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Species genetic diversity can reflect their adaptability to environmental changes. Coral reefs worldwide are in rapid decline due to climate change and human activities, highlighting the need for conservation intervention. The South China Sea (SCS) is an important biodiversity hotspot, particularly in the Xisha Islands (XS) that contain the majority of coral species in the SCS. However, few studies exist on coral genetic diversity in the SCS. Montipora digitata is the dominant reef-building coral species in the XS. In this study, two mitochondrial DNA fragments and 11 microsatellite markers were employed to investigate the genetic diversity of coral host of M. digitata, and ITS amplicon sequencing was employed to investigate the Symbiodiniaceae community structure. We sampled five wild populations of M. digitata in Hainan Island and the Xisha Islands. Montipora digitata showed low genetic diversity across populations in the SCS. We found significant genetic differentiation between the Sanya (SY) and XS populations but no significant genetic differentiation within XS populations. We identified four Symbiodiniaceae genera, with Cladocopium and Durusdinium being the most common, as well as Gerakladium and Fugacium. The Symbiodiniaceae types of SY and XS are significantly different, C15 is abundant in all populations, while D1a is also abundant in SY. We analyzed the correlation between 16 environmental factors and the genetic diversity of symbionts, genetic diversity of coral host and Symbiodiniaceae community was significantly correlated with sea surface temperature (SST) and other environmental factors. Our study provided a detailed paradigm from the perspective of genetic diversity of how a dominant coral species can be indicative of poor environmental adaptation potential.

Understanding the wave and current conditions of coral reef ecosystems is essential for maintaining their health, as many reef processes are controlled by these hydrodynamic conditions. In this study, high-frequency measurements of tides, waves, and currents were made using acoustic, electromagnetic, and pressure instruments over a 28-d period on the fore-reef and reef flat of a coral reef atoll in the South China Sea. The research revealed wave transformation, tidal and wave modulation of flow, and wave setup conditions for the first time at this typical atoll. Three large wave processes dominated by gravity waves (GWs) are observed in the fore-reef. The GWs are significantly attenuated on the reef flat, whereas infragravity (IG) waves strengthened. The tidal modulation of GWs and IG waves on the reef flat is significant when the incident wave height exceeded 1 m. In the fore-reef, the modulation of progressive tidal waves and large waves leads to relatively stronger upper-layer currents, and weak near-bottom currents are primarily attributed to the dissipation of tidal wave energy by the rough coral terrain. In calm conditions, flow variations on the reef flat are modulated by tides, thereby allowing seawater flow to pass through the reef flat during spring tides. Conversely, during periods with large waves, tidal modulation of flow on the reef flat is less significant, and the cross-reef flow velocity increases with increasing incident wave height. The occurrence of wave setup on the reef flat enhances cross-reef flow towards the lagoon. The wave setup is positively linearly correlated with the incident wave height. The magnitude of wave setup is associated with the distance between the measurement sites on the fore-reef and reef flat.

Coral reefs are essential for marine ecology and biodiversity. Global climate change has resulted in severe coral reef degradation, partly via coral bleaching, which is caused by rising sea temperatures and solar light intensity. In this study, we examined the impact of strong light (300 µmol.m−2.s−1) and high temperature (33°C) on the growth, immunity, and gene expression of Galaxea fascicularis. Strong light caused coral bleaching in the absence of high sea temperatures, while no obvious bleaching was observed under high temperature alone. The effect of strong light on calcification rate of G. fascicularis is significantly weaker than that of high temperature. Both strong light and high temperatures significantly affected the immune enzyme activity of G. fascicularis symbionts, with the former having a strong effect on their photosystem. Temperature affected the digestive system, replication and repair, and cell growth and death of coral hosts, as indicated by transcriptomics analysis. These results provide a valuable for strategies to mitigate coral bleaching. Teaser: We explored the effects of strong light exposure and high temperature on coral reefs and their symbiont algae.

The Sakyamuni Pagoda of Fogong Temple, also known as the Yingxian Wooden Pagoda or the Wooden Pagoda of Ying County, is China’s oldest and tallest wooden pagoda. This pagoda was constructed in 1056 and has faced many challenges, including earthquakes, wars, and mistreatment. However, it is currently in danger of potential collapse due to severe structural challenges. Preserving this historic monument requires interdisciplinary collaboration across architectural history, materials science, and engineering. This paper proposes the development of a parametric model to build the pagoda that can be used for future preservation efforts. While not precisely reflecting the pagoda’s current condition, with the changes in inputs, the geometries of the structural members can be updated in real time, which offers adaptability crucial for preservation efforts. With the understanding of the original construction techniques, including its leaning column systems, the model not only helps preservation but also reveals the creativity of the architects or the craftsmen at the time. The 3D model, which includes more than 32,000 pieces along with the parametric files that can generate the column grid and dougongs, has been published along with this paper, and those files are available in the Data Availability Statement. In summary, the full digital model presented alongside this paper, unavailable elsewhere to the general public, serves as a practical preservation tool that can also be used for raising awareness for this cultural heritage site.

Coral reefs represent distinctive yet vulnerable marine ecosystems. Recently, these ecosystems have faced threats and degradation from multiple factors. A comprehensive understanding of coral distribution and niche information forms the theoretical foundation for addressing the ongoing coral crisis. This study employed the MaxEnt model to predict coral distribution in the central and southern regions of the South China Sea (SCS), while also obtaining ecological niche information. Utilizing CMIP6 data, the future exposure risk of corals was evaluated under two forcing scenarios (SSP245 and SSP585). The findings revealed that the highly suitable areas for corals in the SCS were approximately 31,360 km2, mainly distributed in the middle and east of Xisha, Zhongsha Atoll, Huangyan Island, and the north of the Nansha Islands. The probability of coral presence in the north and west of Xisha and the south of Nansha was low. The key environmental factors exerting significant influences on coral occurrence included seawater temperature, photosynthetically active radiation, current velocity, and dissolved oxygen. Among them, seawater velocity and nitrate emerged as the primary factors discerning differences in coral fitness across the study regions, which also verified the results of principal component analysis. Under extreme scenarios predicted by the end of this century (SSP585-2090s), over 43 % of coral distribution areas would face the highest exposure risk, mainly concentrated in southern Nansha. The primary drivers of this increased risk were the substantial changes occurring in temperature, dissolved oxygen, and nitrate. This research serves as a reference for coral conservation under climate change in the future.