The Moss Landing Marine Labs Global Kelp Systems class went to Chile and learned to process samples of algae and invertebrates to get carbon and nitrogen isotopes.  These isotopes were collected to help scientists learn about the impact of creating a kelp farm where kelp would not have been otherwise.  Algae and inverts have different isotope signals, so isotopes can help in tracking where nutrients go.  What did this kelp crab have for dinner?  Looks like algae from the kelp farm!