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bioRxiv · 10.1101/2022.04.27.489739

Diversity and abundance of archaeal amoA genes in the permanent and temporary oxygen minimum zones of Indian Ocean.

PrasannaKumar, C.·Elamaran, A.
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Abstract

Oxygen minimum zones are results of oxygen consumption exceeding the oxygen availability in stratified water columns of the marine environment. We compared the ammonia monooxygenase subunit A (amoA) gene abundance and the diversity of ammonia-oxidising archaea (AOA) in the Arabian Sea (AS) with those of the Bay of Bengal (BoB). Three primer pairs targeting amoA genes of water column A (WCA), water column B (WCB) and total AOA (amoAt) captured different densities of gene copy numbers in both marginal seas. Water column A (WCA) ecotypes were more abundant in the AS than in the BoB. Core-OMZ depths of the BoB contained 10 times lower amoA copy numbers than those of the AS. Along with sampling depth, concentration of ammonia shapes the WCA/WCB ecotypes in AS/BoB. Among the total AOA populations, WCB ecotypes were more abundant. The amoA gene sequences were either of Nitrosopumilales or Ca. Nitrosotaleales members and belonged to NP-{gamma}, NP-{delta}, NS-{beta}, NS-{gamma} and NS-{varepsilon} sub-clades. Pairwise distance and nucleotide diversity index analysis reveals that BoB nurtures two times more diverse amoA sequences than the AS. The core OMZ region of the BoB contains a two-fold higher diversity of amoA gene sequences compared to the AS, whereas the AS contains 13 times more abundant amoA copies than the BoB.

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PrasannaKumar, C., Elamaran, A.. 2022-04-27. Diversity and abundance of archaeal amoA genes in the permanent and temporary oxygen minimum zones of Indian Ocean.. https://doi.org/10.1101/2022.04.27.489739

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