Sunday, July 22, 2012

Deep cast

We’ve been working 14+-hour days now for as long as I can remember, and TENSIONS ARE RUNNING HIGH.

I look around every once in awhile and try to spot the secret video cameras, because I swear we’re all unknowing test subjects in a warped study on human endurance. Turns out people need time off or they start to Lose Their Minds…or at very least start having vivid mental fantasies about, oh, I don’t know…forcefully pushing coworkers off boats, tripping people down stairs, or throwing their Kindle’s into the lake (just to name a few... off the top of my head…)

But as we say on Team Tanganyika, there is no punishment for mental crimes ;).

Sensing that I might be on the verge, Pete told me I could hang back from boat work yesterday and have a few hours off the water. But it was Deep Cast day and I really didn’t want to miss out since it’s an activity that has potential to be super cool. Or it would be super cool if JUST ONCE our gear would cooperate (SPOILER ALERT! Our equipment failed! Again! I know…it was a shocker to me as well since everything had been going so smoothly up until this point…)

So: the deep cast. Benja and Pete got a fancy new piece of equipment this year that can record temperature at Super-Deep Depths (the limit on most instruments is the intense pressure at depth). Again, casts are a good way to monitor the thermocline, see if upwelling is occurring (i.e., evidence of cooler water higher in the water column), and document changes in water temp since the last published study 8 years ago. 

So we loaded up our gear, pointed the boat west towards the Congo, and drove until we could no longer see land (~12km offshore). 

I’ll say that again: WE COULD NO LONGER SEE LAND (Have I mentioned lately how ridiculously big this lake is!). The weather was eerily (and very uncharacteristically) calm and absolutely perfect for the task at hand.

Yes, I am wearing the same clothes in every single blog post, because apparently I no longer care about personal hygiene.... It's tight quarters in the old Zodiac with all that Heavy Gear.

We finally arrived at our destination, Benja slowly lowered the instrument down to 1200 meters (!!!!!!!), and then it was time to bring it up with the winch. It became progressively harder as we took turns cranking away, and at some point we noticed the pile of metal shavings that accompanied the loud metal-on-metal screeching sound. It took THREE people (given, I wasn’t as much help as the guys here) FORTY-FIVE minutes to get it back to the surface, and that was the end of our adventure since further use would have likely irreparably damaged the winch. 

Sadly Pete lost his field hat, so he re-purposed some boxers for his last day in the field. He assured me they were clean...
After the cast, we intended to send the Niskin bottle down to collect water every 50 or 100m throughout the water column, checking the conductivity and filtering/collecting water for nutrients. Tanganyika is permanently stratified, so this part (while ridiculously annoying on some level, because it’s so tedious and physically taxing) is actually really awesome. Last year around 100m the water started smelling strongly of sulfur, and after a quick glance among my team members to identify the guilty party, I realized the stench was coming from the water. Pete said that water had been at that depth for over 1500 years (!!!), and THAT is incredible. 

This is from last year's collection since I apparently don't have a current Niskin bottle pic.

Alas, that task will have to wait for another day, and we reluctantly turned the boat around and headed home. Take home message: the lake is warming (sigh), and the thermocline is a’rising. 

Rumpelstiltskin? Benja managed to fix the winch with an old saw blade (appropriate technology!). Here he's changing out the wire on the spool.

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