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Wang M.,Xiamen University | Gao X.,Xiamen University | Gao X.,Guangxi Mangrove Research Center | Wang W.,Xiamen University
Ecological Engineering | Year: 2014

Density and morphology of crab burrows were compared using resin casts between exotic Spartina alterniflora marsh (SPA) and four mangrove habitats (Avicennia marina forest, AM; Kandelia obovata forest, KO; Aegiceras corniculatum forest, AC; Mudflat, MF) at a subtropical mangrove estuary, Yunxiao, China. Five burrow-morphological parameters (density, opening diameter, depth, branching and total burrow volume per m2) were measured. The results showed that there were significant differences in the morphology (depth and volume) of crab burrows between SPA and mangrove habitats. The depth (ANOVA, d.f.=27, F=24.212, P=0.000) and total burrow volume (ANOVA, d.f.=23, F=3.666, P=0.022) per m2 in SPA were significantly lower than those in the other four mangrove habitats. Correlation analysis indicated significant negative correlation between burrow depth and root density. We concluded that over-dense roots and subterranean stems of Spartina alterniflora impeded crabs excavating burrows extensively, both in the vertical and horizontal directions. Consequently, the invasion of Spartina alterniflora weakened the ecosystem engineering effects of mangrove crabs. The burrows in KO and AM had significantly higher burrow complexity than those in the other three habitats. We speculated that mangrove root was the main environmental variable resulting in the varied complexity of crab burrows. Higher root density or lower root density both impede crabs constructing complex burrows, while intermediate root density contributes to the development of higher borrow complexity. © 2014 Elsevier B.V.


Lin Y.-M.,Xiamen University | Liu X.-W.,Xiamen University | Zhang H.,Xiamen University | Fan H.-Q.,Guangxi Mangrove Research Center | Lin G.-H.,Xiamen University
Plant and Soil | Year: 2010

Despite a growing knowledge of nutrient limitation for mangrove species and how mangroves adapt to low nutrients, there is scant information about the relative importance of N:P ratio and leaf phenolics variability in determining nutrient conservation. In this study, we evaluated possible nutrient conservation strategies of a mangrove Rhizophora stylosa under nutrient limitation. 1. The leaf nutrient concentrations of R. stylosa changed with season, with the highest N concentration in winter and the highest P concentration in spring for both mature and senescent leaves. Leaf N and P concentrations decreased significantly during leaf senescence. Based on N:P ratios R. stylosa forest was N-limited. Accordingly, the nitrogen resorption efficiency (NRE) was significantly higher than phosphorus resorption efficiency (PRE) for the R. stylosa leaves during leaf senescence. The NRE and PRE both reached the highest in the autumn. Average N and P concentrations in the senescent leaves were 0.15% and 0.06% for R. stylosa, respectively, indicating a complete resorption of N and an incomplete resorption of P. There was a significant negative correlation between nitrogen resorption proficiency (NRP) and NRE, meanwhile phosphorus resorption proficiency (PRP) and PRE correlation was also highly significantly. 2. R. stylosa leaves contained relatively high tannin level. Total phenolics, extractable condensed tannins and total condensed tannins contents increased during leaf senescence, and changed between seasons. The lowest concentrations of total phenolics, extractable condensed tannins and total condensed tannins occurred in summer, total phenolics concentrations were inversely related to nitrogen or phosphorus concentrations. 3. Our results confirmed that resorption efficiency during leaf senescence depends on the type of nutrient limitation, and NRE was much higher than PRE under N-limited conditions. R. stylosa forest developed several nutrient conservation strategies in the intertidal coastline surroundings, including high nitrogen resorption efficiency, low nutrient losses and high tannins level. © Springer Science + Business Media B.V. 2009.


Chen X.,Guangxi Mangrove Research Center | Chen X.,Wenzhou University | Xiang D.,Wenzhou University | Ai W.,Wenzhou University | Shi X.,Guangxi Mangrove Research Center
Mitochondrial DNA | Year: 2015

The complete mitochondrial genome of the pelagic thresher Alopias pelagicus is first presented in this study. It is 16,692bp in length and contains the 37 genes and 1 control region with the typical gene order and transcriptional direction in the vertebrates. The overall base composition is 32.1% A, 29.3% T, 25.3% C and 13.3% G. Totally, 27bp overlaps and 25bp short intergenic spaces are dispersal in the mitogenome. The tRNA-Ser2 (GCU) cannot be folded into the typical cloverleaf structure because of lacking the dihydrouridine arm. Two start codons (ATG and GTG) and three stop codons (AGG, TAG and TAA/T) were used in the 13 protein-coding genes. © 2013 Informa UK Ltd.


Chen X.,Guangxi Mangrove Research Center | Chen X.,Wenzhou University | Xiang D.,Wenzhou University | Xu Y.,Wenzhou University | Shi X.,Guangxi Mangrove Research Center
Mitochondrial DNA | Year: 2015

The complete mitochondrial genome of the endangered scalloped hammerhead Sphyrna lewini was firstly determined in this study. It is 16,726 bp in length with the typical gene composition and orders in vertebrates. The overall base composition is 31.4% A, 26.3% C, 13.2% G and 29.1% T. Two start codon (ATG and GTG) and three stop codon (TAG, AGA and TAA/TA/T) patterns were found in protein-coding genes. Except for the tRNA-Ser2, the remaining 21 tRNAs can be folded into the typical cloverleaf structure. The control region possess the highest A + T content (66.1%) and lowest G content (12.6%) among all mitochondrial partitions. © 2013 Informa UK Ltd.


Chen X.,Guangxi Mangrove Research Center | Chen X.,Wenzhou University | Xiang D.,Wenzhou University | Ai W.,Wenzhou University | Shi X.,Guangxi Mangrove Research Center
Mitochondrial DNA | Year: 2015

In this study, we first presented the complete mitochondrial genome of the blue shark Prionace Glauca, a pelagic and oceanic species. It is 16,705bp in length and contains 2 rRNA genes, 22 tRNA genes, 13 protein-coding genes and 1 putative control region. The overall base composition is 31.6% A, 24.4% C, 13.1% G and 30.9% T. Overlaps and short inter-genic spaces are located in the genome. The tRNA-Ser2 loses the dihydrouridine arm and cannot be folded into the typical clover-leaf secondary structure. Two start codons (GTG and ATG) with two stop codons (TAG and TAA) or with one incomplete stop codon (T) are found in the 13 protein-coding genes. The control region contains high A+T (69.9%) and low G (12.0%). © 2013 Informa UK Ltd.


Chen X.,Guangxi Mangrove Research Center | Chen X.,Wenzhou University | Peng Z.,Guangxi Mangrove Research Center | Cai L.,Wenzhou University | Xu Y.,Wenzhou University
Mitochondrial DNA | Year: 2015

In this article, we first presented the complete mitogenome of the spot-tail shark Carcharhinus sorrah, which is a medium-sized shark distributed in the tropical Indo-Pacific and is currently listed as "Near Threatened" on the International Union for Conservation of Nature (IUCN) Red List. The complete mitogenome of C. sorrah is 16,707 bp in length and contains typical 37 genes and one control region. The overall base composition is 31.4% A, 25.8% C, 13.2% G and 29.6% T. The control region is 1066 bp in length with the highest A + T content (66.8%) and lowest G content (13.2%). © 2014 Informa UK Ltd.


Kaiser D.,Leibniz Center for Tropical Marine Ecology | Unger D.,Leibniz Center for Tropical Marine Ecology | Unger D.,German Electron Synchrotron | Qiu G.,Guangxi Mangrove Research Center | And 3 more authors.
Science of the Total Environment | Year: 2013

Global understanding of land-ocean nutrient fluxes increasingly recognizes the disproportionate importance of small rivers. We studied nutrient fluxes from a small catchment in fast developing southern China to uncover effects of land-use. Water was sampled in the macro-tidal estuary of Nanliu River and adjacent Lianzhou Bay in spring and summer of investigate spatial and temporal variations of dissolved nutrients. High riverine concentrations of nitrate (NO3; up to 220μM) and phosphate (PO4; up to 3.7μM) mainly originated from agricultural fertilizer input. Riverine dissolved silica (Si; up to 47μM) increased in the oligosaline part of the estuary through human disturbance of bottom sediments. Dissolved organic nitrogen (DON; up to 194μM) and ammonium (NH4; up to 40μM) concentrations increased within the estuary due to inputs from livestock and mussel beds, respectively. Aquaculture ponds contained high concentrations of NH4 (up to 355μM) and DON (up to 151μM) but are not an important source to the estuary due to rare wastewater discharge and low absolute nutrient amounts relative to river export. Nutrient concentrations in Lianzhou Bay were low because tidal currents disperse land-derived nutrients offshore into the adjacent Beibu Gulf. A high proportion of regenerated nitrogen in the bay suggests that primary production is sustained by rapid in situ nutrient cycling between primary producers and benthic consumers. High nutrient export makes the Nanliu River an important nutrient source for the north-western South China Sea, despite its proportionately small size.Macro-tide induced short-term concentration changes exceed variability on seasonal and sub-seasonal scales. All nutrients vary inter-annually and between seasons, depending on precipitation-driven river runoff. Total nutrient export to Beibu Gulf coastal waters is stronger during the high discharge period in summer and autumn. In recent years changing nitrogen to phosphorus ratios have alleviated phosphorus limitation in Lianzhou Bay, permitting increased primary productivity. © 2013 Elsevier B.V.


He B.,Guangxi Mangrove Research Center | Lai T.,Guangxi Mangrove Research Center | Peng Z.,Guangxi Mangrove Research Center | Wang X.,Guangxi Mangrove Research Center | Pan L.,Guangxi Mangrove Research Center
Mitochondrial DNA | Year: 2013

In this study, we present the complete mitochondrial DNA sequences of Epinephelus areolatus for the first time, which is 16,893 bp in length and contains 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a putative control region. The overall base composition of the H-strand is 27.0% T, 28.0% C, 28.6% A, and 16.3% G. The CO1 gene is initiated by GTG codon and ATP6 gene is initiated by TTG codon. The tRNA-Ser2 cannot be folded into the typical cloverleaf secondary structure because its dihydrouridine arm is replaced by a simple loop. A long-tandem repeat motif (76 bp), repeated six times, is found in the control region. © 2013 Informa UK, Ltd.


Kaiser D.,Leibniz Center for Tropical Marine Ecology | Unger D.,Leibniz Center for Tropical Marine Ecology | Qiu G.,Guangxi Mangrove Research Center | Qiu G.,CAS Research Center for Eco Environmental Sciences
Continental Shelf Research | Year: 2014

Estuarine particle fluxes are an integral part of land-ocean-connectivity and influence coastal environmental conditions. In areas with strong anthropogenic impact they may contribute to coastal eutrophication. To investigate the particulate biogeochemistry of a human affected estuary, we sampled suspended, sedimentary and plant particulate matter along the land-ocean continuum from Nanliu River to Lianzhou Bay in southern China. Riverine particle fluxes exceed inputs from land based pond aquaculture. Elemental (C/N) and isotopic composition of particulate organic carbon (δ13C) and total nitrogen (δ15N) showed that suspended and sedimentary organic matter (OM) mainly derive from freshwater and marine phytoplankton, with minor contributions from terrestrial and aquaculture derived particles. Amino acid composition indicates subseasonal variability of production and freshness of phytoplankton OM. Strongest compositional changes of suspended particles are associated with storm-related extreme precipitation events, which introduce soil derived OM. High concentrations of chlorophyll a reflect eutrophic conditions in riverine and coastal waters. Human impact results in high δ15N signals in suspended, sedimentary and plant particulate matter. Using these in a comparison with two little affected sites shows that anthropogenic influence disperses from the Nanliu River to remote estuaries and mangrove areas. Our results suggest that autochthonous production binds anthropogenic nutrients in particles that are transported along the coast. © 2014 Elsevier Ltd.


Liao S.-M.,Guangxi University | Liao S.-M.,Guangxi Academy of science | Liao S.-M.,Guangxi Mangrove Research Center | Du Q.-S.,Guangxi Academy of science | And 5 more authors.
Chemistry Central Journal | Year: 2013

Background: Among the 20 natural amino acids histidine is the most active and versatile member that plays the multiple roles in protein interactions, often the key residue in enzyme catalytic reactions. A theoretical and comprehensive study on the structural features and interaction properties of histidine is certainly helpful. Results: Four interaction types of histidine are quantitatively calculated, including: (1) Cation-π interactions, in which the histidine acts as the aromatic π-motif in neutral form (His), or plays the cation role in protonated form (His+); (2) π-π stacking interactions between histidine and other aromatic amino acids; (3) Hydrogen-π interactions between histidine and other aromatic amino acids; (4) Coordinate interactions between histidine and metallic cations. The energies of π-π stacking interactions and hydrogen-π interactions are calculated using CCSD/6-31+G(d,p). The energies of cation-π interactions and coordinate interactions are calculated using B3LYP/6-31+G(d,p) method and adjusted by empirical method for dispersion energy. Conclusions: The coordinate interactions between histidine and metallic cations are the strongest one acting in broad range, followed by the cation-π, hydrogen-π, and π-π stacking interactions. When the histidine is in neutral form, the cation-π interactions are attractive; when it is protonated (His+), the interactions turn to repulsive. The two protonation forms (and pKa values) of histidine are reversibly switched by the attractive and repulsive cation-π interactions. In proteins the π-π stacking interaction between neutral histidine and aromatic amino acids (Phe, Tyr, Trp) are in the range from -3.0 to -4.0 kcal/mol, significantly larger than the van der Waals energies. © 2013 Liao et al.; licensee Chemistry Central Ltd.

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