Eduard Metzger (Avtor), D. Langlet (Avtor), E. Viollier (Avtor), Neža Koron (Avtor), Bettina Riedel (Avtor), Michael Stachowitsch (Avtor), Jadran Faganeli (Avtor), M. Tharaud (Avtor), E. Geslin (Avtor), F. Jorissen (Avtor)

Povzetek

Long-term experimental studies suggest that, under transient anoxic conditions, redox fronts within the sediment shift upwards, causing sequential rise and fall of benthic fluxes of reduced species (Mn(II), Fe(II) and S(-II)). Infaunal benthic organisms are associated with different redox fronts as micro-habitats and must be affected by such changes during natural hypoxia events. In order to document the geochemical evolution of the sediment during prolonged anoxia in the framework of an in situ experiment designed to mimic natural conditions, benthic chambers were deployed on the seafloor of the Northern Adriatic and sampled after 9, 30 and 315 days of incubation. Oxygen and sulfide were measured continuously in the early stages (9 days) of the experiment. High-resolution pore water profiles were sampled by DET probes and redox-sensitive species (S(VI), Mn(II) and Fe(II)) and alkalinity were measured. Starting oxygen saturation was about 80% within the chamber. After 7 days, anoxia was established in the bottom waters within the chambers. Mn(II) and Fe(II) started diffusing towards the anoxic water column until they reached the surficial sediment. Being reoxidized there, Mn and Fe reprecipitated, giving a rusty coloration to the seafloor. Infaunal species appeared at the sediment surface. After 20 days, all macro-organisms were dead. Decomposition of macro-organisms at the sediment–water interface generated S(-II) within the entire height of the chamber, leading to a downward flux of sulfides into the sediment, where they were quickly oxidized by metallic oxides or precipitated as FeS. S(-II) was below detection in the water column and pore waters at the end of the experiment. Our results suggest that S(-II) enrichment in the water column of coastal systems, which are episodically anoxic, is strongly controlled by the biomass of benthic macrofauna and its decay during anoxia, whereas its residence time in the water column is controlled by iron availability (as solid oxides or as dissolved reduced cations) within the sediment, even without water circulation.

Ključne besede

Jadransko morje;sedimenti;morski sedimenti;anoksija;pomanjkanje kisika;morje;Adriatic Sea;marine sediments;anoxia;Northern Adriatic;

Podatki

Jezik: Angleški jezik
Leto izida:
Tipologija: 1.01 - Izvirni znanstveni članek
Organizacija: NIB - Nacionalni inštitut za biologijo
UDK: 551.44(497.4)
COBISS: 3105103 Povezava se bo odprla v novem oknu
ISSN: 1726-4170
Št. ogledov: 26
Št. prenosov: 19
Ocena: 0 (0 glasov)
Metapodatki: JSON JSON-RDF JSON-LD TURTLE N-TRIPLES XML RDFA MICRODATA DC-XML DC-RDF RDF

Ostali podatki

Sekundarni jezik: Slovenski jezik
Sekundarne ključne besede: Jadransko morje;sedimenti;morski sedimenti;anoksija;pomanjkanje kisika;morje;
Vrsta datoteke: application/pdf
Vrsta dela (COBISS): Delo ni kategorizirano
Komentar vira: Soavtorji: D. Langlet, E. Viollier, N. Koron, B. Riedel, M. Stachowitsch, J. Faganeli, M. Tharaud, E. Geslin, and F. Jorissen;
Strani: str. 2211-2224
Letnik: ǂVol. ǂ11
Zvezek: ǂno. ǂ8
Čas izdaje: 2014
DOI: 10.5194/bg-11-2211-2014
FP7: Austrian Science Fund (FWF; project P21542-B17)
ID: 24644261