Publications by authors named "O F GROSSO"
Iron is an essential nutrient that regulates productivity in ~30% of the ocean. Compared with deep (>2000 meter) hydrothermal activity at mid-ocean ridges that provide iron to the ocean's interior, shallow (<500 meter) hydrothermal fluids are likely to influence the surface's ecosystem. However, their effect is unknown.
View Article and Find Full Text PDFDiazotrophs are widespread microorganisms that alleviate nitrogen limitation in 60% of our oceans, thereby regulating marine productivity. Yet, the group-specific contribution of diazotrophs to organic matter export has not been quantified, which so far has impeded an accurate assessment of their impact on the biological carbon pump. Here, we examine the fate of five groups of globally-distributed diazotrophs by using an original combination of mesopelagic particle sampling devices across the subtropical South Pacific Ocean.
View Article and Find Full Text PDFArticle Synopsis
- Trichodesmium, a cyanobacterium found in low latitude oceans, is known for fixing nitrogen (N) and contributing to primary productivity, raising questions about its abilities in deeper, darker ocean layers.
- Recent findings show that Trichodesmium colonies that sink to depths of 170 to 1000 meters can fix nitrogen at rates similar to those observed in surface waters, comprising a significant portion of overall nitrogen fixation in those layers.
- Experiments indicate that while high pressure and low temperatures in the dark ocean reduce Trichodesmium's nitrogen fixation, it can still function by using stored carbon from photosynthesis, thus providing essential nutrients to other organisms in the mesopelagic zone.
The unicellular diazotrophic cyanobacterium Crocosphaera contributes significantly to fixed nitrogen inputs in the oligotrophic ocean. In the western tropical South Pacific Ocean (WTSP), these diazotrophs abound thanks to the phosphorus-rich waters provided by the South Equatorial Current, and iron provided aeolian and subsurface volcanic activity. East of the WTSP, the South Pacific Gyre (SPG) harbors the most oligotrophic and transparent waters of the world's oceans, where only heterotrophic diazotrophs have been reported before.
View Article and Find Full Text PDFBackground: The vaginal microenvironment, regulated by an immune system, can be protected or altered by many factors, including contraceptive methods.
Objective: The objective of this study is to evaluate the impact of contraceptive methods on the basic vaginal states (BVSs) and to identify culturable vaginal Lactobacillus species.
Methods: This is a prospective, consecutive, longitudinal, and descriptive study.