If multiple samples were taken from a single source, is it safe to assume that bacterial content is constant?

[deleted-675414]

If for example, 5 samples were to be taken from a river. Would it be safe to assume that all 5 samples will have the same amount of bacteria?

[17eugenekim]

It's tough to say. The primary factor, at least to me, would be whether they were taken from the same exact space and time in the river. For instance, did you take the five samples consecutively, within the span of a few minutes, from the same place in the river? Differences across both time and space will hurt your assumption. Remember that from a source like a river, you'll be looking at differences in both bacterial content (how much bacteria) as well as bacterial diversity (what kinds of bacteria).

Whatever you choose, make sure that you clearly state your assumption so that others viewing your project can understand that you did so. Then it makes it easier to analyze error.

[deleted-675414]

well, my research project is about microbial fuel cells. If the bacterial content of the wastewater were to be different, the energy output would also change. That's kind of my problem right now; my research won't be valid because it wouldn't be known if the energy output would be the same across all attempts at using mfc. What is a possible solution to this problem? I'm stumped.

[17eugenekim]

Sorry it took so long to get back to you. Something is wrong with my subscription considering I have stopped getting notifying emails...

What exactly are you investigating about the MFC? Are you just trying to construct a functioning model? Is this question going to be a primary drive for your project, or is it something that you think the judges will ask? I'm not sure I'm on the right page. What do you mean by "across all attempts at using MFC"?

I think that, especially with wastewater, bacterial content can vary a significant degree between different timepoints, though I suspect due to the nature of what they metabolize, the bacterial species diversity would be a bit more constant. The thing about bacteria, though, is that they replicate quickly and can be incubated with relative ease. So if you wanted your specifically developed MFC to be replicated by others, they could take a bacterial sample out of your model.

If your project is more focusing on a certain method or technique in building MFCs, well in that case I think answering this question is a bit beyond your project parameters and it would be unrealistic to expect you to deal with the differences in bacterial communities across different wastewater plants. That is only my unlicensed opinion, though.

I wish I could help you further. Perhaps if I understood your project better I'd be able to tell you more pertinent information.