Light-dependent sulfide oxidation in the anoxic zone of the Chesapeake Bay can be explained by small populations of phototrophic bacteria

Microbial sulfide oxidation in aquatic environments is an important ecosystem process, as sulfide is potently toxic to aerobic organisms. Sulfide oxidation in anoxic waters can prevent the efflux of sulfide to aerobic water masses, thus mitigating toxicity. The contribution of phototrophic sulfide-oxidizing bacteria to anaerobic sulfide oxidation in the Chesapeake Bay and the redox chemistry of the stratified water column were investigated in the summers of 2011 to 2014. In 2011 and 2013, phototrophic sulfide-oxidizing bacteria closely related to Prosthecochloris species of the phylum Chlorobi were cultivated from waters sampled at and below the oxic-anoxic interface, where measured light penetration was sufficient to support populations of low-light-adapted photosynthetic bacteria. In 2012, 2013, and 2014, light-dependent sulfide loss was observed in freshly collected water column samples. In these samples, extremely low light levels caused 2- to 10-fold increases in the sulfide uptake rate over the sulfide uptake rate under dark conditions. An enrichment, CB11, dominated by Prosthecochloris species, oxidized sulfide with a K... value of 11 ...M and a V... value of 51 ...M min... (mg protein...). Using these kinetic values with in situ sulfide concentrations and light fluxes, we calculated that a small population of Chlorobi similar to those in enrichment CB11 can account for the observed anaerobic light-dependent sulfide consumption activity in natural water samples. We conclude that Chlorobi play a far larger role in the Chesapeake Bay than currently appreciated. This result has potential implications for coastal anoxic waters and expanding oxygen-minimum zones as they begin to impinge on the photic zone. (ProQuest: ... denotes formulae/symbols omitted.).

Medienart:

Artikel

Erscheinungsjahr:

2015

Erschienen:

2015

Enthalten in:

Zur Gesamtaufnahme - volume:81

Enthalten in:

Applied and environmental microbiology - 81(2015), 21, Seite 7560

Sprache:

Englisch

Beteiligte Personen:

Alyssa J Findlay [VerfasserIn]
Alexa J Bennett [Sonstige Person]
Thomas E Hanson [Sonstige Person]
George W Luther [Sonstige Person]

Links:

Volltext
search.proquest.com

BKL:

42.30

58.30

Themen:

Aquatic ecosystems
Bacteria, Photosynthetic
Bacterial proteins
Gram-negative bacteria
Oxidation
Oxidation-reduction reaction
Photosynthesis
Physiological aspects
Research
Sulfides
Sulfur
Toxicity

RVK:

RVK Klassifikation

doi:

10.1128/AEM.02062-15

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

OLC1964004578