Is there more photosynthesis in the oceans than on dry land?

The NASA graphs show Net Primary Productivity in kg carbon per square
meter per year. The summary equation for photosynthesis indicates that
one O2 is produced per carbon fixed so it could also be expressed in kg
O2 rather than kg carbon if a conversion factor was used.

I've never heard of an oxygen produced to oxygen consumed ratio. There
is a respiratory quotient, the ratio of CO2 respired to O2 consumed,
that varies depending on the substance being respired. Respiratory
quotient is measured for nonphotosynthetic organisms or
nonphotosynthetic plant parts such as roots.


David R. Hershey

[Only registered users see links. ] wrote:

Most unfortunately, Ivan appears to have decided not to bother with a
group containing the self-appointed Cerberus; and I don't blame him. He
seemed to me like a man who had the references to at his fingertips;
but it's been reported recently in Britain, just as Ivan described. I
heard it on BBC Radio 4 last week, but I think it's been in New
Scientist. Ggling got, among others, the following, which is a
starting-place:
[Only registered users see links. ]

--
Mike.

They are not using photosynthesis...they are using chemosynthesis.
Chemosynthetic bacteria use not the sun, but chemical energy to make
food. They use hydrogen sulfide gas coming from the vents in the same
way that plants use carbon dioxide and water.

Do a google search for chemosynthetic bacteria for more information...
-Scott

[Only registered users see links. ] wrote:

Ivan Kobrinsky wrote:
<SNIP>
It is my understanding that these bacteria are using chemosynthesis and
not photosynthesis.

Here is an article from NOAA:

[Only registered users see links. ]

Chemosynthesis

Most life on Earth is dependent upon photosynthesis, the process by
which plants make energy from sunlight. However, at hydrothermal vents
in the deep ocean a unique ecosystem has evolved in the absense of
sunlight, and its source of energy is completely different:
chemosynthesis. Chemosynthesis is the process by which certain microbes
create energy by mediating chemical reactions. So the animals that live
around hydrothermal vents make their living from the chemicals coming
out of the seafloor in the vent fluids! Because they are a local food
source, hydrothermal vents typically have high biomass, in stark
contrast to the very sparse distribution of animals outside of vent
areas where animals are dependent on food dropping down from above.

Chemosynthetic microbes provide the foundation for biological
colonization of vents. Chemosynthetic microbes live on or below the
seafloor, and even within the bodies of other vent animals as symbionts.
Where microbial mat covers the seafloor around vents, grazers such as
snails, limpets, and scaleworms eat the mat, and predators come to eat
the grazers. Tubeworms flourish in small clumps, waving in the warm
fluids. A typical picture of an active hydrothermal vent is therefore
one with shimmering warm hydrothermal fluids, tubeworms and many other
vent species, all densely clustered around the vent, with white
microbial mat material covering the surrounding area.

Steve Austin <6000000@dollar.man> wrote in
newsF_we.173431$IO.28095@tornado.tampabay.rr.com :


Recent discoveries have shined light on the subject. Apparently there
is also a bit of light there, and it is being taken advantage by
organisms to make biological energy using photosynthesis.

It is all over the science news this last week or so.

Sean

Rafael Almeida <[Only registered users see links. ].br> wrote in
news:d9ml4j$8su$[Only registered users see links. ].org:

_bio_problem.html

That ratio might be greater, but remember that the ocean is a
nutrient poor environment. Low levels of Iron especially limit
growth. That accounts for the lower levels of photosynthesis in the
oceans.

Sean

In article <1120166842.674376.274560@f14g2000cwb.googlegroups .com>,
Mike Lyle <[Only registered users see links. ].uk> wrote:

Thanks for the ref, Mike. It was in our local newspaper on Wednesday.
Here's the text of the ref:

Published online before print June 20, 2005, 10.1073/pnas.0503674102
PNAS | June 28, 2005 | vol. 102 | no. 26 | 9306-9310

An obligately photosynthetic bacterial anaerobe from a deep-sea
hydrothermal vent

J. Thomas Beatty, Jörg Overmann, Michael T. Lince, Ann K. Manske,
Andrew S. Lang, Robert E. Blankenship, Cindy L. Van Dover,
Tracey A. Martinson and F. Gerald Plumley

I read the article, and it's as Ivan originally described. The
researchers found, propagated and characterised a green sulfur
bacterium from a water sample obtained from the plume of a black smoker
vent in the East Pacific Rise, which was not present in water away from
the plume. Like all GSBs, is it obligately photosynthetic, an anaerobe
which reduces CO2 to organic carbon by oxidizing sulfur compounds.
GSBs are capable of using light of extremely low intensity, and this
critter uses "geothermal radiation that includes wavelengths absorbed
by photosynthetic pigments of this organism". It's related to a couple
of well-known genera of GSB, but the authors haven't named it yet.

They speculate that the bacterium normally lives in a microbial mat
within centimeters of the vent, "eking out an existence by infrequent
harvesting of rare geothermal photons", comparing it to a GSB that
lives at 80m in the Black Sea, which has an in situ division time of
2.8 years. In culture, both grow like crazy.

There's refs to a couple of papers about a bacterium that appears to
use light as an auxiliary source of energy to supplement its
chemotrophic metabolism, but this is the first report of an obligate
phototroph that depends on geothermal light.

Extremely cool stuff. I'm always amazed and delighted when I hear
about how some organism has managed to develop an unusual livelihood in
an unlikely environment. I guess I still have a little of that
childlike sense of wonder after all these years.

Thanks, Sean, I'll check that out.

Sean Houtman wrote:

[Only registered users see links. ]:


Well done, cowboy.





As my original post shows:

MID <1119617254.174168.76730@g43g2000cwa.googlegroups. com>

| Have a look at online-before-print version that presents
| now the international researcher team in PNAS:
|
| "An obligately photosynthetic bacterial anaerobe from a
| deep-sea hydrothermal vent";
| [Only registered users see links. ]