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I read a paper about lake and got confused about the following sentence (lower left in page 11256), because it has so many "and", "that", "in proportion to". I do not know which part of the sentence belongs to which word above.

Short-term bioassays indicated that C-limited (i.e., carbon limited) photosynthesis and algal growth and did not predict the continued growth of algal biomass in proportion to P (i.e., phosphorus).

From the view of English grammar instead of knowledge of environmental science, how can I decompose this sentence? It is frustrating that I konw the meaning of every word in this sentence, but I cannot understand this sentence.

  • No wonder you can't understand it. It is not grammatical. There is no verb in the first clause. – Jim Sep 11 at 14:59
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    @Jim I'd guess that that should be removed. – StoneyB on hiatus Sep 11 at 15:02
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    @Jim "Indicated" is often used in scientific contexts to signify "indicated the presence of". – StoneyB on hiatus Sep 11 at 16:49
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    I suppose @StoneyB is right. Following parts constitiute this sentence : (1) Short-term bioassays indicated the presence of C-limited (i.e., carbon limited) photosynthesis and algal growth; (2) Short-term bioassays did not predict the continued growth of algal biomass in proportion to P (i.e., phosphorus). – T X Sep 12 at 14:33
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    PS: The biological meaning of Sentence (2) means that “There is no presence of P-limited photosynthesis and algal growth.” – T X Sep 12 at 14:34
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I think the comments by StoneyB and the OP have it more correct than the existing answers...

It's not really fair to try to read this sentence without context.

For the first five years (1969–1974), the ratio of N to P in fertilizer was added at 12: 1 by weight, well above the Redfield ratio, to ensure that phytoplankton had adequate N and P supplies during the period when we were testing the C limitation hypothesis

The sentence you refer to involves data from 1969-1974, with adequate N and P.

I would rewrite the sentence as:

(Short-term bioassays) indicated (carbon-limited photosynthesis and algal growth), and (therefore) did not predict the continued growth of algal biomass in proportion to P (i.e., phosphorus).

Or, maybe in English that is more clear:

Algae were carbon-limited so the level of phosphorus didn't affect algal growth.


I think what probably happened is that in editing they went from:

Short-term bioassays indicated that carbon limited photosynthesis

(meaning their tests showed carbon was limiting photosynthesis)

to

Short-term bioassays indicated carbon-limited photosynthesis

(meaning their tests showed the lake was in a state called 'C-limited/carbon-limited photosynthesis'...which has the same overall meaning as above)

and left in the "that" when converting to the compound adjective.


Caveat: I'm a neuroscientist, and plants don't have brains, so this is typically a bit outside my wheelhouse... I'm giving this answer as someone familiar with science writing, not someone familiar with lake eutrophication except as a childhood neighbor to a eutrophic lake with a terrible phosphorus problem resulting from nearby farms.

  • Such a great answer! Thanks to explain one possible way how this "strange that" came from. I will improve my ability of science writing. Also hope I can do something for the eutrophic lake near your childhood house in the future (if I can be a specialist). – T X Sep 21 at 13:47
  • @TX So far alum treatments, carp removal, stocking better fish, and raising the water level by a foot and a half to match historical levels has helped a bit. – Bryan Krause Sep 21 at 13:55
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From the view of English grammar, it looks like you have a surplus "and" that creates a loose end in the sentence, or like you're missing part of the sentence that lists a third factor for predicting growth of algal biomass.

It should look like one of the two options:

  1. Eliminating the surplus "and": Short-term bioassays indicated that C-limited photosynthesis and algal growth did not predict the continued growth of algal biomass in proportion to P.

  2. Adding a third factor: Short-term bioassays indicated that C-limited photosynthesis and algal growth and N-fixing cyanobacteria did not predict the continued growth of algal biomass in proportion to P.

Disclaimer: For the third factor, I just picked up something random from the text...

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Short-term bioassays indicated that C-limited (i.e., carbon limited) photosynthesis and algal growth and did not predict the continued growth of algal biomass in proportion to P (i.e., phosphorus).

"That" above is being used to indicate the particular C-limited photosynthesis previously mentioned. It is not being used as a conjunction. Were you reading it aloud, "that" would be pronounced to rhyme with the word "bat," not to rhyme with the word "bet."

Short-term bioassays indicated that C-limited (i.e., carbon limited) photosynthesis and algal growth and did not predict the continued growth of algal biomass in proportion to P (i.e., phosphorus).

"In proportion to" means "to a relative size comparable with." It's saying that short-term bioassays didn't forecast the ongoing increase of algal biomass in a manner proportionate to P.

  • Or it could be an example of incorrect grammar (which looks the favourite to me; your reading is grammatical, but doesn't seem to construe well). Obviously, more context is needed to decide. – Edwin Ashworth Sep 11 at 16:50
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    Thanks! I think your explanation about "that" not being a conjunction is appropriate. In addition, I suppose StoneyB's comment can also be helpful. – T X Sep 12 at 14:38
  • Either "that" or "and" is superfluous. The presence of "that" means that the photosynthesis and growth have some effect which is not stated if "and" is present as well. If "that" is omitted then indication of photosynthesis and growth are one outcome of the studies and the prediction is another. – BoldBen Sep 20 at 6:45

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