Hydrodynamics and dissolved organic matter components shaped the fate of dissolved heavy metals in an intensely anthropogenically disturbed estuary.

Anthropogenic activities and natural erosion caused abundant influx of heavy metals (HMs) and organic matter (OM) into estuaries characterized by the dynamic environments governed by tidal action and river flow. Similarities and differences in the fate of HM and OM as well as the influences of OM on HMs remain incomplete in estuaries with seasonal human activity and hydrodynamic force. To address this gap, dissolved HMs (dHMs) and fluorescence dissolved OM (FDOM) were investigated in the Pearl River Estuary, a highly seasonally anthropogenic and dynamic estuary.

Dynamics of the surface carbonate system in oil fields with a high concentration of wells on the northwestern South China Sea shelf.

Oil exploitation may pose adverse effects on marine ecosystems, but its impacts on surface carbonate dynamics remain unknown. In a carbonate system with low air-sea ∆pCO, such as the South China Sea (SCS), human activities may affect the pCO distribution patterns and potentially alter CO sink or source at the surface. This study investigates the surface carbonate system in two oil fields, namely the Wenchang Oil Feld and Enping Oil Feld, located on the northwestern SCS (NWSCS) shelf.

Identification of anthropogenic source of Pb and Cd within two tropical seagrass species in South China: Insight from Pb and Cd isotopes.

Seagrass beds are susceptible to deterioration and heavy metals represent a crucial impact factor. The accumulation of heavy metal in two tropical seagrass species were studied in South China in this study and multiple methods were used to identify the heavy metal sources. E.

Microplastic size-dependent biochemical and molecular effects in alga Heterosigma akashiwo.

Micro- and nano-plastics (MNPs) are increasingly prevalent contaminants in marine ecosystems and have a variety of negative impacts on marine organisms. While their toxic impact on freshwater microalgae has been well-documented, limited research has been conducted on the influence of MNPs on marine red tide algae, despite their significant implications for human health and coastal ecological stability. This study investigated the physiological, biochemical and molecular reactions of the common harmful algal species, Heterosigma akashiwo, when exposed to polystyrene (PS) MNPs of 80 nm and 1 µm in size with the concentrations of 0, 1, 10, and 20 mg L in 12 days.

Characterization of metal resistance genes carried by waterborne free-living and particle-attached bacteria in the Pearl River Estuary.

Toxic metals can substantially change the bacterial community and functions thereof in aquatic environments. Herein, metal resistance genes (MRGs) are the core genetic foundation for microbial responses to the threats of toxic metals. In this study, waterborne bacteria collected from the Pearl River Estuary (PRE) were separated into the free-living bacteria (FLB) and particle-attached bacteria (PAB), and analyzed using metagenomic approaches.

Saltwater intrusion regulates the distribution and partitioning of heavy metals in water in a dynamic estuary, South China.

The mixing processes of fresh-salt water in estuarine and coastal regions have a substantial impact on the characteristics of heavy metals. A study was conducted in the Pearl River Estuary (PRE), located in South China, to examine the distribution and partitioning of heavy metals and the factors that influence their presence. Results showed that the hydrodynamic force, caused by the landward intrusion of the salt wedge, was the major contributor to the aggregation of heavy metals in the northern and western PRE.

The Ecological Status and Change in High-Latitude Coral Assemblages at the Xuwen Coral Reef, Northern South China Sea: Insight into the Status and Causes in 2020.

Taking the coral communities of the Xuwen coral reef in 2020 as the research object, we analyzed the species composition, diversity, and interspecific Spearman correlation of the scleractinian coral communities, investigated the features and spatial distribution of the scleractinian coral community, and discussed the correlation between the community composition and environmental factors to identify the affecting factors and their sources. These results showed that (1) compared with the survey in 2004, the coverage of corals in 2020 had significantly decreased, while the dominant genera were still and . The coral morphology was massive, and the diversity of the coral community (Shannon-Wiener index, ) was 2.

Characteristics of sedimentary and dissolved heavy metals in the Chukchi plateau and adjacent waters.

Heavy metals in sediments and waters in the Chukchi Plateau and adjacent waters were investigated in this study. The results showed that most metals (especially Ni, As and Co) have accumulated in sediments, and their levels followed the order of Zn > Ni > Co > Cr > Cu > As > Pb > Cd. Spatial variations of environmental variables and metal characteristics were revealed based on the transect research.

Pectinariidae (Annelida, Polychaeta) from the coastal waters of China, with description of new species and new records.

Pectinariidae Quatrefages, 1865 is widely distributed, and easily distinguished from other polychaetes by their characteristic semi-circular operculum with two rows of stout golden paleae and ice-cream cone-shaped tubes made of sand or shell fragments. A total of 387 specimens of pectinariids from the coastal waters of China were examined. Eleven species belonging to three genera of pectinariids were identified and described, including four new species (Amphictene jianqingi n.

High vulnerability and a big conservation gap: Mapping the vulnerability of coastal scleractinian corals in South China.

Scleractinian corals build the most complex and diverse ecosystems in the ocean with various ecosystem services, yet continue to be degraded by natural and anthropogenic stressors. Despite the rapid decline in scleractinian coral habitats in South China, they are among the least concerning in global coral vulnerability maps. This study developed a rapid assessment approach that combines vulnerability components and species distribution models to map coral vulnerability within a large region based on limited data.

The complete mitochondrial genome of (Sedentaria: Chaetopteridae).

The benthic and tube-building polychaete worm is abundantly present on the coast of the western Pacific. Here, we report the complete mitochondrial genome of , which is 19,326 bp in length and contains 13 protein-coding genes, 2 rRNA genes and 22 tRNA genes. All 37 genes are encoded on the heavy strand, and AT content is 70.

Characteristics of nutrients and heavy metals and potential influence of their benthic fluxes in the Pearl River Estuary, South China.

Nutrient and heavy metal concentrations in porewater/overlying water and their benthic fluxes were investigated to study their accumulation and transport at the sediment-water interface and the influences of sediment in the Pearl River Estuary, China. Results revealed that distribution of nutrients and metals reflected the effects of terrestrial inputs and some physicochemical processes. Benthic fluxes also suggested that nutrients and heavy metals Pb, Zn and Cd diffused from sediment to overlying water, but not for As, Co, Cr, Fe, Mn and Ni.

Heavy metal accumulation and ecological risk on four seagrass species in South China.

Zn, Pb, Cr, Cu, Ni, Cd concentration and ecological risk were studied in three bays to evaluate the heavy metal (HM) contamination of seagrasses. Seasonal HM accumulation varied according to locations, seagrass species and tissues. Halophila beccarii had much higher HM concentrations except for Cr in Zhelin Bay, however, bioconcentration factors (BCF) of Cu, Ni, Pb, Zn were higher in Liusha than Zhelin Bay.

A new species of (Annelida, Pectinariidae), with comments on McIntosh, 1885.

The genus Malmgren, 1866 is a small and poorly known genus of the annelid family Pectinariidae Quatrefages, 1866. A previous revision of the genus found that the type material of the species McIntosh, 1885 had been lost. While searching for material from the type locality, we were able to examine material from a similar area but collected in much shallower water from off South Africa which represents another undescribed species of .

Evidence for massive and recurrent toxic blooms of in the Alaskan Arctic.

Among the organisms that spread into and flourish in Arctic waters with rising temperatures and sea ice loss are toxic algae, a group of harmful algal bloom species that produce potent biotoxins. , a cyst-forming dinoflagellate that causes paralytic shellfish poisoning worldwide, has been a significant threat to human health in southeastern Alaska for centuries. It is known to be transported into Arctic regions in waters transiting northward through the Bering Strait, yet there is little recognition of this organism as a human health concern north of the Strait.

Metal pollution in the Pearl River Estuary and implications for estuary management: The influence of hydrological connectivity associated with estuarine mixing.

Understanding the metal pollution can help governments and estuary management groups manage metal inputs. Here, we comprehensively analyzed the behaviors of seven metals Cd, Zn, Cu, As, Pb, Cr, and Hg in water and the responses of these metals to hydrological connectivity in the Pearl River Estuary. The analyses were based on the field measurements of August-2016 in the estuary and January-2016 in the upper river mouth.

The identification of fish eggs of two species, the ovate sole Solea ovata and black porgy Acanthopagrus schlegelii.

Fish eggs of the ovate sole Solea ovata and black porgy Acanthopagrus schlegelii were identified through DNA barcoding of cytochrome c oxidase subunit I (COX1). Visual taxonomic features were achieved, and photographs of the eggs of both species at different developmental stages were reported for the first time. In addition, the dissolution of oil globules caused by ethanol as egg fixatives was observed.

Influence of sedimentary organic matter sources on the distribution characteristics and preservation status of organic carbon, nitrogen, phosphorus, and biogenic silica in the Daya Bay, northern South China Sea.

Surface sediment samples were collected from Daya Bay in October 2018, and analyzed for total organic carbon (OC), total nitrogen (TN) and their stable isotopes (δC and δN), total phosphorus (TP), biogenic silica (BSi), sediment textures and specific surface area (SSA). The primary objective was to evaluate the influence of mariculture/aquaculture on the distribution characteristics of organic matter (OM), and preservation status of OC, TN, TP, and BSi in sediments. The average δC and δN values, and OC/TN ratios were -21.

Two new species of Sabellariidae (Annelida, Polychaeta) from the abyss of eastern Australia.

In May-June 2017 an expedition on board RV 'Investigator' sampled benthic communities along the lower slope and abyss of eastern Australia from off Tasmania to the Coral Sea. Over 200 sabellariid specimens of the genera Phalacrostemma and Gesaia were collected during the voyage and deposited in the Australian Museum. Here we describe two new species Gesaia csiro n.

Long-term changes in summer phytoplankton communities and their influencing factors in Daya Bay, China (1991-2017).

Spatial variations in summertime phytoplankton community structure from 1991 to 2017 in Daya Bay, China were investigated in this research. The abundance of total phytoplankton and diatoms significantly increased during the study period in all regions of the bay while an increase in dinoflagellates abundance was only significant in the inner and middle bay areas. Pseudo-nitzschia spp.

Spatial-temporal variations and trends predication of trace metals in oysters from the Pearl River Estuary of China during 2011-2018.

Estuaries are often considered to be the filters of pollutants from the land-derived outflows of freshwater to open seawater. Oysters are efficient bioaccumulators of metals in the estuarine environment, however, little information is available on the long-term tissue variability of metals in a large dynamic estuary under complex urbanized and anthropogenic impacts. Thus, an eight-year biomonitoring study of metals (Ag, Cd, Cr, Cu, Ni, Pb, and Zn) in the oysters from 10 sites were carried out to reveal the highly spatial-temporal variations in the Pearl River Estuary (PRE) of China during 2011-2018.

Low dissolved oxygen in the Pearl River estuary in summer: Long-term spatio-temporal patterns, trends, and regulating factors.

Several large semi-enclosed seas and coastal bodies have formed seasonal hypoxic water masses over large areas. The dominant cause for such formations is believed to be the increasing inflow of nutrients from watersheds and urban areas into estuaries and coastal waters. Several studies have reported hypoxic events in the Pearl River estuary (PRE).

A revision of Australian Pectinariidae (Polychaeta), with new species and new records.

Samples of Pectinariidae in the Australian Museum and Museums of Victoria, Australia were examined. Thirteen species were identified, including three additional records of previously recorded species of Amphictene and two new species, A. cercusa n.

A revision of the genus Petta Malmgren, 1866 (Annelida: Pectinariidae), with two new species from deep waters of southeastern Australia, and comments on phylogeny of the family.

Petta Malmgren, 1866 is a small and poorly known genus of the annelid family Pectinariidae Quatrefages, 1866. Prior to this study, the genus comprised four species P. pusilla Malmgren, 1866 (type locality Gullmarsfjord, west coast of Sweden), P.

The Po / Pb disequilibrium in a spring-blooming marginal sea, the Southern Yellow Sea.

The Southern Yellow Sea (SYS) is suffering from the increasing environment problems, such as the recurrent algal bloom. The Po/Pb disequilibrium is very useful for assessing particulate organic matter dynamics during phytoplankton blooming. In this study, 23 surface samples were collected from the SYS after the 2009 spring bloom, to investigate the disequilibrium between these two radionuclides.