3. Algal accrual on nutrient diffusing substrates (NDS)

We used in situ nutrient diffusing artificial substrates (NDS) to test for nutrient limitation of benthic algae. Concentrated nutrients are enclosed in vials with diffusive fritted glass tops, which allow nutrients contained in an agar gel to slowly leach through the substrates. Periphyton accumulates on diffusive surfaces when NDS are deployed in natural waters, and differences in accumulation rates between nutrient treatments and controls are interpreted as evidence of periphyton nutrient limitation. The NDS data are original, whereas the associated ambient data have been previously released in Brightbill and Frankfurter (2010) and Mebane and others (2014), and are repeated here for convenience References Brightbill, R.A. and J.D. [...]