Emission of nitrous oxide and dinitrogen by diverse earthworm families from Brazil and resolution of associated denitrifying and nitrate‐dissimilating taxa. Issue 2 (17th September 2012)

• Record Type: Journal Article
• Authors: Depkat‐Jakob, Peter S.; Brown, George G.; Tsai, Siu M.; Horn, Marcus A.; Drake, Harold L.
• Is Part Of: FEMS microbiology ecology. Volume 83:Issue 2(2013)
• Page Start: 375
• Page End: 391
• Publication Date: 2012-09-17
• Subjects: Microbial ecology -- Periodicals; Microbiology -- Periodicals; 579.17
• DOI: 10.1111/j.1574-6941.2012.01476.x
• Languages: English
• ISSNs: 0168-6496

Abstract

<abstract abstract-type="main" id="fem1476-abs-0001"> <title>Abstract</title> <p>The anoxic earthworm gut augments the activity of ingested microorganisms capable of anaerobiosis. Small earthworms (<italic>Lumbricidae</italic>) emit denitrification‐derived N<sub>2</sub>O, whereas the large <italic>Octochaetus multiporus</italic> (<italic>Megascolecidae</italic>) does not. To examine this paradox, differently sized species of the families <italic>Glossoscolecidae</italic> (<italic>Rhinodrilus</italic>, <italic> Glossoscolex</italic>, <italic> Pontoscolex</italic>), <italic>Megascolecidae</italic> (<italic>Amynthas</italic>, <italic> Perionyx</italic>), <italic>Acanthodrilidae</italic> (<italic>Dichogaster</italic>), and <italic>Eudrilidae</italic> (<italic>Eudrilus</italic>) from Brazil were analyzed. Small species and the large <italic>Rhinodrilus alatus</italic> emitted N<sub>2</sub>O, whereas the large <italic>Glossoscolex paulistus</italic> did not, even though its gut could denitrify. N<sub>2</sub> and N<sub>2</sub>O were emitted concomitantly, and <italic>R. alatus</italic> emitted the highest amount of N<sub>2</sub>. Denitrifiers and dissimilatory nitrate reducers were analyzed by barcoded amplicon pyrosequencing of <italic>narG</italic>, <italic>nirK</italic>, and <italic>nosZ</italic>. Gene sequences in gut and soil of the large <italic>G. paulistus</italic> were similar, whereas sequences in gut and soil of the small <italic>Amynthas gracilis</italic> were different and were also different compared with those of the gut and soil of <italic>G. paulistus</italic>. However, the denitrifying gut microbiota for both earthworms appeared to be soil‐derived and dominated by <italic>Rhizobiales</italic>. The results demonstrated that (1) the emission of denitrification‐derived N<sub>2</sub>O is widespread in different earthworm families, (2) large earthworms can also emit nitrogenous gases, and (3) ingested members of <italic>Rhizobiales</italic> are associated with this emission.</p> </abstract>