Summertime M2 Internal Tides in the Northern Yellow Sea

The summertime M2 internal tide in the northern Yellow Sea is investigated with moored current meter observations and numerical current model results. The hydrodynamic model, which is implemented from the Regional Ocean Model System (ROMS) with 1 km horizontal resolution, is capable of resolving the internal tidal dynamics and the results are validated in a comparison with observations. The vertical pattern of a mode-1, semi-diurnal internal tide is clearly captured by the moored ADCP as well as in the simulation results. Spectral analysis of the current results shows that the M2 internal tide is dominant in the northern Yellow Sea. Analysis of the major M2 internal tide energetics demonstrated a complex spatial pattern. The tidal mixing front along the Korean coast and on the northern shelf provided proper conditions for the generation and propagation of the internal tides. Near the Changshan islands, the M2 internal tide is mainly generated near the local topography anomalies with relatively strong current magnitude, equal to about 30% of the barotropic component, thus modifying the local current field. These local internal tides are short-lived phenomena rapidly being dissipated along the propagation pathway, restricting their influence within a few kilometers around the islands.

Rapid Reclamation and Degradation of Suaeda salsa Saltmarsh Along Coastal China’s Northern Yellow Sea

Suaeda salsa saltmarshes are an important coastal wetland habitat of China’s northern Yellow Sea, which plays a critical role in sequestering carbon (blue carbon), protecting shorelines, maintaining biodiversity, and has substantial economic value (e.g., ecotourism). However, the area of S. salsa has been rapidly declining due to several different threats from reclamation and invasive species that impact its natural succession. Here, we map the changes in the distribution of the S. salsa saltmarshes along the northern Yellow Sea of China (NYSC) at 5-year intervals by applying the supervised maximum likelihood method to analyze Landsat images from 1988 to 2018 and investigate the potential impact of three important factors on habitat change by analyzing the temporal changes in S. salsa saltmarshes with other land covers. S. salsa saltmarsh areas have decreased by 63% (264 km2 ha to 99 km2), and the average loss of S. salsa saltmarshes was 5.5 km2/year along the NYSC over the past three decades. There have been many dramatic declines in the two main distribution areas of S. salsa saltmarshes with a 77% loss of habitat area in Liaodong Bay (from 112 km2 to 26 km2) and a 52% loss in the Yellow River Delta wetland-Guangli-Zhima estuarine wetland (from 137 km2 to 65 km2). Land reclamation is the most important impact factor in the loss of S. salsa saltmarshes, while there have been limited effects of natural succession and smooth cordgrass (Spartina alterniflora) invasion. In light of the important ecological services and economic value of the S. salsa habitat, emergency conservation actions (e.g., habitat restoration, strictly supervision) are needed to limit the rapid habitat loss, which should include the immediate cessation of extensive land reclamation along the NYSC.

A new species and new recorded species of Orbiniidae Hartman, 1942 (Annedia: Polychaeta) from China

A new species of the orbiniid genus Phylo, P. heterochaetus sp. n., is described based on material collected from northern Yellow Sea, China. This is the thirteenth species in Phylo Kinberg, 1866. The new species can be easily identified by the combination of the following characters: anterior thorax with 13 setigers, interramal cirri absent, anterior thoracic neuropodia with 4–5 rows of uncini, intermixed with few subuluncini in the first 1–2 rows, ventral fringe of numerous of stomach papillae present on setigers 12–24. We also described and illustrated P. fimbriata, which is recorded for the first time from China seas.

New species of Thoonchus (Enoplida, Enchelidiidae) from the Yellow Sea and redescription of T. giganticus Belogurova et al., 1986

The family Enchelidiidae is recovered as monophyletic and appears to be a more recently derived taxon within the superfamily Oncholaimoidea. It combines nematodes with buccal cavity with three unequal teeth, crenate pharynx, and absence of demanian system. Genus Thoonchus was erected for nematodes characterized by the large buccal cavity with heavily cuticularized walls and several rows of denticles, short and arcuate spicules and gubernaculums with expanded corpus. One new species is described here from the Sishili Bay, located in the northern Yellow Sea. Thoonchus covidus sp. nov. is characterized by the body length 3195‒4339 µm, outer labial and cephalic setae in one circle, pocket shaped amphid above the buccal cavity base, secretory-excretory pore at the base of cephalic setae, arched spicules, gubernaculum with thin proximal extension parallel to spicules, preanal supplement absent, three pairs of preanal papillae. It differs from other congeners by the position of secretory-excretory pore, absence of supplementary organ in males and presence of three pairs of precloacal papillae. Redescription of T. giganticus is also provided. After critical evaluation of the genus we recognize 4 valid species and provide a taxonomic key to species.