Arsenic and high affinity phosphate uptake gene distribution in shallow submarine hydrothermal sediments

Abstract

The toxicity of arsenic (As) towards life on Earth is apparent in the dense distribution of genes associated with As detoxification across the tree of life. The ability to defend against As is particularly vital for survival in As-rich shallow submarine hydrothermal ecosystems along the Hellenic Volcanic Arc (HVA), where life is exposed to hydrothermal fluids containing up to 3000 times more As than present in seawater. We propose that the removal of dissolved As and phosphorus (P) by sulfide and Fe(III)(oxyhydr)oxide minerals during sediment–seawater interaction, produces nutrient-deficient porewaters containing < 2.0 ppb P. The porewater arsenite-As(III) to arsenate-As(V) ratios, combined with sulfide concentration in the sediment and/or porewater, suggest a hydrothermally-induced seafloor redox gradient. This gradient overlaps with changing high affinity phosphate uptake gene abundance. High affinity phosphate uptake and As cycling genes are depleted in the sulfide-rich settings, relative to the more oxidizing habitats where mainly Fe(III)(oxyhydr)oxides are precipitated. In addition, a habitat-wide low As-respiring and As-oxidizing gene content relative to As resistance gene richness, suggests that As detoxification is prioritized over metabolic As cycling in the sediments. Collectively, the data point to redox control on Fe and S mineralization as a decisive factor in the regulation of high affinity phosphate uptake and As cycling gene content in shallow submarine hydrothermal ecosystems along the HVA.Electronic supplementary materialThe online version of this article (10.1007/s10533-018-0500-8) contains supplementary material, which is available to authorized users.

Antimicrobial Activity of Metals and Metalloids

“…At this site, the arsenic efflux gene, acr3 (27), is the most abundant arsenic-detoxifying gene found in microbial communities (12,32). These modern shallow marine hydrothermal ecosystems are differentiated into iron oxide, sulfidic, anoxic, and oxic ecosystems similar to those that predominated the Precambrian world (29,119).…”

The sulfur cycle connects microbiomes and biogeochemistry in deep-sea hydrothermal plumes

“…3b), indicating core sulfur oxidizers can have distinct distributions locally. Metabolic overlaps existed as some sulfur oxidizers had additional metabolic potential associated with utilizing various small carbon substrates and hydrogen, reducing nitrate/nitrite, and oxidizing iron/manganese/arsenite 36 (Fig. 3c).…”

Geochemical evidence for arsenic cycling in living microbialites of a High Altitude Andean Lake (Laguna Diamante, Argentina)

“…Hence, detoxification process is likely to occur in the studying microbialites. Detoxifying genes are present in most of the organisms that live in As-rich environments, from humans (Schlebusch et al, 2013) to microbial living in shallow submarine hydrothermal ecosystems along the Hellenic Volcanic (Fru et al, 2018). In any case, the products of both bioenergetics and detoxification reactions will eventually be expelled from the cell and accumulate in the EPS.…”