Oil droplet size distribution (ODSD) plays a critical role in the rising velocity and transport of oil droplets in subsurface oil releases. In this paper, subsurface oil release experiments were conducted to study ODSD under different experimental conditions in a laboratory water tank observed by two high-speed cameras in March and April 2017. The correlation formulas Oh=10.2Re^–1 and Oh=39.2Re^–1 (Re represents Reynolds number and Oh represents Ohnesorge number) were established to distinguish the boundaries of the three instability regimes in dimensionless space based on the experimental results. The oil droplet sizes from the experimental data showed an excellent match to the Rosin–Rammler distribution function with determination coefficients ranging from 0.86 to 1.00 for Lvda 10-1 oil. This paper also explored the influence factors on and change rules of oil droplet size. The volume median diameter d₅₀ decreased steadily with increasing jet velocity, and a sharp decrease occurred in the laminar-breakup regime. At Weber numbers (We) <100, the orifice diameter and oil viscosity appeared to have a large influence on the mean droplet diameter. At 100<We<1 000, the oil viscosity appeared to have a larger influence on the relative mean droplet diameter.

Marine plastic debris has been a pervasive issue since the last century, and research on its sources and fates plays a vital role in the establishment of mitigation measures. However, data on the quantity of plastic waste that enters the sea on a certain timescale remain largely unavailable in China. Here, we established a model using material flow analysis method based on life cycle assessment to follow plastic product from primary plastic to plastic waste with statistical data and monitoring data from accurate sources. This model can be used to estimate and forecast the annual input of plastic waste into the sea from China until 2020. In 2011, 0.547 3–0.751 5 million tons of plastic waste entered the seas in China, with a growth rate of 4.55% per year until 2017. And the amount will decrease to 0.257 1 to 0.353 1 million tons in 2020 under the influence of governmental management. The amount of plastic waste discharged from coastal areas calculated in this study was much larger than that from river, thus it is suggested to strengthen the governance and control of plastic waste in coastal fishery activities in China in order to reduce the amount of marine plastic waste input.

The daily and monthly-mean characteristics of cold water patches (CWPs) off the Jiangsu coast in 35 a of 1982–2016 are examined based on advanced very high resolution radiometer (AVHRR) data. Most of the CWPs are found to occur in the warm and hot months (May–September), with some CWPs in the cool and cold months (October–April). The average radius and intensity of the monthly-mean CWPs are about 81 km and 0.6°C, respectively. The average difference in the sea surface temperature (SST) between the centers of the CWPs and the nearshore is about 2.0°C. The correlation analysis between the CWPs, winds and tides indicates that most of the CWPs occurred during the southerly winds, with some CWPs occurring during the northerly winds. The average intensity of the CWPs during spring tides is slightly stronger than that during neap tides in the warm and hot months, and the difference is very small in the cool and cold months.

A taxonomic study of Hyalinoecia species based on the materials deposited in the Marine Biological Museum of the Chinese Academy of Sciences (MBMCAS) yielded two species: Hyalinoecia tubicola (Müller, 1776) and H. papillata Imajima, 1999. Both species were collected from the sandy bottoms in the northern South China Sea. Hyalinoecia tubicola is widely distributed from the coast of Guangdong Province southwards to the Xisha Islands. Hyalinoecia papillata is reported for the first time in the South China Sea. It differs from H. tubicola in having a prolonged, tongue-like prechaetal lobe with papillae along the lateral margins in the first parapodium (vs. auricular prechaetal lobe with smooth margins). The morphological description and illustration of both species are given.

Two new free-living marine nematode species from the mangrove wetlands of Fujian Province, China are identified and illustrated. Sabatieria conicoseta sp. nov. is characterized by its short conical somatic setae. There are 12–15 tubular pre-cloacal supplements and 12–15 μm long straight gubernacular apophyses. Dorylaimopsis papilla sp. nov. is characterized by spicules which are 1.5–1.8 a. b. d. long with media cuticularized strip along entire spicules, and have a cephalated proximal end with small hooked. There are 16–18 small papillate pre-cloacal supplements and 37–40 μm long dorso-caudal gubernacular apophyses.

Sabaco sinicus sp. nov. is described based on material collected from Chinese coast. It has been misidentified as Asychis gangeticus Fauvel, 1932 since Uschakov and Wu (1962). Here, we recognized it as a new species based on combination of the following characters: dark-brown pigmentation spots on nuchal grooves and first three chaetigers; glandular pattern on chaetigers 4–6; preanal achaetigerous segments absent; anal plaque trumpet-shaped with a disc-shaped dorsal lobe; notochaetae consisting of geniculate capillaries and fine capillaries with or without spinose spiral bands; neurochaetae presented as a single row of rostrate uncini. Asychis gangeticus differ from the new species in having no pigmentations on body and a triangular dorsal lobe of anal plaque. Distribution region of this species have moved northward significantly from sea area south of Changjiang Estuary since the 1950s.

A new species of the family Pheronematidae is described in this study. Specimens were collected at Yap seamount and Caroline seamount in the Northwest Pacific Ocean. Poliopogon distortus sp. nov. contains oval macramphidiscs, three categories of amphidiscs, clavate monaxons and sceptres, making it distinguished from the eight known congeners easily. This is the fourth record of genus Poliopogon from the Northwest Pacific Ocean. We also used a partial sequence of 16S rDNA gene to confirm the family assignment of the new specimen.

Based on specimens collected in Yinggehai, Hainan, China from 2013 to 2016, a stable epiphytic taxon is found on the surface of the individual of marine green alga Cladophora aokii Yamada. According to the morphological characteristics, the taxonomy of Cl. aokii and its epiphytes is carried out. There are some epiphytes attached on Cl. aokii Yamada including Cl. fascicularis (Mertens ex C. Agardh) Kützing, Chaetomorpha pachynema (Montagne) Kützing, Ceramium camouii Dawson, Licmophora abbreviata Agardh, Lyngbya sp. and Chattonella sp.. The formation of the individual of Cl. aokii is dissected and explained, which can help to analyze the adaption in details among this species, its epiphytes and native marine environment. The results reveal the marine macro-epiphytic taxonomy in Hainan, China, and preliminarily explain the adaptive relationship between macroalgae and environment.

A small armed dinoflagellate bloomed in the aquaculture ponds off the coast of Liaodong Bay, Bohai Sea of China, resulting in heavy mortalities of the cultured prawns (Penaeus japonicus) and larvae of Chinese mitten handed crabs (Eriocheir sinensis). The bloom-forming species was successfully isolated, and cellular morphology of the specimen was consequently investigated through light, fluorescent and electron microscopy. The small ((14.4±1.6) μm in length) ellipsoid cells show typical Heterocapsa thecal plate arrangement (Po, cp, 5′, 3a, 7′′, 6c, 5s, 5′′′, 2′′′′). The episome is evidently bigger than the hyposome. One to three spherical pyrenoids are located above or beside the large elongated nucleus. The body scale is characterized by a triangle basal plate with one central upright and nine peripheral spines. Above all, Heterocapsa bohaiensis could be distinguished from other Heterocapsa species by the combination of the cell size, morphology, cellular structure and body scale. Sequence analyses of both ITS and LSU regions reveal the significant genetic divergence between H. bohaiensis and other established species in this genus, further supporting novelty of this species. Noticeably, different sample treatment methods resulted in morphological variation of the apical pore complex (APC) of H. bohaiensis, which needs to be taken into account in future study.

Epipont peritrich ciliates are one of the most sessilie protists that attached to the substrate of zooplankton communities especially copepods and crustaceans. Peritrich ciliates can be solitary or colonial form found from the coastal zones and embayment around the world. Present research report is the first snapshot study of the peritrich ciliates and the horizontal distribution in open waters from surface to 200 m depth in the eastern Indian Ocean. Recently, five peritrich ciliates, e.g., Vorticella oceanica, Zoothamnium alternans, Z. alrasheidi, Z. pelagicum, and Z. marinum were collected from plankton net tow samples during the cruise from April 10 to May 13, 2014. The characteristics of the peritrich ciliate were determined according to the shape of the zooids, the ciliary structure and the stalks. The morphometric shape, sizes and characters also explained by examination under light/scanning electron microscopy. Vorticella oceanica and Z. pelagicum showed their association with host such as diatom (i.e, Chaetoceros coarctatus) and copepod (Oithona brevicornis) including some individuals around the dinoflagellate species (Ceraitum tripose). The distribution of these sessilid ciliates was dominated by the V. oceanica, Z. pelagicum and Z. marinum at the southeast zone while the large colonies of Z. alrasheidi observed at the Bay of Bengal. This distribution can be influenced by substrate availability like diatom (Ch. coarctatus) and copepods (O. brevicornis).