English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Macroalgae has bloomed in the brackish lake of Shenzhen Bay, China continuously from 2010 to 2014.  Gracilaria tenuistipitata  was identified as the causative macroalgal species. The aim of this study was to explore the outbreak mechanism of  G. tenuistipitata , by studying the effects of salinity and nitrogen sources on growth, and the different nitrogen sources uptake characteristic. Our experimental design was based on environmental conditions observed in the bloom areas, and these main factors were simulated in the laboratory. Results showed that salinity 12 to 20 ‰ was suitable for  G. tenuistipitata  growth. When the nitrogen sources' (NH 4   + , NO 3   − ) concentrations reached 40 µM or above, the growth rate of  G. tenuistipitata  was significantly higher. Algal biomass was higher (approximately 1.4 times) when cultured with NH 4   +  than that with NO 3   −  addition. Coincidentally, macroalgal bloom formed during times of moderate salinity (∼12 ‰) and high nitrogen conditions. The NH 4   +  and NO 3   −  uptake characteristic was studied to understand the potential mechanism of  G. tenuistipitata  bloom. NH 4   +  uptake was best described by a linear, rate-unsaturated response, with the slope decreasing with time intervals. In contrast, NO 3   −  uptake followed a rate-saturating mechanism best described by the Michaelis-Menten model, with kinetic parameters  V max   = 37.2 µM g −1  DM h −1  and  K s   = 61.5 µM. Further, based on the isotope  15 N tracer method, we found that  15 N from NH 4   +  accumulated faster and reached an atom% twice than that of  15 N from NO 3   − , suggesting when both NH 4   +  and NO 3   −  were available, NH 4   +  was assimilated more rapidly. The results of the present study indicate that in the estuarine environment, the combination of moderate salinity with high ammonium may stimulate bloom formation.

Growth and Nitrogen Uptake Characteristics Reveal Outbreak Mechanism of the Opportunistic Macroalga Gracilaria tenuistipitata