Anaerobic Ammonium Oxidation in the Marine Environment

Linking crenarchaeal and bacterial nitrification to anammox in the Black Sea

“…Similarly, direct nitrificationanammox coupling has been suggested in the Benguela upwelling system (5), where anammox was only detected in incubations with 15 NH 4 ϩ but not with 15 NO 3 Ϫ at one site or more, implying that nitrification rather than nitrate reduction was the source of nitrite for anammox in those cases. Currently, 30-50% of global marine nitrogen loss is estimated to occur in oceanic OMZs (9, 10) and increasing evidence has pointed to the prevalence of anammox over denitrification (5)(6)(7)(8). If the same nitrification-anammox coupling, as observed in the Black Sea suboxic waters, also occurs in oceanic OMZs, then a substantial portion of total oceanic nitrogen loss would have come from regenerated NH 4 ϩ from the surface ocean, and not directly from deep-sea nitrate (SI Fig.…”

“…It connects the recycling of organic nitrogen to the ultimate nitrogen loss from the oceans, because its products are substrates for denitrification and anaerobic ammonium oxidation (anammox), the only two presently known nitrogen loss processes. In productive waters such as upwelling regions, high fluxes of organic matter and thus remineralization create strong subsurface oxygen minima, enabling denitrification (1-4) or anammox (5)(6)(7)(8) to occur. Nitrogen losses from these oxygen minimum zones (OMZs) are estimated to account for 30-50% of total nitrogen loss from the oceans (9,10).…”

Geomicrobial functional groups: A window on the interaction between life and environments

“…However, an estimate of nitrogen budget reveals that nitrogen loss is clearly greater than nitrogen inputs in modern marine environments [73]. In addition to denitrification, anammox, a process that converts ammonium and nitrite into nitrogen gas [74], may contribute 30%-50% of the nitrogen loss. The anammox bacteria, phylogenetically falling into Planctomycetes, are characterized by slow growth, but a diverse occurrence in anoxic marine or lacustrine environments or even high-temperature petroleum reservoirs [75,76].…”

Transformações do nitrogênio e diversidade de Planctomycetes em sedimentos de manguezais

“…Neste processo denominado anammox (oxidação anaeróbica de amônio), alguns organismos heterotróficos podem oxidar amônio e utilizar nitrito como aceptor de elétrons, liberando gás nitrogênio (MULDER et al, 1995;STROUS et al, 1999;DALSGAARD, 2002;KUYPERS et al, 2006). Há estimativas que o processo anammox represente entre 20 e 70% da produção total de N 2 em sedimentos com baixo conteúdo orgânico e baixa disponibilidade de oxigênio.…”

“…Assim, os efeitos do enxofre para processo anammox deve ser considerados, principalmente em BrMgv02, que apresentou a maior porcentagem deste elemento, juntamente com as menores taxas para ambos os processos. Autores sugerem que a ocorrência da via anammox pode ser limitada pela ocorrência de matéria orgânica com alto teor de sulfeto (LYIMO et al, 2002;KUYPERS et al, 2006). Autores sugerem ainda, que em sedimentos, o sulfeto pode desempenhar inibição irreversível também na oxidação aeróbia do amônio (JOYE; HOLLIBAUGH, 1995;DOLLHOPF et al, 2005).…”