At http://phys.org/print304250664.html … a fascinating piece on ocean life cycles and sampling a cup full of sea water. A glass of water from the oceans would possess several bursts of organic matter with an origin in dying organisms (as small as plankton), continuous showers of 'marine snow' from the upper layers of water columns, and nutrients leaking from creatures so tiny they are invisible to the naked eye.
A new project has been set in motion to study the ocean by Australian scientists (and a US donation and a US science centre) with an emphasis on microscopic plants (algae) and marine bacteria. Chemical transformation in the ocean as a result of microbe activity influences the transfer of gases into the atmosphere, and therefore impacts on climate.
Chalk, a geological process that is apparently not happening in the modern world, involves the fossilisation of algae blooms. Chalk has bands of very thin organic matter and flint tends to form where fossilised organic matter (larger than algae and animals rather than plants) occurs, also very often with banding. You require a geological magnifying glass or a microscope to see the individual bits that make up chalk. The new research might shed some light on what created chalk formations – but even if it doesn't it will be invaluable in understanding the food chain in the ocean.