Evolution of Deep-Sea Ecosystems

Project overview

Project period: ongoing since 2004

Participating departments from the museum: Palaeobiology

The deep ocean harbors a wide range of unique and extreme habitats. The main focus of this project is on so-called chemosynthetic ecosystems such as methane-seeps, that are fueled by geochemical energy. Due to their independence from photosynthetic primary production, they are considered to have had their own, unique evolutionary history. Many hypotheses on the origin and evolution of chemosynthetic ecosystems employ events of the geologic past, but rarely consider fossil evidence.

Project description

The fossil record of deep-sea ecosystems, mainly found in uplifted deep-water sediments along active continental margins, is used to describe the past biodiversity in deep-sea habitats and to detect large-scale evolutionary patterns, as well as their (geological) drivers. The project encompasses exploratory fieldwork, geochemical analyses, descriptions of newly discovered sites and fossils (alpha taxonomy), and the analysis of large datasets.

Focus on Mesozoic and Cenozoic molluscs

Molluscs (clams and snails) are the most common and abundant fossils in Mesozoic and Cenozoic deep-water deposits, especially at ancient methane seeps. Hence, they are used as model group to understand the evolution of these ecosystems. Other clades of interest are brachiopods, annelids, and corals, which also have calcarous hard parts, and occassionally fish remains.

Scientific results

The project provided numerous new insights into the evolution and ecology of deep-sea ecosystems. As a result of the extensive field work, NRM now houses the largest collection of fossil methane-seep faunas worldwide. Some of the main scientific achievments include:

• Identification of changing marine sulfate concentrations as main driver of the evolution of methane-seep and hydrothermal vent faunas (Kiel, 2015);
• new insights of the ecology of brachiopods at ancient methane-seeps and in cryptic habitats, and their reliance on methane-oxidizing bacteria (rather than sulfur-oxidizers) (Kiel & Peckmann, 2019, Kiel et al. 2021);
• discovery of the first fossil traces of the bone-eating worm Osedax (Kiel et al. 2010);
• discoveries of the first methane-seep faunas of Triassic age (Peckmann et al. 2011, Kiel et al. 2017);
• and documenting the impact of predation by pinnipeds on the geographic distribution of the ‘Living Fossil’ Nautilus (Kiel et al. 2022).

The project has also resulted in numerous newly described fossil species and genera, from Mesozoic and Cenozoic strata from all over the world. Examples include:

• Mollusks from Neogene methane-seep deposits in the Philippines (Kiel et al. 2018, 2022);
• mollusks and crustaceans from Paleogene methane-seep deposits in western South America (Kiel et al., 2019, 2020, 2021);
• mollusks from Neogene methane-seep deposits in Italy (Kiel & Taviani, 2017; Kiel et al., 2023);
• the first fossil record of the deep-water octocoral family Chrysogorgiidae (Goedert et al. 2022);
• and the first description of fossilized egg capsules of deep-sea catsharks (Treude et al. 2011).