Abstract

Recently, there has been a resurgent interest in the exploration of deep-sea mineral deposits, particularly polymetallic nodules in the Clarion-Clipperton Zone (CCZ), central Pacific. Accurate environmental impact assessment is critical to the effective management of a new industry and depends on a sound understanding of species taxonomy, biogeography, and connectivity across a range of scales. Connectivity is a particularly important parameter in determining ecosystem resilience, as it helps to define the ability of a system to recover post-impact. Scavenging amphipods in the superfamilies Alicelloidea Lowry and De Broyer, 2008 and Lysianassoidea Dana, 1849 contribute to a unique and abundant scavenging community in abyssal ecosystems. They are relatively easy to sample and in recent years have become the target of several molecular and taxonomic studies, but are poorly studied in the CCZ. Here, a molecular approach is used to identify and delimit species, and to investigate evolutionary relationships of scavenging amphipods from both abyssal plain and deep (>3000 m) seamount habitats in three APEIs (Areas of Particular Environmental Interest, i.e., designated conservation areas) in the western CCZ. A total of 17 different morphospecies of scavenging amphipods were identified, which include at least 30 genetic species delimited by a fragment of the cytochrome c oxidase subunit I (COI) barcode gene. The scavenging communities sampled in the western CCZ included the most common species (Abyssorchomene gerulicorbis (Shulenberger and Barnard, 1976), A. chevreuxi (Stebbing, 1906), Paralicella caperesca Shulenberger and Barnard, 1976, and P. tenuipes Chevreux, 1908) reported for other ocean basins. Only four morphospecies, representing five genetic species, were shared between APEIs 1, 4, and 7. The two abyssal plain sites at APEIs 4 and 7 were dominated by two and three of the most common scavenging species, respectively, while the APEI 1 seamount site was dominated by two species potentially new to science that appeared to be endemic to the site. The presence of common species in all sites and high genetic diversity, yet little geographic structuring, indicate connectivity over evolutionary time scales between the areas, which span about 1500 km. Similar to recent studies, the differences in amphipod assemblages found between the seamount and abyssal sites suggest that ecological conditions on seamounts generate distinct community compositions.

Highlights

  • It has been known that large deposits of metals such as nickel, iron, copper, cobalt, and manganese, in the form of polymetallic nodules exist in the abyssal deep sea (Mewes et al, 2014)

  • A total of 5749 specimens were captured during five 22 + hour deployments of baited traps, of which 1057 individual amphipods were captured on the APEI 1 seamount, 2399 on the APEI 4 abyssal plain site, 2292 (1801 plus 491 individuals from two different deployments) on the APEI 7 abyssal plain site, and a single specimen on the APEI 7 seamount site (Table 1)

  • The assemblage composition of the three areas was highly dominated by a few species (Figure 1), with common deep-sea amphipod scavenger species dominating the communities in APEI 4 (Abyssorchomene gerulicorbis: 45%, Paralicella tenuipes complex: 25%, and P. caperesca complex: 21%) and APEI 7 (P. tenuipes complex: 75%, and P. caperesca complex: 16%)

Read more

Summary

Introduction

It has been known that large deposits of metals such as nickel, iron, copper, cobalt, and manganese, in the form of polymetallic nodules exist in the abyssal deep sea (Mewes et al, 2014). The Clarion-Clipperton Zone (CCZ), located in the central Pacific, has one of the largest known deposits of polymetallic nodules and deep-sea mining exploration in the area has greatly increased in the last decade. The ISA has implemented a regional environmental management plan, provisionally designating nine representative areas where mining activities will be prohibited (Areas of Particular Environmental Interest, APEI) to preserve the biodiversity and ecosystem functions across the region (Wedding et al, 2013) Their effectiveness depends on several key ecological criteria, the degree to which APEI community compositions are representative of mining contract areas and whether they could maintain regional connectivity in the event of miningrelated habitat loss

Methods
Results
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call