In:
Biogeosciences, Copernicus GmbH, Vol. 17, No. 7 ( 2020-04-07), p. 1845-1876
Kurzfassung:
Abstract. The largest and commercially appealing mineral deposits
can be found in the abyssal sea floor of the Clarion-Clipperton Zone (CCZ), a
polymetallic nodule province, in the NE Pacific Ocean, where experimental
mining is due to take place. In anticipation of deep-sea mining impacts, it
has become essential to rapidly and accurately assess biodiversity. For this
reason, ophiuroid material collected during eight scientific cruises from
five exploration licence areas within CCZ, one area being protected from mining
(APEI3, Area of Particular Environmental Interest) in the periphery of CCZ
and the DISturbance and re-COLonisation (DISCOL) Experimental Area (DEA),
in the SE Pacific Ocean, was examined. Specimens were genetically analysed
using a fragment of the mitochondrial cytochrome c oxidase subunit I (COI).
Maximum-likelihood and neighbour-joining trees were constructed, while four
tree-based and distance-based methods of species delineation (automatic barcode gap discovery, ABGD; barcode index numbers, BINs;
general mixed Yule–coalescent, GMYC; multi-rate Poisson tree process, mPTP) were employed to propose secondary species hypotheses (SSHs)
within the ophiuroids collected. The species delimitation analyses'
concordant results revealed the presence of 43 deep-sea brittle star SSHs,
revealing an unexpectedly high diversity and showing that the most
conspicuous invertebrates in abyssal plains have been so far considerably
underestimated. The number of SSHs found in each area varied from five (IFREMER area) to 24 (BGR (Federal Institute for Geosciences and Natural Resources,
Germany) area) while 13 SSHs were represented by
singletons. None of the SSHs were found to be present in all seven areas while
the majority of species (44.2 %) had a single-area presence (19 SSHs).
The most common species were Ophioleucidae sp. (Species 29), Amphioplus daleus (Species 2)
and Ophiosphalma glabrum (Species 3), present in all areas except APEI3. The biodiversity
patterns could be mainly attributed to particulate organic carbon (POC) fluxes that could explain the
highest species numbers found in BGR (German contractor area) and UKSRL (UK Seabed Resources Ltd, UK
contractor area) areas. The five exploration contract areas belong to a
mesotrophic province, while conversely the APEI3 is located in an
oligotrophic province, which could explain the lowest diversity as well as
very low similarity with the other six study areas. Based on these results
the representativeness and the appropriateness of APEI3 to meet its purpose
of preserving the biodiversity of the CCZ fauna are questioned. Finally,
this study provides the foundation for biogeographic and functional analyses
that will provide insight into the drivers of species diversity and its role
in ecosystem function.
Materialart:
Online-Ressource
ISSN:
1726-4189
DOI:
10.5194/bg-17-1845-2020
DOI:
10.5194/bg-17-1845-2020-supplement
Sprache:
Englisch
Verlag:
Copernicus GmbH
Publikationsdatum:
2020
ZDB Id:
2158181-2
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