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1.
Environ Int ; 171: 107699, 2023 01.
Article in English | MEDLINE | ID: mdl-36529082

ABSTRACT

The rising demand of ecosystem services, due to the increasing human population in coastal areas, and the subsequent need to secure healthy and sustainable seas constitute a major challenge for marine ecosystems management. In addition, global anthropogenic changes have transformed the marine realm, thereby challenging ecosystem health and the services necessary for human welfare. These changes have opened ecological space for opportunistic organisms, such as jellyfish, resulting in ecosystem-wide and economic implications that threaten marine ecosystem services. Here, we used a comprehensive dataset of jellyfish hazards over the period 1960-2019 to track their dynamics and implications for human welfare. Our results revealed that their large-scale patterns have been mainly enhanced in human-perturbed Large Marine Ecosystems, although the contribution of jellyfish Class to hazard type changed across ocean regions. The long-term variability of these events suggests that their temporal patterns mirror the pace of ocean warming and ocean health degradation nurtured by global anthropogenic changes in recent decades. These results warn of the wide socioecological risks of jellyfish hazards, and their implications advocate for transboundary, regional cooperation to develop effective ecosystem-based management actions. Failure to integrate jellyfish into ocean surveys will compromise coastal ecosystem services governance. Classification: Social Sciences/Sustainability Science, Biological Sciences/Ecology.


Subject(s)
Ecosystem , Humans , Oceans and Seas
2.
PLoS One ; 17(11): e0278288, 2022.
Article in English | MEDLINE | ID: mdl-36449479

ABSTRACT

During an investigation program of faunal diversity in the shallow reef zone of the active volcanic island off northeastern Taiwan in July and September 2020, numerous individuals of the starfish Echinaster luzonicus (Gray, 1840) were found, and some individuals were found with associated symbionts. Starfish sampling in the 150-m coral reef zone was undertaken at a depth of 8 m through scuba diving. For each type of potential macrosymbiont, both the dorsal and ventral sides were carefully examined. The prevalence of macrosymbionts on the starfish E. luzonicus was recorded. The most common symbiotic organism on E. luzonicus was the ectoparasitic snail Melanella martinii (A. Adams in Sowerby, 1854), followed by the pontoniine shrimp Zenopontonia soror (Nobili, 1904) and the rare polychaete scaleworm Asterophilia carlae Hanley, 1989. The prevalence ratio with host E. luzonicus was low and varied by 8.62% and 4.35%, 6.03% and 0%, and 0.86% and 0.72% in July and September 2020 for M. martinii, Z. soror, and A. carlae, respectively. The present study is the first to discover the scaleworm A. carlae as a macrosymbiont of the tropical starfish E. luzonicus, with a widespread distribution, off Taiwan's northeastern coast, an area influenced by the Kuroshio Current.


Subject(s)
Diving , Starfish , Animals , Pacific Islands , Coral Reefs , Seafood
3.
Biology (Basel) ; 11(9)2022 Sep 16.
Article in English | MEDLINE | ID: mdl-36138836

ABSTRACT

During this research, the average surface temperature, salinity, dissolved oxygen, and pH were 24.65 ± 1.53 (°C), 34.21 ± 0.07 (PSU), 6.85 ± 0.18 (mg/L), and 8.36 ± 0.03, respectively. Based on these environmental parameters, stations were arranged into three groups. Group A represents stations located around Keelung Island with the relative highest average dissolved oxygen, lowest average temperature, and pH values. Instead, the lowest average dissolved oxygen and highest average temperature, salinity, and pH values were recorded at the offshore stations. Keelung Island area was charged by cold water masses, which were driven by the Northeast monsoon, and stations in group C were affected by the Kuroshio Current. Kueishan Island area was mainly affected by mixed water masses resulting from the Kuroshio intrusion and monsoon-derived cold water. In this study, a total of 108 copepod species were identified, with an average abundance of 774.24 ± 289.42 (inds. m-3). Most species belong to the orders Calanoida and Poecilostomatoida, with an average relative abundance (RA) of 62.96% and 30.56%, respectively. Calanoid copepodites were the most dominant group, with a RA of 28.06%. This was followed by Paracalanus aculeatus, with a RA of 18.44%. The RA of Clausocalanus furcatus and Canthocalanus pauper was 4.80% and 3.59%, respectively. The dominant species P. aculeatus, C. pauper, Paracalanus parvus, and Temora turbinata were positively correlated with dissolved oxygen and negatively correlated with temperature in the surface waters. pH showed a negative correlation with P. parvus and T. turbinata, while the temperature was negatively correlated with these two dominant species. Indicator species were selected by an indicator value higher than 50%. Temora turbinata, Calanopia elliptica, C. pauper, Euchaeta concinna, Temora discaudata, Acartia pacifica, Macrosetella gracilis, Corycaeus speciosus, and P. parvus were considered as monsoonal cold water indicator species in Group A. Indicator copepod species for the Kuroshio Current were Farranula concinna, Copilia mirabilis, Candacia aethiopica, Corycaeus agilis, Farranula gibbula and Acrocalanus monachus in the study area. Paracandacia truncata, Oncaea clevei, P. aculeatus, and Centropages furcatus were considered suitable indicators for mixed water masses.

4.
Proc Natl Acad Sci U S A ; 117(36): 22281-22292, 2020 09 08.
Article in English | MEDLINE | ID: mdl-32843340

ABSTRACT

Seawater Mg:Ca and Sr:Ca ratios are biogeochemical parameters reflecting the Earth-ocean-atmosphere dynamic exchange of elements. The ratios' dependence on the environment and organisms' biology facilitates their application in marine sciences. Here, we present a measured single-laboratory dataset, combined with previous data, to test the assumption of limited seawater Mg:Ca and Sr:Ca variability across marine environments globally. High variability was found in open-ocean upwelling and polar regions, shelves/neritic and river-influenced areas, where seawater Mg:Ca and Sr:Ca ratios range from ∼4.40 to 6.40 mmol:mol and ∼6.95 to 9.80 mmol:mol, respectively. Open-ocean seawater Mg:Ca is semiconservative (∼4.90 to 5.30 mol:mol), while Sr:Ca is more variable and nonconservative (∼7.70 to 8.80 mmol:mol); both ratios are nonconservative in coastal seas. Further, the Ca, Mg, and Sr elemental fluxes are connected to large total alkalinity deviations from International Association for the Physical Sciences of the Oceans (IAPSO) standard values. Because there is significant modern seawater Mg:Ca and Sr:Ca ratios variability across marine environments we cannot absolutely assume that fossil archives using taxa-specific proxies reflect true global seawater chemistry but rather taxa- and process-specific ecosystem variations, reflecting regional conditions. This variability could reconcile secular seawater Mg:Ca and Sr:Ca ratio reconstructions using different taxa and techniques by assuming an error of 1 to 1.50 mol:mol, and 1 to 1.90 mmol:mol, respectively. The modern ratios' variability is similar to the reconstructed rise over 20 Ma (Neogene Period), nurturing the question of seminonconservative behavior of Ca, Mg, and Sr over modern Earth geological history with an overlooked environmental effect.

5.
PLoS One ; 15(3): e0230742, 2020.
Article in English | MEDLINE | ID: mdl-32214356

ABSTRACT

The sulphur-rich and acidic vent waters of a shallow hydrothermal vent field next to Kueishan Island in Taiwan provide a specific and generally toxic environment. Among only a few aquatic organisms able to survive there, the grapsoid crab Xenograpsus testudinatus is the dominant species with a high population density in the vent area. Here we study the gender-specific distribution, morphological traits, and relationship of wet weight vs. carapace width of this crab. A total of 1120 individuals including 831 male and 289 female (included 15 ovigerous) were examined during August and September in 2011 and May and September in 2012. Except in August 2011, there are no significant differences in the distribution of X. testudinatus in the hydrothermal vent area from the vent spout during most months. Among crabs, the weight of male (6.87 ± 2.90 g) was significantly heavier than that of females (4.17 ± 1.25 g) (p < 0.001, Student's t-test). As for the wet weight of crabs, significant differences were noted in both the length of chela and the width of carapace between males and females. Sexual dimorphism of X. testudinatus is evident in three morphological traits. Pearson's correlation showed a significant and positive correlation (p < 0.001) of wet weight, width of carapace and length of chela of the two sexes. Ovigerous crabs (shortest carapace width: 1.93 cm) were present in the specimen collected from August 2011 and May 2012. The ovigerous crabs were not found in the samples collected from September in both years 2011 and 2012, indicating that reproduction may have ceased during the period of sampling. The present results suggested that the reproductive period of X. testudinatus was before September. The distribution pattern and sexual dimorphism of X. testudinatus provided a better understanding of the idiobiology of this dominant metazoan in the hydrothermal vent area.


Subject(s)
Brachyura/physiology , Hydrothermal Vents , Islands , Sex Characteristics , Animals , Body Size , Brachyura/anatomy & histology , Breeding , Female , Male , Seasons , Taiwan
6.
Sci Rep ; 9(1): 18572, 2019 12 09.
Article in English | MEDLINE | ID: mdl-31819110

ABSTRACT

The white spot syndrome virus (WSSV) causes mass mortalities in the aquaculture of shrimps worldwide. The mud shrimp Austinogebia edulis (Ngoc-Ho & Chan, 1992) is an economically important sea food item occurring along the west coast of Taiwan. While the population of A. edulis began to decrease with some fluctuations in the last decade, the current study aims to discover the causes for such sporadic population decline. This study explores the effects of microbial pathogens and innate immunity on the populations of A. edulis. Here, we report firstly about WSSV infection of A. edulis from the coastal zone of western Taiwan which is one of the possible causes of population decrease of A. edulis in Shengang. However, WSSV infection is not the only reason for its population decrease because a similar infection rate of WSSV was found in Wangong. Population changes may be related to both environmental pollution stress and WSSV. Both factors likely caused a massive reduction of hemocytes and an abnormal increase of phenoloxidase and superoxide dismutase activity, which were spectrophotometrically measured. Since there is no effective way to treat WSSV infection, improving the coastal environment appears the most effective way to increase the population size of feral shrimps.


Subject(s)
Decapoda/virology , Virus Diseases/veterinary , White spot syndrome virus 1/isolation & purification , Animals , Aquaculture , Hemocytes/virology , Immunity, Innate , Microscopy, Electron, Transmission , Monophenol Monooxygenase/metabolism , Superoxide Dismutase/metabolism , Taiwan , Virus Diseases/diagnosis
7.
Sci Rep ; 9(1): 16926, 2019 11 15.
Article in English | MEDLINE | ID: mdl-31729442

ABSTRACT

Shallow hydrothermal vents are of pivotal relevance for ocean biogeochemical cycles, including seawater dissolved heavy metals and trace elements as well as the carbonate system balance. The Kueishan Tao (KST) stratovolcano off Taiwan is associated with numerous hydrothermal vents emitting warm sulfur-rich fluids at so-called White Vents (WV) and Yellow Vent (YV) that impact the surrounding seawater masses and habitats. The morphological and biogeochemical consequences caused by a M5.8 earthquake and a C5 typhoon ("Nepartak") hitting KST (12th May, and 2nd-10th July, 2016) were studied within a 10-year time series (2009-2018) combining aerial drone imagery, technical diving, and hydrographic surveys. The catastrophic disturbances triggered landslides that reshaped the shoreline, burying the seabed and, as a consequence, native sulfur accretions that were abundant on the seafloor disappeared. A significant reduction in venting activity and fluid flow was observed at the high-temperature YV. Dissolved Inorganic Carbon (DIC) maxima in surrounding seawater reached 3000-5000 µmol kg-1, and Total Alkalinity (TA) drawdowns were below 1500-1000 µmol kg-1 lasting for one year. A strong decrease and, in some cases, depletion of dissolved elements (Cd, Ba, Tl, Pb, Fe, Cu, As) including Mg and Cl in seawater from shallow depths to the open ocean followed the disturbance, with a recovery of Mg and Cl to pre-disturbance concentrations in 2018. The WV and YV benthic megafauna exhibited mixed responses in their skeleton Mg:Ca and Sr:Ca ratios, not always following directions of seawater chemical changes. Over 70% of the organisms increased skeleton Mg:Ca ratio during rising DIC (higher CO2) despite decreasing seawater Mg:Ca ratios showing a high level of resilience. KST benthic organisms have historically co-existed with such events providing them ecological advantages under extreme conditions. The sudden and catastrophic changes observed at the KST site profoundly reshaped biogeochemical processes in shallow and offshore waters for one year, but they remained transient in nature, with a possible recovery of the system within two years.

8.
PLoS One ; 14(7): e0219815, 2019.
Article in English | MEDLINE | ID: mdl-31329626

ABSTRACT

The present study recorded the population of the goby fish (Perciformes: Gobiidae), Eutaeniichthys cf. gilli Jordan & Snyder, 1901, from the tunnel burrowed by the mud shrimp Austinogebia edulis Ngo-Ho and Chan, 1992 in a mudflat in Shengang and Wangong of Changhua County, western Taiwan. This finding is not only a new record of the genus in Taiwan, it is also the first record of this species in a mudflat near an industrial park. In total, 56 individuals of E. cf. gilli were collected from June 2016 to September 2018. Morphological traits of males and females were measured. The resin casting method trapped bodies of E. cf. gilli that were present in the tunnel burrow and proved that the fish inhabits burrows of the mud shrimp A. edulis. In addition, a species of snapping shrimp was also found in the same tunnel. Symbiotic interaction may occur between E. cf. gilli, A. eduli and the snapping shrimp. The China Coastal Current (CCC) runs along the coastlines of Japan, Korea, China, and reaches western Taiwan during the northeast monsoon period. The CCC, therefore, might play an important role in the biogeographic distribution of E. cf. gilli in the western Pacific Ocean. Since E. cf. gilli is listed in the Red List as an endangered species of Japan for many years, Taiwan waters may provide a refuge for this fish species warranting a broader investigation. Since Taiwan is some distance away from the previously recorded locations in Japan, Korea, the Yellow Sea, and the Bohai Sea, a phylogenic analysis is warranted for population and species differentiation in the future.


Subject(s)
Decapoda/physiology , Perciformes/physiology , Symbiosis , Animals , Behavior, Animal , Biodiversity
9.
PLoS One ; 14(7): e0219319, 2019.
Article in English | MEDLINE | ID: mdl-31295285

ABSTRACT

Zooplankton plays a pivotal role in linking primary production to higher level consumers in the food webs of marine ecosystems. The distribution of zooplankton is affected by general water conditions, monsoons, currents, and spatial and temporal factors. In the Arctic Ocean, the sea surface is naturally covered with ice. Under ice, water masses interplay to create complex environments that facilitate the transport and distribution of zooplankton, thus altering community structures at geospatial and vertical scales. The present study investigated the species composition and copepod community structures by using geospatial and multiple depth scales, and using multivariate analyses to evaluate the relation of sampling stations and layers. During July-August 2010, zooplankton samples were collected and the temperature and salinity of seawater measured from three stations in the Canada Basin and two stations in the Makarov Basin of the Arctic Ocean (maximum distance of approximately 1400 km). A total of 55 copepod species (including 25 species that were solely identified to the generic level) and 7 taxa of copepodites, altogether belonging to 28 genera, 11 families, and 2 orders were identified, and significant differences were detected in copepod community structures among sampling strata and at geospatial scales. Numerically, Calanus hyperboreus, Calanus copepodite, Calanoida copepodite, Calanus glacialis, and Metridia longa were the most dominant species and taxa. At the local scale, copepod compositions responded differently at each of the sampling stations. At the geospatial scale, the distance between stations MS03 and ICE explained variations in the pattern of dominant species and of copepod community richness. Our study demonstrated varied spatial distribution which indicates that (1) the abundance of copepods at 0-200 m was significantly higher than at other strata, (2) vertical strata affected the distribution of copepod communities, and (3) the interplay of North Pacific and Atlantic waters shaping the copepod assemblage structure at geospatial scales in the Arctic Ocean. The results of our research provide base data for Arctic zooplankton biodiversity and biogeographic distribution.


Subject(s)
Copepoda/physiology , Ecosystem , Zooplankton/physiology , Animals , Arctic Regions/epidemiology , Biodiversity , Canada/epidemiology , Food Chain , Oceans and Seas/epidemiology , Salinity , Seasons , Seawater , Temperature
10.
Environ Sci Pollut Res Int ; 26(8): 7752-7762, 2019 Mar.
Article in English | MEDLINE | ID: mdl-30673948

ABSTRACT

The trace metal cadmium (Cd) is a toxic pollutant known to induce oxidative stress and other sublethal to lethal effects on aquatic organisms. We exposed the marine mud shrimp Austinogebia edulis to Cd concentrations of 0, 0.5, and 5 mg/kg for up to 4 days (24, 48, 72, 96 h). We studied the activity of antioxidant enzymes in the hepatopancreas, gill, and muscle of A. edulis. Antioxidant enzymes (SOD, CAT, and GPx) decreased with increasing Cd concentration and extended exposure time in these three organs of the mud shrimp A. edulis. Increasing Cd concentration led to an increase in ROS and resulted ultimately in membrane lipid peroxidation at higher Cd concentrations. Significant damage of the hepatopancreas of A. edulis was noticed at higher concentrations of Cd, showing damages like the disappearance of epithelial cell boundaries, detachment of cells from the basal lamina, cellular swelling, necrosis, and reduction of glycogen. In conclusion, Cd caused oxidative damage by reducing the activities of antioxidant enzymes and by damaging the tissue structure in major organs of the mud shrimp A. edulis.


Subject(s)
Cadmium/toxicity , Water Pollutants, Chemical/toxicity , Animals , Antioxidants , Cadmium/analysis , Decapoda/physiology , Gills , Hepatopancreas , Necrosis , Oxidation-Reduction , Oxidative Stress , Superoxide Dismutase , Toxicity Tests , Trace Elements
11.
Mar Pollut Bull ; 136: 114-124, 2018 Nov.
Article in English | MEDLINE | ID: mdl-30509792

ABSTRACT

The environmental impact caused by thermal discharge waters of power plants is of global concern since thermal discharge directly affects the environmental situation near power plants. The present study used the vital stain neutral red to identify live and dead zooplankton collected from stations at the intake and the outlet of two nuclear power plants (NPPs). Significantly higher mortalities occurred at the outlet station than at the intake station (p < 0.01) at both NPPs. The mortalities of most zooplankton taxa and all zooplankton assemblages were significantly positive correlated to differences of water temperature (ΔT) at NPP I (p < 0.05), whereas it was not significantly positive correlated with ΔT at NPP II (p > 0.05). The weight of organic matter of zooplankton fragments was higher at the outlet station than at the intake station at both NPPs, indicating the physical damage of zooplankton when passing the cooling system.


Subject(s)
Environmental Monitoring/methods , Nuclear Power Plants , Water Pollution , Zooplankton/growth & development , Animals , Body Weight , Neutral Red , Staining and Labeling , Taiwan , Temperature , Water Pollution/adverse effects , Water Pollution/analysis
12.
PLoS One ; 13(5): e0197382, 2018.
Article in English | MEDLINE | ID: mdl-29851995

ABSTRACT

Climate variability plays a central role in the dynamics of marine pelagic ecosystems shaping the structure and abundance changes of plankton communities, thereby affecting energy pathways and biogeochemical fluxes in the ocean. Here we have investigated complex interactions driven a climate-hydrology-plankton system in the southern East China Sea over the period 2000 to 2012. In particular, we aimed at quantifying the influence of climate phenomena playing out in tropical (El Nino 3.4) and middle-high latitudes (East Asia Winter Monsoon, EAWM, and Pacific Decadal Oscillation, PDO) on pelagic copepods. We found that the EAWM and El Nino 3.4 showed a non-stationary and non-linear relationship with local temperature variability. In the two cases, the strength of the relationship, as indexed by the wavelet coherence analysis, decreased along with the positive phase of the PDO. Likewise, the influence of EAWM and El Nino3.4 on copepods exhibited a non-stationary link that changed along with the PDO state. Indeed, copepods and EAWM were closely related during the positive phase, while the link copepods-El Nino 3.4 was stronger during the negative phase. Our results pointed out cascading effects from climate to plankton driven by the positive phase of the PDO through its effect on temperature conditions, and likely through a larger southward transport of nutrient-rich water masses to northern Taiwan and the Taiwan Strait. We suggest a chain of mechanisms whereby the PDO shapes interannual dynamics of pelagic copepods and highlight that these results have implications for integrative management measures, as pelagic copepods plays a prominent role in food web dynamics and for harvested fish in the East China Sea.


Subject(s)
Climate , Seasons , Zooplankton/physiology , Animals , Biomass , Carbon Cycle , China , Chlorophyll/analysis , Ecosystem , El Nino-Southern Oscillation , Fishes , Food Chain , Geography , Oscillometry , Plankton , Population Dynamics , Taiwan , Temperature
13.
PLoS One ; 12(12): e0187647, 2017.
Article in English | MEDLINE | ID: mdl-29236717

ABSTRACT

The mud shrimp Austinogebia edulis, being abundant in the intertidal zone of western Taiwan, constructs deep burrows (>1 m). This study highlights the potential of mud shrimps to modify sediment characteristics of the tidal flat by its burrowing behavior. We studied the structure of the burrow wall, compared the difference in the sediment composition of the burrow and the background sediment, and compared the organic content inside the burrow wall. This study was carried out from September 2015 to November 2016 in three areas of the western coast of Taiwan, namely Shengang, Hanbow, and Wangong. The present study found significant differences between burrow wall and the burrow lumen. The diameter of the burrow wall was double as wide as the inner burrow lumen at the opening and gradually increased to 10 times of the burrow lumen at 30 cm depth. The burrow wall of A. edulis showed low permeability and increased the sheer strength. Statistically, a significant difference was noticed in the comparison between the sediment composition of the burrow wall and the background (p < 0.05, Student's t-test). An accumulation of 3.63 for fine sand (t = -5.22, p < 0.001, fine sand) and 9 for clay (t = -25.01, p < 0.001, clay) was found in the upper burrow wall of A. edulis. This indicated that they somehow chose finer particles to build burrows. This will gradually change the sediment distribution-vertically and horizontally. The burrow wall consisted of a 24 times higher organic matter content than one individual of mud shrimp. The burrow may provide organic material as a potential food source. The mud shrimp thus transforms the sediment characteristics as an ecological engineer, which is expected to have a significant ecological impact on the ecosystem.


Subject(s)
Behavior, Animal , Crustacea/physiology , Ecosystem , Animals , Taiwan
14.
PLoS One ; 12(9): e0182649, 2017.
Article in English | MEDLINE | ID: mdl-28880871

ABSTRACT

Hydrothermal vent organisms are adapted to their extreme and patchily distributed habitats. They are expected to have evolved mechanisms that keep them in their specific habitation. Since little is known about the recruitment or habitat selection of HV organisms such as brachyurans, we examined the properties of several hydrothermal vent-associated cues on the behavior of the hydrothermal vent (HV) crab Xenograpsus testudinatus in the laboratory that were contrasted by the offering of non-vent cues. This crab species is endemic and dominates the vent fauna of Turtle Island off the NE coast of Taiwan. HV crabs were separately and in combination offered the following vent-specific cues: (1) sulfuric sediment, (3) air-bubbling, (4) elevated temperature, (5) dead settled zooplankton, (7) other crabs, and (8) shade. The non-vent-specific cues were: (2) quarz sediment, (6) dead fish, (8) light. These cues were provided on either side of a two-choice chamber. The movement of individual crabs was monitored: as initial and final choices, and as the proportion of time the crabs spent in each compartment (resident time). Cues were offered alone and no such cue as a control in the same set-up. Sulfuric sediments and dead fish were significantly more attractive to females, and other crabs irrespective of gender were significantly more attractive to males. When compared to expected distributions, crabs, irrespective of gender, significantly avoided light and tended to select other crabs, air-bubbling, sulfuric sediment, elevated temperature, dead fish, dead zooplankton, and quarz sediments in the order of decreasing importance. Data do not support the hypothesis that dead settled zooplankton was particularly attractive nor that the other gender was selected. A combination of several vent-associated cues (sulfuric sediment, elevated temperature, air-bubbling) facilitated the strongest attraction to the crabs as reflected by all response variables. The 'first choice' responses were always consistent with the side of the choice compartment in which they spent the longest amount of time (resident time), but not with the 'final choice' of crabs, suggesting that the 'resident time' in addition to their 'first choice' is more reliable than just the 'final choice'. The present results provide the first indication that several vent-associated habitat cues function as attractors for HV crabs. Habitat choice is also reflected by crab larval distribution in the field which tend to stay near the bottom not to be carried away from their specific habitat.


Subject(s)
Adaptation, Physiological/physiology , Brachyura/physiology , Ecosystem , Animals , Female , Hydrothermal Vents , Male , Sulfur , Temperature , Zooplankton
15.
ACS Comb Sci ; 19(9): 585-593, 2017 09 11.
Article in English | MEDLINE | ID: mdl-28745488

ABSTRACT

This study is the first to employ combinatorial hydrothermal synthesis and facile spin-coating technology to fabricate TiO2-reduced graphene oxide (rGO) nanorod composition spreads. The features of this study are (1) the development of a self-designed spin-coating wedge, (2) the systemic investigation of the structure-property relationship of the system, (3) the high-throughput screening of the optimal ratio from a wide range of compositions for photocatalytic and photoelectrochemical (PEC) applications, and (4) the effective coupling between the density gradient TiO2 nanorod array and the thickness gradient rGO. The formation of rGO in the fabricated TiO2-rGO sample was monitored through Fourier transform infrared spectrometry. Transmission electron microscopy images also suggested that the TiO2 nanorod surfaces were covered with a thin layer of amorphous rGO. The rutile TiO2 plane evolution along the composition variation was verified through X-ray diffraction. 7% TiO2-93% rGO on the nanorod composition spread exhibited the most promising photocatalytic ability; the corresponding photodegradation kinetics, denoted by the photodegradation rate constant (k), was determined to be approximately 12.7 × 10-3 min-1. The excellent performance was attributed to the effective coupling between the TiO2 and rGO, which improved the charge carrier transport, thus inhibiting electron-hole pair recombination. A cycling test implied that 7% TiO2-93% rGO is a reliable photocatalyst. A photoluminescence spectroscopy study also supported the superior photocatalytic ability of the sample, which was attributed to its markedly poorer recombination behavior. In addition, without further treatment, the sample exhibited excellent PEC stability; the photocurrent density was more than three times higher than that exhibited by the density gradient TiO2 nanorods.


Subject(s)
Graphite/chemistry , Nanocomposites/chemistry , Nanotubes/chemistry , Oxides/chemistry , Titanium/chemistry , Catalysis , Electrochemical Techniques , Graphite/radiation effects , Light , Microscopy, Electron , Nanocomposites/radiation effects , Nanotubes/radiation effects , Oxides/radiation effects , Particle Size , Photolysis , Titanium/radiation effects
16.
Zool Stud ; 55: e7, 2016.
Article in English | MEDLINE | ID: mdl-31966152

ABSTRACT

Parinya Limviriyakul, Li-Chun Tseng, Jiang-Shiou Hwang, and Tung-Wei Shih (2016) Symbiotic anomuran and brachyuran crabs were identified after extensive surveys of reef zones, especially from sponges, scleractinian corals, crinoids, and sea urchins, in the coastal areas of the southern East China Sea. Twenty-nine species belonging to 17 genera, 9 families, and 2 infraorders were identified (3 were identified to the generic level). More crabs belonged to the infraorder Brachyura (82.8%) than to Anomura (17.2%). Two anomuran symbionts (Allogalathea elegans and Petrolisthes virgatus) and 5 brachyuran symbionts (Tetralia glaberrima, Tetralia rubridactyla, Trapezia cymodoce, Trapezia septata, and Cymo melanodactylus) are common in this area. Two species of Anomura (Lauriea simulata, Petrolisthes virgatus) and 3 of Brachyura (Gonatonotus nasutus, Tetralia aurantistellata and Tetralia nigrolineata) were identified for the first time from waters adjacent to Taiwan. These records represent the northernmost recorded of L. simulata and T. aurantistellata. The occurrence of P. virgatus is the second in the western Pacific Ocean. This study revealed the geospatial distribution of symbiotic crabs, which connects the region from the southern Ryukyu arc to the Coral Triangle, and provides the supporting taxonomic account of symbiotic anomuran and brachyuran crab fauna inhabiting the reef zone in northern Taiwan.

17.
Mar Pollut Bull ; 87(1-2): 345-351, 2014 Oct 15.
Article in English | MEDLINE | ID: mdl-25110048

ABSTRACT

Mesozooplankton (Body size 20-200 µm) along with the surface water were collected from coastal regions of Sundarban, northeastern part of Bay of Bengal considering three seasons, namely premonsoon, monsoon and postmonsoon. Samples were analyzed for community structure and the dominant copepod species were further analyzed for trace metal concentration. In total, 50 copepods were identified (22 families and 43 genera). The dominant mesozooplankton species included 9 copepods and an epipelagic chaetognath, exhibited both spatial and seasonal variations. Metal concentration exhibited considerable inter-specific variations for the copepods and the mean concentrations were: Fe, 1350.2-51118.3 µg/g; Al, 647.2-73019.1 µg/g; Ni, 32.4-110.3 µg/g; Mn, 122.8-1066.5 µg/g; Pb, 0.04-97.5 µg/g; Pb, 10.6-97.5 µg/g; Cd, 4.2-21.6 µg/g; Cu, 17.4-145.1 µg/g; Zn, 225.7-1670.9 µg/g; Cr, 21.7-194.3 µg/g; Co, 1.32-111.1 µg/g. Metal concentrations showed the following order: Sagitta bedoti>Coryceas danae>Oithona sp.>Eucalanus subcrassus>Labidocera euchaeta>Paracalanus parvus>Acartiella tortaniformis>Acartia spinicauda>Pseudocalanus serricaudatus.


Subject(s)
Environmental Monitoring/methods , Wetlands , Zooplankton/chemistry , Animals , India , Seasons , Seawater , Trace Elements/analysis , Zooplankton/metabolism
18.
Mar Pollut Bull ; 85(2): 648-58, 2014 Aug 30.
Article in English | MEDLINE | ID: mdl-24321880

ABSTRACT

The response of metal accumulation in coral Tubastraea coccinea to various degrees of metal enrichment was investigated from the Yin-Yang Sea (YYS) receiving abandoned mining effluents, the Kueishan Islet (KI) hydrothermal vent field, and the nearshore area of remoted Green Island (GI). The concentrations of most dissolved metals were highest in seawater at YYS, followed by KI, and then GI, showing the effects of anthropogenic and venting inputs on metal levels. Five metals (Co, Fe, Mn, Ni, and Zn) yielded significant differences (p<0.05) among the skeleton samples. We identified similar patterns in the metal-Ca ratios, indicating that the elevated metals in skeletons was a consequence of external inputs. The coral tissues were relatively sensitive in monitoring metal accumulation, showing significant differences among three locations for Cd, Co, Cu, Fe, Pb, Ni, and Zn. Specific bioconcentration factors provided strong support for the differential metal accumulation in skeletons and tissues.


Subject(s)
Anthozoa/chemistry , Environmental Monitoring/methods , Metals, Heavy/analysis , Metals/analysis , Water Pollutants, Chemical/analysis , Animals , Geography , Hydrothermal Vents , Seawater/chemistry
19.
J Environ Biol ; 29(3): 275-80, 2008 May.
Article in English | MEDLINE | ID: mdl-18972677

ABSTRACT

This study analyses distribution and abundance patterns of mesozooplankton communities at 13 stations in the coastal waters over a marine outfall area in the northeastern South China Sea. Cruises were conducted in March, June and September 2002, and plankton samples were collected with a 333 microm North Pacific net. The Mesozooplankton was dominated by calanoid Copepods, Cladocera, Chaetognatha and Pteropoda. Stations located near the entrance of the harbor provided a relatively higher abundance of Noctilucales and Radiolarians. In total, 20 zooplankton groups were identified in which, Calanoida, Cladocera, Chaetognatha, Pteropoda, Poecilostomatoida and Appendicularia comprised 92.77% of the total zooplankton abundance. Copepoda dominated in all three cruises, comprising 65.32% of the total mesozooplankton abundance. Samples collected in June recorded higher mesozooplankton abundance than March and September samples. Onshore stations recorded higher BOD values, higher abundance of Noctilucales and Radiolarians and a relativelylower abundance of the overall mesozooplankton. Total mesozooplankton abundance did not correlate significantly with temperature, pH, or dissolved oxygen, but correlated negatively with BOD.


Subject(s)
Marine Biology , Zooplankton/physiology , Animals , China , Oceans and Seas
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