Society for Freshwater Science Meeting!

There was a great showing at the annual SFS meeting in Jacksonville, Florida.  Good times were had, and our Icelandic research was well represented. Here's a photo of Delor Sander in front of her poster on N-fixation - together with Jon Olafsson, Gisli Gislason, and Jim Hood.

Other Iceland team presentations included:

Jim Hood et al. - "Patterns of nitrogen and phosphorus uptake across a thermal gradient of subarctic streams"

Jim Junker et al. - "Patterns of epilithic CNP stoichiometry across a natural temperature gradient in Icelandic streams"

Dan Nelson et al. - "Experimental whole-stream warming increases algal standing crop but reduces consumer biomass"

Jill Welter et al. - "Effect of temperature on N2-fixation rates and N2-fixer species assemblages in streams in the Hengill region of Iceland"

Paula Furey et al. - "Composition and abundance of nitrogen-fixing algal assemblages in nitrogen-limited streams along a geothermal gradient in the Hengill region of Iceland"

Experimental channels go online!

Today (May 20th) our experimental channels went online for real! Our little basalt tiles (pictured below) have reached the terminus of their long journey, all the way from my office floor back in Montana (see original post here). Jon Benstead and I lugged these tiles, all 1,650 of them (~100 pounds) to our site in what Jim Hood calls "typical Hengill weather." Equal parts sunshine, rain, sleet, snow and a sprinkling of hail for good measure! Now we keep our fingers crossed for the next 8 weeks while this experiment runs.

Close-up of a single basalt tile. 

Slotting the tiles into our 15 channels (5 temperature treatments with 3 replicates at each temperature).

The tiles snug in their new homes (at least for the next 8 weeks). The channel discharge may not look like much, but over the next 8 weeks we'll pass over 2.5 million liters of water through these channels.  

Temperature data from the experimental channels

Here are the first temperature data from the streamside channels. Tanner downloaded these data to see how things are shaping up before the experiment actually begins (now scheduled for May 20th!).

Things are pretty much on target (we love physics), but the coldest treatment ("ambient") appears to be gaining a few degrees between the inlet stream and the experimental channel.  In an effort to reduce this effect, and keep our coldest temperature cold, Tanner painted the black tubing extending between the stream and the channels.  We'll see if this helps!

BEFORE                                                                   AFTER

 

The sweet sulfurous stench of successful science!

Good news faithful followers! The coolers, channels, and piping are all in place. We've successfully plumbed all components together and have water flowing in the channels. The plan is to let the system run without tiles for 3-4 days to work out the kinks and and get the whole thing operation for our 8-week experiment by the middle of May.

PI's Cross and Benstead (in association with visiting professor Bob Hall from the University of Wyoming) steadfastly transporting the channels the kilometer (or so) out to our hot pots.

The coolers in place and plumbed into the heat exchange system. 

Assigning temperature treatments to channels in a randomized 3 block design.

Success! Water flowing in our channels for the first time!

Many thanks to undergraduate scholar Raquel (University of Barcelona) for coming out on this particularly damp afternoon to help assemble the final pieces. 

Streamside channels

Things are really coming together on the streamside channels. We expect that we'll have water flowing in them by this time tomorrow (late Thursday afternoon). Today, on what was probably the most beautiful day I've ever experienced out at Hengill, we got the channel racks assembled and finished construction on the dam.  The dam will provide a consistent water reservoir that will feed our channels all summer.

Our finished dam, the inlet pipe for our channels, and a nice pool of water (Lake Allison) 

The assembled PVC pipe frame that the channels will sit on. You can see from these photos that the snow is melty quickly now. It was even a sweat inducing 12 C (53 F) out there today!

The channels prepped and ready to for delivery tomorrow. Stay posted and soon you'll see some flowing channel action!

HEX2 construction: Days 4 and 5

Day 4 of the HEX2 installation started with the uncoiling and joining of the 600 feet of 2-inch tubing. Once completed, we were able to get water flowing down it as it lay along the channel. We waited until the next day to move it over to the heat exchanger site.

Alex also donned a pair of chest waders and plumbed the depths of the big 25C pool. It's deeper than we thought! Deeper than he could go anyway. That's good for us: plenty of volume is great for the heat exchangers.

Other activities on Day 4 included placing the spiral heat exchanger in the 50C hot pot and prepping the other two heat exchangers for deployment (or, more appropriately, LAUNCH).

Day 5 began with a slight delay, as the water in the 2-inch tubing had frozen (it has been unseasonably cold in Iceland this spring). Once flowing again, we moved the tubing over to the site. We had running water - a major milestone.

All that remained was to launch the straight heat exchangers and connect up the rest of the tubing and valves.

We turned the valve on the 2-inch feed and found we had hot and cold running water! It was time to celebrate with the customary can of Gull.

We ended the day by tweaking the valves to manipulate temperature in the five outflows. Before too long we had buckets at around 6C (ambient), 11C, 16C, 21C, and 25C. Not bad, but we can do better. In fact, we're headed up there now to play around with it some more. Everything downstream of our work (header tanks, channels) is being done by the Montana State crew (gulp...), who arrive soon. Watch this space as the whole channel set-up is completed and the experiment begins on June 1.