Eukaryotic diversity associated with carbonates and fluid–seawater interface in Lost City hydrothermal field

Abstract

Lost City is a unique off-axis hydrothermal vent field characterized by highly alkaline and relatively low-temperature fluids that harbours huge carbonate chimneys. We have carried out a molecular survey based on 18S rDNA sequences of the eukaryotic communities associated with fluid-seawater interfaces and with carbonates from venting areas and the chimney wall. Our study reveals a variety of lineages belonging to eight major taxa: Metazoa, Fungi, Heterokonta (Stramenopiles), Alveolata, Radiolaria, Cercozoa, Heterolobosea and Euglenozoa. We detected one fungal lineage that appears to be widespread in hydrothermal systems both submarine and continental. Alveolates were the most abundant and diverse group in Lost City samples, although their distribution was very different in carbonate, where ciliates dominated, and in fluid-seawater libraries, where dinoflagellates, Group I and Group II (Syndiniales) marine alveolates were profuse. Similarly, Euglenozoa also displayed a differential distribution, kinetoplastids being present on carbonates and a novel group of diplonemids so far exclusively observed in the deep sea being dominant in fluid-seawater libraries. Protist lineages identified in this ecosystem likely correspond to grazers, decomposers and parasites, playing key roles in the food web of the Lost City ecosystem.

The influence of vent systems on pelagic eukaryotic micro-organism composition in the Nordic Seas

“…Atkins (2000) suggested that flagellate protozoans could maintain metabolism within the extreme conditions of hydrothermal vents with high concentrations of, e.g., sulphide in the water column. This conclusion is strengthened by the high protistan diversity described in López-García et al (2007). Bennet et al (2013) also found an increase in total organic carbon (TOC) compared to surrounding waters.…”

“…Although eukaryotic micro-organisms in Nordic Seas plumes have not been studied before, several other studies have focused on the effect of hydrothermal plumes from other parts of the world on both the mesozooplankton (Berg and Van Dover 1987;Burd and Thomson 1995;Burd et al 2002;Vinogradov and Vereshchaka 2005;Olsen et al 2013) and the microplankton (Atkins 2000;López-García et al 2007;Bennet et al 2013). While hydrothermal vents clearly contribute to increasing the available metabolic energy, how this increased energy affects the biodiversity remains unclear.…”

Subsurface ecosystem resilience: long-term attenuation of subsurface contaminants supports a dynamic microbial community

“…Since that time, additional nonculture-based studies describing eukaryotic diversity in a variety of ecological settings have emerged. Among these habitats are: a multipond saltern (Casamayor et al, 2002), rice soil (Murase et al, 2006), an anoxic Norwegian fjord (Behnke et al, 2006), Mediterranean sea water (Diez et al, 2001), a sulfide-rich freshwater spring (Luo et al, 2005), a seafloor hydrothermal vent field (Ló pez- García et al, 2007) and an anaerobic aquifer polluted with landfill leachate (Brad et al, 2008). The latter study, most relevant to data presented here, used Eukarya-specific PCR primers (Diez et al, 2001) to amplify 18S rRNA genes and analyze them through denaturing gradient gel electrophoresis profiling and sequence analysis.…”

Micro-eukaryotic diversity of the human distal gut microbiota: qualitative assessment using culture-dependent and -independent analysis of faeces

“…In these environments, eukaryotes interact with other microbes to form complex communities that play primary roles in both ecosystem structure and function (Fleet, 1999(Fleet, , 2003Lopez-Garcia et al, 2007). The first cultureindependent analysis of the fungal community populating a mammalian intestine revealed an unprecedented diversity and abundance of fungal species in the murine GI tract (Scupham et al, 2006).…”

“…Micro-eukaryotic species are ubiquitous components of various natural ecosystems, including hydrothermal environments (Gadanho et al, 2003;Lopez-Garcia et al, 2007), soil (van Elsas et al, 2000;Moon-van der Staay et al, 2006), the rumen (Ranilla et al, 2007) and food and beverage communities (Romano et al, 2003;Fleet, 2007;Quiros et al, 2008). In these environments, eukaryotes interact with other microbes to form complex communities that play primary roles in both ecosystem structure and function (Fleet, 1999(Fleet, , 2003Lopez-Garcia et al, 2007).…”