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A mass balanced model of trophic structure and energy flows of a semi-closed marine ecosystem
Dongyan HAN, Ying XUE, Chongliang ZHANG, Yiping REN
doi: 10.1007/s13131-017-1071-6
The marine ecosystem of the Jiaozhou Bay has degraded significantly in fisheries productivity and its ecological roles as spawning and nursery ground for many species of commercial importance has been declining in recent years. A mass-balanced trophic model was developed using Ecopath with Ecosim to evaluate the trophic structure of the Jiaozhou Bay for improving ecosystem management. The model were parameterized based on the fisheries survey data in the Jiaozhou Bay in 2011, including 23 species groups and one detritus group according to their ecological roles. The trophic levels of these ecological groups ranged from 1 (primary producers and detritus) to 4.3 (large demersal fishes). The estimated total system throughput was 12 917.10 t/(km2·a), with 74.59% and 25.41% contribution of the total energy flows from phytoplankton and detritus, respectively. Network analyses showed that the overall transfer efficiency of the ecosystem was 14.4%, and the mean transfer efficiency was 14.5% for grazing food chain and 13.9% for detritus food chain. The system omnivory index (SOI), Finn’s cycled index (FCI) and connectance index (CI) were relatively low in this area while the total primary production/total respiration (TPP/TR) was high, indicating an immature and unstable status of the Jiaozhou Bay ecosystem. Mixed trophic impact analysis revealed that the cultured shellfish had substantial negative impacts on most functional groups. This study contributed to ecosystem-level evaluation and management planning of the Jiaozhou Bay ecosystem.
key words: Ecopath with Ecosim, Jiaozhou Bay, energy flow, trophic structure
Ecosystem carbon stock of a tropical mangrove forest in North Sulawesi, Indonesia
Shunyang CHEN, Bin CHEN, Pramudji SASTROSUWONDO, I Wayan Eka DHARMAWAN, Danyun OU, Xijie YIN, Weiwei YU, Guangcheng CHEN
doi: 10.1007/s13131-018-1290-5
Recent studies have highlighted the valuable role played by mangrove forests in carbon sequestration and storage. Although Indonesia accounts for a large proportion of global mangrove area, knowledge on the carbon stock and sources in the Indonesian mangrove is still limited. In this study, we quantified the ecosystem organic carbon (OC) stock and its spatial variation at an oceanic mangrove in Wori, North Sulawesi, Indonesia. The sources of soil OC were also investigated. The results showed that the mangrove soil had a substantial OC stock containing 15.4 kg/m2 (calculated by carbon) in the top 50 cm soil, and represented the majority of the ecosystem OC stock at the Wori mangrove. The mangrove biomass and ecosystem OC stock were 8.3 kg/m2 and 23.7 kg/m2, respectively. There was no significantly difference in the soil OC stock among the stations with difference distances offshore, while the highest mangrove biomass OC stock was found at the seaward station. Isotope mixing calculations showed that the rich OC in mangrove soils was attributed to the accumulated autochthonous mangrove source while the suspended organic matter in tidal water and the mangrove-adjacent seagrass contributed less than 20% to the soil OC. The results further demonstrated the importances of the oceanic mangrove in carbon storage and the mangrove plants in contributing OC to their soils.
key words: mangrove, carbon stock, biomass, soil, stable isotopes, Indonesia
Development of a 16S rRNA gene-based microarray for the detection of marine bacterioplankton community
Wei ZHAO, Jingjing WANG, Yajie LIANG, Zhiyong HUANG
doi: 10.1007/s13131-017-1055-6
A better understanding of bacterioplankton community shifts following change in marine environments is critical to predict the marine ecosystem function. In order to get a snapshot of the microbial taxonomy profiling of a wide range marine area, a quick, convenient and low cost method would be favorable. In this study, we developed a 16S rRNA gene-based microarray using ARB software, which contained 447 probes targeting 160 families of marine bacteria. The specificity, sensitivity and quantitative capability of this microarray were assessed by single cloned 16S rRNA genes. The reliability of this microarray was tested by eight environmental samples. The results showed that the microarray was specific, only 1.16% false results were detected in five single-clone hybridization tests. The microarray could detect DNA samples as few as 1 ng/μL and the signal intensity could reflect the relative abundance of the bacteria in the range of 1 ng/μL to 100 ng/μL of DNA concentration. Hybridization with environmental samples showed that it can discriminate bacterioplankton communities by sites and time. High throughput sequencing results from the eight samples confirmed the hybridization results. It indicated that this developed microarray could be used as a convenient tool to monitor the bacterioplankton community in marine environment.
key words: microarray, bacterioplankton community, 16S rRNA gene, marine environment
Bioprospection of marine actinomycetes: recent advances, challenges and future perspectives
Swati Sharma, Abhay B. Fulke, Asha Chaubey
doi: 10.1007/s1313-018-1340-z
In exploring new sources for economically important products, marine environment draws particular attention because of its remarkable diversity and extreme conditions; it is known to produce metabolic products of great value. It represents untapped source for the discovery of novel secondary metabolites with varying potential such as antibiotic, anti-tumor, antifouling and cytotoxic properties. Marine actinomycetes distributed throughout the marine environment from shallow to deep sea sediments have proved to be a finest source for this discovery. Secondary metabolites derived from marine actinomycetes have proved their worth in industries based on the research on their properties and wide range applications. Spotlight of the review is range of marine based actinomycetes products and significant research in this field. This shows the capability of marine actinomycetes as bioactive metabolite producers. Additionally, the present review addresses some effective and novel approaches of procuring marine microbial compounds utilizing the latest screening strategies of drug discovery from which traditional resources such as marine actinobacteria has decreased due to declining yields. The aim is in the context of promoting fruitful and profitable results in the near future. The recent surfacing of new technologies for bioprospection of marine actinomycetes are very promising, resulting in high quality value added products, and will be de?ning a new era for bioactive compounds with medical and biotechnological applications.
key words: marine actinomycetes, bioprospection, commercial use, bioactive compounds, genome mining
Protoraphis Simonsen, a newly recorded marine epizoic diatom genus for China
Lang Li, Changping Chen, Lin Sun, Jiawei Zhang, Junrong Liang, Yahui Gao
doi: 10.1007/s13131-019-1467-z
Epizoic diatoms on marine copepods are common in nature and may have a special ecological relationship with their hosts. However, this special ecological group is not well known, and it has only rarely been studied in the China seas. To address this knowledge gap, the species diversity and classification of epizoic diatoms on planktonic copepods were studied with samples collected from the East China Sea. In the present study, a marine araphid diatom genus Protoraphis and its type species, Pr. hustedtiana, were observed and identified by light and electron microscopy, thus representing the first record of this genus and its type species in China. This genus is characterized by a median sternum strongly bent to opposite sides and terminate in two transapical grooves at the valve ends. Protoraphis hustedtiana was found to be epizoic on the posterior body appendages and segments of the marine calanoid copepod Candacia bradyi. An internal view shows a complex, ear-shaped process that is close to the apical slit field. The ecological habitats and geographical distributions of Protoraphis were also discussed, and, together with complementary morphological studies, our results have increased the number of records for marine epizoic diatoms to three genera with three species in China, including Pseudohimantidium and Pseudofalcula.
key words: marine epizoic diatom, copepod, Protoraphis, newly recorded genus, ear-shaped process
Estimation of catch losses resulting from overexploitation in the global marine fisheries
Qi DING, Xinjun CHEN, Yong CHEN, Siquan TIAN
doi: 10.1007/s13131-017-1096-x
Many fish stocks in the world are depleted as a result of overexploitation, which reduces stock productivity and results in loss of potential yields. In this study we analyzed the catch trends and approximate thresholds of sustainable fishing for fished stocks to estimate the potential loss of catch and revenue of global fisheries as a result of overexploitation during the period of 1950–2010 in 14 FAO fishing areas. About 35% of stocks in the global marine ocean have or had suffered from overexploitation at present. The global catch losses amounted to 332.8 million tonnes over 1950–2010, resulting in a direct economic loss of US$298.9 billion (constant 2005 US$). Unsustainable fishing caused substantial potential losses worldwide, especially in the northern hemisphere. Estimated potential losses due to overfishing for different groups of resources showed that the low-value but abundant small-medium pelagics made the largest contribution to the global catch loss, with a weight of 265.0 million tonnes. The geographic expansion of overfishing not only showed serial depletion of world’s fishery resources, but also reflected how recent trends towards sustainability can stabilize or reverse catch losses. Reduction of global fishing capacity and changes in fishery management systems are necessary if the long-term sustainability of marine fisheries in the world is to be achieved.
key words: overfishing, catch loss, sustainability, exploitation status
Size fraction of phytoplankton and the contribution of natural plankton to the carbon source of Zhikong scallop Chlamysfarreri in mariculture ecosystem of the Sanggou Bay
Zengjie JIANG, Meirong DU, Jinghui FANG, Yaping GAO, Jiaqi LI, Li ZHAO, Jianguang FANG
doi: 10.1007/s13131-017-0970-x
The biomass and size fraction of phytoplankton in terms of chlorophyll a (Chl a) was measured during four cruises conducted in April, July, October 2013 and January 2014 in mariculture area, the Sanggou Bay, China. Results show that total Chl a levels in the surface seawater of the Sanggou Bay generally range from 0.10 to 20.46 μg/L, with an average value of 2.13 μg/L. Nano-phytoplankton was the most important size-fraction and accounted for about 65.1% of total Chl a. In order to evaluate the importance of the " protozoan trophic link” for energy transfer from the microbial loop to filter-feeding feeders, Zhikong scallop Chlamys farreri was then offered a natural planktonic community as potential prey. Results show that scallops obtained carbon source from natural plankton with the rate of 11 033.05 μg/(g·d). Protists (nanoflagellates and ciliates) were the dominant source of carbon retained by scallop (48.78%). The microbial loop provided 58.45% of the carbon source for farmed scallops. These results indicate that the microbial loop represent a valuable trophic resource in mariculture system of the Sanggou Bay.
key words: phytoplankton, picoplankton, protist, microbial food web, Chlamys farreri
An assessment of “fishing down marine food webs” in coastal states during 1950–2010
Qi DING, Xinjun CHEN, Wei YU, Yong CHEN
doi: 10.1007/s13131-017-1003-5
Mean trophic level of fishery landings (MTL) is one of the most widely used biodiversity indicators to assess the impacts of fishing. Based on the landing data compiled by Food and Agriculture Organization combined with trophic information of relevant species in FishBase, we evaluated the status of marine fisheries from 1950 to 2010 for different coastal states in Pacific, Atlantic and Indian Oceans. We found that the phenomenon of " fishing down marine food webs” occurred in 43 states. Specifically, 27 states belonged to " fishing-through” pattern, and 16 states resulted from " fishing-down” scenario. The sign of recovery in MTL was common in the Pacific, Atlantic and Indian Oceans (occurred in 20 states), but was generally accompanied by significantly decreased catches of traditional low trophic level species. In particular, 11 states showed significant declining catches of lower trophic levels. The MTL-based assessment of " fishing down marine food webs” needs to be interpreted cautiously.
key words: coastal states, exploitation history, fishing down marine food webs, sustainability, marine fisheries, mean trophic level of fishery landings
Prevalence of Bacillus sp. among the biofilm forming community on Ti surface in marine environment
Chokkalingam PRIYA, Ganessin ARAVIND, Wilson Richard THILAGARAJ
doi: 10.1007/s13131-017-1045-8
Prevalence of bacterial species involved in biomineralization of manganese on titanium (Ti) surfaces in marine environment was revealed in this research work. This study involves one year sea water exposure of Ti and their periodical biofilm characterization was carried out to quantify the manganese oxidizing bacterial (MOB) presence in the biofilm formed on titanium surfaces. The total viable count study of Ti coupons exposed to sea water for one year resulted in 60% of the MOB in overall biofilm population. The biochemical characterization of MOB isolates were performed for the genus level identification of the seven bacterial isolates. Further, the seven strains were subjected to 16S rRNA gene sequencing. Evolutionary analysis was performed using MEGA 7 to obtain closely related strains within the groups. The manganese oxidizing ability of the bacterial isolates were determined with Leucoberbelin Blue Assay (LBB) and Atomic Absorption Spectroscopy studies (AAS). The results show that among the isolated marine MOB species, Bacillus sp. and Leptothrix sp. have the maximum Mn oxidizing property. The microtitre plate assay was performed to determine the biofilm forming ability of the isolated marine MOB species. All the results have confirmed the prevalence of Bacillus sp. among the biofilm colonizers on Ti surfaces when exposed in sea water.
key words: biomineralization, titanium surfaces, manganese oxidizing bacteria, 16S rRNA gene sequencing, Leucoberbelin Blue Assay, Atomic Absorption Spectroscopy
Comparison of toxicity effects of fuel oil treated by different dispersants on marine medaka (Oryzias melastigma) embryo
Xiang GAO, Guanghui DING, Xishan LI, Deqi XIONG
doi: 10.1007/s13131-018-1255-8
This study aims to evaluate the subacute toxic effects of oil under different treatments on marine organism by simulating natural contaminative processes. In this study, 120# (RMD15) fuel oil was selected as the pollutant and marine medaka (Oryzias melastigma) embryos as the experimental organism. The developmental toxicity of different volume concentrations (0.05%, 0.2%, 1% and 5%) of water-accommodated fractions, biologically-enhanced water-accommodated fractions, and chemically-enhanced water-accommodated fractions on the embryos in different exposure time (8, 15 and 22 d) were compared and the content of relevant polycyclic aromatic hydrocarbons (PAHs) was studied (in dispersion and in vivo). The subacute toxic effects were assessed in terms of antioxidant activities of enzymes (superoxide dismutase, catalase and glutathione S-transferase) and the blue sac disease (BSD) indexes.The results showed that the BSD indexes of the treatment groups were significantly higher than the respective control groups and showed positive correlations with both concentration and exposure time. The experiments with three antioxidant enzymes indicated that enzymatic activities of the embryos changed dramatically under the oxidation stress of petroleum hydrocarbons, especially after adding the dispersants. With the increase of petroleum hydrocarbon concentration and exposure time, the three enzymes showed different degrees of induction and inhibition effects.
key words: marine medaka, petroleum hydrocarbon, oil dispersant, antioxidant enzymes, 120# fuel oil

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