Aquatic nitrogen-fixing cyanobacteria associated with blooms of Didymosphenia geminata: insights from a field study

作者：Novis Phil^*; Schallenberg Marc; Smissen Rob

来源：Hydrobiologia, 2016, 770(1): 37-52.

DOI：10.1007/s10750-015-2567-8

• Cyanobacteria
• Didymosphenia geminata
• Godleya
• Nitrogen fixation

The nuisance diatom Didymosphenia geminata has recently increased in abundance worldwide and has spread through oligotrophic rivers in the South Island of New Zealand. However, it remains absent from the North Island. Its proliferation in oligotrophic environments has prompted work on phosphorus acquisition, but potential nitrogen acquisition pathways have received little attention. We partially sequenced the nifD gene, encoding a component of nitrogenase, from South Island samples containing D. geminata and compared its diversity with that of North Island sites independently ranked as high, medium and low risk for infestation. Godleyacean cyanobacteria were present in all four South Island provinces investigated, and also in three North Island sites rated medium or high risk. Most high-risk sites were dominated by Nostoc sequences, as were some infested South Island sites. Monte Carlo simulations and the weighted UniFrac metric showed that nifD diversity in low-risk North Island sites differed significantly from sites rated medium and high risk, and from infested South Island sites; however, random resampling showed that the data were insufficient to separate didymo-infested and high-risk sites from medium-risk sites. The relationships we discovered suggest that success of D. geminata in New Zealand could be mediated by indigenous nitrogen-fixing cyanobacteria.

• 出版日期2016-5