Guangxi Institute of Oceanography

China has assumed a leadership position in global kelp cultivation and export. However, the kelp harvesting process in China still relies primarily on manual labor, with only limited adoption of semi-mechanized devices. This dependence results in suboptimal efficiency and elevated labor intensity. The industry now faces an acute labor shortage driven by an aging workforce and rising labor costs, highlighting the urgent need for a fully mechanized harvesting solution. This paper comprehensively reviews current research on mechanized kelp harvesting devices for raft cultivation systems in China. It compares domestic and international practices in kelp seedling cultivation, cultivation models, and harvesting devices, with particular emphasis on the technical challenges hindering harvesting device development in China. Based on this analysis, we propose several recommendations, including the simultaneous advancement of cultivation model optimization and harvesting device innovation, the development of harvesting technologies aligned with specific downstream processing requirements, and the design of modular and multifunctional kelp harvesting vessels. Looking ahead, future research should prioritize integrating automation and intelligent systems, reflecting evolving trends in China’s marine aquaculture. Furthermore, to support China’s “dual carbon” goals, future harvesting systems should incorporate carbon-reduction features.

Abstract Submesoscale fronts and filaments are jet‐like motions, associated with cross‐scale kinetic energy (KE) flux through eddy‐mean flow interaction. However, the diagnostic method for KE flux in jets with a steady zonal flow axis is not suitable for submesoscale processes with arbitrary axes. Based on a high‐resolution ocean model and observations, we propose a method for diagnosing KE flux via mesoscale strains and submesoscale stresses from an anisotropic perspective. Furthermore, we develop a three‐dimensional anisotropic KE flux algorithm under the hydrostatic assumption, which is important for diagnosing the energy sources and distributions of submesoscale vertical instabilities. Horizontally, we find that the inverse KE cascade mainly arises from shear strain throughout the filament's lifespan, triggering anisotropic frontogenesis and ageostrophic secondary circulations (ASCs). In ASCs, the cross‐filament shear strain provides an energy source for the geostrophic shear production (GSP) and causes the forward flux through the symmetric instability. Meanwhile, the forward KE flux caused by the centrifugal instability can reach 35% of GSP which is regulated by the anisotropic eddy KE but has been neglected in previous studies. This finding effectively explains the directional dependence of strains, stresses, and instabilities, broadening our understanding of energy balance and providing a foundation for improving submesoscale parameterizations.

Coral reefs are increasingly threatened by global climate change, and mass bleaching and mortality events caused by elevated seawater temperature have led to coral loss worldwide. Hainan Island hosts extensive coral reef ecosystems in China, yet seasonal variation in Symbiodiniaceae communities within this region remains insufficiently understood. We aimed to investigate the temperature-driven adaptability regulation of the symbiotic Symbiodiniaceae community in reef-building corals, focusing on the environmental adaptive changes in its community structure in coral reefs between cold (23.6-24.6 °C) and warm (28.2-30.6 °C) months. Symbiodiniaceae shuffling and rare genotype turnover were discovered in adaptability variations in the symbiotic Symbiodiniaceae community between two months. Symbiodiniaceae genetic diversity increased during warm months, primarily due to temporal turnover of rare genotypes within the Cladocopium and Durusdinium genera. Coral Favites, Galaxea, and Porites exhibited the shuffling of Symbiodiniaceae between tolerant Durusdinium and sensitive Cladocopium. Symbiodiniaceae interactions in G. fascicularis and P. lutea exhibited the highest levels of stability with the increase in temperature, whereas the interactions in A. digitifera and P. damicornis showed the lowest levels of stability. Rare genotypes functioned as central hubs and important roles within Symbiodiniaceae communities, exhibiting minimal responsiveness to temperature fluctuations while maintaining community structural stability. The temperature-driven adaptability regulation of symbiotic Symbiodiniaceae could be achieved by Symbiodiniaceae shuffling and rare genotype turnover. The process might be aggravated by concurrent adverse factors, including elevated salinity, pollution, and anthropogenic disturbance. These findings provide insights into how the Symbiodiniaceae community influences the adaptation and resilience of coral hosts to temperature fluctuations in coral reefs. Furthermore, they may contribute to assessing the reef-building coral's capacity to withstand environmental stressors associated with global climate change.

The treatment of oil-contaminated wastewater represents a significant environmental challenge. In this study, five highly efficient diesel-degrading bacterial strains were successfully isolated from oily wastewater, which was designated as Pseudomonas sp. ZC1, Vibrio sp. ZL2, Acinetobacter sp. ZY3, Citrobacter sp. GO5, and Enterobacter cloacae GM6. To construct an efficient bacterial consortium based on these five strains, the optimized strain combination of 26 different consortia composed of two, three, four, and five bacterial strains was conducted. The results suggested that a consortium comprising three strains (ZL2, ZY3, and GM6) showed the highest diesel degradation efficiency of 89.66% on day 3, while other strain combinations exhibited lower degradation rates and tended to require more time to achieve comparable efficiency. The orthogonal experiments further determined the optimal inoculation ratios of 1.0%, 0.5%, and 1.5% for strains ZL2, ZY3, and GM6 improved diesel degradation efficiency to 93.65% by day 3. The application of this consortium in the oily wastewater bioremediation confirmed its degrading capacity for n-alkanes (C8-C40) and polycyclic aromatic hydrocarbons (PAHs). This study highlights the excellent performance of the engineered bacterial consortium in the bioremediation of petroleum-contaminated wastewater, demonstrating its potential for scaling up to pilot and full-scale applications.