【目的】推进海洋自然资源资产价值核算研究是海洋资源保值增值、维护海洋生态安全的重要课题。海洋因其特有的广阔性、流动性、连通性等特性，其资产价值的确认、计量、核算呈现出复杂性和特殊性，实践中存在核算范围不统一、价值内涵模糊、核算方法多样等问题，亟须推进构建统一的海洋自然资源资产价值核算方法。【方法】本文聚焦海洋自然资源资产内涵界定、价值构成分析、核算方法构建和账户体系编制4项关键问题开展海洋自然资源资产价值核算方法研究，建立了海洋自然资源资产价值核算系统性框架。进一步，以江苏省盐城市海洋自然资源资产为对象开展实证研究。【结果】①海洋自然资源资产包括海洋资源型资产和海洋生态型资产两类；②除部分交易市场比较活跃的资产价格可以通过直接市场法测算外，采用间接市场法或成本法测算资产价格，通过净现值法核算价值是目前适用于海洋自然资源资产价值核算的常用方法；③核算期间盐城市海洋自然资源资产价值呈上升趋势，期末资产价值总量比期初增长约1181亿元，增幅约44%，资源型资产价值是主要组成部分。【结论】将海洋自然资源资产分为资源型资产和生态型资产可以较为全面地反映海洋自然资源资产构成和价值实现情况，基于“实物量核算-价格测算-价值核算”的技术路线和分类型账户体系能够较为科学有效地核算海洋自然资源资产价值，反映资产数量、分布、价值，直观表达资产管理成效，为海洋自然资源资产价值核算提供了科学有效的技术路径和研究思路，可为自然资本核算、资产负债表编制等工作提供参考与借鉴。

Modulated by diverse climatic and oceanic forcing factors, the sea ice durations in the nearshore waters of the Bohai and northern Yellow Seas exhibit complex fluctuations on interannual and interdecadal timescales. Systematically analyzing the oscillatory patterns and trend stationarity of long-term sea ice duration series provides robust theoretical and practical guidance for coastal ice disaster early warning, marine industrial safety, and coastal economic sustainability. This study analyzes annual sea ice duration series recorded over 59 winters (1966–2024) at six representative coastal marine stations spanning the full spatial gradient of regional ice regimes across the Bohai and northern Yellow Seas. Isolated missing values were filled by linear interpolation, and the Ljung–Box Q test confirmed that the residual series do not follow a white-noise process. Two categories of stationarity tests—conventional unit root tests and Fourier series expansion-augmented stationarity tests—are adopted to quantify the stationary properties, nonlinear trend transitions, and smooth structural breaks of sea ice durations at each station. The results reveal marked spatial differences in interannual volatility and evolutionary trends among stations: two smooth transitional shifts are identified for Bayuquan (BYQ) and Qinhuangdao (QHD), whereas the remaining stations each exhibit a single shift. Long-term trends range from multistage declining patterns to a rising pattern for Donggang (DGG), while Zhimaowan (ZMW) shows a statistically insignificant trend. This work provides quantitative statistical evidence for sea ice risk evaluation and coastal structural safety protection across the Bohai and northern Yellow Seas, and offers actionable decision-making references for climate change adaptation and integrated coastal zone governance in ice-affected coastal zones worldwide.

Site-level carbon density data remain limited for many seagrass meadows, especially where the mapped meadow extent has not been paired with repeated carbon-pool measurements. This study quantified biomass carbon density, 0–1 m sediment organic carbon density, total carbon density, and sediment contribution at 10 fixed stations in a meadow dominated by Zostera marina Linnaeus in Caofeidian, Bohai Bay, China, in 2021, 2024, and 2025. Sediment grain-size composition and five water-quality variables were also summarized for 2025 as environmental context. Sediment organic carbon dominated the station-level carbon pool. In 2025, biomass carbon density was 0.269–0.900 Mg C ha⁻¹, sediment organic carbon density was 8.108–39.730 Mg C ha⁻¹, and total carbon density was 8.377–40.566 Mg C ha⁻¹. The median total carbon density was 23.391 Mg C ha⁻¹ in 2021, 18.827 Mg C ha⁻¹ in 2024, and 20.040 Mg C ha⁻¹ in 2025. The rank association between fine sediment fraction and carbon density was positive in 2025 (Spearman’s ρ = 0.491, p = 0.150). These fixed-station records support seagrass monitoring, restoration planning, and sustainable coastal management. They also help link the mapped meadow extent with field carbon data for blue carbon assessment under climate and marine sustainability goals.

Coastal salt marsh restoration can support blue carbon sequestration, but spatial pre-assessment is needed to identify where environmental conditions support vegetation establishment before restoration design and carbon accounting. This study developed a threshold-based framework for spatial pre-assessment of coastal salt marsh restoration suitability. The framework combines species-specific limits for tidal inundation duration, seawater salinity and sediment salinity with sediment type in a geographic information system workflow. Tidal inundation limits are translated into critical-elevation boundaries, and retained polygons are examined against planning, historical-distribution and use-right conditions. A general threshold library was compiled for five representative native salt marsh species, while regional records define the candidate set for each application. In Yingkou, China, Suaeda heteroptera and Phragmites australis formed the candidate set. For S. heteroptera, the 3 h d⁻¹ inundation limit corresponded to a critical elevation of 1.90 m. July 2024 sediment salinity (0.96–1.08%) and September 2025 seawater salinity (29.715–29.825‰) met the corresponding screening limits for S. heteroptera and excluded P. australis. The integrated restoration-suitability area covered 76.5 ha, and 99.5% of the mapped current S. heteroptera distribution fell within it. The framework identifies candidate restoration space for field verification, restoration planning and subsequent carbon accounting.

Direct economic losses from storm surge disasters are driven jointly by natural hazard factors and socioeconomic exposure. Because loss data are inherently zero-inflated and right-skewed, a single linear model cannot adequately capture them. Using a balanced panel of 11 coastal provinces in China over 2001–2024, this study decomposes the loss-generation process into two stages—whether a disaster occurs and the magnitude of losses—and develops a two-stage (Hurdle-type) panel model, further employing instrumental-variable two-stage least squares (IV-2SLS) to address the endogeneity of disaster prevention and mitigation expenditure. The results show that, at the annual provincial scale, disaster occurrence is determined nearly deterministically by whether a storm surge process occurs, so that the disaster-occurrence probability equation exhibits complete separation and its coefficients are not separately identifiable. Conditional on disaster occurrence, storm surge height is the most robust positive driver of loss magnitude: each additional centimeter of storm surge height raises direct economic losses by approximately 1.5% on average, a finding confirmed by robustness checks that replace the dependent variable, winsorize the losses, exclude extreme samples, and apply two-way and wild cluster bootstrap inference. After correction for endogeneity with the proposed instrument, the positive effect of disaster prevention and mitigation expenditure weakens substantially and becomes statistically insignificant, indicating that the positive OLS relationship is not robust to the proposed IV specification. Accordingly, this study proposes differentiated disaster-management measures that distinguish the stages of disaster occurrence and loss magnitude and strengthen the monitoring and early warning of hazard intensity. These findings provide an evidence-based basis for sustainable coastal development and for enhancing coastal disaster resilience.