Amount of Phytoplankton in Sea Water

[Sundog]

Does anyone know how much phytoplankton is in sea water? Say surrounding reefs and near the surface? I couldn’t find a number so I don’t know if it would be in ppm or something els.
Thanks!

 

[ISamson]

how much

Are you measuring in individuals per (? (what unit of distance or area?)).

 

[jim mcnamara]

Phytoplankton biomass is often measured by satellite telemetry, based on chlorophyll levels in the uppermost water column. And then converted to biomass.

In Northern (and Southern) temperate waters, there is what is called an 'algal bloom' in the late meteorological spring. Another smaller bloom occurs in late summer. For these reasons and many others, phytoplankton biomass is ephemeral (comes and goes by orders of magnitude) value in a given ecosystem. In other words, it is a value that can change often. And a lot. So estimates are often a percent of total biomass.

And measurements are affected by the vertical movement of plankton in the water column. -- vertical distribution of the organisms changes by time of day, and one gets varying results over the duration of a day, since the top layer is what is measured by telemetry. Bathymetric (depth measuring) devices that sample water as well as depth, can bring small samples to the surface. Phytoplankton is usually within ~30m of the surface (depends on time of year, water temperature, nutrients, etc.), with the greatest concentration of phyto-beasties very near the surface during mid-day. In early June (or December).

Fuzzy answer from wikipedia:

Apart from bacteria, the total global biomass has been estimated at about 560 billion tonnes C. Most of this biomass is found on land, with only 5 to 10 billion tonnes C found in the oceans. ... It has been estimated that about 1% of the global biomass is due to phytoplankton, and 25% is due to fungi.

If you really want details, please read:
https://en.wikipedia.org/wiki/Biomass_(ecology)

Anyway, the phytoplankton biomass estimate works out to 5 billion metric tons of carbon, which is how biomass is reported. Not chlorophyll.

@Ivan Samsonov
Phytoplankton in a more closed system like a pond or a small given body of water is sometimes reported as X_minimum - X_maximum mg/ml of chlorophyll - usually for a specified date range. And then a biomass estimate may (or may not) be derived from those values.

 

[Sundog]

Whatever you could find or know. I can’t seem to find anything.

 

[Sundog]

Thanks! Good info