PREDICTING THE EFFECT OF CLIMATE WARMING ON NITROGEN FIXATION AND ITS ECOLOGICAL CONSEQUENCES IN AQUATIC ECOSYSTEMSDelorianne SanderDr. Jill Welter, Mentor

Hengill Watershed, Iceland

• Why Iceland?–Geothermal activity – streams 5-25°C–Proximity of study sites

• Study nitrogen-fixing algal species across a large temperature gradient

~5 ft 21°C18°C

Non nitrogen-fixing species Nitrogen-fixing speciesN2 N2

N2 N2 N2

Prediction: N2-fixation increases as temperature increases

Research Question and Prediction

Measure indirectly using analogous gas (ARA)

Measure directly using 15N2 isotope

1 2

3 4

5 615N2 gas

Nitrogenase enzyme

N2

gasNitrogenase enzyme

Acetylenegas

MEASURING N2 FIXATION - ICELAND

RESULTS

6 8 10 12 14 16 18 20 220

102030405060708090

100anabaena spp.

nostoc spp. (golden)

nostoc spp. (gray)

nostoc spp. (pink)

Average Stream Temperature (°C)Aver

age

Fixa

tion

Rat

e (m

g N

/m2/

h) a. ARA results

Anabaena spp.

Nostoc spp. (golden)

Nostoc spp. (gray)

Nostoc spp. (pink)

0 5 10 15 20 250

10

20

30

40

50

60

70

b. 15N2 results

MEASURING N2 FIXATION - SCU•Preparing samples for C, N, and P analyses

•Independent work learning new protocols

•Data management

•Communication is critical!

C/N

anal

ysis

prep

P sa

mpl

e pr

ep a

nd a

naly

sis

MANY PRESENTATIONS Day at the Capitol NCUR AMP SCU Sr. Seraphim

Gibbons Undergraduate Research Symposium (www.uwlax.edu)

THE TRANSFORMATION Boosted

confidence! Transition to

professional working environment Method

development Data processing and

management Lab equipment

Preparation for graduate school

ACKNOWLEDGEMENTSThank you to our collaborators from Montana

State University, the University of Alabama, and the Veiðimálastofnun, as well as our collaborators here in Minnesota.

A special thank you to Dr. Jill Welter and Bayley Lawrence for their hard work on this project.

Most importantly, thank you to the AMP program and our generous SCU alumnae and donors for making this project possible!