Next-generation neutrino telescopes with substantially improved sensitivity are required to pinpoint the sources of the diffuse astrophysical neutrino flux detected by IceCube and uncover the century-old puzzle of cosmic-ray origins. A detector near the Equator will provide a unique viewpoint of the neutrino sky, complementing IceCube and other neutrino telescopes in the Northern Hemisphere. Here we present results from an expedition to the northeastern region of the South China Sea, in the western Pacific Ocean. A favourable neutrino telescope site was found on an abyssal plain at a depth of ~3.5 km. At depths below 3 km, the sea current speed, water absorption and scattering lengths for Cherenkov light were measured to be v_c < 10 cm s⁻¹, λ_abs ≈ 27 m and λ_sca ≈ 63 m, respectively. Accounting for these measurements, we present the design and expected performance of a next-generation neutrino telescope, Tropical Deep-sea Neutrino Telescope (TRIDENT). With its advanced photon-detection technology and large dimensions, TRIDENT expects to observe the IceCube steady source candidate NGC 1068 with 5σ significance within 1 year of operation. This level of sensitivity will open a new arena for diagnosing the origin of cosmic rays and probing fundamental physics over astronomical baselines.

Frontal processes play a significant role in estuarine and coastal ecosystem dynamics. In this study, a hydrodynamic model of the Changjiang River plume was developed based on the Regional Ocean Modeling System, and Lagrangian Coherent Structures (LCSs) were applied to the model simulations to analyze the horizontal transport characteristics of the river plume with the surface plume front, the tidal front, and the far‐field plume front in summer. The results show that the plume currents during the ebb tide were supercritical upstream of the near‐field surface plume front and tidal front and subcritical downstream of the fronts. In the LCSs results, transport barriers existing in the frontal regions indicated that the materials hardly crossed the fronts and tended to accumulate. The water parcels near the surface plume front and the tidal front in the near‐field entirely originated from the Changjiang River Estuary. The surface East China Sea shelf water could not influence the near‐field region due to the transport barrier formed by the far‐field plume front. Momentum balance analysis results reveal that the plume currents were in geostrophic balance around the near‐field fronts, rendering the flows mainly in the along‐front direction and significantly weakening the cross‐shore flows. These physical processes provided enough residence time of the plume water and growth time for phytoplankton in the frontal region and thus favored algal blooming with sufficient nutrients. Even though the frontal convergence induced by transport barriers also appeared near the far‐field plume front, insufficient supply of nutrients limited the phytoplankton growth.

Marine protected areas (MPAs) are vital for protecting biodiversity, maintaining ecosystem integrity, and tackling future climate change. The effectiveness of MPA networks relies on connectivity, yet connectivity assessments are often skipped in the planning process. Here we employed a multi-species biophysical model to examine the connectivity patterns formed among the 21 national MPAs in the Yellow and East China Seas. We simulated the potential larval dispersal of 14 oviparous species of five classes. Larvae of non-migratory species with pelagic larval duration (PLD) were assumed to be passive floating particles with no explicit vertical migration. A total of 217,000 particles were released according to spawning period, living depth, and species distribution, and they were assumed to move with currents during the PLD. Most larvae were dispersed around the MPAs (0–60 m isobaths) and consistent with the currents. Larval export increased with PLD and current velocity, but if PLD was too long, few larvae survived due to high daily mortality during pelagic dispersal. The overall connectivity pattern exhibited a north-to-south dispersal trend corresponding to coastal currents. Our results indicated that the national MPAs in the Yellow and East China Seas did not form a well-connected network and nearly 30% of them were isolated. These MPAs formed three distinct groups, one in the Yellow Sea ecoregion and two in the East China Sea ecoregion. Four MPAs (all in coastal Zhejiang) emerged as key nodes for ensuring multi-generational connectivity. Under the pressure of future climate change, high self-recruitment and low connectivity present significant challenges for building well-connected MPA networks. We suggest adding new protected areas as stepping stones for bioecological corridors. Focused protection of the Yellow Sea ecoregion could have a good effect on the southern part of the population recruitment downstream. Conservation management should be adjusted according to the life cycles and distributions of vulnerable species, as well as seasonal changes in coastal currents. This study provides a scientific basis for improving ecological connectivity and conservation effectiveness of MPAs in the Yellow and East China Seas.

Large aggregations of the copepod Calanus finmarchicus occur each spring in the shelf‐slope‐oceanic regions off the Lofoten‐Vesterålen Islands where productive fisheries have traditionally supported local economies. The retention and off‐shelf transport of populations of C. finmarchicus populations were studied by analyzing ocean color remote sensing, satellite altimetry data, and Lagrangian Coherent Structures (LCS) between 2010 and 2019. Our analysis revealed the existence of a transport barrier reoccurring at the shelf break that retains C. finmarchicus on the shelf for 30–70 days in the spring when C. finmarchicus were seasonally ascending to the surface layer. The analysis of baroclinic and barotropic energy conversions indicated that the topographically steered Norwegian Atlantic Current is the primary mechanism in the formation of the transport barrier, which restricts exchanges of C. finmarchicus populations between shelf and oceanic waters. In the mid‐ to late April, an increase in baroclinicity leads to an increase in mesoscale eddies generated on the shelf break near Lofoten‐Vesterålen Islands, breaking down transport barriers and causing off‐shelf transport of C. finmarchicus. The transport barrier predictably reoccurs in early spring which supports the entrapment of C. finmarchicus in the shelf region.