Thursday, July 27, 2017

If You Don't Like the Weather in Iceland, Just Wait Five Minutes...

We have a confession to make...

The majority of our blogposts give our readers a false sense of weather here in Iceland. Although the climate is mild for the latitude, rainy days are common at our field site. Here is a little dose of reality. Enjoy.

Can you see the glistening rain jackets? 

Sunday, July 9, 2017

Channel Sampling is Almost Here!

The channels have been running for a whopping 45 days now (which is basically years in “channel time”), and things have been going great at the site. The hotpot that was giving us trouble in the beginning has been stable, which means we have consistent temperature treatments, and our biofilm has been busy growing under the varying temperature and nutrient treatments. Heath and I have been busy maintaining the experiment during this time, as well as collecting samples for our biomass time series. These time series data can show us differences in biofilm growth rates among the nutrient conditions (i.e., low-N vs. high-N treatments), as well as whether these nutrient effects change under different temperature regimes. We won’t have answers until the samples are processed back at OSU, so for now it’s lots of scrubbing biofilm off tiles and filtering the samples for transport back to Ohio.
A quick look at differences in biofilm growth among channel treatments

We’ve also been taking background water chemistry samples for each channel, to ensure that the nitrogen and phosphorus additions for each treatment are at the correct concentrations.

But perhaps most importantly, we’re busy gearing up for our first round of metabolism, nutrient uptake, and nitrogen-fixation measurements. This will be a 4-5 day push with the entire team involved in the sampling efforts. During sampling, we incubate the biofilm in small plastic chambers, so we’ve spent the last few days ensuring the chambers and equipment is in working order.
Chambers: Geared up and ready to sample some biofilm

Things are looking good so far, and we should be ready for sampling in the next few days. Check back for pictures and updates of the main event!

Monday, July 3, 2017

Update: 15N additions and channel experiment

I am back from Iceland, after an ultimately successful trip, despite weather that was often difficult and that postponed the start of our five-day 15N additions to the two cold and two warm streams. The shot above is of everyone sampling food web compartments in Stream 11 during the drip. The sun did come out every now and then! The channel experiment continues to go well too. Here's a shot of our REU student Heath Goertzen and MS student Lyndsie Collis collecting and processing tiles for the biomass accumulation time series. You can just make out the diversity of growth responses that are being driven by differences in temperature and nutrient concentrations. Some tiles are still effectively bare after six weeks, while a thick algal growth is threatening to overtop some channels. Maybe we'll see some interesting temperature-nutrient interactions. Time will tell.