I can’t believe we are almost halfway through our time here in Cherskiy. Everyone is so involved in their research that time is flying, each long day passing by incredibly quickly. It’s amazing to see how many different types of projects are going on, from the impacts of fire on terrestrial carbon cycling to the effects of vegetation type on the chemistry of small rivers. I’m studying the impact of nutrient additions on microbial extracellular enzyme rates. Microbes release exoenzymes in aquatic ecosystems to breakdown complex organic matter and make it small enough to ingest. There are two main types of enzymes, the oxidases that breakdown the most complex organic matter, and the hydrolases that breakdown less complex organic matter already partially broken down by the oxidases. By measuring enzyme activity, you can determine the relative chemistry of the water (i.e. what nutrients there are a lot of and what nutrients there are not so many of). If activity rates increase with the addition of a certain nutrient, such as phosphorus, that indicates the water was phosphorus limited. I’ve run samples from large rivers in the Kolyma watershed, and have not seen drastic results in response to increased levels of nitrogen and phosphorus. But, this could indicate that in large rivers the organic matter has already been completely broken down along its journey through small streams and smaller rivers, creating little need for exoenzymes because the organic matter is already small enough for microbes to ingest. I am planning to run this experiment with samples from smaller streams and rivers over the next few days, and will hopefully see a different response than that of the large rivers. Everyone is trying to make the most of the time left we have here, hopefully we will have enough time to finish!
Comments(4)-
-
-
-
Gary LaRue says
July 10, 2012 at 2:42 pmMaddie, Thanks for clearly explaining your project(even I understand it, mostly). When you explore those small streams don’t forget the mosquitoe net. Good luck and can’t wait to hear more.
lollie says
July 11, 2012 at 1:34 amHI Maddie,
the work that you are doing sounds incredible.. and yes, I was able to understand most of it! This is such an amazing experience. Keep up the good work and keep us posted.
Mir / Das vi donya ( ?)
Mary Lee says
July 11, 2012 at 1:39 amMaddie – I can’t believe you are half way through! That doesn’t seem possible! Your investigations sound interesting, and I am looking forward to reading more. Stay safe and have fun! So glad you are having this incredible experience! Love, Aunt Mary
Dean Austin says
July 17, 2012 at 12:18 pmDear Maddie:
Back on Mount St James, we follow your adventure with great interest. You’re missing a very hot summer in the US and, while I know from talking to Professor Sobczak that the mosquitoes in Cherskiy have to be seen to be believed, there are plenty here in Massachusetts right now. Keep up the good work and safe travels home again.
Tim Austin