Abstract

Abyssal seafloor communities cover more than 60% of Earth’s surface. Despite their great size, abyssal plains extend across modest environmental gradients compared to other marine ecosystems. However, little is known about the patterns and processes regulating biodiversity or potentially delimiting biogeographical boundaries at regional scales in the abyss. Improved macroecological understanding of remote abyssal environments is urgent as threats of widespread anthropogenic disturbance grow in the deep ocean. Here, we use a new, basin-scale dataset to show the existence of clear regional zonation in abyssal communities across the 5,000 km span of the Clarion–Clipperton Zone (northeast Pacific), an area targeted for deep-sea mining. We found two pronounced biogeographic provinces, deep and shallow-abyssal, separated by a transition zone between 4,300 and 4,800 m depth. Surprisingly, species richness was maintained across this boundary by phylum-level taxonomic replacements. These regional transitions are probably related to calcium carbonate saturation boundaries as taxa dependent on calcium carbonate structures, such as shelled molluscs, appear restricted to the shallower province. Our results suggest geochemical and climatic forcing on distributions of abyssal populations over large spatial scales and provide a potential paradigm for deep-sea macroecology, opening a new basis for regional-scale biodiversity research and conservation strategies in Earth’s largest biome.

Publication Date

2023-01-01

Publication Title

Nature Ecology and Evolution

Volume

7

Issue

9

Acceptance Date

2023-06-08

Deposit Date

2026-06-30

Funding

This work was part of the UK Natural Environment Research Council funded Seabed Mining and Resilience to Experimental impact (SMARTEX) project (grant reference NE/T003537/1). D.O.B.J., E.S.L., N.B., A.M.S., G.B.C. and A.G.G. also received support from TMC (The Metals Company) through its subsidiary Nauru Ocean Resources (NORI); this is contribution TMC/NORI/D/007. S.P.R. was supported by funds from FCT/MCTES in the scope of the CEEC contract (CEECIND/00758/2017) and funds attributed to CESAM (UIDP/50017/2020, UIDB/50017/2020 and LA/P/0094/2020). Samples from the BGR license area were made available by C. Rühlemann and A. Vink from the Federal Institute for Geosciences and Raw Materials (BGR) in Hannover. P.M.A. and K.U. acknowledge EU JPIO-Oceans project Ecological Aspects of Deep-Sea Mining and MinigImpact-2 (German Ministry for Science and Education BMBF contract 03F0707E and 03F0812E.). The KODOS and APEI-9 datasets had been collected through environmental baseline studies for the polymetallic manganese nodules exploration contract of Republic of Korea (Ministry of Ocean and Fisheries’ R&D no. 20160099). D.C. acknowledges funding from Mining2/0002/2017, Mining2/0005/2017, granted by FCT/MCTES and DGPM and OP AZORES 2020 (01-0145-FEDER-000140 ‘MarAZ Researchers: Consolidate a body of researchers in Marine Sciences in the Azores’ and funds attributed to Okeanos-UAç (UIDB/05634/2020, UIDP/05634/2020 and M1.1.A/REEQ.CIENTIFICOU I&D/2021/010). The funders had no role in the conceptualization, design, data collection, analysis, decision to publish or preparation of the manuscript.

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

First Page

1388

Last Page

1397

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