Hasil untuk "Oceanography"

G. Pickard

M. Ghil, P. Malanotte‐Rizzoli

C. Johnson, S. Banks, N. Barrett et al.

A. Gordon

I. Seguro, K. Vikström, K. Vikström et al.

<p>The balance between the uptake of CO<span class="inline-formula">₂</span> by phytoplankton photosynthesis and the production of CO<span class="inline-formula">₂</span> from prokaryoplankton, zooplankton and phytoplankton respiration controls how much carbon can be stored in the ocean and hence how much remains in the atmosphere to affect climate. Yet, despite its crucial role, knowledge on the respiration of plankton groups is severely limited because traditional methods cannot differentiate the respiration of constituent groups within the plankton community. The reduction of the iodonitrotetrazolium salt (INT) to formazan, which when converted to oxygen consumption (O<span class="inline-formula">₂</span>C) using an appropriate conversion equation, provides a proxy for both total and size fractionated plankton respiration. However, the method has not been thoroughly tested with prokaryoplankton. Here we present respiration rates, as O<span class="inline-formula">₂</span>C and formazan formation (INT<span class="inline-formula">_R</span>), for a wide range of relevant marine prokaryoplankton including the gammaproteobacteria <i>Halomonas venusta</i>, the alphaproteobacteria <i>Ruegeria pomeroyi</i> and <i>Candidatus Pelagibacter ubique</i> (SAR11), the actinobacteria <i>Agrococcus lahaulensis</i>, and the cyanobacteria <i>Synechococcus marinus</i> and <i>Prochlorococcus marinus</i>. All species imported and reduced INT, but the relationship between the rate of O<span class="inline-formula">₂</span>C and INT<span class="inline-formula">_R</span> was not constant between oligotrophs and copiotrophs. The range of measured O<span class="inline-formula">₂</span>C <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M9" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="880d1b22cfae9b4167ff115d05c6894c"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-22-6225-2025-ie00001.svg" width="8pt" height="14pt" src="bg-22-6225-2025-ie00001.png"/></svg:svg></span></span> INT<span class="inline-formula">_R</span> conversion equations equates to an up to 40-fold difference in derived O<span class="inline-formula">₂</span>C. These results suggest that when using the INT method in natural waters, a constant O<span class="inline-formula">₂</span>C <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M13" display="inline" overflow="scroll" dspmath="mathml"><mo>/</mo></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="8pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="8550e2e9970f84100ffbfa4da4f4f543"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="bg-22-6225-2025-ie00002.svg" width="8pt" height="14pt" src="bg-22-6225-2025-ie00002.png"/></svg:svg></span></span> INT<span class="inline-formula">_R</span> relationship cannot be assumed, but must be determined for each plankton community studied.</p>

Yunyun Gai, Longsheng Li, Zikang Li et al.

When the XBeach model is used to simulate beach profiles, the selection of four sensitive parameters—facua, gammax, eps, and gamma—is crucial. Among these, the two key parameters, facua and gamma, are particularly sensitive. However, the XBeach model does not specify the exact choice of these four key parameters, offering only a broad range for each one. In this paper, we investigate the applicability of tuning these four parameters within the XBeach model. We employ Generalized Likelihood Uncertainty Estimation (GLUE) to optimize the model settings. The Brier Skill Score (<i>BSS</i>) for each parameter combination is calculated to quantify the likelihood probability distribution of each parameter. The optimal parameter set (facua = 0.20, gamma = 0.50) was ultimately determined. Here, the facua parameter represents the degree of influence of wave skewness and asymmetry on the direction of sediment transport, while the gamma parameter represents the equivalent random wave in the wave dissipation model and is used to calculate the probability of wave breaking. Six profiles of the southern beach on Chudao Island are selected to validate the results, establishing the XBeach model based on profile measurement data before and after Typhoon “Lekima”. The results indicate that after parameter optimization, the simulation accuracy of XBeach is significantly improved, with the <i>BSS</i> increasing from 0.3 and 0.17 to 0.68 and 0.79 in P1 and P6 profiles, respectively. This paper provides a recommended range for parameter values for future research.

吴娟娟1，田佳宁1，陈奕蒙1，王成成1，王玉明1,2 , 姜晓明1, 薛长湖1, 张恬恬1 WU Juanjuan1, TIAN Jianing1, CHEN Yimeng1, WANG Chengcheng1, WANG Yuming1,2, JIANG Xiaoming1, XUE Changhu1, ZHANG Tiantian1

为了揭示雌、雄膨腹海马磷脂组成及其差异，用溶剂萃取法分别提取雌、雄膨腹海马脂质，冷丙酮提取其中的磷脂，进一步采用薄层色谱法和硅胶柱层析分离制备各磷脂组分，利用气相色谱技术分析比较雌、雄膨腹海马磷脂及其各组分的脂肪酸组成。结果表明：雌、雄膨腹海马的磷脂含量丰富，分别占总脂的18.11%和18.72%；膨腹海马磷脂包括磷脂酰乙醇胺、磷脂酰胆碱、溶血磷脂酰胆碱和鞘磷脂，其中磷脂酰胆碱含量最高；膨腹海马磷脂中共鉴定出20种脂肪酸，且不饱和脂肪酸含量高于饱和脂肪酸含量；雌、雄膨腹海马磷脂中海洋特征性n-3多不饱和脂肪酸DHA和EPA总含量分别为18.30%、19.61%；膨腹海马的磷脂酰乙醇胺、磷脂酰胆碱和溶血磷脂酰胆碱饱和脂肪酸都以C16∶ 0和C18∶ 0为主，而在鞘磷脂中以C14∶ 0和C16∶ 0为主；膨腹海马4种磷脂组分的单不饱和脂肪酸均以C18∶ 1为主，多不饱和脂肪酸均以EPA和DHA为主；除了雄性膨腹海马溶血磷脂酰胆碱外，其余磷脂组分DHA和EPA总含量均超过16%。综上，膨腹海马磷脂组成多样，海洋特征性n-3多不饱和脂肪酸含量丰富，具有较高的营养价值。 In order to reveal the phospholipids compositions and differences between male and female Hippocampus abdominalis, the lipids of female and male Hippocampus abdominalis were extracted by solvent extraction method, then phospholipids in the lipids were extracted by cold acetone. Moreover, the different phospholipids fractions were separated by thin-layer chromatography and silica gel column chromatography, then the fatty acid composition of phospholipids and the different phospholipids fractions from female and male Hippocampus abdominalis were analyzed by gas chromatography. The results showed that the female and male Hippocampus abdominalis were rich in phospholipids, accounting for 18.11% and 18.72% of the total lipids, respectively. The phospholipids of Hippocampus abdominalis included phosphatidylethanolamine, phosphatidylcholine, lysophosphatidylcholine and sphingomyelin, among which phosphatidylcholine was the most abundant. The phospholipids of Hippocampus abdominalis identified 20 kinds of fatty acids, and the content of unsaturated fatty acids was higher than that of saturated fatty acids. Furthermore, the total content of marine characteristic n-3 polyunsaturated fatty acids DHA and EPA in female and male Hippocampus abdominalis phospholipids were 18.30% and 19.61%, respectively. The saturated fatty acids of phosphatidylethanolamine, phosphatidylcholine and lysophosphatidylcholine in both male and female Hippocampus abdominalis were all dominated by C16∶ 0 and C18∶ 0, whereas those in sphingomyelin were dominated by C14∶ 0 and C16∶ 0. The monounsaturated fatty acids of the four phospholipid fractions of the male and female Hippocampus abdominalis were all dominated by C18∶ 1, and the polyunsaturated fatty acids were all dominated by EPA and DHA. The total contents of DHA and EPA were more than 16%, except for lysophosphatidylcholine in male Hippocampus abdominalis. In conclusion, phospholipids composition of Hippocampus abdominalis is diverse, with abundant marine characteristic n-3 polyunsaturated fatty acids and high nutritional value.

O. Ulloa, D. Canfield, E. Delong et al.

M. Leppäranta, K. Myrberg

Hendra Hendra, Widodo Setiyo Pranowo, Choirul Umam et al.

The Malacca Strait is a strategic waterway for Indonesia as it serves as an international shipping route connecting East Asia with the Middle East and Europe. In addition, the Malacca Strait also has great potential for natural resources, such as oil and gas as well as fish and other marine products. This study aims to describe the Thermocline Layer in the Malacca Strait based on Marine Copernicus Data in 2020 with a depth of up to 1000 meters. The temperature data was visualized using ODV 5.5.2 software. The results of processing the Marine Copernicus Temperature Data in 2020 in the Malacca Strait with a depth of up to 1000 meters show that the thermocline boundary varies each season. In the western season, the thermocline boundary is at a depth between 11 meters to 131 meters, in the first transitional season, it is at a depth between 22 meters to 131 meters, in the eastern season, it is at a depth between 56 meters to 156 meters, and in the second transitional season, it is at a depth between 78 meters to 131 meters.   Bagian Selat Malaka adalah perairan yang strategis bagi Indonesia karena menjadi jalur pelayaran internasional yang menghubungkan Asia Timur dengan Timur Tengah dan Eropa. Selain itu, Selat Malaka juga memiliki potensi sumber daya alam yang besar, seperti minyak dan gas bumi serta ikan dan hasil laut lainnya. Penelitian ini bertujuan untuk mengidentifikasi dan menganalisis Lapisan Termoklin di Perairan Selat Malaka berdasarkan Data Marine Copernicus tahun 2020 dengan kedalaman sampai 1000 meter. Data Temperatur diolah dan dianalisis menggunakan software ODV 5.5.2. Hasil pengolahan Data Temperatur Marine Copernicus tahun 2020 di Perairan Selat Malaka dengan kedalaman mencapai 1000 meter dengan batas termoklin setiap musim dimana pada Musim barat batas termoklin berada pada kedalaman antara 11 meter sampai dengan 131 meter, Musim Peralihan I batas termoklin berada pada kedalaman antara 22 meter sampai dengan 131 meter, Musim Timur batas termoklin berada peda kedalaman antara 56 meter sampai dengan 156 meter dan Musim Peralihan II batas termoklin berada pada kedalaman antara 78 meter sampai dengan 131 meter.

杨 越聪, 张 倩茹, 郑 关超 et al.

贻贝是我国沿海常见的经济贝类，作为监测海洋污染情况的前哨物种对多种贝类毒素均具有较强的蓄积能力，但不同贻贝蓄积能力的种间差异尚不清晰。基于贝类软组织质量比原则，将紫贻贝与厚壳贻贝分别暴露于链状亚历山大藻，研究两种贻贝对麻痹性贝类毒素(paralytic shellfish toxins, PSTs)的蓄积代谢与生理应激差异。结果表明，紫贻贝和厚壳贻贝中PSTs最高蓄积量分别为889.1和358.6 μg STXeq/kg，前者超出后者的2倍。代谢3天后，厚壳贻贝PSTs的清除率为88.8%，而紫贻贝仅为42.5%。皮尔逊相关性分析表明，两种贻贝各组织单日PSTs蓄积量与其产毒藻吸收率呈显著正相关(P&lt;0.05)，而与清滤率无显著相关性(P&gt;0.05)。在生理应激方面，紫贻贝对产毒藻的清滤率与吸收率为厚壳贻贝的两倍。此外，紫贻贝肝胰腺组织的氧化应激与组织损伤更严重，导致其肝胰腺中PSTs向其他组织转移量与清除率均显著低于厚壳贻贝(P&lt;0.05)。综上所述，产毒藻暴露下厚壳贻贝通过改变摄食行为降低PSTs的蓄积量，导致厚壳贻贝中PSTs的安全风险明显低于紫贻贝，研究结果为探究不同双壳贝类对PSTs的蓄积差异机理提供了思路。

Kyeong-Tae Lee, Garance Perrois, Hyun-Sung Yang et al.

This study was carried out to determine the levels of resistance and resilience of kelp forests to large-scale physical disturbances. Our study site, Seongsan, Jeju Island, was impacted by super typhoon ‘Hinnamnor’. Before the typhoon, Seongsan had shown high ecosystem stability. Our results indicated that the ecological stability of a kelp forest facing a severe typhoon is strongly linked to the prevailing environmental conditions. Although typhoon impact resulted in a significant loss of brown macroalgae canopy, <i>Ecklonia cava</i> remained dominant within the kelp forest community. Resistance and resilience levels strongly depended on water temperature and movement and presence of turf-forming algae. Hence, hydrodynamic and biological factors strongly influence the overall stability of a kelp forest. We also report the first occurrences of a scleractinian coral species (i.e., <i>Montipora millepora</i>) at Seongsan, which became visible after canopy loss following the typhoon. Our findings provide valuable ecological information about the benthic community of kelp-dominated ecosystems and are essential to mitigate the impacts of expected climate change-driven rises in seawater temperature and the frequency of super typhoons.

Zongliang Zhang, Xueming Wu, Enshang Xiao et al.

Abstract Based on the emergency rescue, the subsequent disposal, and the development and utilization projects of the Hongshiyan Landside Dam in Ludian, Yunnan, China, research has been conducted on key technical issues facing the development and utilization of landside dams, including the possibilty evaluation of development and utilization, structure analysis of wide gradation material, performance evaluation, investigation and design, dam seepage control, construction technology and equipment, and safe operation assessment. And innovative results has made in all seven aspects mentioned above, writing the history in this field. The achievements were directly applied to the development planning, investigation and design, construction, and operation and maintenance of the Hongshiyan Landside Dam, a comprehensive water conservancy project that integrates flood control, water supply, irrigation, and power generation, with significant comprehensive benefits.

Nuria Navarro, Inmaculada Rodríguez-Santalla

Coastal wetlands are valuable and sensitive environments that are among the most productive yet highly threatened systems in the world [...]

Sung Youn Boo, Steffen Allan Shelley, Seung-Ho Shin et al.

There has been growing interest recently in hybrid installations integrating the offshore wind farm and aquaculture farm as co-existence while optimizing ocean space use. The offshore marine farms beyond coastal or sheltered areas will require mooring to ensure the station-keeping of the farm system during the storms. In the present work, a sub-surface longline farm is installed in a fixed offshore wind farm at a distance from the wind foundations. The farm is designed to cultivate oysters in multi-compartment bags attached to the longlines vertically. The farm with a cultivating area of 200 m × 200 m is supported by the various farm lines made of polypropylene and buoys that is moored with catenary mooring arrangements. Drag coefficients of a full-scale oyster bag in wave and current are determined using the results of wave basin tests. A lumped model is developed and validated with a complete model for a partial farm. The lumped model is used to simulate the coupled responses of the whole farm in the site extreme waves and currents of a 50-year return period. The strength and fatigue designs of the mooring and farm lines are evaluated against the industry standards and confirmed to comply with the design requirements.

Shi‐Yun Yu, Lei Fan, Xiao‐Tong Zheng et al.

Abstract Using 51 models of the AMIP and historical experiments of CMIP6, we investigate the inter‐model diversity of atmospheric and coupled models in the strength of the Indian Summer Monsoon Rainfall (ISMR)–El Niño‐Southern Oscillation (ENSO) relationship. In atmospheric models, the Walker Circulation (WC) intensity associated with the western Pacific convective activity is most responsible for the inter‐model diversity. Models with strong WC have a strong ISMR–ENSO relationship via enhancing ENSO‐induced anomalies of the WC and monsoon circulation. The secondary source is the monsoon circulation differences associated with meridional rainfall contrast over the Indian monsoon region. In coupled models, the primary (secondary) source is the ENSO amplitude (WC intensity). In observation, the decadal variation of WC can also explain the changes in the ISMR–ENSO relationship. This study provides a basis for improving the model performance and advances our understanding of the observed ISMR–ENSO relationship changes.

Chenfang Wang, Longxi Han, Yi Zhang et al.

The natural dispersion of oil depends on the oil types, wave-mixing energy, and the temperature and salinity of water. Laboratory experiments were conducted to investigate the effects of these factors on oil dispersion. The results demonstrated that the increase in temperature significantly enhanced the oil dispersion efficiency, particularly for low-viscosity oils. At 30 °C, the dispersion efficiency is 2 times higher than that at 15 °C, while salinity has no significant effect on dispersion efficiency. Nonlinear fitting results revealed an exponential increase in dispersion efficiency with the energy dissipation rate. Furthermore, partial correlation analysis was employed to examine the effects of oil density, viscosity, and surface tension on dispersion efficiency. The results indicated a high correlation between density, viscosity, and dispersion efficiency (<i>r</i> = −0.801, <i>r</i> = −0.812), whereas the correlation coefficient of surface tension was low (<i>r</i> = −0.286). Based on these findings, linear and nonlinear regression models were established between dispersion efficiency and density and viscosity, enabling a rough estimation of oil spill dispersion efficiency under low sea state conditions.

Grace Chang, Galen Egan, Joseph D. McNeil et al.

Abstract Novel analysis of in situ acoustic and optical data collected in a shallow, wave‐ and current‐driven environment enabled determination of (1) particle characteristics that were most affected by near‐bed physical forcing over seasonal scales and (2) characteristic shear stress, τchar, at which the rate of change to particle characteristics was most pronounced. Near‐bed forcing and particle responses varied by season. Results indicated that moderate τchar values of 0.125 Pa drove changes in particle composition during summer. In winter, particle concentration effects were most affected at τchar of 0.05 Pa, suggesting dominance of fluff layer resuspension. Changes to particle size were most relevant during a biologically productive springtime period, with initiation of particle disaggregation occurring most commonly at τchar of 0.25 Pa. These results suggest that it may be more important to parameterize τchar, as opposed to critical shear stress for erosion, for sediment transport models.

Dan Wang, Dan Wang, Nan Yang et al.

Soil salinity is an important environmental problem that seriously affects plant growth and crop productivity. Phytoremediation is a cost-effective solution for reducing soil salinity and potentially converting the soils for crop production. Sesuvium portulacastrum is a typical halophyte which can grow at high salt concentrations. In order to explore the salt tolerance mechanism of S. portulacastrum, rooted cuttings were grown in a hydroponic culture containing ½ Hoagland solution with or without addition of 400 mM Na for 21 days. Root and leaf samples were taken 1 h and 21 days after Na treatment, and RNA-Seq was used to analyze transcript differences in roots and leaves of the Na-treated and control plants. A large number of differentially expressed genes (DEGs) were identified in the roots and leaves of plants grown under salt stress. Several key pathways related to salt tolerance were identified through KEGG analysis. Combined with physiological data and expression analysis, it appeared that cyclic nucleotide gated channels (CNGCs) were implicated in Na uptake and Na+/H+ exchangers (NHXs) were responsible for the extrusion and sequestration of Na, which facilitated a balance between Na+ and K+ in S. portulacastrum under salt stress. Soluble sugar and proline were identified as important osmoprotectant in salt-stressed S. portulacastrum plants. Glutathione metabolism played an important role in scavenging reactive oxygen species. Results from this study show that S. portulacastrum as a halophytic species possesses a suite of mechanisms for accumulating and tolerating a high level of Na; thus, it could be a valuable plant species used for phytoremediation of saline soils.