DOI: 10.5194/bg-17-1231-2020
论文题名: Deep-sea sponge grounds as nutrient sinks: Denitrification is common in boreo-Arctic sponges
作者: Rooks C. ; Kar-Hei Fang J. ; Mørkved P.T. ; Zhao R. ; Tore Rapp H. ; Xavier R.J. ; Hoffmann F.
刊名: Biogeosciences
ISSN: 17264170
出版年: 2020
卷: 17, 期: 5 语种: 英语
英文摘要: Sponges are commonly known as general nutrient providers for the marine ecosystem, recycling organic matter into various forms of bioavailable nutrients such as ammonium and nitrate. In this study we challenge this view. We show that nutrient removal through microbial denitrification is a common feature in six cold-water sponge species from boreal and Arctic sponge grounds. Denitrification rates were quantified by incubating sponge tissue sections with 15 NO 3 - 15 NH 4 + -3 sponge d-1 under oxic conditions, and from 24 to 279 nmol N cm-3 sponge d-1 under anoxic conditions. A positive relationship between the highest potential rates of denitrification (in the absence of oxygen) and the species-specific abundances of nir S and nir K genes encoding nitrite reductase, a key enzyme for denitrification, suggests that the denitrifying community in these sponge species is active and prepared for denitrification. The lack of a lag phase in the linear accumulation of the 15N -labelled N2 gas in any of our tissue incubations is another indicator for an active community of denitrifiers in the investigated sponge species. Low rates for coupled nitrification-denitrification indicate that also under oxic conditions, the nitrate used to fuel denitrification rates was derived rather from the ambient seawater than from sponge nitrification. The lack of nif H genes encoding nitrogenase, the key enzyme for nitrogen fixation, shows that the nitrogen cycle is not closed in the sponge grounds. The denitrified nitrogen, no matter its origin, is then no longer available as a nutrient for the marine ecosystem. These results suggest a high potential denitrification capacity of deep-sea sponge grounds based on typical sponge biomass on boreal and Arctic sponge grounds, with areal denitrification rates of 0.6 mmol N m-2 d-1 assuming non-pumping sponges and still 0.3 mmol N m-2 d-1 assuming pumping sponges. This is well within the range of denitrification rates of continental shelf sediments. Anthropogenic impact and global change processes affecting the sponge redox state may thus lead to deep-sea sponge grounds changing their role in marine ecosystem from being mainly nutrient sources to becoming mainly nutrient sinks. © 2020 BMJ Publishing Group. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/158739
Appears in Collections: 气候变化与战略
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作者单位: Department of Biological Sciences, University of Bergen, P.O. Box 7803, Bergen, 5020, Norway; Department of Applied Biology and Chemical Technology, Hong Kong Polytechnic University, Hung Hom, Hong Kong; Department of Earth Sciences, University of Bergen, Postboks 7803, Bergen, 5020, Norway; K.G. Jebsen Centre for Deep Sea Research, University of Bergen, Postboks 7803, Bergen, 5020, Norway; NORCE, Norwegian Research Centre, NORCE Environment, Nygärdsgaten 112, Bergen, 5008, Norway; CIIMAR - Interdisciplinary Centre of Marine and Environmental Research of the University of Porto, Matosinhos, 4450-208, Portugal
Recommended Citation:
Rooks C.,Kar-Hei Fang J.,Mørkved P.T.,et al. Deep-sea sponge grounds as nutrient sinks: Denitrification is common in boreo-Arctic sponges[J]. Biogeosciences,2020-01-01,17(5)