current system in the light of the theoretical debate over the respective merits of community-based management and co-management. The paper is based on documentary material and data from interviews carried out during fieldwork in 2004, from which it concludes that provided the co-management system incorporates community principles within it, it will be an effective form of fisheries governance.     

An evaluation of self-governance in the New Zealand Bluff oyster fishery – The indicator system approach

The use of self-governance as a fisheries management tool is increasing in New Zealand and elsewhere. Researchers argue that in theory self-governance can lead to improved outcomes, but evaluating actual benefits is difficult because of the need to distinguish self-governance impacts from other influences on fisheries performance. An indicator system was developed in this paper to evaluate the contribution of selfgovernance to the performance of the Bluff Oyster fishery (OYU5), which is also managed under New Zealand's Quota Management System. There is evidence that self-governance makes a positive contribution to economic efficiency, institutional effectiveness and resource preservation in the Bluff Oyster fishery.     

Some investigation results in the sea region off the Wilkes Land, Antarctica

During February and March in 1985, the research project of seven hydrographic sections in the sea region off the Wilkes Land (147°-162°E) Antarctica was finished. Hydrographic, chemical and biological data were obtained. According to preliminary analysis, some conclusions were made as follows:     

Variations in the Atlantic inflow to the Nordic Seas, 1955–1996

Hydrographic observations on the Svinøy section, which runs NW from about 62°N on the Norwegian coast to 64°40′N on the prime meridian, have been used to investigate variations in the Atlantic inflow to the Nordic Seas. The data are from the winter 1955 to 1973 and from the spring and the summer 1978 to 1996. The observations show that in the summer there exist two cores of water with salinity above 35.25 at about 100 m depth, but in the spring and the winter the core furthest offshore is less distinct. Geostrophic calculations show that, for all data sets, there are two kernels with northward currents in the Svinøy section: one over the inner part of the continental slope (over 600–800 m depths) and one further offshore (over 1400–2500 m depth). The mean volume transports of Atlantic water in the section are 4.5, 5.0 and 5.6 Sv in spring, summer and winter, respectively. Results from an Empirical Orthogonal Function analysis of the summer data indicate that there is a dual structure in the section when interannual variations are considered. In the western part of the section the temperature and salinity are negatively correlated with the winter North Atlantic Oscillation index, but in the eastern part of the section they are weakly positively correlated. This is not found in the winter data from 1955 to 1973. The geostrophic volume transport in the summer through the Svinøy section is positively correlated with the NAO indices for winter and spring, where the March NAO index gave the best correlation. Also, the summer volume transports west and east in the section seem to be in opposite phase. From the summer data 1978 to 1996 there is a positive linear trend for the eastern transport (+2.4 Sv), but there is a negative linear trend for the western transport (−2.0 Sv). The transport through the whole section has increased by 1.1 Sv during the same similar period. The atmospheric conditions were different in years with relatively low temperatures and salinities in the western part of the section compared to those years with relatively high temperatures and salinities. It is proposed that interannual variations of temperature, salinity and volume transport in the Svinøy section are controlled mostly by a large-scale variable pressure system (i.e. the North Atlantic Oscillation index).