Introduction Xenophyophores are large benthic agglutinated Foraminifera that are a major component of the Clarion-Clipperton Zone megafauna. Methods Two xenophyophore specimens were obtained and submitted to genomic investigations. Results For both specimens, it was possible to obtain a ca. 25 kb circular xenophyophore-associated mitochondrial genome (XAM) showing similar gene contents with other Retaria, with which they are a...

The abyssal Pacific Clarion Clipperton Zone (CCZ) hosts vast, commercially valuable seafloor deposits of polymetallic nodules. Foraminifera (testate protists) dominate benthic communities in this region. Here, we present a taxonomic survey, combining morphological and genetic data and focussing on mainly meiofauna-sized Foraminifera from the eastern CCZ. Sequences obtained from >100 specimens, the majority photographically doc...

Benthic foraminifera cannot be sampled adequately using a single device. Smaller taxa are best collected using multicorers, the larger with box corers, but towed devices (dredges, trawls and epibenthic sledges) also retain many larger species. Here, we describe macrofaunal (>300 µm) foraminiferal assemblages obtained using an epibenthic sledge (EBS) in the Clarion-Clipperton Zone (eastern equatorial Pacific), a region hosting...

The abyssal plains are vast areas without large scale relief that occupy much of the ocean floor. Although long considered relatively featureless, they are now known to display substantial biological heterogeneity across different spatial scales. Ecological research in these regions benefits increasingly from non-destructive visual sampling of epifaunal organisms with imaging technology. We analysed images from ultra-high-defi...

The Clarion Clipperton Zone (CCZ) is a vast area of the central Pacific Ocean where the abyssal seabed is a focus for future polymetallic nodule mining. Broad-scale environmental gradients occur east-to-west across the CCZ seabed, including organic matter supply and nodule abundance, factors that influence benthic faunal community structure and function. A network of protected areas across the CCZ, called Areas of Particular E...

Benthic foraminiferal research in the North Pacific has a long history, with works published over a century ago providing important information about the taxonomy and distribution of morphospecies. These studies focused mainly on areas outside the Clarion-Clipperton Zone (CCZ). Our knowledge of foraminiferal faunas within the CCZ originates largely from recent baseline investigations related to likely future seabed mining of t...

The abyssal seafloor is a mosaic of highly diverse habitats that represent the least known marine ecosystems on Earth. Some regions enriched in natural resources, such as polymetallic nodules in the Clarion-Clipperton Zone (CCZ), attract much interest because of their huge commercial potential. Since nodule mining will be destructive, baseline data are necessary to measure its impact on benthic communities. Hence, we conducted...

The cycling of carbon (C) by benthic organisms is a key ecosystem function in the deep sea. Pulse‐chase experiments are designed to quantify this process, yet few studies have been carried out using abyssal (3500–6000 m) sediments and only a handful of studies have been undertaken in situ. We undertook eight in situ pulse‐chase experiments in three abyssal strata (4050–4200 m water depth) separated by tens to hundreds of kilom...

Large nematodes form an important component of deep‐sea macrofaunal assemblages, but are often considered to be part of the meiobenthos and are rarely studied. We analysed the standing stocks, diversity, and functional group and genus‐level composition of macrofaunal nematodes at lower bathyal depths (3,500 m water depth) in the Whittard Canyon system ( NE Atlantic) and on the adjacent continental slope. Five replicate sample...