Origins of the Deep-Sea Biodiversity — a crustacean perspective

Until well into the 19th century, the deep sea was considered an uninhabited, dark, cold, and monotonous desert; harsh and hostile to any form of life. Important natural scientists of that time spread the idea that animal life could not exist in the great depths of the sea. They all ignored or overlooked reports of animal catches from depths of over 1000 m, which had already been published during their lifetime. Only the Scottish natural scientist Wyville Thomson, with the help of the then vice president of the British Royal Society, William Carpenter, was finally able to conclude with the theory of the lifeless deep sea on an expedition with the British ship “Porcupine” in the years 1868-1870. It is thus only just over 150 years ago that the mere existence of deep-sea animals was generally known. Of course, deep-sea research has made enormous progress since then. Nonetheless, even today scientists agree that only the proverbial surface of the deep sea has been scratched and that many groundbreaking discoveries about this fascinating habitat can still be expected.

In May 2020, the book accompanying the new deep-sea exhibition will be published in the Senckenberg Books series. The book will be attractively illustrated and will provide first-hand information about deep-sea research and its background in a language that is easy to understand, written by scientists from Senckenberg and its science partner GEOMAR. Contributions by the Senckenberg crustacean researchers are also included:

Müller T, Hoffmann-Wieck G (Eds) (2020) Tiefsee – Vielfalt in der Dunkelheit. Schweizerbart Science Publishers, Stuttgart. 204 pages, 177 illustrations. ISBN: 978-3-510-61415-8 (in German)

Today, although we know that the supposedly homogeneous deep-sea plains are inhabited by a remarkable diversity of mainly small organisms, the understanding of their origins is vague. The phylogenetic origins of deep-sea organisms and their ties to shallow-water relatives, their biogeographic ranges including historical changes of the like, or the ecological factors promoting coexistence of diverse assemblages in the deep sea are loosely known.

This project aims for improved understanding of

  • how so many species are capable of coexisting in abyssal sediments,
  • which factors drive their evolution, and
  • where their phylogeographic origins lie.

A combination of population genetic, phylogenetic, taxonomic, biogeographic and ecological methodologies is applied in this endeavor combining samples and results from various campaigns and projects. These all share their common goal to gain a better understanding of the origins of the deep-sea biodiversity. In particular, “A crustacean perspective of the origins of the deep-sea biodiversity” is the habilitation theme of Dr. Torben Riehl who primarily uses the isopod crustacean family Macrostylidae as a model but also other crustacean taxa to infer rather general patterns for the origins of the deep-sea biodiversity.

Papers published in the framework of this habilitation project: 

Riehl T, Brandão SN, Brandt A (2020) Conquering the ocean depths over three geological eras. In: Thiel M, Poore GCB (eds) Evolution and Biogeography. Oxford University Press, New York, pp 155–182. (to be published in June 2020)

Riehl T, De Smet B (2020) Macrostylis metallicola spec. nov. — An isopod with geographically clustered genetic variability from a polymetallic-nodule area in the Clarion-Clipperton Fracture Zone. PeerJ 8:1–44.

Riehl T, Kühn MAL (2020) Uniting what belongs together — reevaluation of the isopod species Macrostylis grandis and M. ovata using ontogenetic, morphological and genetic evidence. Prog Oceanog 181:102238.

Brandão SN, Hoo H, Hoppema M, Kamenev GM, Karanovic I, Riehl T, Tanaka H, Vital H, Brandt A (2019) Review of Ostracoda (Crustacea) living below the Carbonate Compensation Depth and the deepest record of a calcified ostracod. Prog Oceanog.

McCallum A, Riehl T (2020) Intertidal to Abyss: Crustaceans and Depth. In: Thiel M, Poore GCB (eds) Evolution and Biogeography. Oxford University Press, New York, pp 429–449. (to be published in June 2020)

Brandt A, Alalykina I, Brix S, Brenke N, Błażewicz M, Golovan OA, Johannsen N, Hrinko AM, Jażdżewska AM, Jeskulke K, Kamenev GM, Lavrenteva AV, Malyutina MV, Riehl T, Lins L (2019) Depth zonation of Northwest Pacific deep-sea macrofauna. Prog Oceanog 176:102131.

Riehl T, Lins L, Brandt A (2018) The effects of depth, distance, and the Mid-Atlantic Ridge on genetic differentiation of abyssal and hadal isopods (Macrostylidae). Deep-Sea Res Pt II 148:74–90.

Bober S, Brix S, Riehl T, Schwentner M, Brandt A (2018) Does the Mid-Atlantic Ridge affect the distribution of abyssal benthic crustaceans across the Atlantic Ocean? Deep-Sea Res Pt II 148:91–104.

Kniesz K, Brandt A, Riehl T (2018) Peritrich ciliate epibionts on the new hadal isopod species Macrostylis marionae from the Puerto Rico Trench as an indicator for sex-specific behaviour. Deep-Sea Res Pt II 148:105–129.

Johannsen N, Lins L, Riehl T, Brandt A (2020) Changes in species composition of Haploniscidae (Crustacea: Isopoda) across potential barriers to dispersal in the Northwest Pacific. Prog Oceanog 180:102233.