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How many species live in the world’s largest marine mineral exploration region?

The Clarion-Clipperton Zone (CCZ) is found in the central and eastern Pacific. It covers 6 million km2 and is one of the few remaining areas of the global ocean that has not yet been disturbed by humans. Deep sea ecosystems are known to be especially vulnerable and long to recover. With growing interest in opening the CCZ for extraction of deep-sea mineral resources, it is ever more crucial that baseline biodiversity data is made available, especially for assessing species extinction risk and potential environmental impacts.

Although much remains unknown, recent advances over the last decade have led to rapid growth in published data available for the CCZ. This study offers the first comprehensive synthesis of this data, providing a checklist and initial inventory of metazoan fauna thereby establishing an important baseline for future assessments.

Prior to this analysis, it was estimated that there are over 80% undescribed species in the CCZ. The study provides the first quantitative support for this figure, with calculations that about 88%–92% of species in the CCZ region are waiting to be described. That is, 92% of species identified from the CCZ are new to science (436 named species from a total of 5,578 recorded). Also, that 5,142 unnamed species (informal names) have been recorded while total estimates of species richness range from >6,000–>8,000.

Fig1

Figure 1. The rate of species descriptions documented in the CCZ since 1980.

Fig2

Figure 2. The proportion of species in the CCZ which remain undescribed.

How OBIS was used in this study

Data were harnessed from OBIS, the Global Biodiversity Information Facility (GBIF) and other sources. Occurrence data in OBIS were downloaded using a functionality of the robis package. DeepData records have been harvested by OBIS since June 2021 and published by the OBIS ISA node. After thorough data cleaning procedures, the researchers used the data from these different sources to produce the checklist which offers an important first step towards the development of field guides for the region which will aid future species identification efforts.

The study highlights there are significant remaining taxonomic barriers to overcome for understanding CCZ biodiversity. For example, rocky seamounts and outcrops have barely been sampled. The authors suggest that filling these gaps in knowledge will require extensive collaboration between stakeholders and appropriate and sustained funding. Programs like the Sustainable Seabed Knowledge Initiative (SSKI) of ISA, recognized under the UN Ocean Decade, should be leveraged to fund descriptions in all taxonomic groups. Also, the authors emphasise the need for a robust standardised approach to open nomenclature to ensure that species-level taxa can be referenced and that datasets are comparable and linked to open verified datasets.

Full publication available at:

Rabone, M., J.H. Wiethase, E. Simon-Lledó, A.M. Emery, D.O.B. Jones, T.G. Dahlgren, G. Bribiesca-Contreras, H. Wiklund, T. Horton and A.G. Glover. 2023. How many metazoan species live in the world’s largest mineral exploration region? Current Biology, Volume 33, 12.