Search

A self-powered double-photoelectrode sensing device is proposed for the rapid quantification of ciprofloxacin.

Freezing phenomenon has troubled people for centuries, and efforts have been made to lower the liquid freezing temperature, raise the surface temperature or mechanical de-icing. Inspired by the elytra of beetle, we demonstrate a novel functional surface for directional penetration of liquid to reduce icing. The bionic functional surface is fabricated by projection micro-stereolithography (PµSL) based 3D printing technique with the wettability on its two sides tailored by TiO2 nanoparticle sizing agent. A water droplet penetrates from the hydrophobic side to the superhydrophilic side of such a bionic functional surface within 20 ms, but it is blocked in the opposite direction. Most significantly, the penetration time of a water droplet through such a bionic functional surface is much shorter than the freezing time on it, even though the temperature is as low as -90 ℃. This work opens a gate for the development of functional devices for liquid collection, condensation, especially for hyper-antifogging/freezing.

Coastal areas have been intensively urbanized in Asia, causing changes to the structure and function of intertidal macrobenthic communities. In this study, the intertidal assemblages on two natural rocky shores, two rocky shores disturbed by construction works, and two shores with mixed artificial seawalls and mudflats in the Dongtou Islands were studied. We examined the influence of coastal engineering by comparing macrobenthic community structures in different transects. The statistical results revealed significant differences between macrobenthic community structures in natural and influenced transects, although all the high tidal zones shared common species. The most common species on mudflats were opportunistic polychaetes; however, historical evidence suggests that the mudflats in Dongtou used to be dominated by Mollusca. We inferred that this change in community structure occurred when the seawalls were constructed five5 years previously. The macrobenthic community does not appear to have subsequently recovered. We also observed an absence of habitat-forming macroalgae in our study area, although similar investigation results revealed that they still prevail on an uninhabited island in Dongtou. The increasing disturbance caused by construction work may explain the decline in brown algae, which are mainly distributed in the low tidal zone.

Antibiotic residues in the environment and in foods pose a serious threat to ecosystems and human health. Developing sensitive and on-site detection methods is therefore in high demand. In this work, a portable paper-based colorimetric sensor with a smartphone platform with an ultrahigh sensitivity has been designed for on-site and quantitative analysis of antibiotic residues based on aptamer-regulated nanozyme activity. The developed excellent peroxidase-like nanozymes, carbon-protected NiCo bimetal oxides with a unique hollow nanocage structure (NiCo@C HCs), could effectively catalyze the oxidation of chromogenic substrates by H

This study conducted four cruises during 2014–2017 to investigate relationships between macrobenthic communities and sediment contaminations in sea area around the Zhoushan Archipelago. Fourteen sites were categorized into three groups: high total heavy metal contamination content (HTHM), high total petroleum hydrocarbon content (HTPH), and low content ratio of heavy metal contamination content/ total petroleum hydrocarbon content (HMC/TPH) areas. Four main taxa of macrofauna (polychaetes, bivalves, gastropods, and crustaceans) were determined to respond to environmental factors differently. While tolerant polychaetes being the minimal impact by environmental factors, bivalves were threated by heavy metal pollutions in sediment. Additionally, body size distribution frequency demonstrated that macrofauna in the low HMC/TPH areas were less disturbed by contamination than those in the HTHM and HTPH areas. The result represented the presentation of sensitive species while tolerant species are usually considered as small size organisms. Overall, this study confirmed the hypothesis that the contamination levels of small-scale patches is indicated by the condition of macrobenthic communities.

Obvious spatiotemporal heterogeneity is a distinct characteristic of ecosystems in subtropical bays. To aid targeted management and ecological restoration in long and narrow semi-enclosed subtropical bays, we analyzed seasonal and regional differences in long-term changes (1980–2019) in the biomass and abundance of large mesozooplankton (LMZ; >505 µm) in Xiangshan Bay, Zhejiang, China. We found spatiotemporal heterogeneity in the historical changes of LMZ. Significant negative trends in LMZ biomass were found in the inner and middle bay during the warm season (summer and autumn), when the nutrient concentration (especially dissolved inorganic nitrogen) and temperature increased simultaneously. Nutrient changes in Xiangshan Bay began in the late 1980s or early 1990s, coinciding with large-scale fish cage development. A rapid decline in LMZ biomass occurred after 2005 when power plants commenced operation, accelerating the warming trend. Therefore, the joint stress of eutrophication and warming likely precipitated the decline in LMZ biomass. Conversely, a significant increase in LMZ biomass was found in the outer bay in spring. This trend was consistent with the trend of LMZ biomass near the Changjiang (Yangtze) River estuary, which indicates that the pelagic ecosystem in the outer bay was affected by water from the Changjiang River estuary during spring. Based on our results, ecosystem management and restoration in semi-enclosed subtropical bays should focus on internal waters, which have a poor capacity for water exchange. For Xiangshan Bay, the changes in the Changjiang River estuary ecosystem during the cold season (winter and spring) should also be considered.

Engineering biological systems to test new pathway variants containing different enzyme homologs is laborious and time-consuming. To tackle this challenge, a strategy was developed for rapidly prototyping enzyme homologs by combining cell-free protein synthesis (CFPS) with split GFP. This strategy featured two main advantages: 1) dozens of enzyme homologs were parallelly produced by CFPS within hours, and 2) the expression level and activity of each homolog was determined simultaneously by using the split GFP assay. As a model, this strategy was applied to optimize a 3-step pathway for nicotinamide mononucleotide (NMN) synthesis. Ten enzyme homologs from different organisms were selected for each step. Here, the most productive homolog of each step was identified within 24 h rather than weeks or months. Finally, the titer of NMN was increased to 1213 mg/L by improving physiochemical conditions, tuning enzyme ratios and cofactor concentrations, and decreasing the feedback inhibition, which was a more than 12-fold improvement over the initial setup. This strategy would provide a promising way to accelerate design-build-test cycles for metabolic engineering to improve the production of desired products. This article is protected by copyright. All rights reserved.

It remains unclear how the suspended non-fed bivalve mariculture will alter the coastal transfer and cleaning process of trace elements, the non-degradable contaminants, which have been reported to accumulate in sediment from bivalve mariculture areas. Herein, we set up a field in situ comparative test in the suspended oyster (Crassostrea plicatula) farming area (OF) and reference area (RA) of Xiangshan Bay to verify our hypothesis that the biodepositon of suspended oysters would consolidate trace elements from the water column and transport them to the sediment. Distribution of trace elements in multiple media of biodeposits (BDs), settling particles (SPs), sediments (SEs), and seawater demonstrate that the accelerated deposition of BDs which enriched trace elements from the water column by oysters filtering suspended particles led to trace elements accumulation in SEs from OF. Additionally, As, Cd, Co, Cr, Cu, Ni, V, and Zn were strongly regulated by this process with significant (p 0.05) higher concentrations in SEs from OF (10.96, 0.20, 13.98, 82.40, 38.47, 38.22, 108.57, and 111.20 μg/g, repectively) than those from RA (9.43, 0.13, 11.76, 63.30, 30.34, 29.55, 86.59, and 100.24 μg/g, repectively), but the extent was different for Mn, Mo, Pb, and W with concentrations in SEs from OF (737.37, 0.81, 30.98, and 3.96 μg/g, repectively) and RA (765.25, 0.69, 31.27, and 3.34 μg/g, repectively), especially for Rb and Sr with concentrations in SEs from OF (131.13 and 96.24 μg/g, repectively) and RA (142.21 and 161.10 μg/g, repectively), due to their geochemical and geophysical properties. Moreover, the harvest of hyper-accumulated oysters as a sink for removing trace elements from water column cannot hide the impact of this process.

Complex three-dimensional (3D) microstructures are attracting more and more attention in many applications such as microelectromechanical systems, biomedical engineering, new materials, new energy, environmental protection, and wearable electronics. However, fabricating complex 3D microstructures by 3D printing techniques, especially those with long suspended structures, needs to introduce additional supporting structures, which are difficult to be removed. Here, we propose a simple method in which the supporting structures can be easily removed by optimizing their size and the grayscale value working with ultrasonic treatment in ethanol solution. The 3D microstructures and the supporting structures made of the same insoluble materials are fabricated simultaneously by using a projection microstereolithography system with a dynamic mask. The results demonstrate that the supporting structures play a key role in the fabrication of the long suspended structures while they can be easily removed. The removal time decreases with the increase in the height of the supporting microstructures, and the breaking force and shearing force of the supporting structures increase with the increase in their grayscale and the diameter. In addition, theory and the multiphysics simulation validate that the stress concentration at the top and the bottom of the supporting structures due to the cavitation from ultrasonic vibration dominates the removal of the supporting structures. Finally, a tree-like structure is precisely fabricated by using our method. The present study provides a new way for the removal of the supporting structures for 3D printed suspended microstructures.

A portable three-dimensional (3D) printed bionic sensing device with enhanced photoelectric response was fabricated for sensitive detection of Bisphenol A (BPA). The proposed sensor is operated upon by using a highly reactive dual-electrode system to generate electrical output and provide the sensing signal under photoirradiation, without an external power source. The fern-shaped nitrogen doped BiVO

Accurate on-site analysis of food quality, environmental pollutants, and disease biomarkers is of great significance for safeguarding public health. In this work, based on the novel nanozymes, MnCo oxides@carbon yolk-shell nanocages (MnCo@C NCs), a portable colorimetric sensor with smartphone platform has been developed for rapid, on-site and quantitative analysis of total antioxidant capacity (TAC) and phenolic compounds. The MnCo@C NCs are synthesized via one-step calcination of polydopamine-coated MnCo Prussian blue analogs (MnCo-PBA@PDA). The PDA-derived carbon shell is found to be able to protect the nanocages from collapsing, thus increasing their specific surface areas and porosity. Benefiting from the unique structure and multivalent MnCo bimetallic oxides, the MnCo@C NCs perform outstanding catalytic performance and multiple enzyme-mimicking activities including oxidase, laccase and catalase. Hence, a multifunctional application platform integrated smartphone has been constructed for rapid and sensitive colorimetric detection of three model analytes (i.e., ascorbic acid (AA), 2,4-dichlorophenol (2,4-DP), and epinephrine) with extremely low detection limits of 0.29 μM, 0.76 μM, and 0.70 μM, respectively. This sensor device is successfully applied in TAC analysis in vegetables, fruits, and beverages, as well as epinephrine determination in human serum samples. This work provides new insights into designing multifunctional nanozymes to advance the instant detection technology in the field of food supervision, environment monitoring, and human health.

To explore the ecological risks of trace metals in sediments and their relationship with benthic organisms, 12 trace metals were analyzed and the macrobenthos were identified in the sediments collected from the south coast of Zhejiang province which belongs to the East China Sea. Spatially, the concentrations of most trace metals were high in the estuary, except for Ba and Sr. There was no obvious enrichment for trace metals, except that the concentration of Cd slightly exceeded the coastal background. The ecological risks calculated by the concentrations of Cr, Cd, Cu, Zn, Pb, and Ni in sediments showed that the methods based on sediment quality guidelines could judge the ecological risk more intuitively than the methods based on background value (PN, PLI, RI). The significant correlations between ecological risks and benthos density and biomass revealed the negative impact of trace metals at high concentrations on macrobenthic survival in sediments.

Sediment oxygen consumption (SOC) is important in modulating the oxygen budget in the East China Sea where seasonal hypoxia occurs. Porewater advection, molecular diffusion and bioturbation supply oxygen for sedimentary organic matter degradation. A pelagic‒benthic coupled model was applied to quantify the SOC. A comparison with observations showed good model performance in reproducing the hydrographic and ecological environments, particularly for the interannual variation in the hypoxic zone. Simulation results show that porewater-advection-induced flux is the predominant component of the SOC in sandy areas on the Changjiang bank and outer shelves, while the bioturbation‒induced flux is predominant at mud depocenters. By comparing SOC to the water oxygen consumption (WOC) below the pycnocline, the contribution of SOC is generally below ∼40% in the hypoxic zone. The spatial distribution of SOC in summer is relatively steady from year to year, while the high WOC patches explain more about the interannual variation in the hypoxic zone. WOC rather than SOC drives the variation of hypoxia. Particularly on the Changjiang bank, milder hydrodynamics are favorable for both the higher WOC and bioturbation-induced benthic oxygen flux but substantially suppress the porewater advective flux, which results in the net lower contribution of SOC to hypoxia. This finding may shed light on other pelagic‒benthic coupling processes in coastal shelf seas where hypoxia occurs on permeable sediments.

This study investigates the relationship between macrobenthic functional group composition and hypoxia in the Changjiang River estuary and its adjacent sea areas. A total of 82 stations were divided into three areas, named non-hypoxic area, hypoxic area and the Changjiang River, respectively. A total of 256 macrobenthic species were collected, which were divided into five functional groups, including carnivorous, detritivorous, omnivorous, phytophagous, and the planktivorous functional group. A similarity analysis performed on the macrobenthic functional groups of the three zones indicates that the functional group distributions of non-hypoxic and hypoxic zones are not significantly different, whereas the functional group compositions of the Changjiang River estuary and the other two zones are rather different. The results of canonical correspondence analysis reveal that the distribution of macrobenthic functional groups is compounded by various environmental factors, of which dissolved inorganic nitrogen, salinity, and temperature exert a significant effect. Combining the results of previous studies, we speculate that macrobenthos are able to adapt to the occurrence of hypoxia by changing their body morphology, distribution location, and community structure. When the environmental conditions prevent the hypoxia from occurring, persisitent hypoxic zones can recover their marine microbenthic community.

Sulfate-reducing bacteria (SRB) are ubiquitous anaerobic microorganisms that play significant roles in the global biogeochemical cycle. Coastal wetlands, one of the major habitats of SRB, exhibit high sulfate-reducing activity and thus play significant roles in organic carbon remineralization, benthic geochemical action, and plant-microbe interactions. Recent studies have provided credible evidence that the functional rather than the taxonomic composition of microbes responds more closely to environmental factors. Therefore, in this study, functional gene prediction based on PacBio single molecular real-time sequencing of 16S rDNA was applied to determine the sulfate-reducing and organic substrate-decomposing activities of SRB in the rhizospheres of two typical coastal wetland plants in North and South China: Zostera japonica and Scirpus mariqueter. To this end, some physicochemical characteristics of the sediments as well as the phylogenetic structure, community composition, diversity, and proportions of several functional genes of the SRB in the two plant rhizospheres were analyzed. The Z. japonica meadow had a higher dissimilatory sulfate reduction capability than the S. mariqueter-comprising saltmarsh, owing to its larger proportion of SRB in the microbial community, larger proportions of functional genes involved in dissimilatory sulfate reduction, and the stronger ability of the SRB to degrade organic substrates completely. This study confirmed the feasibility of applying microbial community function prediction in research on the metabolic features of SRB, which will be helpful for gaining new knowledge of the biogeochemical and ecological roles of these bacteria in coastal wetlands.

The performance of photoelectrochemical (PEC) analysis system relies closely on the properties of the photoelectric electrodes. It is of great significance to integrate photoactive materials with flexible substrates to construct ultra-sensitive PEC sensors for practical application. This work reports a novel photoelectrode developed by immobilizing α-Fe

Temperature increase caused by thermal discharge from power plants promotes phytoplankton growth and frequent bloom in eutrophic subtropical waters, particularly in cold seasons. Suspension filter-feeding bivalves show size-selective grazing on phytoplankton. Thus, we hypothesized that algal bloom under thermal stimulation could be controlled and that phytoplankton community was structured by oyster farming. Here, ten cruises were conducted in two oyster farms (OFs) and control areas (CAs) adjacent to the Ninghai Power Plant in the upper section of Xiangshan Bay during 2009-2015. We found that thermal discharge induced severe winter algal blooms. Phytoplankton abundance and chlorophyll a (chla) were significantly lower (46.3% and 28.3%, respectively) in OF than in CA, indicating a high filtration efficiency by oysters and the associated biofouling assemblages. In addition, oyster farming significantly increased species richness (by 26.3%), Shannon-Wiener diversity (by 38.3%), and Pielou's evenness indices (by 28.8%) and reduced suspended solids (by 12.2%), total organic carbon (by 18.4%), dissolved inorganic nitrogen (by 1.5%), and phosphorus (by 3.7%). Furthermore, oyster farming considerably reduced (increased) micro-chla contribution (pheophytin/chla) by 34.8% (71.1%), suggesting a strong size-selective grazing on phytoplankton. Analysis of similarity revealed a significant difference in phytoplankton community composition between OF and CA. However, after the removal of culture rafts, all the abundance, chla, species diversity, dominant species, size structure, and community composition of phytoplankton showed no significant difference. Our study demonstrated that oyster farming effectively alleviated eutrophication and algal bloom and enhanced phytoplankton diversity, which provides guidance for aquaculture and ecological restoration in subtropical coastal eutrophic waters.

The impacts of fish cage culture and suspended oyster culture on macrobenthic communities were investigated in Xiangshan Bay, China, on a seasonal basis from January to October of 2015. Samples were collected from a fish cage farm, a suspended oyster farm, and two corresponding reference sites. Two-way ANOVA results showed that species richness, abundance, biomass, and Shannon-Wiener diversity differed significantly between the four different investigated areas, and different seasons as well. Cluster analysis showed that macrobenthic community composition in the fish and oyster culture areas significantly differed from that in the reference sites, respectively. Trophic structure of macrobenthos in the fish and oyster culture areas mostly clustered together owing to higher abundance and biomass of surface-deposit feeders and carnivores. The macrobenthic communities and feeding guilds correlated highly with environmental factors, such as bottom water chlorophyll a and nutrients, as well as sediment total organic carbon. Although integrated multi-trophic aquaculture is regarded as a suitable approach to coordinate desirable economic, social, and environmentally sustainable outcomes, coastal ecosystems may suffer from large-scale nutrient enrichment due to aquaculture and other human activities, which should not be considered in isolation.

Commercial marine organisms were collected from the coast of Xiangshan Bay to investigate the concentrations of eight heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) and evaluate the potential health risks. The results indicated considerable variations in the heavy metal concentrations among six species groups, of them mollusks (seasnail, benthic bivalve, and oyster) generally contained relative high levels of most metals, followed by crustaceans (crab and shrimp), by contrast, fish had low concentrations of all metals, except Hg. Three heavy metal groups were identified to interpret the accumulative characteristics in the marine organisms. Spatial distributions illustrated the geographical variations of heavy metal concentrations in the sampling areas. Moreover, maricultured organisms demonstrated lower heavy metal concentrations than did the wild. Health risks of most heavy metals exposed from marine organism consumption were safe, except for As which is associated with the high target cancer risk values.

The impact of suspended oyster farming on macrobenthic communities, and their recovery following oyster farm removal, are reported for Xiangshan Bay, China. Sampling was conducted in 2009, 2010, and 2015 to assess: 1) spatial pattern in macrobenthic community structure at progressively increasing distances from farm; 2) spatial and seasonal variability in macrobenthic community structure beneath two farms and a reference site; and 3) potential recovery of macrobenthic community 3 years after cessation of oyster farming. A site located at the edge of a farm had peaks in macrobenthos species richness, abundance, biomass, Shannon–Wiener diversity (H′), and Margalef richness (d). Macrobenthic communities beneath two farms differed significantly from those at a reference site. Significant differences in macrobenthic community structure between farms are attributed to differing hydrological and sedimentary characteristics. Macrobenthos species richness, abundance, H′, and d increased significantly 3 years after oyster farming ceased. The post-fallowing presence of Ampelisca sp., and increased abundances of Heteromastus filiformis and Scapharca kagoshimensis contributed most to differences in macrobenthic communities before and after farming ceased. We suggest that an assessment of the ecological carrying capacity of shellfish aquaculture in Xiangshan Bay is necessary to ensure sustainable, regional aquaculture development.

The performance of photoelectrochemical (PEC) analysis system relies closely on the properties of the photoelectric electrodes. It is of great significance to integrate photoactive materials with flexible substrates to construct ultra-sensitive PEC sensors for practical application. This work reports a novel photoelectrode developed by immobilizing α-Fe2O3 nanoparticles (NPs)/defect-rich carbon nitride (d-C3N4), an excellent Z-scheme heterojunction photoelectric material, onto three-dimensional (3D) flexible carbon fiber textile. Specifically, 3D hierarchical structure of flexible carbon fiber textile provides larger specific surface area and higher mechanical strength than traditional electrodes, resulting in more reaction sites and faster reaction kinetics to achieve signal amplification. Simultaneously, α-Fe2O3/d-C3N4 Z-scheme heterojunction exhibits enhanced light absorption capability and high redox ability, thus dramatically improving the PEC performance. This photoelectrode was used to construct a flexible PEC aptasensor for ultrasensitive detection of penbritin, demonstrating excellent performance in terms of wide linear range (0.5 pM–50 nM), low detection limit (0.0125 pM) and high stability. The design principle is applicable to the manufacture of other photoelectric sensing systems, which provides an avenue for the development of portable environmental analysis and field diagnostics equipment.

Concentrations of the heavy metals As, Cd, Cu, Hg, Pb, and Zn in various tissues of five marine fish species and one crab species collected from the middle coast of Zhejiang Province of China were investigated in this study. The results indicated considerable variation in heavy metal concentrations in different tissues and species. Elevated concentrations of most heavy metals were identified in fish gills and crab gills and hepatopancreas, with some differences by heavy metal type. In addition, carnivorous and benthivorous fish species generally contained relatively high concentrations of heavy metals due to feeding habits and habitats. Geographical variations of heavy metal concentrations in muscle may be attributable to species-dependent differences and terrigenous contamination. The potential health risk assessment suggested that exposure doses of most heavy metals were safe for human consumption, with the exception of As.

Eutrophication, mainly caused by the oversupply of nitrate (NO3−) and phosphate, has become a serious environmental problem in Xiangshan Bay (east China), but the sources of the nitrate are poorly understood. In this study, the estuarine distributions of dual stable isotopes (δ15N and δ18O) of NO3− measured in May 2012 were used in combination with concurrent measurements of salinity, pH, dissolved oxygen, and nutrients (nitrate, nitrite, ammonium, and phosphate) to investigate NO3− sources and the processes that control NO3− distributions within the bay. In the lower bay, high concentrations of NO3− (up to 60.6 μmol L−1), an N/P ratio of 52, and low values of nitrate δ15N (δ15NNO3 = 5.7‰–6.7‰) and δ18O (δ18ONO3 = 1.8‰–3.5‰) indicate that NO3− in this area was likely from the Changjiang and Qiantangjiang rivers as well as local nitrification-associated inputs. In the upper bay, constituent concentrations and high values of δ15NNO3 (up to 8.8‰) and δ18ONO3 (up to 6.8‰) suggest that NO3− distributions here were controlled mainly by the mixing of coastal and fresh waters, phytoplankton assimilation, and inputs of riverine NO3−, possibly derived from manure and sewage. Spatial variations of Δ(15,18), the nitrate δ15N-to-δ18O anomaly, is possibly resulted from the different water residence times across the bay, which could in turn lead to different degrees of nitrification or variable amounts of NO3− from atmospheric deposition.

Macrobenthos samples were collected from the Yellow and East China Seas in four seasons during 2011 to 2012. The seasonal distribution of macrobenthos and its relationship with environmental factors were analyzed. A total of 562 macrobenthic species were identified, with polychaetes and mollusks accounting for 67% of the total number of species. A similarity percentage (SIMPER) analysis showed that the dominant species were bivalve mollusks in the Yellow Sea and small-sized polychaetes in the East China Sea. A two-factor analysis of variance showed significant seasonal variations in species number, density and diversity index, and significant regional differences of biomass and density. Two-factor community similarity analysis also showed significant seasonal and regional differences in macrobenthic communities. Canonical correspondence analysis indicated that the main environmental factors affecting the macrobenthic communities were water depth, temperature, dissolved oxygen, and inorganic nitrogen. The results demonstrate significant regional differences and seasonal variations in macrobenthos in the two seas. Sediment properties and water mass characteristics are speculated to be the causes of regional differences.

Many coastal habitats are being substantially altered by non-indigenous plants (NIP). In the present study, intertidal macrobenthic communities of three habitats – a non-vegetated tidal flat (TF), a marsh with the smooth cordgrass Spartina alterniflora (SA) and a Kandelia candel mangrove forest (KC) – were examined during periods of ebb tide in February, May, August and November 2015 in Ximen Island Special Marine Protected Area, Zhejiang Province, China. S. alterniflora was introduced from North America in 1979 and invaded Ximen Island spontaneously. K. candel was a direct, artificial introduction in 1957 from Fujian, China. A total of 48 species of macrobenthos were collected from Ximen Island. The average density of macrobenthos in TF, SA and KC was 1365, 1398 and 669 ind./m2, respectively, and the average biomass of macrobenthos in TF, SA and KC was 144.13, 43.00 and 138.70 g/m2, respectively. There were no significant differences among the three habitats on density and biomass of macrobenthos, with the exception of density in spring and biomass in autumn. Diversity indices of macrobenthos did not exhibit significant differences among the three habitats, except for Margalef’s richness index (d) in KC. However, Results of one-way analysis of similarity (ANOSIM) revealed significant differences in macrobenthic community structure among the three habitats and four seasons. It was concluded that, although few significant differences were observed in the density, biomass and diversity indices of macrobenthos among habitats, there were significant changes in the macrobenthic communities’ structure after the introduction of S. alterniflora and K. candel. Therefore, when we use plants as ecological engineering materials, we need to take into account all of their potential ecological consequences.

Centropages abdominalis Sato, a common cold-water copepod that is distributed widely in the coastal waters of the North Pacific, appears seasonally in winter and spring as the key zooplankton in the Xiangshan Bay, a typical subtropical semi-closed bay in China. Here, we hypothesised that C. abdominalis could produce diapause eggs as an over-summering strategy in late spring as a response to the increasing temperature and day length. We conducted 11 cruises and in situ reproduction experiments from April 2017 to June 2018 to reveal the variation in the reproductive strategies of C. abdominalis and the related environmental factors. The results showed that the revival of diapause eggs in the inner and middle part of the Xiangshan Bay should contribute to the initial population recruitment in early winter. Sustaining subitaneous egg production supported the instantaneous population recruitment in later winter and spring, and diapause eggs were mainly produced at the upper thermal distribution of C. abdominalis (16.12–21.32 °C) to over-summer in late spring. Temperature was the essential environmental factor that affected the shift in reproductive strategy for C. abdominalis, with an optimum temperature of 19.51 °C for diapause egg production and 11.63 °C for subitaneous one in the Xiangshan Bay. Furthermore, the long-day photoperiod possibly acted as a seasonal change signal for C. abdominalis to produce diapause eggs in late spring in the Xiangshan Bay. The timing of diapause egg production for C. abdominalis could be earlier in lower-latitude waters with shorter day length, as an acclimatisation to warmer habitats. Besides, salinity and Chl a concentration had less effects on diapause eggs production of C. abdominalis in this case. Confronted with ocean warming, the diapause egg period of cold-water copepod (like C. abdominalis) would be prolongated, leading to a reduced population appearance period, especially in lower-latitude waters.

To evaluate the effects of different anthropogenic activities on zooplankton and the pelagic ecosystem, we conducted seasonal cruises in 2010 to assess spatial heterogeneity among the mesozooplankton communities of Xiangshan Bay, a subtropical semi-enclosed bay in China. The evaluation included five different areas: a kelp farm, an oyster farm, a fish farm, the thermal discharge area of a power plant, and an artificial reef, and we aimed to identify whether anthropogenic activities dominated spatial variation in the mesozooplankton communities. The results demonstrated clear spatial heterogeneity among the mesozooplankton communities of the studied areas, dominantly driven by natural hydrographic properties, except in the area near the thermal discharge outlet of the power station. In the outlet area, thermal shock caused by the discharge influenced the mesozooplankton community by decreasing abundance and biomass throughout the four seasons, even causing a shift in the dominant species near the outlet during summer fromAcartia pacificato eurythermal and warm water taxa. Unique features of the mesozooplankton community in the oyster farm may be due to the combined effects of oyster culture and the natural environment in the branch harbour. However, kelp and fish culture, and the construction of an artificial reef did not exert any obvious influence on the mesozooplankton communities up to 2010, probably because of the small scale of the aquaculture and a time lag in the rehabilitation effects of the artificial reef. Thus, our results suggested that the dominant factors influencing spatial variations of mesozooplankton communities in Xiangshan Bay were still the natural hydrographic properties, but the thermal discharge was an anthropogenic activity that changed the pelagic ecosystem, and should be supervised.

Coastal eutrophication and its associated harmful algal blooms have emerged as one of the most severe environmental problems worldwide. Seaweed cultivation has been widely encouraged to control eutrophication and algal blooms. Among them, cultivated kelp (Saccharina japonica) dominates primarily by production and area. However, the responses of water quality and phytoplankton community to kelp farming remain unclear. Here, thirteen cruises were conducted in the kelp farms and control areas in the turbid, highly eutrophic Xiangshan Bay of the East China Sea from 2008 to 2015. Results indicated that kelp cultivation slightly increased dissolved oxygen and pH, but reduced dissolved inorganic nitrogen and phosphorus. We estimated that kelp harvesting would remove 297 t of nitrogen and 42 t of phosphorus from this bay annually. Because of decreased flow velocity, turbulence, and sediment resuspension, kelp farming greatly reduced suspended solids and increased transparency, resulting in increases in phytoplankton chlorophyll a and abundance. Additionally, kelp farming appreciably increased phytoplankton species number, Marglef richness, and Shannon–Wiener diversity indices by 51.6%, 40.1%, and 13.1%, respectively. Analysis of similarity and similarity percentages demonstrated that phytoplankton community composition differed significantly between the farm and control area, which was mostly attributed to long-chained diatoms and single-celled dinoflagellates. However, after the kelp harvesting, all measurements of water quality and phytoplankton biomass, diversity, and community composition exhibited no significant difference. Our study highlights that kelp cultivation alleviates eutrophication and acidification and enhances phytoplankton diversity, thus providing guidance for macroalgal aquaculture and remediation in eutrophic waters.

Benthic macrofaunal communities along an estuarine gradient of a macrotidal estuary of the Jiaojiang River, China were analyzed to reveal spatial variations in those communities and their relationships with environmental variables. Benthic macrofauna were collected from 15 sampling stations in May and October 2010. Polychaetes and Mollusks are the dominant taxonomic groups. The species richness, density and Shannon diversity index generally tended to increase as one moved away from shore toward the outer stations of the estuary. Cluster analysis and multidimensional scaling ordinations indicated the presence of three distinct zones of macrofaunal communities in the estuary. Multivariate analyses showed a strong relationship exists between the macrofaunal communities and the environmental parameters in the Jiaojiang River estuary. Aside from salinity, dissolved inorganic nitrogen and soluble reactive phosphate contents were also the major factor affecting the structure of the macrofaunal communities. The results demonstrated the important effects of nutrient-load on the distributional patterns of benthic macrofaunal communities in nutrient-rich estuaries.

To assess the effects of hypoxia, macrobenthic communities along an estuarine gradient of the Changjiang estuary and adjacent continental shelf were analyzed. This revealed spatial variations in the communities and relationships with environmental variables during periods of reduced dissolved oxygen (DO) concentration in summer. Statistical analyses revealed significant differences in macrobenthic community composition among the three zones: estuarine zone (EZ), mildly hypoxic zone (MHZ) in the continental shelf, and normoxic zone (NZ) in the continental shelf (Global R =0.206, P =0.002). Pairwise tests showed that the macrobenthic community composition of the EZ was significantly different from the MHZ (pairwise test R =0.305, P =0.001) and the NZ (pairwise test R =0.259, P =0.001). There was no significant difference in macrobenthic communities between the MHZ and the NZ (pairwise test R =0.062, P =0.114). The taxa included small and typically opportunistic polychaetes, which made the greatest contribution to the dissimilarity between the zones. The effects of mild hypoxia on the macrobenthic communities are a result not only of reduced DO concentration but also of differences in environmental variables such as temperature, salinity, and nutrient concentrations caused by stratification.

Plant invasions in coastal ecosystems may substantially alter benthic community composition and food web structure. We combined analyses of stable isotopes and fatty acids (FA) to examine the effects of two non-indigenous plants (Spartina alterniflora and Kandelia candel) on the food sources of three deposit feeders (Assiminea brevicula, Cerithidea cingulata and Uca arcuata) and a carnivorous opportunistic predator (Periophthalmus modestus) in Yueqing Bay, China. A wide range of differences was found in δ13C and δ15N among the macrobenthos. The deposit feeders in K. candel mangrove forest (KC) were markedly more 13C-depleted than those in S. alterniflora marsh (SA) and unvegetated tidal flat (TF), unlike the carnivorous feeder. PERMANOVA showed that FA composition significantly differed among the macrobenthos. Diatom FA markers were higher in tissues of the deposit feeders than in the carnivorous feeder, and slightly lower in macrobenthos from the KC and SA habitats as compared with the TF. In contrast, vascular plant FA markers of macrobenthos were higher in the KC and SA than in the TF, indicating the contribution of mangrove and Spartina detritus to the consumers. The findings show that the food sources of macrobenthos were markedly affected by non-indigenous plants, through the addition of organic detritus derived from vascular plants in the diets together with a decreased contribution of diatoms, although the impacts may differ among different functional feeding groups of macrobenthos.

Commercial marine fish, crustacean, and mollusc samples were collected from Sanmen Bay and its adjacent areas to investigate the accumulation of heavy metals in various species of marine organisms and evaluate the potential health risk for local consumers. The results indicated significant variations in metal contents among species. The highest concentrations of studied metals were found in molluscs, followed by crustaceans and fish. The first metal group of arsenic (As), cadmium, copper, and zinc were associated by their relatively high concentrations in the tissues of marine organisms, whereas chromium, mercury, and lead were identified the other group with low concentrations. Human health risk evaluation indicated that the exposure doses of most elements for coastal people were safe, except for As, which scored a high total target hazard quotient and target cancer risk value. Potential health risk of heavy metal exposure from seafood consumption should not be ignored.

The distributions of N utilizing bacteria (denitrifying bacteria and ammonifying bacteria), P utilizing bacteria (organic phosphobacteria and inorganic phosphobacteria) and heterotrophic bacteria in the Changjiang Estuary, and the roles of main environmental factors in distributing bacteria, are explored with observations from two cruises in June and August 2006. Comparisons between the two important periods of initial hypoxia phase (June) and developed hypoxia phase (August) show differences in both bacterial distributions and the associated main environmental factors. First, the primary group of ammonifying bacteria has larger magnitude with spatial maximum value in the hypoxic stations related to sediment in August. The phosphobacterial abundance and detection rates in August are much lower than those in June, but the denitrifying bacterial abundance becomes greater in August. However, the difference of heterotrophic bacterial abundance between June and August is not obvious. Second, main environmental factors influencing bacteria vary from initial hypoxia phase to developed hypoxia phase. Two parameters (salinity and NO3−) in surface water and five environmental parameters (pH, salinity, PO43−, NO3− and temperature) in bottom water and surface sediment play major roles in the bacterial abundance in June, while different parameter combinations (salinity and PO4−) in surface water and different parameter combinations (DO, DOC, NO3−, PO43− and pH) in bottom water and surface sediment play major roles in August. Moreover, the bottom bacteria distributions in area south of 31°N are related to the position of the Taiwan Warm Current in June. The bacterial abundance and distribution may respond to the environmental change in the hypoxia processes of initial phase and developed phase. During the hypoxia processes, the whole structure of bacterial functional groups probably turns to different states, causing the recycling of nutrient regeneration and aggravating hypoxia regionally.

With the rapid development of economy and increase of population in the drainage areas, the nutrient loading has increased dramatically in the Changjiang estuary and adjacent coastal waters. To properly assess the impact of nutrient enrichment on phytoplankton community, seasonal microcosm experiments were conducted during August 2010–July 2011 in the coastal waters of Zhejiang Province. The results of the present study indicated that the chl a concentration, cell abundance, diversity indices, species composition and community succession of the phytoplankton varied significantly with different N/P ratios and seasons. Higher growth was observed in the 64:1 (spring), 32:1 (summer), 16:1 (autumn) and 128:1, 256:1 (winter) treatments, respectively. The values of Shannon-Wiener index (H′) and Pielou evenness index (J) were lower in the 8:1 and 16:1 treatments in autumn test, while H′ value was higher in the 128:1 and 8:1 treatments in winter test. A definite community succession order from diatoms to dinoflagellates was observed in the autumn and winter tests, while the diatoms dominated the community throughout the culture in the spring and summer tests.

Four cruise surveys were carried out in summer, winter, spring, and autumn from 2006 to 2007 to evaluate the seasonal distribution of macrobenthos in the Yangtze River estuary and its adjacent waters. A total of 59 sites were sampled and divided into three areas (estuary, inshore, and offshore areas). In all, 335 taxa were collected with polychaetes and mollusks being the dominant groups. Two-way ANOVA revealed significant differences among the numbers of species, densities, and biomasses in the areas. However, several differences were found among seasons. SIMPER analysis showed that the dominant species of macrobenthos varied in different areas, and the inshore area was the most complex of the three. The abundance/biomass comparison (ABC) curve of macrobenthos in the inshore area showed apparent rises and falls, which are characteristic of disturbance to macrobenthos. Canonical correspondence analysis showed that echinoids were closely related to the presence of silicates and temperature, whereas polychaetes were closely related to depth and temperature.

There is concern about the impact of expanding coastal aquaculture activity, particu- larly in China, with the biggest aquaculture industry in the world. We conducted 3 cruises to the oyster, kelp and fish farms of the Xiangshan Bay during the winterspring transition (02/2009), winter (01/2010) and spring (04/2010). Our aim was to explore the spatial heterogeneity of the phytoplankton community in different culture habitats and evaluate the effects of mariculture on phytoplankton. Different culture types formed unique small-scale habitats that exhibited various en vironmental gradients and forms of phytoplankton community patchiness. Both environmental (i.e. temperature, salinity, transparency, suspended solids, dissolved oxygen, pH, dissolved inor- ganic nitrogen, PO4-P, SiO3-Si, N/P, and total organic carbon) and phytoplankton (i.e. cell density, chlorophyll a, species richness, main dominant species, and community structure) parameters were significantly different among the 3 culture habitats. Canonical correspondence analysis showed that phytoplankton distribution was mainly influenced by temperature, nutrition, salinity and suspended solids. Oyster and kelp farming effectively alleviated coastal eutrophication and also increased species richness and diversity; fish farming did not. Temperature elevation caused by the thermal discharge from a power plant induced phytoplankton blooms during the winter and winterspring transition. Nevertheless, the filtering effect of suspended oysters dramatically reduced microalgal biomass. The kelp and oyster farms were much better than the fish farm in terms of water quality, phytoplankton composition, and habitat restoration function. These results provide guidelines for future policy-making in aquaculture as well as eutrophication control and management.

Recently, the impact of petroleum pollution on marine plankton has been complemented by a great concern. This review summarizes the reports about toxic effects of oil water accommodated fraction (WAF) on marine phytoplankton, zooplankton and early life stage of animal. For the oil WAF, toxicants are mainly composed of the aromatic hydrocarbons, such as the benzene hydrocarbons and polycyclic aromatic hydrocarbons (PAHs) with 2–5 rings. The oil WAF, especially the PAHs, can be accumulated in plankton due to their great lipophilic abilities, and thus elicites various deleterious effects. Toxicological tests show that marine plankton is very sensitive to the petroleum WAF, as the order of median effective/lethal concentration is merely μg/L or mg/L. There are species and developmental stages differences of plankton tolerance to petroleum WAF, and the toxicity of different oil WAF is various. Generally, its toxicity enhances with increasing carbonic chain length and benzene ring number. Many studies on the acute and sub-acute toxic effects of oil WAF have been done, however few researches on its chronic toxic effects has been carried out till now. Besides, most reports focused on the levels from molecule to individual, though very little work of petroleum toxic effects has ever been performed on the marine plankton population or community levels. Therefore, it is necessary to continue these studies in future.

To understand the distribution and seasonal changes of macrobenthos in Zhoushan sea area, two cruise surveys were carried out in the summer and winter. A total of 219 species were recorded in the sampling sediment during the two seasons. Two-way ANOVA results showed that the differences were not significant among sections in all the community parameters (species number, biomass and density) and species diversity (Shannon-Weiner index and Pielou's evenness index), but significant between seasons in species number, density and Shannon-Weiner index. This might be influenced by two factors as follows: (1) water currents' differences between seasons; (2) considerable differences in temperature between seasons.

The major objective of this study is to understand the upper thermal limits and potential impact of temperature elevation on copepods caused by coastal power plants. Laboratory experiments were designed to evaluate the upper incipient lethal temperature (UILT) and critical thermal maximum (CTMax) of eight coastal copepod species collected from a subtropical bay in spring and summer. The 48h-UILT of copepods acclimatized at 16.0, 20.0, 28.0 °C were 26.4–29.1, 27.3–30.1, 32.9–36.9 °C, respectively. And the CTMax of copepods acclimatized at 28.0 °C was 35.80–41.03 °C. The UILT of copepods increased significantly with rising acclimatization temperatures, but the difference values between UILT and acclimatization temperatures decreased, which indicated that the seawater temperature elevation induced the growing mortalities of copepods with increasing natural seawater temperatures from the thermal addition of power plants. The results also showed that estuarine copepods had more tolerances to the thermal stress than those from other more stable marine environments. As to the calanoid copepod species, there was a significant negative correlation between the CTMax and body length ( p

The tolerance of marine copepods to short-term thermal stress was measured by the median lethal temperature (LT50) tests in laboratory. Experiments on LT50 of copepods from different acclimation and acclimatization conditions collected from the Yueqing Bay were carried out under heat exposure for 15, 30 and 45 min. The LT50 of copepods decreased with increasing exposure time but increased with rising acclimation and acclimatization temperatures. However, the differences in copepod LT50 decreased with rising acclimatization temperatures, which suggested that entrained copepod mortality increased with raised water temperature due to the acute thermal stress of coastal power stations. Results also revealed that the thermal tolerance of Labidocera euchaeta was much higher than that of Calanus sinicus in spring. The thermal tolerances of different copepod species in summer were in the order, Pseudodiaptomus marinus, Acartia spinicauda, Acartia pacifica and L. euchaeta.