Thursday, August 18, 2016

Where is all the algae going?

Hippos and wildebeest load a lot of nutrients into the Mara River... like, a lot. All of those nutrients should fertilize the river and produce a lot of algae. It's what the textbooks say should happen, and it's what research in other rivers show should happen. We see it happen in some portions of the river where there are only moderate levels of hippo inputs. However, it is not what happens where the hippo and wildebeest inputs are highest. Why not? I don't know. 

This-- getting results that don't fit your expectations, that surprise you-- is simultaneously the most exciting and the most frustrating part of science. It's the part that makes science addictive, that keeps you coming back for more, that makes you think grand discovery is on your doorstep. It's also the part that can drive you crazy and make it difficult to publish your research. If you're getting an unexpected result, you need to 1) be absolutely sure it's a real result and not an artifact of something you screwed up on accident, and 2) figure out why you're getting it. "This is weird, and I don't know why it's happening," will only get you so far. 

So, back to our algae... Why don't we see more in the river? Is it not growing in the first place? Or is it growing and going somewhere? I have been asking this question a lot over the last year as I have been working on the final papers from my dissertation, and this summer I was able to run a pilot experiment to test what is becoming my primary hypothesis... hippo and wildebeest inputs provide so much food for bugs and fish that their populations increase and they then graze down the algae. This would be really cool if it turns out to be true, because it would show that animal inputs can enter the river food web through various pathways, and which pathway they follow determines how those inputs shape the river ecosystem. Or I could be wrong and it could be something else entirely... See? Exciting, and a little frustrating. 

So, to test this hypothesis, I set out a grazing exclusion experiment this summer. I basically grew algae in the river on glass discs (the white circles in the picture below). Some discs were protected from grazing (either by a cage to restrict fish or by insecticide to restrict bugs) and others were not. If there was more algae growing on the protected discs than on the not-protected discs, that would suggest that algae can grow in the river, but it doesn't accumulate there because it gets grazed down. 

Before deployment in the river
I wasn't originally planning to run this experiment this year, as we already had a full schedule, but I was excited to be able to put this together almost completely with supplies we had stored around our camp. I built two of these that I deployed at two different sites in the river. I left them out for two weeks and hoped they didn't get stepped on by a hippo, washed away in a flood or collected by an enterprising Maasai person with a need for some glass discs. I always consider it a major win when we put something out in the river and return later to find it still there. 

After 2 weeks in the river
After two weeks, we collected the glass discs and measured the chlorophyll on them as an indication of how much algae was growing there. To my excitement, the discs protected from grazing by insects had more algae than the discs that weren't protected, supporting my hypothesis! To my frustration, the cages protecting the discs from fish caught a lot of hippo feces which influenced those data, and the variability was so high that my insect results weren't statistically significant. Ah science... the perfect career for those who love a good challenge! So, I can't say I've solved this mystery yet, but I'm getting closer, and I'm already excited about getting back to the field next year to try again. 


drivetrain said...

Transmission slip yokes area unit factory-made with many U-joint series, therefore it's necessary to decide on the U-joint that matches your power unit and torsion necessities. Spline count, seal diameter and length can establish the slip yoke that's needed for your transmission. Transmission slip yokes .

Get Admission Abroad said...

Wonderful, this information is truly unknown to me yet.
Thank you for sharing such knowledge via your blog and article. I am glad to inform you that I have also created content on Study in Yale University. You can check that article on my website How to get Admission in Abroad. I will assure you; there are some other unknown facts. Also, I am waiting for your review.

Get Admission Abroad said...

Thanks for Sharing.
Your content is very nice & that helps, useful to every person. Save your seat today and live your Career, for more information, website Study in Yale University & Call 9718417575 for more data/to approach your inquiries and for taking confirmation for Study in Yale University

Credit Loan Solution said...

Do you need Personal Loan?
Business Cash Loan?
Unsecured Loan
Fast and Simple Loan?
Quick Application Process?
Approvals within 24-72 Hours?
No Hidden Fees Loan?
Funding in less than 1 Week?
Get unsecured working capital?
Contact Us At :
Whatsapps +1-(551) 356-3808 (call/WhatsApp)

Chetan Chhabra said...

Thanks for your blog ? Thanks for the visit
Timmu Gears
Paras Machines in Delhi
Floor Polishing Machine
Floor Cleaning Machine

Vyaparinfo said...

Really Nice Information It's Very Helpful Thanks for sharing such an informative post.

BeachRiders Dubai said...

It is a good blog. Thanks for sharing activities
Deep sea fishing dubai
Water adventure dubai
Dubai water adventure
Dubai deep sea fishing trip
Deep sea fishing
Water activities in dubai
Fishing packages
Dubai water activities
Charter fishing
Dubai fishing trip
Water sports rental dubai