Growth rate-dependent synthesis of halomethanes in marine heterotrophic bacteria and its implications for the ozone layer recovery.

Halomethanes (e.g., CH Cl, CH Br, CH I and CHBr ) are ozone-depleting compounds that, in contrast to the human-made chlorofluorocarbons, marine organisms synthesize naturally.

Microbial rhodopsins are major contributors to the solar energy captured in the sea.

All known phototrophic metabolisms on Earth rely on one of three categories of energy-converting pigments: chlorophyll- (rarely -), bacteriochlorophyll- (rarely -), and retinal, which is the chromophore in rhodopsins. While the significance of chlorophylls in solar energy capture has been studied for decades, the contribution of retinal-based phototrophy to this process remains largely unexplored. We report the first vertical distributions of the three energy-converting pigments measured along a contrasting nutrient gradient through the Mediterranean Sea and the Atlantic Ocean.

Mosaic patterns of B-vitamin synthesis and utilization in a natural marine microbial community.

Aquatic environments contain large communities of microorganisms whose synergistic interactions mediate the cycling of major and trace nutrients, including vitamins. B-vitamins are essential coenzymes that many organisms cannot synthesize. Thus, their exchange among de novo synthesizers and auxotrophs is expected to play an important role in the microbial consortia and explain some of the temporal and spatial changes observed in diversity.

Multiple B-vitamin depletion in large areas of the coastal ocean.

B vitamins are some of the most commonly required biochemical cofactors in living systems. Therefore, cellular metabolism of marine vitamin-requiring (auxotrophic) phytoplankton and bacteria would likely be significantly compromised if B vitamins (thiamin B(1), riboflavin B(2), pyridoxine B(6), biotin B(7), and cobalamin B(12)) were unavailable. However, the factors controlling the synthesis, ambient concentrations, and uptake of these key organic compounds in the marine environment are still not well understood.

Aeolian contamination of Se and Ag in the North Pacific from Asian fossil fuel combustion.

Energy production from fossil fuels, and in particular the burning of coal in China, creates atmospheric contamination that is transported across the remote North Pacific with prevailing westerly winds. In recent years this pollution from within Asia has increased dramatically, as a consequence of vigorous economic growth and corresponding energy consumption. During the fourth Intergovernmental Oceanographic Commission baseline contaminant survey in the western Pacific Ocean from May to June, 2002, surface waters and aerosol samples were measured to investigate whether atmospheric deposition of trace elements to the surface North Pacific was altering trace element biogeochemical cycling.