Tuesday, July 17, 2012

Just the half of it

Now that our work in Mahale has finished up, it’s time to start field sampling in Kigoma! (I’m trying to be enthusiastic here (as evidenced by the careful placement of that exclamation point), but it’s actually really hard to be here after having seen the mostly-pristine beauty of the mountains). So after one very luxurious day of doing Absolutely Nothing (it was all I hoped it could be and more!), we fueled up the engines and inflated the boats and were back to the grind of collecting data.

Since we didn’t get a chance to get in the water before we left Kigoma the first time (remember all the residency permit issues early on??…), a boatload of work awaited us upon our return to reality. Step one was to hit each of our 12 sites for what Team McIntyre affectionately calls “Weeklies.” Since I’m “boat girl” during this event, for me it’s an exercise in sunburn, dehydration, and testing the limits of my bladder. 

Boat girl and water boy
Basically Benja and I hightail it to a site (Pete came along this week for good measure), and while we dangle a sonde off the side of the boat, Ben hops in and fills some syringes with lake water for me to filter onboard. He then free dives down to 15 feet and carefully places IER’s (Ion Exchange Resins) onto the benthos. 

IER's attached with some coated wire, zip ties, and rubber bands from the CFL mailboxes.
Tanganyika is special for many reasons, but The Big Question we’re trying to answer is how such a nutrient-poor lake is so productive and can support such high species diversity. It’s a real head-scratcher, but water sampling and IER’s tell us a weekly story of how many nutrients are out there, available for uptake.

The second big task was to get the thermistor chain in the water and recording the temperature of the lake at various intervals down to 120 meters. 

As a totally unrelated aside, I’d like to point out that at its deepest point, Tanganyika is over 1600 METERS. A MILE. Remember field day in elementary school when the gym coach made you run around the track 4 times? For whatever reason, that’s always been my mile-reference for life, and that’s a damn long way down.

Going back to the fact that this lake is nutrient-scarce, one of the hypothesized sources of nutrients is upwelling events that bring all the (good) stuff that has sunk to the bottom of the lake back to the top. Those events are associated with slight changes in temperature (deep water is cooler), and the idea is that we will be able to watch it happen by putting loggers at various depths and downloading the digital story.
We made it almost all the way to the drop location before Benja realized he didn't actually activate the loggers. Pete doesn't mess around when it comes to safety (as evidenced by his wearing of the PFD indoors...)
In a perfect world, you’d be able to slap a buoy onto the line that holds your NINE THOUSAND DOLLAR piece of equipment, but here in Africa that would be the equivalent of a giant neon sign saying “COME STEAL ME! I AM VALUABLE!!!” So there is no surface buoy, and the buoy holding the chain is sunk to 30 feet. It takes a GPS, a good eye, and a whole lot of luck to find it again (read: a miracle)…

Go time! Pete lowers the Super Heavy Anchor over the side, and I slowly lower the rope through a series of carabiners.
It mostly went well, and after following Ben’s advice to keep it simple, it’s in the lake, doing its thing, collecting data. Last year we celebrated our successful endeavor by jumping off a cliff; this year (since The Boss was along and didn’t want us engaging in life-endangering activities) I gave the guys knucks. Goooo, team.

Totally unrelated picture to this post, but I saw this boat out during Weeklies. Biggest life raft ever? Maybe...

1 comment:

  1. Looks like a commuter boat! I have not seen one quite that big in PNG but that is what the boats look like in the morning when everyone is going to the city and taking the kids to school. Great post - the photo and reference to Pete with his safety vest on in the shed made ma laugh. :)