The Chemoautotrophically Based Movile Cave Groundwater Ecosystem, a Hotspot of Subterranean Biodiversity

Traian Brad,Sanda Iepure,Serban Sarbu

doi:10.3390/d13030128

Abstract

Movile Cave hosts one of the world’s most diverse subsurface invertebrate communities. In the absence of matter and energy input from the surface, this ecosystem relies entirely on in situ primary productivity by chemoautotrophic microorganisms. The energy source for these microorganisms is the oxidation of hydrogen sulfide provided continuously from the deep thermomineral aquifer, alongside methane, and ammonium. The microbial biofilms that cover the water surface, the cave walls, and the sediments, along with the free-swimming microorganisms, represent the food that protists, rotifers, nematodes, gastropods, and crustacean rely on. Voracious water-scorpions, leeches, and planarians form the peak of the aquatic food web in Movile Cave. The terrestrial community is even more diverse. It is composed of various species of worms, isopods, pseudoscorpions, spiders, centipedes, millipedes, springtails, diplurans, and beetles. An updated list of invertebrate species thriving in Movile Cave is provided herein. With 52 invertebrate species (21 aquatic and 31 terrestrial), of which 37 are endemic for this unusual, but fascinating environment, Movile Cave is the first known chemosynthesis-based groundwater ecosystem. Therefore, Movile Cave deserves stringent attention and protection.

Highlights

Movile Cave is an underground void, which has no natural opening to the surface.It is located on the outskirts of the town of Mangalia (SE Romania), 2 km from the BlackSea shore [1] and it was intercepted 18 m below the surface by an artificial geological survey shaft dug in June 1986
The energy source for these microorganisms is the oxidation of hydrogen sulfide provided continuously from the deep thermomineral aquifer, alongside methane, and ammonium
The cave is developed in Sarmatian limestones (12.5 MY), which were covered by Quaternary deposits, approximately 2.5 million years ago [2], and it was formed by classical karst dissolution processes combined with sulfuric acid speleogenesis (SAS), a process mediated by sulfur-oxidizing bacteria [3]

Summary

Introduction

Movile Cave is an underground void, which has no natural opening to the surface. It is located on the outskirts of the town of Mangalia (SE Romania), 2 km from the Black. The water is relatively stagnant at the surface in the Lake Room and in the nearby Air-Bells, while some flow (i.e., 5 l s−1 ) was detected at depths over 1 m in the flooded cave passages [3]. Aquatic invertebrates that graze on microorganisms, roam at the water surface where O2 dry sections of the cave, but they are unusually abundant in the lower, partially flooded is available in small concentrations. Terrestrial invertebrates are rarely found in the upper cave level (Figure 1), in the Lake Room and the Air-Bells, where isopods, pseudoscorpions, dry sections of the cave, but they are unusually abundant in the lower, partially flooded millipedes, and insects feed on nearly any organic debris or graze on soil microorganisms, cave level (Figure 1), in the Lake Room and the Air-Bells, where isopods, while predatory chilopods and spiders chase their prey, consisting of isopods, collembola, pseudoscorpions, millipedes, and insects feed on nearly any organic debris or graze on beetles or other spiders. The purpose of this study is to provide an up-to-date list of invertebrate cave-dwelling species living in the peculiar Movile Cave ecosystem and to draw attention to the scientific importance of these species and their fascinating habitat

Aquatic Fauna

Findings

Terrestrial Fauna