Tag: annelids

Insights into the biodiversity of annelids in the world’s largest deep-sea mineral exploration region

This study, published in Biodiversity Data Journal, is an important step in creating field guides for CCZ wildlife, which will help promote sustainable practices and informed decision-making.

The demand for rare raw materials, such as cobalt, is fuelling the exploration of the deep-sea floor for mining. Commercial deep-sea mining is currently prohibited in areas beyond national jurisdiction, but companies are permitted exploratory operations in certain areas to assess their mineral wealth and measure environmental baselines. The Clarion-Clipperton Zone (CCZ) is an area of the Pacific deep-sea floor spanning up to 6 million km², found roughly between Hawaii and Mexico. Currently, it has 17 contracts for mineral exploration covering 1.2 million km². However, despite relatively extensive mineral exploration beginning in the 1960’s, baseline biodiversity knowledge of the region is still severely lacking. Even the most basic scientific question: “What lives there?” has not been fully answered yet.

Annelids found in the Clarion-Clipperton Zone.

In a new paper researchers report on the marine life of the CCZ, focusing on annelid worms. Annelids represent one of the largest group of macroinvertebrates living within the mud covering the sea floor of CCZ, both in terms of number of individuals and the number of species. Data from recent oceanographic cruises enabled researchers from the University of Gothenburg, Sweden and the Natural History Museum London to discover more than 300 species of annelids from around 5000 records. The annelid species, many considered to be new to science, were discovered through employment of traditional morphological approaches and modern molecular techniques. The current study focuses on 129 such species across 22 annelid families. Previously, the authors of this study formalized 18 new species, while altogether reporting on 60 CCZ species, including most recently 6 species in family Lumbrineridae. The lead author Helena Wiklund from University of Gothenburg comments: ‘Taxonomy is the most important knowledge gap we have when studying these unique habitats and the potential impact of mining operations. We need to know what lives there to inform the protection of these ecosystems.”

To further understand the CCZ, scientists sail the Pacific Ocean on research expeditions that employ sampling techniques ranging from the technical, like remote-controlled vehicles that traverse the ocean floor, to the simple, like a sturdy box corer collecting sediment at the bottom.

“Sadly, the soft-bodied annelids are often damaged during the collection and sediment sieving onboard” says annelid taxonomist Lenka Neal from the Natural History Museum London. As a result, the traditional morphological approach is often of limited use when working with the deep-sea specimens, with taxonomists increasingly employing DNA techniques as well.

Over the last decade, scientists have generated a large amount of annelid data. Such data are only of use when made available through publication to the wider scientific community and other stakeholders. “A priority is to make the data are FAIR, or Findable, Accessible, Interoperable and Reusable so it can be redeployed easily, if you’ll excuse the pun, for future analysis” says co-author Muriel Rabone. “The same applies to samples, where accessibility of the specimen vouchers and molecular samples allows for reproducibility and continuation of the work. This is one step of the process. And ultimately, having more robust knowledge can lead to more robust evidence-based environmental policy”.

“More often than not, ecological papers describing biodiversity do not include a list of all the species and specimens used to make the broader ecological inferences, and even more rarely make the specimens and all associated metadata available in a FAIR way. In this study, we have made a significant and time-consuming attempt to do this, in a region of the global oceans where critical policy decisions are being made that could impact the way humanity obtains its resources and manages its environment in a sustainable way,” the researchers write in their paper, which was published in the open-access Biodiversity Data Journal.

The team behind the research hope that this still partial checklist of CCZ annelids, many in too poor state of preservation to be immediately described, is a key step forward towards creating future field guides for the area’s wildlife. Given that mining operations in the area could be imminent with the International Seabed Authority considering applications this year, the use of biological data for environmental management has become more important than ever.

This research was supported by funding from UK Seabed Resources Ltd.

Research article:

Wiklund H, Rabone M, Glover AG, Bribiesca-Contreras G, Drennan R, Stewart ECD, Boolukos CM, King LD, Sherlock E, Smith CR, Dahlgren TG, Neal L (2023) Checklist of newly-vouchered annelid taxa from the Clarion-Clipperton Zone, central Pacific Ocean, based on morphology and genetic delimitation. Biodiversity Data Journal 11: e86921. https://doi.org/10.3897/BDJ.11.e86921

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Conservation and nameless earthworms: Assessors in the dark?

Species that live exclusively in a single region are at a particular risk of extinction. However, for them to be protected, thorough assessments of the environmental impacts need to be performed.

There are more than 100 earthworm species living in the soil and dead wood of KwaZulu-Natal Province, South Africa. Most of them live exclusively in small regions in the province, which makes them extremely vulnerable.

To scientists Dr Adrian J. Armstrong, Ezemvelo KZN Wildlife, and Ms Thembeka Nxele, KwaZulu-Natal Museum, the problem is twofold. Firstly, they note that the expression “out of sight, out of mind” is very suitable for the case of the endemic earthworms in South Africa. Secondly, they point out that the lack of common names for these species is a stumbling block that hinders their inclusion in conservation assessments.

As a result, the researchers try to rectify this situation by assigning standardised English names to the endemic earthworms in KwaZulu-Natal. Their article is published in the open access journal African Invertebrates.

Scientific names are often intractable to non-specialists, and the lack of common names leaves environmental assessors in the dark when they need to figure out which earthworms may occur at a development site. In the meantime, it has been found that about 50% of the native vegetation in KwaZulu-Natal has already been removed as a result of infrastructure construction and the figure is rising.

“The indigenous earthworms generally don’t survive in developed areas,” say the authors.

For instance, the informal use of an English name (green giant wrinkled earthworm) for the species Microchaetus papillatus, has facilitated the inclusion of this species in environmental impact assessments in KwaZulu-Natal.

While the green giant wrinkled earthworm does occur in a relatively large and rapidly developing area in KwaZulu-Natal, other species live in smaller areas that have been urbanised even more.

The extinction of these earthworms is not only undesirable from the point of view of biodiversity advocates – the role of this group of soil organisms is impossible to replace fully with non-native earthworms. For example, some of the large indigenous earthworms (more than 1 m in length) burrow much deeper than the non-native species, thereby enriching and aerating the soil at greater depth.

The authors are hopeful that by giving the indigenous earthworms in KwaZulu-Natal common names, the threatened and endemic species will be conserved through inclusion in environmental impact assessments. Furthermore, they believe that earthworms could draw attention to the areas where they occur whenever a choice for new protected areas is to be made.

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Original source:

Armstrong AJ, Nxele TC (2017) English names of the megadrile earthworms (Oligochaeta) of KwaZulu-Natal. African Invertebrates 58(2): 11-20. https://doi.org/10.3897/AfrInvertebr.58.13226

Unfamiliar bloodline: New family for an earthworm genus with exclusive circulatory system

New earthworm family, named Kazimierzidae, has been established for a South African indigenous genus of 21 species. Although the circulatory system in the group has been regarded as exclusive upon their original description in 2006, their raising to a family status have only recently been confirmed by a research team from South Africa.

Scientists Mrs Thembeka Nxele, Dr Danuta Plisko (original discoverer of the genus Kazimierzus, now known as family Kazimierzidae), affiliated with Natal Museum (NMSA), Oliver Tendayi Zishiri, affiliated with University of KwaZulu-Natal, and Dr Taro Mwabvu, University of Mpumalanga, looked into the earthworm collection at the NMSA, as well as the type material and the available literature. Their study is published in the open access journal African Invertebrates.

When compared to the rest of the members in the family Microchaetidae, where the former genus had been placed, the studied earthworms show a number of distinct characters, including an “exclusive” circulatory system. In these species it is a simple single tube stretching along the whole body.

All 21 earthworm species, now members of the newly established family, can only be found in small areas restricted in the western and south-western Atlantic coast of South Africa. These locations have long been known for their endemic invertebrates and diverse flora.

In their paper, the authors note that it is actually the restricted range, and therefore the specific ecological requirements, that might have led these earthworms to become that different from other species. Their distribution and, hence, poor dispersal ability, are also the reason why the newly established group would be particularly vulnerable if the habitat is transformed.

“The species distribution of earthworms in Southern Africa is presently poorly known hence the urgency for extended study on earthworm diversity and their distribution patterns,” point out the scientists. “Extensive earthworm collection in the western Atlantic coast may bring more data on this and other taxa.”

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Original source:

Nxele TC, Plisko JD, Mwabvu T, Zishiri TO (2016) A new family Kazimierzidae for the genus Kazimierzus, earlier recorded to the composite Microchaetidae (Annelida, Oligochaeta). African Invertebrates 57(2): 111-117. doi: 10.3897/AfrInvertebr.57.10042