Diversity of culturable filamentous Ascomycetes in the eastern South Pacific Ocean off Chile.

Our study reports the diversity of culturable mycoplankton in the eastern South Pacific Ocean off Chile to contribute with novel knowledge on taxonomy of filamentous fungi isolated from distinct physicochemical and biological marine environments. We characterized spatial distribution of isolates, evaluated their viability and assessed the influence of organic substrate availability on fungal development. Thirty-nine Operational Taxonomic Units were identified from 99 fungal strains isolated from coastal and oceanic waters by using Automatic Barcode Gap Discovery.

Hypoxia causes preservation of labile organic matter and changes seafloor microbial community composition (Black Sea).

Bottom-water oxygen supply is a key factor governing the biogeochemistry and community composition of marine sediments. Whether it also determines carbon burial rates remains controversial. We investigated the effect of varying oxygen concentrations (170 to 0 μM O) on microbial remineralization of organic matter in seafloor sediments and on community diversity of the northwestern Crimean shelf break.

Fungal parasites infect marine diatoms in the upwelling ecosystem of the Humboldt current system off central Chile.

This is the first report of fungal parasitism of diatoms in a highly productive coastal upwelling ecosystem, based on a year-round time series of diatom and parasitic Chytridiomycota abundance in the Humboldt Current System off Chile (36°30.80'S-73°07.70'W).

Melting glacier impacts community structure of Bacteria, Archaea and Fungi in a Chilean Patagonia fjord.

Jorge Montt glacier, located in the Patagonian Ice Fields, has undergone an unprecedented retreat during the past century. To study the impact of the meltwater discharge on the microbial community of the downstream fjord, we targeted Bacteria, Archaea and Fungi communities during austral autumn and winter. Our results showed a singular microbial community present in cold and low salinity surface waters during autumn, when a thicker meltwater layer was observed.

Assessing the micro-phytoplankton response to nitrate in Comau Fjord (42°S) in Patagonia (Chile), using a microcosms approach.

Anthropogenic (aquaculture) changes in environment nutrient concentrations may affect phytoplankton (biomass and taxa composition) in marine coastal waters off the Chilean Patagonia. The effects of adding nitrate (NO₃(-)) to natural phytoplankton assemblages were evaluated considering biomass, cell abundance, and taxonomic composition. Microcosm experiments were performed in the spring, summer, and winter in the Comau Fjord located in Subantarctic Patagonia.

A single-cell sequencing approach to the classification of large, vacuolated sulfur bacteria.

The colorless, large sulfur bacteria are well known because of their intriguing appearance, size and abundance in sulfidic settings. Since their discovery in 1803 these bacteria have been classified according to their conspicuous morphology. However, in microbiology the use of morphological criteria alone to predict phylogenetic relatedness has frequently proven to be misleading.

Biofilm growth kinetics of a monomethylamine producing Alphaproteobacteria strain isolated from an anaerobic reactor.

Industrial fishing effluents are characterized by high loads of protein and sulfate that stimulate the activity of proteolytic and sulfate reducing bacteria during anaerobic digestion. Their metabolic products (NH3 and H2S respectively) have a well-known detrimental effect on the activity of methanogens. Since methylamine is a carbon source used by methylaminotrophic methane producing archaea (mMPA) but not by sulfate reducing bacteria (SRB), enriched mMPA anaerobic biofilms have been developed on ceramics.

Two chemically distinct pools of organic nitrogen accumulate in the ocean.

The chemical dynamics of marine dissolved organic nitrogen (DON), a reservoir featuring surface accumulations even in areas where nitrogen limits productivity, have yet to be resolved. We exploited differences in the acid lability of amide bonds within high-molecular-weight (HMW) DON to show that vertical DON profiles result in part from the presence of two chemically distinct pools of amide. Half of HMWDON in surface waters is present as N-acetyl amino polysaccharides.