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Mariculture of bivalves (e.g., mussels, scallops, and oysters) is developing rapidly in coastal waters. This process releases shell debris that can accumulate on the seabed under farms. The ecological consequences of shell accumulation on the bioturbation of benthic macrofauna, which play a key role in the biogeochemical processes of sediment, are not yet fully understood. Thus, it is necessary to quantify the shell debris that accumulated under bivalves farms and evaluate whether the shell debris hinders the burrowing capacity of macrofauna. Oysters are common bivalve species cultured worldwide. However, no data are available on shell accumulation due to oyster farming and its possible effects on the burrowing capacity of polychaetes. Thus, we conducted a preliminary study on shells debris accumulation under an oyster farm in Daya Bay, southern China, and assessed the effects of shell accumulation on the burrowing activity of the polychaete Perinereis aibuhitensis in a mesocosm experiment for 32 days. The results showed that oyster farming significantly (p < 0.05) increased the accumulation of shell debris under the farm. The amount of shell debris under oyster farm (6.0 ± 1.3 kg (dry weight (DW)) m-2 or 130.0 ± 24.7 g (DW) kg-1 dry sediment) was approximately two times that in a non-culture area (3.5 ± 0.9 kg (DW) m-2 or 74.9 ± 10.5 g (DW) kg-1 dry sediment). The presence of shell debris did not affect the survival of P. aibuhitensis in experiment, but the animals in sediment with shell added exhibited greater losses of body weight compared with those without, indicating that the presence of shell causes animals to expend more energy in burrowing. The numbers of burrowing holes were lower in sediment with shell debris added compared with those in sediment without shell addition throughout the experiment. Whereas, this does not due to the P. aibuhitensis in +Shell treatment were less active in terms of their burrowing activities. The lower numbers of holes in +Shell treatment was mainly due to P. aibuhitensis were unable to use surface areas where shells were present, the amount of area occupied by shell material physically prevented P. aibuhitensis from forming burrows in these locations. The hindering effects of shells on the burrowing activity of P. aibuhitensis would decrease as the shells degraded into debris. Therefore, we recommend using small shells when conducting “shell addition” bioremediation strategies to avoid the possible negative effects of shells on burrowing by polychaetes.

Microalgae blooms are a frequent occurrence in coastal waters worldwide. It is reasonable to assume that these blooms have various influences on bacterial communities, which in turn may affect the development and dissipation of the bloom. However, the bacterial community characteristics, particularly of attached bacteria, associated with microalgae blooms remain unclear. In this study, we investigated the community profiles of bacteria using high-throughput sequencing during a Phaeocystis globosa bloom in Mirs Bay, southern China, in January 2021. Bacteria living in three habitats, i.e., bacterioplankton, particle-attached bacteria, and colony-attached bacteria, were studied from the exponential growth phase to the decline growth phase of the bloom. Distinct variations in bacterial community composition existed among the three habitats. Bacteroidota, Proteobacteria, and Cyanobacteria were the dominant phyla of bacterioplankton, particle–attached bacteria, and colony-attached bacteria, respectively. Richness and diversity were significantly highest (p < 0.01) in particle-attached bacteria, followed by bacterioplankton, and lowest in colony-attached bacteria. The community diversities of bacterioplankton and particle-attached bacteria decreased significantly (p < 0.05) as the bloom shifted from the exponential to the decline phase. During the decline growth phase of the bloom, Bacteroidota and Verrucomicrobiota were the dominant remarkably abundant bacteria in the bacterioplankton community, whereas Verrucomicrobiota was dominant in the particle-attached bacteria community. No significant difference was observed in the colony-attached bacterial community between the exponential and decline phases of the P. globosa bloom owing to their complex network. The results of this study suggest that P. globose bloom has a profound impact on marine bacteria, particularly species that can decompose organic matter, which could play a crucial role in the dissipation of algal blooms.

ABSTRACT Ocean microbiomes provide insightful details about the condition of water and the global impact of marine ecosystems. A fine-scale analysis of ocean microbes may shed light on the dynamics and function of the ocean microbiome community. In this study, we evaluated the changes in the community and function of marine bacteria, protists, and diatoms corresponding to different ocean depths using next-generation sequencing methods. We found that diatoms displayed a potential water-depth pattern in species richness (alpha diversity) and community composition (beta diversity). However, for bacteria and protists, there was no significant relationship between water depth and species richness. This may be related to the biological characteristics of diatoms. The photosynthesis of diatoms and their distribution may be associated with the fluctuating light regime in the underwater climate. Moreover, salinity displayed negative effects on the abundance of some diatom and bacterial groups, which indicates that salinity may be one of the factors restricting ocean microorganism diversity. In addition, compared to the global ocean microbiome composition, function, and antibiotic resistance genes, a water depth pattern due to the fine-scale region was not observed in this study. IMPORTANCE Fine-scale analysis of ocean microbes provides insights into the dynamics and functions of the ocean microbiome community. Here, using amplicon and metagenome sequencing methods, we found that diatoms in the northern South China Sea displayed a potential water-depth pattern in species richness and community composition, which may be related to their biological characteristics. The potential effects of the differences in geographic sites mainly occurred in the diatom and bacterial communities. Moreover, given the correlation between the environmental factors and relative abundance of antibiotic resistance genes (ARGs), the study of ocean ARG distribution patterns should integrate the potential effects of environmental factors.

Creseis acicula is a swimming shelled pteropod species, widely distributed in the world’s oceans. In 2020, an unprecedented bloom of C. acicula was observed in Daya Bay, and lasted from June to July. To date, there is very limited information on the physiological characteristics of this species, which is essential to understand bloom dynamics. In the present study, the physiological performances of C. acicula in response to temperature (17–35°C) and salinity (18–38 ppt) were investigated. The oxygen consumption (OCR) and calcification rates (CR) of C. acicula peaked at 32 and 26°C, respectively, while ammonia excretion rate (AER) significantly increased with increasing temperature. The thermal coefficient Q10 (respiration) of C. acicula dropped to a minimum value between 32 and 35°C, suggesting that they were in a stressful status. The O:N ratio ranged from 3.24 to 5.13, indicating that protein was the major catabolism substrate. Temperature exerted a stronger effect on the OCR and AER of C. acicula. Salinity has a more influence on CR. The preferable temperature for C. acicula ranges from 29 to 32°C, and the preferable salinity ranges from 28 to 33 ppt. Based on a comprehensive consideration, we presumed that the warmer seawater temperature around the thermal discharge area of Daya Bay nuclear power plant is a possible cause for the bloom of C. acicula.

Benthic sediment bacteria are important drivers for material circulation and energy flow in aquatic ecosystem, and they are sensitive to environmental changes. Large scale suspended mariculture in coastal waters induces high organic loading to the sediment through biodeposition, and causes changes in sediment biogeochemical features. However, the impacts of mariculture on sediment bacterial communities are not fully understood. In the present study, sediment samples were collected from three coastal semi-enclosed bays of China, i.e., Sanggou Bay, Daya Bay, and Maniao Bay, where large scale mariculture were carried out since the 1980s. High-throughput sequencing was used to examine the spatial and seasonal variations of bacterial communities. The results indicated that the dominant phyla of three bays were Proteobacteria (39.18–47.21%), Bacteroidetes (9.91–19.25%), and Planctomycetes (7.12–13.88%). Spatial variations played a greater role in shaping the bacterial communities than seasonal variation. The bacterial diversity indices (Chao1, Pielou’s evenness, and Shannon-Wiener index) of Sanggou Bay were significantly lower than those of Daya Bay and Maniao Bay. For seasonal variation, bacterial diversity indices in spring were significantly lower than that in autumn. Five keystone taxa belonging to Planctomycetes, Alphaproteobacteria, and Acidobacteria were identified in Sanggou Bay. Temperature, particulate organic carbon, pH, and salinity were the most important environmental factors shaping the spatial and seasonal variations of bacterial communities in the studied areas. The abundances of bacteria, particularly Bacteroidetes, Gammaproteobacteria, and Deltaproteobacteria, were significantly correlated with the mariculture-driven chemical properties of the sediment. These results indicated that intensive mariculture could induce profound and diverse impacts on the bacterial communities, and therefore modify their role in marine ecosystem. The interactions between mariculture and sediment bacterial communities should be considered in regard to mariculture management and carrying capacity.

We report the first mitochondrial genome sequences for the three band pennant fish, Heniochus chrysostomus. The whole mitogenome of H. chrysostomus was circular in shape and 16,650 bp in length. The mitogenome consists of 13 typical vertebrate protein-coding genes, 22 tRNA genes, 2 rRNA genes (12S rRNA and 16S rRNA), and 2 putative non-coding regions. Phylogenetic tree analysis revealed that H. chrysostomus was closely related to Heniochus diphreutes. This study will provide useful genetic information for future phylogenetic and taxonomic classification of Chaetodontidae.

Summary: The seasonal patterns of the denitrifiers (denitrifying bacteria) in the sediment of Daya Bay, southern China, were examined using quantitative PCR and high-throughput MiSeq sequencing methods in spring, summer and winter. The abundance and diversity of nirS-encoding denitrifiers were much higher than that of nirK-encoding denitrifiers, indicating that the former probably dominated the denitrification processes in sediments of Daya Bay. The average abundance and diversity of nirS-encoding denitrifiers were much higher in spring than that in summer and winter, on the other hand, the abundance of nirK-encoding denitrifiers showed the opposite pattern. The species composition of nirS-encoding denitrifiers community in spring differed significantly from that in summer and winter, whereas, no significant difference existed between summer and winter. The dominant environmental drivers for the diversity of community species were NO2−, NO3− and DO concentrations. The abundances of dominant genera of nirS- encoding denitrifiers, Accumulibacter sp. and Cuprizvidus sp., were significantly higher in summer and winter than that in spring, and were negatively correlated with NO2−, NO3−, and DO concentrations (p

In recent years, the GPS wave buoy has been developed for in situ wave monitoring based on satellite GPS signals. Many research works have been completed on the GPS-based wave measurement technology and great progress has been achieved. The basic principle of the GPS wave buoy is to calculate the movement velocity of the buoy using the Doppler frequency shift of satellite GPS signals, and then to calculate the wave parameters from the movement velocity according to ocean wave theory. The shortage of the GPS wave buoy is the occasional occurrence of some unusual values in the movement velocity. This is mainly due to the fact that the GPS antenna is occasionally covered by sea water and cannot normally receive high-quality satellite GPS signals. The traditional solution is to remove these unusual movement velocity values from the records, which requires furthering extend the acquisition time of satellite GPS signals to ensure there is a large enough quantity of effective movement velocity values. Based on the traditional GPS wave measurement technology, this paper presents the algorithmic flow and proposes two improvement measures. On the one hand, the neural network algorithm is used to correct the unusual movement velocity data so that extending the acquisition time of satellite GPS signals is not necessary and battery power is saved. On the other hand, the Gaussian low-pass filter is used to correct the raw directional wave spectrum, which can further eliminate the influence of noise spectrum energy and improve the measurement accuracy. The on-site sea test of the SBF7-1A GPS wave buoy, developed by the National Ocean Technology Center in China, and the gravity-acceleration-type DWR-MKIII Waverider buoy are highlighted in this article. The wave data acquired by the two buoys are analyzed and processed. It can be seen from the processed results that the ocean wave parameters from the two kinds of wave buoys, such as wave height, wave period, wave direction, wave frequency spectrum, and directional wave spectrum, are in good consistency, indicating that the SBF7-1A GPS wave buoy is comparable to the traditional gravity-acceleration-type wave buoy in terms of its accuracy. Therefore, the feasibility and validity of the two improvement measures proposed in this paper are confirmed.

Background: Hemoglobin (HGB) was the most important factors which could cause dysmenorrhea in women. Metals exposure and hemoglobin level in dysmenorrhea female was unclear. We aimed to explore the associations of multi-metal exposure and HGB level in female college students with dysmenorrhea. Methods: 253 female students who had dysmenorrhea was included in our study. The Last Absolute Shrinkage and Selection Operator (LASSO) regression, generalized linear model (GLM), and Bayesian Kernel Machine Regression (BKMR) models were used to explore the associations of multi-metal exposure and HGB levels in female college students with dysmenorrhea. Results: GLM results showed that plasma Fe, Ni and Rb was positively associated with HGB and plasma Co was negatively associated with HGB. In menarche age ≤13 years old group, plasma Co and Rb only was negatively and positively associated with HGB level, respectively, and plasma Ni had positive association with HGB level in menarche age >13 years old group. BKMR results showed the reverse U-shaped relationship between the five metals mixture (Co, Fe, Ni, Cu and Rb) and HGB levels in overall and menarche age ≤13 years old group. However, there were positive association between the five metals mixture and HGB levels in menarche age >13 years old group. Conclusion: Our present study revealed that metals (Fe, Ni, Co, Rb, Cu) mixture exposure could effect HGB levels in female college students with dysmenorrhea. And the relationships were different during different menarche age in female college students.