Search

To enhance the nutrient removal efficiency of Oocystis borgei for mariculture wastewater (MW), the effects and processes of three phytohormones on nitrogen and phosphorus removal from synthetic mariculture wastewater (SMW) by O. borgei under sequential batch operation were compared. The findings revealed that the supplementation with 10−6 M 3-indoleacetic acid (IAA), gibberellic acid (GA3), and zeatin (ZT) resulted in the most effective elimination, while there was no appreciable difference among them. The nitrogen and phosphorus indices of the effluent dramatically reduced (p < 0.01) upon the supplementation of phytohormones, and the removal effects were ranked as NO3−-N > PO43−-P > NH4+-N > NO2−-N. The removal rates for NH4+-N and PO43−-P were 0.72–0.74 mg·L−1·d−1 and 1.26–1.30 mg·L−1·d−1, respectively. According to physiological studies, phytohormones enhanced the levels of photosynthetic pigments and chlorophyll fluorescence parameters (Fv/Fm and φPSII), thereby improving photosynthetic activity. Additionally, they stimulated Nitrate Reductase (NR) and Glutamine Synthetase (GS) activities to promote nitrogen metabolism and increased Superoxide Dismutase (SOD), Catalase (CAT), and carotenoid contents to mitigate oxidative stress damage caused by abiotic stress. These activities contribute to the proliferation of O. borgei, which in turn resulted in an increase in the assimilation of nitrogen and phosphorus from SMW. In conclusion, phytohormone supplementation significantly increased nutrient removal from SMW by O. borgei in a sequential batch reactor, which has potential application in MW treatment. [ABSTRACT FROM AUTHOR]

"It takes a village to finish (marine) science these days" Paraphrased from Curtis Huttenhower (the Human Microbiome project) The rapidity and complexity of climate change and its potential effects on ocean biota are challenging how ocean scientists conduct research. One way in which we can begin to better tackle these challenges is to conduct community-wide scientific studies. This study provides physiological datasets fundamental to understanding functional responses of phytoplankton growth rates to temperature. While physiological experiments are not new, our experiments were conducted in many laboratories using agreed upon protocols and 25 strains of eukaryotic and prokaryotic phytoplankton isolated across a wide range of marine environments from polar to tropical, and from nearshore waters to the open ocean. This community-wide approach provides both comprehensive and internally consistent datasets produced over considerably shorter time scales than conventional individual and often uncoordinated lab efforts. Such datasets can be used to parameterise global ocean model projections of environmental change and to provide initial insights into the magnitude of regional biogeographic change in ocean biota in the coming decades. Here, we compare our datasets with a compilation of literature data on phytoplankton growth responses to temperature. A comparison with prior published data suggests that the optimal temperatures of individual species and, to a lesser degree, thermal niches were similar across studies. However, a comparison of the maximum growth rate across studies revealed significant departures between this and previously collected datasets, which may be due to differences in the cultured isolates, temporal changes in the clonal isolates in cultures, and/or differences in culture conditions. Such methodological differences mean that using particular trait measurements from the prior literature might introduce unknown errors and bias into modelling projections. Using our community-wide approach we can reduce such protocol-driven variability in culture studies, and can begin to address more complex issues such as the effect of multiple environmental drivers on ocean biota.

A new marine woloszynskioid dinoflagellate, Biecheleria donggangensis sp. nov., germinated from the sediments of Rizhao coastal area, China, was examined by light and scanning electron microscopy. Its phylogenetic position was inferred from nuclear rDNA (partial LSU, SSU and ITS1–5.8S–ITS2) sequences. Cells were spherical to ellipsoidal (8.5‒19.2 μm long and 5.9‒11.5 μm wide) with numerous small and discoid chloroplasts, and a centrally located nucleus. Scanning electron microscopy showed an apical furrow area consisting of a single elongated apical vesicle (EAV) with 20 to 34 small globular knobs at the top of the epicone, and 13–15 latitudinal series of amphiesmal vesicles (AVs). Biecheleria donggangensis can be distinguished from other congeneric species by the configuration of the AVs bordering the EAV, the number of latitudinal AVs, and the trichocyst pore (TP) structures around the EAV. Thick-walled and spherical (or oval) cysts were 16.1‒23.5 μm in diameter and decorated with needle-like processes, each with a distal swelling. Molecular phylogenies using maximum likelihood (ML) were examined by three statistical methods (bootstrap, approximate Bayes and the Shimodaira-Hasegawa-like approximate likelihood-ratio test), which clearly demonstrated that the isolate belonged to the genus Biecheleria but formed a clade distinct from all previously described species. Genetic distance analyses justified describing the isolate as a new species rather than a new ribotype of B. cincta. [ABSTRACT FROM AUTHOR]