Maintenance mechanism of Enteromorpha prolifera green tide: From perspective of nutrients utilization

293-297Green tide caused by macroalgae is one of the global ocean ecological disasters and nutrients with high concentration are considered as materials base for the outbreak of green tide. Nevertheless, there is no continuous nutrients supply for macroalgae during their floating in sea areas. Thus, there must be special nutrients utilization strategy for the macroalgae to maintain growth and proliferation even if the nutrients in seawater can not supply enough nutrients for them. To verify the hypothesis, Enteromorpha prolifera responsible for green tide was exposed to nutrients with different concentrations. E. prolifera absorbed and stored excrescent nutrients when it encountered nutrient eutrophication, then released and reutilized those stored nutrients for growth and proliferation in the nutrient-shortage seawaters. Thus, the green tide can be maintained by the nutrients regulation ability of E. prolifera. Results of the present work may be helpful to provide enlightenment on prediction and controlling of macroalgae green tide

A blessing or a curse: Responses of eelgrass (Zostera marina) seedlings to combined stressors of nutrients, hypoxia and sulfide

Eelgass (Zostera marina) beds have many functions; however, eelgrass populations have declined in recent decades. Thus, it is important to recover eelgrass populations. Multiple stressors coexist in eelgrass habitats and it is considered that stressors reduce the eelgrass population. Nevertheless, many seedlings are established under combined stressors. It is speculated that there are antagonistic and synergistic effects among these stressors, and the interaction between them determines the seedling fate. To verify this hypothesis, 840 eelgrass seedlings were exposed to combined stressors of nutrients, hypoxia and sulfide for 7 d. All of the seedlings survived. The pH of the experimental system decreased from the 0th to 24th h, but it increased after the 72nd h. The root activity was 119.87±5.48 μg.g−1.h−1 and was inhibited by the interaction of dissolved oxygen (DO) and ammonia, and increased with nitrate and the interaction of phosphate and sulfide. Both the proline content and the Chl a content were not affected by the stressors. The Chl b content was 0.14±0.16 mg.g−1 (calculated by wet weight) and was reduced by nitrate. The ratio of Chl a content to Chl b content was 2.53±0.07 and was affected by the stressors. There is antagonism and synergy among these stressors and the interaction of them determines seedling survival. Nitrate at a high concentration leads to seedling death. It is not accidental that seedlings survive or die under combined stressors, and the intensity and the spatiotemporal distribution of environmental stressors determine the recruitment of seedlings. Targeted habitat improvement contributes to the survival of eelgrass seedlings

Long-Term Investigation into the Membrane Fouling Behavior in Anaerobic Membrane Bioreactors for Municipal Wastewater Treatment Operated at Two Different Temperatures

In this study, the characteristics of activated sludge flocs were investigated and their effects on the evolution of membrane fouling were considered in the anaerobic membrane bioreactors (AnMBR), which were operated at 25 and 35 °C for municipal wastewater treatment. It was found that the membrane fouling rate of the AnMBR at 25 °C was more severe than that at 35 °C. The membrane fouling trends were not consistent with the change in the concentration of soluble microbial product (SMP). The larger amount of SMP in the AnMBR at 35 °C did not induce more severe membrane fouling than that in the AnMBR at 25 °C. However, the polysaccharide and protein concentration of extracellular polymeric substance (EPS) was higher in the AnMBR at 25 °C in comparison with that in the AnMBR at 35 °C, and the protein/polysaccharide ratio of the EPS in the AnMBR at 25 °C was higher in contrast to that in the AnMBR at 35 °C. Meanwhile, the fouling tendencies measured for the AnMBRs could be related to the characteristics of loosely bound EPS and tightly bound EPS. The analysis of the activated sludge flocs characteristics indicated that a smaller sludge particle size and more fine flocs were observed at the AnMBR with 25 °C. Therefore, the membrane fouling potential in the AnMBR could be explained by the characteristics of activated sludge flocs

EXA-2017-1S-FUNDAMENTOS DE TELECOMUNICACIONES-1-2Par.docx

<p>Different litters indicate the statistical differences (p < 0.05).</p

High Colonization Possibility of Some Species of Weeds in <i>Suaeda salsa</i> Community: From an Ecological Stoichiometry Perspective

<div><p><i>Suaeda salsa</i> community is a vegetation type in saline-alkali areas. Weed invasion and colonization in <i>S</i>. <i>salsa</i> communities lead to fragmentationsof <i>S</i>. <i>salsa</i> communities. The colonization of invaded weeds in <i>S</i>. <i>salsa</i> communities is related to community succession of saline-alkali zones. The fragmented <i>S</i>. <i>salsa</i> community may be restored if the mechanism of invaded weed colonization in <i>S</i>. <i>salsa</i> communities is clearly elucidated. Thus, we studied the ecological stoichiometric characteristics of soils and plants in a salt marsh to explain the high colonization possibility of invaded weeds in <i>S</i>. <i>salsa</i> communities. In October 2014, soils and plants were collected from Dongfeng Salt Marsh, Jiaozhou Bay, Shandong Province, China. The ratio of Ex-N/Ex-P in soil was less than 13, which suggests a relative nitrogen limitation for the primary production in the zone. The minimum phosphorus content in plants was higher than 1 mg g^-1, whereas the maximum nitrogen content in plants was less than 13 mg g^-1. These results imply that phosphorus was abundant, whereas nitrogen was deficient in the area. The plants in the salt marsh may be limited by nitrogen. Given the relatively lower nitrogen contents in <i>Cyperus glomeratus</i>, <i>Echinochloa crusgalli</i>, and <i>Aster subulatus</i> than that in <i>S</i>. <i>salsa</i>, these three species exhibited higher competitiveness than S. salsa did when nitrogen was limited in primary production. These weed species may colonize highly in <i>S</i>. <i>salsa</i> communities. Moreover, nitrogen fertilization might be effective to maintain <i>S</i>. <i>salsa</i> community in Dongfeng Salt Marsh, whereas its effects on controlling weeds colonization in <i>S</i>. <i>salsa</i> communities need more studies to verify.</p></div

Ratio of N/P in plant in Dongfeng Salt Marsh.

<p>Different litters indicate the statistical differences (p < 0.05).</p

Modulation synthesis of multi-shelled cobalt-iron oxides as efficient catalysts for peroxymonosulfate-mediated organics degradation

Simple-controlled synthesis of multiple porous and monodisperse cobalt-iron oxides were realized by varying the prepared conditions via a template-assisted glycol solvothermal process. The obtained materials were characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy, Mossbauer spectroscopy and nitrogen adsorption/desorption measurement. It was found that the amounts of metal precursors and the Co:Fe ratio significantly influenced the morphology, the crystallinity, as well as the textural and electronic properties of the cobalt-iron products. The different cobalt-iron oxides with various shells were employed into the catalytic activation of peroxymonosulfate (PMS) for Orange II degradation, among which, multishelled cobalt ferrite microsphere was certified to perform the best activity due to the coefficient contribution of higher content of octahedral Co2+, more exposed active sites and the reservoir effect. Sulfate and hydroxyl radicals were crucial reactive species in Orange II degradation, proved by the scavenger quenching test. This work shows that cobalt-iron oxide microspheres with such architecture make differences in the PMS-mediated aqueous organics degradation system, which extends the perspective and application of such functional oxides in the environmental field

Phosphorus content in plant in Dongfeng Salt Marsh.

<p>Different letters indicate the statistical differences (p < 0.05).</p

Sketch map of sampling sites in Dongfeng Salt Marsh.

<p>Sketch map of sampling sites in Dongfeng Salt Marsh.</p

Nitrogen content in plant in Dongfeng Salt Marsh.

<p>Different letters indicate the statistical differences (p < 0.05).</p