Subjects -> EARTH SCIENCES (Total: 771 journals)
    - EARTH SCIENCES (527 journals)
    - GEOLOGY (94 journals)
    - GEOPHYSICS (33 journals)
    - HYDROLOGY (29 journals)
    - OCEANOGRAPHY (88 journals)

OCEANOGRAPHY (88 journals)

Showing 1 - 77 of 77 Journals sorted by number of followers
Deep Sea Research Part II: Topical Studies in Oceanography     Hybrid Journal   (Followers: 29)
Deep Sea Research Part I : Oceanographic Research Papers     Hybrid Journal   (Followers: 23)
Estuaries and Coasts     Hybrid Journal   (Followers: 23)
Limnology and Oceanography     Hybrid Journal   (Followers: 22)
Progress in Oceanography     Hybrid Journal   (Followers: 21)
Journal of Marine Biology & Oceanography     Hybrid Journal   (Followers: 19)
New Zealand Journal of Marine and Freshwater Research     Hybrid Journal   (Followers: 18)
Journal of Physical Oceanography     Hybrid Journal   (Followers: 18)
Frontiers in Marine Science     Open Access   (Followers: 17)
Journal of Marine Sciences     Open Access   (Followers: 17)
Coastal Engineering     Hybrid Journal   (Followers: 15)
Advances in Oceanography and Limnology     Open Access   (Followers: 15)
Journal of Oceanography     Hybrid Journal   (Followers: 14)
Maritime Studies     Open Access   (Followers: 13)
International Journal of Oceanography     Open Access   (Followers: 12)
Advances in Statistical Climatology, Meteorology and Oceanography     Open Access   (Followers: 11)
Atmospheric and Oceanic Science Letters     Open Access   (Followers: 10)
Bulletin of Marine Science     Full-text available via subscription   (Followers: 9)
Fisheries Oceanography     Hybrid Journal   (Followers: 8)
Journal of Oceanography and Marine Science     Open Access   (Followers: 7)
Open Journal of Marine Science     Open Access   (Followers: 6)
Limnology and Oceanography: Methods     Hybrid Journal   (Followers: 6)
Journal of Operational Oceanography     Hybrid Journal   (Followers: 6)
Physical Oceanography     Hybrid Journal   (Followers: 6)
Paleoceanography and Paleoclimatology     Full-text available via subscription   (Followers: 5)
Marine Science     Open Access   (Followers: 5)
Limnology and Oceanography: Fluids and Environments     Full-text available via subscription   (Followers: 5)
Ocean Yearbook Online     Hybrid Journal   (Followers: 4)
Journal of Oceanology and Limnology     Hybrid Journal   (Followers: 4)
Limnology and Oceanography Letters     Open Access   (Followers: 4)
Journal of Marine Science and Engineering     Open Access   (Followers: 4)
African Journal of Marine Science     Hybrid Journal   (Followers: 4)
Oceanology     Hybrid Journal   (Followers: 3)
Journal of Aquatic Sciences     Full-text available via subscription   (Followers: 3)
Limnology and Oceanography e-Lectures     Open Access   (Followers: 3)
Journal of Coastal Development     Open Access   (Followers: 3)
Ciencias Marinas     Open Access   (Followers: 3)
Journal of Marine Science and Application     Hybrid Journal   (Followers: 3)
Journal of Ocean Engineering and Marine Energy     Hybrid Journal   (Followers: 3)
Tropical Oceanography     Open Access   (Followers: 2)
Indian Journal of Geo-Marine Sciences     Open Access   (Followers: 2)
Mediterranean Marine Science     Open Access   (Followers: 2)
Regional Studies in Marine Science     Hybrid Journal   (Followers: 2)
Annals of Marine Science     Open Access   (Followers: 2)
Limnology and Oceanography: Bulletin     Hybrid Journal   (Followers: 2)
Annals of Limnology and Oceanography     Open Access   (Followers: 2)
Development and Applications of Oceanic Engineering     Open Access   (Followers: 2)
Journal of Ocean Engineering and Technology     Open Access   (Followers: 1)
Acta Aquatica : Aquatic Sciences Journal     Open Access   (Followers: 1)
Ocean Life     Open Access   (Followers: 1)
Marine Systems & Ocean Technology     Hybrid Journal   (Followers: 1)
Marine Life Science & Technology     Hybrid Journal   (Followers: 1)
Journal of Ocean University of China (English Edition)     Hybrid Journal   (Followers: 1)
Journal of Ocean Engineering and Science     Open Access   (Followers: 1)
Coastal Engineering Proceedings : Proceedings of the International Conference on Coastal Engineering     Open Access   (Followers: 1)
Marine Technology Society Journal     Full-text available via subscription   (Followers: 1)
Scientia Marina     Open Access   (Followers: 1)
Western Indian Ocean Journal of Marine Science     Open Access   (Followers: 1)
Asian Journal of Fisheries and Aquatic Research     Open Access  
Thalassas : An International Journal of Marine Sciences     Hybrid Journal  
Oceans     Open Access  
Aquatic Research     Open Access  
Jurnal Kelautan Tropis     Open Access  
Depik Jurnal Ilmu-Ilmu Perairan, Pesisir dan Perikanan     Open Access  
Journal of Agricultural and Marine Sciences     Open Access  
Turkish Journal of Maritime and Marine Sciences     Open Access  
Arquivos de Ciências do Mar     Open Access  
Scientific Drilling     Open Access  
Jurnal Kelautan : Indonesian Journal of Marine Science and Technology     Open Access  
Oceanologia     Open Access  
Revista de Gestão Costeira Integrada     Open Access  
Revista Ciencias Marinas y Costeras     Open Access  
Egyptian Journal of Aquatic Research     Open Access  
China Ocean Engineering     Hybrid Journal  
Revista de Biología Marina y Oceanografía     Open Access  
Latin American Journal of Aquatic Research     Open Access  
Acta Oceanologica Sinica     Hybrid Journal  
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Acta Oceanologica Sinica
Journal Prestige (SJR): 0.334
Citation Impact (citeScore): 1
Number of Followers: 0  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0253-505X - ISSN (Online) 1869-1099
Published by Springer-Verlag Homepage  [2467 journals]
  • Application of an optical nitrate profiler to high- and low-turbidity
           coastal shelf waters

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      Abstract: Abstract Here, we report the results of high-resolution nitrate measurements using an optical nitrate profiler (in situ ultraviolet spectrophotometer, ISUS) along transect across a high-turbidity shelf (East China Sea) and a low-turbidity shelf (Chukchi Sea). The ISUS-measured nitrate concentrations closely reproduced the results measured by conventional bottle methods in low-turbidity waters. However, for high-turbidity waters of the East China Sea (salinity<30), a correction factor of 1.19 was required to match the standard bottle measurements. The high-resolution ISUS data revealed subtle spatial variability (e.g., a subsurface nitrate minimum) that may have been missed if based solely on bottle results. Four main structures of the nitracline on the East China Sea are apparent from the ISUS nitrate profile. High-resolution nitrate data are important for studying nitrate budgets and nutrient dynamics on continental shelves.
      PubDate: 2023-01-21
       
  • Otolith microchemical evidence revealing multiple spawning site
           origination of the anadromous tapertail anchovy (Coilia nasus) in the
           Changjiang (Yangtze) River Estuary

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      Abstract: Abstract The estuarine tapertail anchovy (Coilia nasus) is a high-value commercial fish. Estimating the spawning site or hatchery origin and habitat is essential for its conservation. This study aimed to determine the habitat use and life history characteristics of C. nasus from the Changjiang River Estuary. We investigated the environmental signatures of strontium (Sr) and calcium (Ca) in the otoliths of the collected specimens using electron probe microanalysis; additionally, we examined their gonadal maturity stage. Our results indicate that the 31 adult C. nasus specimens used in this study could be classified into two types based on their otolith Sr:Ca concentration ratios and their gonadal maturity stage. The long freshwater early life history type (Type LF) had wider central region in the otolith with low Sr:Ca concentration ratios ranging from 1.24±0.62 to 1.92±0.78 and a bluish pattern of low Sr content level. These fish are of riverine origin and had a relatively long early life history in freshwater and low gonadal maturation when captured. The short freshwater early life history type (Type SF) had a shorter central region in the otolith with low Sr:Ca concentration ratios ranging from 1.35±0.5 to 2.82±0.97 and a correspondingly bluish pattern. These fish also had a relatively short-term early life history in freshwater and high gonadal maturation when captured. The results of the otolith microchemical analysis indicated that Type LF and Type SF originated in spawning/hatching sites far from and close to the estuary, respectively. The mature gonads of Type SF fish indicated that they may breed in areas close to the estuary, whereas the immature gonads of Type LF fish indicated that they may breed in areas far from the estuary. This study is the first to reveal that the Changjiang River Estuary contains stocks of anadromous C. nasus originating in different spawning sites during the same season. The estuarine habitat plays a critical role in the connectivity between freshwater recruitment and the marine resources available to adult spawners of this commercially valued species. From a conservation perspective, this study provides important information for identifying anadromous C. nasus stocks originating in different spawning sites in the Changjiang River Basin.
      PubDate: 2023-01-21
       
  • Sedimentary record of climate change in a high latitude
           fjord—Kongsfjord

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      Abstract: Abstract The sedimentary record of climate change in the Arctic region is useful for understanding global warming. Kongsfjord is located in the subpolar region of the Arctic and is a suitable site for studying climate change. Glacier retreat is occurring in this region due to climate change, leading to an increase in meltwater outflow with a high debris content. In August 2017, we collected a sediment Core Z3 from the central fjord near the Yellow River Station. Then, we used the widely used chronology method of 210Pb, 137Cs, and other parameters to reflect the climate change record in the sedimentary environment of Kongsfjord. The results showed that after the mid-late 1990s, the mass accumulation rate of this core increased from 0.10 g/(cm2·a) to 0.34 g/(cm2·a), while the flux of 210Pbex increased from 125 Bq/(m2·a) to 316 Bq/(m2·a). The higher sedimentary inventory of 210Pbex in Kongsfjord compared to global fallout might have been caused by sediment focusing, boundary scavenging, and riverine input. Similarities between the inventory of 137Cs and global fallout indicated that terrestrial particulate matter was the main source of 137Cs in fjord sediments. The sedimentation rate increased after 1997, possibly due to the increased influx of glacial meltwater containing debris. In addition, the 137Cs activity, percentage of organic carbon (OC), and OC/total nitrogen concentration ratio showed increasing trends toward the top of the core since 1997, corresponding to a decrease in the mass balance of glaciers in the region. The results of δ13C, δ15N and OC/TN concentration ratio showed both terrestrial and marine sources contributed to the organic matter in Core Z3. The relative contribution of terrestrial organic matter which was calculated by a two-endmember model showed an increased trend since mid-1990s. All these data indicate that global climate change has a significant impact on Arctic glaciers.
      PubDate: 2023-01-21
       
  • Nitrate isotope dynamics in the lower euphotic-upper mesopelagic zones of
           the western South China Sea

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      Abstract: Abstract The dual isotopes (N and O) of nitrate were measured using a denitrifier bacterial method in the western South China Sea (WSCS) during September 2015 to elucidate key information during N transformation in the lower euphotic zone (LEZ)-upper mesopelagic zone (UMZ, down to 500 m in this study) continuum, which is a vital sub-environment for marine N cycle and sequestration of atmospheric CO2 as well. The N isotopic composition (δ15N) of nitrate generally decreased from 500 m toward the base of the euphotic zone (∼100 m), reaching a value of ∼4.6‰ (vs. air N2) at the base of the LEZ, suggesting the imprint of remineralization (nitrification) of isotopically light N from atmospheric source. The δ15N and δ18O of nitrate only generally conform to a 1:1 line at 50 m and 75 m, suggesting that nitrate assimilation is a dominant process to shape nitrate isotope signature in this light-limited and relatively N-replete lower part of the euphotic zone. The fractionation factors of N and O isotopes during nitrate fractionation (15εASSIM, 18εASSIM) using a steady-state model were estimated to be 4.0‰±0.3‰ and 5.4‰±0.3‰, respectively. The occurrence of nitrification at the base of the LEZ and most of the UMZ is corroborated by the decoupling of δ15N and the oxygen isotopic composition (δ18O) of nitrate. Our results will provide insights for better understanding N cycle in the South China Sea from a perspective of present and past.
      PubDate: 2023-01-21
       
  • A simple guideline to apply excitation-emission matrix spectroscopy (EEMs)
           for the characterization of dissolved organic matter (DOM) in anoxic
           marine sediments

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      Abstract: Abstract Marine sediments represent a major carbon reservoir on Earth. Dissolved organic matter (DOM) in pore waters accumulates products and intermediates of carbon cycling in sediments. The application of excitation-emission matrix spectroscopy (EEMs) in the analysis of subseafloor DOM samples is largely unexplored due to the redox-sensitive matrix of anoxic pore water. Therefore, this study aims to investigate the interference caused by the matrix on EEMs and propose a guideline to prepare pore water samples from anoxic marine sediments. The parameters determined by fluorescence spectra include 3D-index derived from EEMs after parallel factor analysis (PARAFAC), fluorescence index (FI) (contribution of terrigenous DOM), biological index (BIX) and humification index (HIX) derived from 2D emission spectra. First, we investigated the impacts of extensively-presented ions as typical electron acceptors, which are utilized by anaerobic microbes and stratified in marine sediments: Fe(II), Fe(III), Mn(II) and sulfide in anoxic pore water resulted in biases of fluorescent signals. We proposed threshold concentrations of these ions when the interference on EEMs occurred. Effective removal of sulfide from sulfide-rich samples could be achieved by flushing with N2 for 2 min. Second, the tests based on DOM standard were further verified using pristine samples from marine sediments. There was a significant change in the fluorescence spectra of DOM in anoxic sediments from the Rhône Delta. This study demonstrated that the change was caused by oxidation of the matrix rather than the intrinsic alteration of DOM. It was confirmed by extracted DOM via both EEMs analysis and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS). Slight oxidation of sulfur-containing compounds (e.g., sulfhydryl) and polyphenol-like compounds occurred. Finally, a sample preparation sequence is proposed for pore water from anoxic sediments. This method enables measurement with small volumes of the sample (e.g., 50 µL in this study) and ensures reliable data without the interference of the redox-sensitive matrix. This study provides access to the rapid analysis of DOM composition in marine sediments and can potentially open a window into examining the carbon cycling of the marine deep biosphere.
      PubDate: 2023-01-21
       
  • Spatial and temporal variation process of seabed dynamic response induced
           by the internal solitary wave

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      Abstract: Abstract Internal solitary wave (ISW) is often accompanied by huge energy transport, which will change the pore water pressure in the seabed. Based on the two-dimensional Biot consolidation theory, the excess pore water pressure in seabed was simulated, and the spatiotemporal distribution characteristics of excess pore water pressure was studied. As the parameters of both ISW and seabed can affect the excess pore water pressure, the distribution of pore water pressure showed both dissipation and phase lag. And parametric studies were done on these two phenomena. Due to influenced by the phase lag of excess pore water pressure, the penetration depth under the site of northern South China Sea with total water depth 327 m, induced by typical internal solitary wave increased by 26.19%, 53.27% and 149.86% from T0 to T0.5 in sand silt, clayey silt and fine sand seabed, respectively. That means the effect of ISW on seabed will be underestimated if we only take into accout the penetration depth under ISW trough, especially for fine sand seabed. In addition, the concept of “amplitude-depth ratio” had been introduced to describe the influence of ISW on seabed dynamic response in the actual marine environment. In present study, it is negatively correlated with the excess pore water pressure, and an ISW with smaller amplitude-depth ratio can wide the range of lateral impacts. Our study results help understand the seabed damage induced by the interaction between ISW and seabed.
      PubDate: 2023-01-14
       
  • Study of coexisting upstream solitary wave packet and downstream wakes
           induced by Diaoyu Dao and its affiliated islands detected by satellite sun
           glitter

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      Abstract: Abstract Taking the advantage of sun glitter (SG) observed from high-resolution satellites Gaofen-1 (GF-1) and Gaofen-6 (GF-6), a new method named Shield and Vortex 1–2 (SAV1-2) for extracting spatial texture information from sun glitter was established. Sea surface texture detail information around Diaoyu Dao and its affiliated islands was extracted using SAV1-2. Meanwhile, the dynamic characteristics of the water environment were analyzed by combining the water color, temperature and dynamic data. The results show the following information. (1) Stable westward shield effect and eastward Karman vortex streets, extracted from SG, appear upstream (westward) and downstream (eastward) of the Diaoyu Dao and its affiliated islands respectively. (2) The dominant direction of the Kuroshio Current in the Diaoyu Dao and its affiliated islands area is east, the Diaoyu Dao and its affiliated islands interacting with Kuroshio, inducing western shield and eastern shelter and wake. Furthermore, wave intervals of the shield in front of the island range from hundreds to thousands of metres, and extend wider than the island itself. (3) Combining with high-resolution sea surface temperature (SST) and chlorophyll a (Chl a) concentration, the directional changes of water color elements are mutually supported and proved with the stable shield (wave packet) effect in the west and vortex street effect in the east. The change of SST upstream of the island (western shield area) is not significant, the temperature in the downstream shelter area decreases slightly, and the SST in the downstream wake area shows a general trend of obvious decrease. The wake area is dominated by Karman vortex streets in shape, supplementing by vortices. The concentration of Chl a in the west shield of island is as low as that in downstream shelter area, while it increases significantly in the downstream wake area with shape in eddy or ribbon. (4) The SAV methods of extracting sea surface texture detail using SG can be widely used in different sea areas and water quality. This paper can provide reference for the protection and development of Diaoyu Dao and its affiliated islands and its surrounding waters. It is suggested that some kind of current buffer, such as marine wind farm, should be established in the western waters of Diaoyu Dao and its affiliated islands to protect the islands, and marine pasture should be developed in the downstream of eastern waters of Diaoyu Dao and its affiliated islands.
      PubDate: 2023-01-11
       
  • An assessment of the subduction rate in the CMIP6 historical experiment

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      Abstract: Abstract Subduction process is a dynamical bridge for the exchanges of heat between the atmosphere and subsurface ocean water, which is regarded as a central proxy for the ocean climate studies. Given its key indicator in climate signals, it is of importance to examine the ability of a model to simulate the global subduction rate before investigating the climate dynamics. In this paper, we evaluated the ability of 21 climate models from Coupled Model Intercomparison Project Phase 6 (CMIP6) in simulating the subduction rate. In general, the simulation ability of the models to the subduction climatology is better than that to the long-term variation trend. Based on the comprehensive analysis of climatology distribution and long-term trend of the subduction rate, GISS-E2-1-G performs better in reproducing the subduction rate climatology and IPSL-CM6A-LR can simulate positive long-term trend for both the global mean subduction rate and the lateral induction term in the Antarctic Circumpolar Current (ACC) region. However, it is still challenging to capture both the distribution characteristics of the subduction climatology and the long-term temporal trend for the 21 CMIP6 models. In addition, the model results demonstrate that, the ACC area is the major region contributing to the long-term trend of the global mean subduction rate. The analysis in this paper indicates that the poor simulation ability of reproducing the long-term trend of global mean subduction rate might be attributed to the ocean dynamics, for example, the zonal velocity at the bottom mixed layer and zonal gradient of mixed layer depth.
      PubDate: 2023-01-05
       
  • Lateral downslope transport and tentative sedimentary organic carbon box
           model in the southern Yap Trench, western Pacific Ocean

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      Abstract: Abstract Sediment collapse and subsequent lateral downslope migration play important roles in shaping the habitats and regulating sedimentary organic carbon (SOC) cycling in hadal trenches. In this study, three sediment cores were collected using a human-occupied vehicle across the axis of the southern Yap Trench (SYT). The total organic carbon (TOC) and total nitrogen (TN) contents, δ13C, radiocarbon ages, specific surface areas, and grain size compositions of sediments from three cores were measured. We explored the influence of the lateral downslope transport on the dispersal of the sediments and established a tentative box model for the SOC balance. In the SYT, the surface TOC content decreased with water depth and was decoupled by the funneling effect of the V-shaped hadal trench. However, the sedimentation (0.002 5 cm/a) and SOC accumulation rates (∼0.038 g/(m2·a) (in terms of OC)) were approximately 50% higher in the deeper hadal region than in the abyssal region (0.001 6 cm/a and ∼0.026 g/(m2·a) (in terms of OC), respectively), indicating the occurrence of lateral downslope transport. The fluctuating variations in the prokaryotic abundances and the SOC accumulation rate suggest the periodic input of surficial sediments from the shallow region. The similar average TOC (0.31%–0.38%), TN (0.06%–0.07%) contents, and SOC compositions (terrestrial OC: (11%–18%), marine phytoplanktonic OC: (45%–53%), and microbial OC: (32%–44%)) of the three sites indicate that the lateral downslope transport has a significant mixing effect on the SOC composition. The output fluxes of the laterally transported SOC (0.44–0.56 g/(m2·a) (in terms of OC)) contributed approximately (47%–73%) of the total SOC input, and this proportion increased with water depth. The results of this study demonstrate the importance of lateral downslope transport in the spatial distribution and development of biomes.
      PubDate: 2023-01-05
       
  • Comparison of short-term toxicity of 14 common phycotoxins (alone and in
           combination) to the survival of brine shrimp Artemia salina

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      Abstract: Abstract Toxic harmful algal blooms (HABs) can cause deleterious effects in marine organisms, threatening the stability of marine ecosystems. It is well known that different strains, natural populations and growth conditions of the same toxic algal species may lead to different amount of phycotoxin production and the ensuing toxicity. To fully assess the ecological risk of toxic HABs, it is of great importance to investigate the toxic effects of phycotoxins in marine organisms. In this study, the short-term toxicity of 14 common phycotoxins (alone and in combination) in the marine zooplankton Artemia salina was investigated. The 48 h LC50 of the 14 phycotoxins varied from 0.019 3 µg/mL to 2.415 µg/mL. The most potent phycotoxin was azaspiracids-3 (AZA3; with a LC50 of 0.019 3 µg/mL), followed by azaspiracids-2 (AZA2; 0.022 6 µg/mL), pectenotoxin-2 (PTX2; 0.046 0 µg/mL) and dinophysistoxin-1 (DTX1; 0.081 8 µg/mL). For the binary exposure, okadaic acid (OA) induced potential additive effects with DTX1, probably due to their similar structure (polyether fatty acid) and mode of action (attacking the serine/threonine phosphoprotein phosphatases). On the other hand, OA showed potential antagonistic effects with PTX2, which might be accounted for by their activation on the detoxification activity of cytochrome P450 activity. In addition, DTX1 induced potential synergetic effects with saxitoxin (STX), yessotoxin (YTX) or PTX2, suggesting the hazard potency of the mixtures of DTX1 and other phycotoxins (like STX, YTX and PTX2) with regard to the ecological risk. These results provide valuable toxicological data for assessing the impact of phycotoxins on marine planktonic species and highlight the potential ecological risk of toxic HABs in marine ecosystems.
      PubDate: 2022-12-27
       
  • Zircon U-Pb geochronology, Hf isotopes, and geochemistry constraints on
           the age and tectonic affinity of the basement granitoids from the
           Qiongdongnan Basin, northern South China Sea

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      Abstract: Abstract Studies in the northern South China Sea (SCS) basement remain important for understanding the evolution of the Southeast Asian continental margin. Due to a thick cover of sediments and scarce borehole penetration, little is known about the age and tectonic affinity of this basement. In this study, an integrated study of zircon U-Pb geochronology, Hf isotopes, and whole-rock major and trace elements on seven basement granitoids from seven boreholes of Qiongdongnan Basin has been carried out. New zircon U-Pb results for these granitoids present middle-late Permian ((270.0±1.2) Ma; (253±3.4) Ma), middle to late Triassic ((246.2±3.4) Ma; (239.3±0.96) Ma; (237.9±0.99) Ma; (228.9±1.0) Ma) and Late Cretaceous ages ((120.6±0.6) Ma). New data from this study, in combination with the previous dataset, indicates that granitoid ages in northern SCS basement vary from 270 Ma to 70.5 Ma, with three age groups of 270–196 Ma, 162–142 Ma, and 137–71 Ma, respectively. Except for the late Paleozoic-Mesozoic rocks in the basement of the northern SCS, a few old zircon grains with the age of (2 708.1±17) Ma to (2 166.6±19) Ma provide clues to the existence of the pre-Proterozoic components. The geochemical signatures indicate that the middle Permian-early Cretaceous granitoids from the Qiongdongnan Basin are I-type granites formed in a volcanic arc environment, which were probably related to the subduction of the Paleo-Pacific Plate.
      PubDate: 2022-12-05
       
  • Tsunami hazard and mitigation analysis for bathing beaches in China based
           on numerical simulations

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      Abstract: Abstract Bathing beaches are usually the first to suffer disasters when tsunamis occur, owing to their proximity to the sea. Several large seismic fault zones are located off the coast of China. The impact of each tsunami scenario on Chinese bathing beaches is different. In this study, numerical models of the worst tsunami scenarios associated with seismic fault zones were considered to assess the tsunami hazard of bathing beaches in China. Numerical results show that tsunami waves from the Pacific Ocean could affect the East China Sea coast through gaps between the Ryukyu Islands. The Zhejiang and Shanghai coasts would be threatened by a tsunami from Ryukyu Trench, and the coasts of Hainan and Guangdong provinces would be threatened by a tsunami from the Manila Trench. The tsunami hazard associated with the Philippine Trench scenario needs particular attention. Owing to China’s offshore topography, the sequential order of tsunami arrival times to coastal provinces in several tsunami scenarios is almost the same. According to the tsunami hazard analysis results, Yalongwan Beach and eight other bathing beaches are at the highest hazard level. A high-resolution numerical calculation model was established to analyze the tsunami physical characteristics for the high-risk bathing beaches. To explore mitigating effects of a tsunami disaster, this study simulated tsunami propagation with the addition of seawalls. The experimental results show that the tsunami prevention seawalls constructed in an appropriate shallow water location have some effect on reducing tsunami hazard. Seawalls separated by a certain distance work even better. The analysis results can provide a scientific reference for subsequent preventive measures such as facility construction and evacuation.
      PubDate: 2022-12-05
       
  • Morphological and histological changes in the brains of turbot
           (Scophthalmus maximus) with gonadal development

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      Abstract: Abstract The brain plays a critical role in controlling reproduction through the hypothalamus-pituitary-gonadal (HPG) axis in vertebrates. Turbot (Scophthalmus maximus) has become an economically important marine fish in Europe and North China. Previous research investigating turbot reproduction has focused on the role of the HPG axis in regulating egg and sperm production. However, the morphology and histology of the organs in the HPG axis have not been studied. In this study, we investigated the morphology and histology of brains in female and male turbot at different stages of gonadal development. The results showed that the brains of both female and male turbot were composed of seven parts that are typical of advanced teleosts: the telencephalon, diencephalon, cerebellum, hypothalamus, pituitary gland, myelencephalon, and olfactory bulbs. The telencephalon was well-developed and contained five distinct lobes, with the contiguous diencephalon at the caudal portion. The torus longitudinales and rostral torus semicircularis of the mesencephalon flattened along the dorsal surface, and the rostral corpus cerebellum was located in the dorsal portion. The actual total brain volume in mature males was significantly greater (p<0.05) than that of females with gonadal development. Notably, the pituitary volume in male turbot significantly increased (p<0.05) from immature to mature stage, but this difference did not occur in females. The data together illustrate a distinct sex difference in the turbot brain during gonadal development, providing insight into their HPG axes.
      PubDate: 2022-12-01
       
  • Construction and analysis of a coral reef trophic network for Qilianyu
           Islands, Xisha Islands

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      Abstract: Abstract Qilianyu Islands coral reefs (QICR), located in the northeastern part of the South China Sea, has been affected by human activities and natural disturbance. To characterize the trophic structure, ecosystem properties and keystone species of this region, a food-web model for the QICR is developed using methods involving a mass-balance approach with Ecopath with Ecosim software. Trophic levels range from 1.00 for detritus and primary producers to 3.80 for chondrichthyes. The mean trophic transfer efficiency for the entire ecosystem is 13.15%, with 55% of total energy flow originating from primary producers. A mixed trophic impact analysis indicates that coral strongly impacts most components of this ecosystem. A comparison of our QICR model with that for other coral reef ecosystems suggests that the QICR ecosystem is immature and/or is degraded.
      PubDate: 2022-12-01
       
  • Increased light availability enhances tolerance against ocean
           

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      Abstract: Abstract Although the adverse impacts of ocean acidification (OA) on marine calcifiers have been investigated extensively, the anti-stress capabilities regulated by increased light availability are unclear. Herein, the interactive effects of three light levels (30 µmol photons/(m2·s), 150 µmol photons/(m2·s), and 240 µmol photons/(m2·s) combined with two pCO2 concentrations (400 ppmv and 1 400 ppmv) on the physiological acclimation of the calcifying macroalga Halimeda opuntia were investigated using a pCO2-light coupling experiment. The OA negatively influenced algal growth, calcification, photosynthesis, and other physiological performances in H. opuntia. The relative growth rate under elevated pCO2 conditions significantly declined by 13.14%–41.29%, whereas net calcification rates decreased by nearly three-fold under OA conditions. Notably, increased light availability enhanced stress resistance through the accumulation of soluble organic molecules, especially soluble carbohydrate, soluble protein, and free amino acids, and in combination with metabolic enzyme-driven activities, OA stress was alleviated. The carotenoid content under low light conditions increased markedly, and the rapid light curve of the relative electron transport rate was enhanced significantly by increasing light intensities, indicating that this new organization of the photosynthetic machinery in H. opuntia accommodated light variations and elevated pCO2 conditions. Thus, the enhanced metabolic performance of the calcifying macroalga H. opuntia mitigated OA-related stress.
      PubDate: 2022-12-01
       
  • Long-term and monthly changes in abundance, size composition and spatial
           distribution of the mantis shrimp Oratosquilla oratoria in the Bohai Sea

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      Abstract: Abstract With the decline in fish resources worldwide, the ecological dominance and economic importance of crustaceans have obviously increased. Among crustacean species, mantis shrimps are increasingly dominant in many coastal waters of the world. In China, Oratosquilla oratoria is the most widely distributed and productive species of mantis shrimp, and its relative resource density is the highest in the Bohai Sea. In this study, we analysed the long-term and monthly population characteristics of O. oratoria in the Bohai Sea, including its relative resource density, body size and spatial distribution. The results showed that the relative resource density of O. oratoria in the Bohai Sea increased from 3.59 kg/h in 1982 to 14.48 kg/h in 2018, and the percentage of this species that serves as a fishery resource increased from 4.22% in 1982 to 35.27% in 2018, based on the mean relative resource density in May and August. The relative resource density of O. oratoria in the fishing moratorium season from May to August was significantly higher than that in the other months of fishing season, and the relative resource density decreased rapidly after the fishing moratorium ended. The relative resource density of O. oratoria was the highest in summer (August), followed by in autumn (October) and spring (May), and it was the lowest in winter (January). The relative resource density of O. oratoria in the western Bohai Sea was higher than that in the eastern Bohai Sea. The mean body weight of O. oratoria in the Bohai Sea decreased from 21.95 g in 1982 to 14.34 g in 2018, based on the mean body weight in May and August. The body size of O. oratoria in the fishing moratorium season was significantly higher than that in the fishing season, and the body size decreased rapidly after the fishing moratorium ended. Overall, in the context of declining resources of most fishery species, the relative resource density of O. oratoria increased due to its hardiness and adaptability, and its body size decreased under intensive fishing over the past 30 years. The fishing moratorium system had a great influence on the population dynamics of O. oratoria in terms of the relative resource density and body size in the Bohai Sea.
      PubDate: 2022-12-01
       
  • Hatschek’s pit and origin of pituitary gland

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      Abstract: Abstract Pituitary gland, or pituitary for short, is characteristic of all vertebrates. As a “master gland” controlling a multitude of important functions in the body, its evolutionary origin has been an object of investigations of evolutionary biology for two centuries. Previous morphological, ultrastructural and immunohistochemical studies suggested the homology of the Hatschek’s pit of amphioxus and vertebrate pituitary. Developmental genetics study showed that the development of Hatschek’s pit and vertebrate pituitary is both subject to regulation by the common genes such as Pit1, Lhx3 and BMP3b. Our recent studies demonstrated that the Hatschek’s pit is able to secrete growth hormone (GH)-like hormone and thyroid-stimulating hormone (TSH)-like hormone that both play functions similar to vertebrate GH and TSH. We thus think that the emergence of Hatschek’s pit represents one of important events during endocrine network evolution, which laid a foundation for the subsequent formation of a hypothalamic-pituitary system in vertebrates.
      PubDate: 2022-12-01
       
  • Scleractinian coral communities of Hormuz Island in the Persian Gulf

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      Abstract: Abstract The abundance and health of scleractinian coral communities of Hormuz Island were investigated. For this purpose, we employed 20 m line intercept transects—12 in the intertidal zone and 15 subtidally to evaluate coral cover and community composition. The estimated dead coral coverage was 6.21%±0.81%, while live coral coverage was 16.93%±1.81%, considered as very poor. Totally, 12 genera were recorded, of which Porites with 11.9%±1.4% live cover was the dominant, while Goniopora had the least cover (0.07%±0.08%). Based on Mann-Whitney U-test, live coral coverage, dead coral coverage, algal coverage, cover of other benthic organisms and abiotic components showed significant univariate differences between zones (p<0.05). The Spearman correlation test between the abundance of biotic and abiotic components indicated significant negative correlation of live coral and sand with zoantharian and significant positive correlation of algae and other benthic organisms with rubble. The reef health indices used for the corals indicated that, in general, the environmental conditions were not suitable, which could be attributed to both natural and anthropogenic factors, the most important of which was zoantharian’ overgrowth on the scleractinian corals in this region.
      PubDate: 2022-12-01
       
  • Sea level rise along China coast in the last 60 years

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      Abstract: Abstract Based on long-term tide gauge observations in the last 60 years, the temporal and spatial variation characteristics of sea level change along the coast of China are analyzed. The results indicate that the sea level along the coast of China has been rising at an increasing rate, with an estimated acceleration of 0.07 mm/a2. The rise rates were 2.4 mm/a, 3.4 mm/a and 3.9 mm/a during 1960–2020, 1980–2020 and 1993–2020, respectively. In the last 40 years, the coastal sea level has risen fastest in the South China Sea and slowest in the Yellow Sea. Seasonal sea levels all show an upward trend but rise faster in winter and spring and slower in autumn. Sea level change along the coast of China has significant periodic oscillations of quasi-2 a, 4 a, 7 a, 11 a, quasi-19 a and 30–50 a, among which the 2–3 a, 11 a, and 30–50 a signals are most remarkable, and the amplitude is approximately 1–2 cm. The coastal sea level in the most recent decade reached its highest value in the last 60 years. The decadal sea level from 2010 to 2019 was approximately 133 mm higher than the average of 1960–1969. Empirical orthogonal function analysis indicates that China’s coastal sea level has been changing in a north-south anti-phase pattern, with Pingtan and Fujian as the demarcation areas. This difference was especially obvious during 1980–1983, 1995–1997 and 2011–2013. The coastal sea level was the highest in 2016, and this extreme sea level event was analyzed to be related mainly to the anomalous wind field and ENSO.
      PubDate: 2022-11-05
      DOI: 10.1007/s13131-022-2066-5
       
  • Detailed seafloor geomorphology of the western region of the North Yellow
           Sea, China: The result of Holocene erosional and depositional processes
           sculpting the offshore continental shelf

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      Abstract: Abstract High-resolution multi-beam/single-beam bathymetric data and seismic profiling data from the latest surveys are used to map and interpret the detailed seafloor geomorphology of the western region of the North Yellow Sea (NYS), China. The mapping area covers 156 410 km2, and incorporates a flat shelf plain, subaqueous accumulation shoals, tidal scouring troughs, and tidal sand ridge groups. Offshore areas with water depths less than 50 m in the western region of the NYS are mainly covered by thick, loose sediments, forming wide spread accumulation geomorphological features; these include the Liaodong Peninsula subaqueous accumulation system containing shoals and rugged scouring troughs, and the large mud wedge of the Shandong Peninsula. In the central part of the NYS, there is a relatively flat residual shelf plain with coarser sediment deposits. This flat shelf plain has a water depth larger than 50 m and a thin layer of sediment, on which there is a large pockmark field caused by seafloor seepage. These geomorphological structures indicate that modern sedimentary processes are the main driving force controlling the sculpture of the current seafloor surface landform. Extensive strong tidal current systems and abundant sediment sources provide the critical external forces and essential conditions for the formation of seafloor geomorphology. The tectonic basement controls the macroscopic morphological shape of the NYS, but is reflected very little in the seafloor geomorphic elements. Our results provide a detailed seafloor geomorphological map of the western region of the NYS, an area that has not previously mapped and also provide a scientific framework for further research into offshore seafloor geomorphology, shelf sedimentary processes, and submarine engineering construction in this region.
      PubDate: 2022-11-04
      DOI: 10.1007/s13131-022-2060-y
       
 
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