The amount of nitrogen in the biotic and abiotic systems at Cape Bird measured from evaporated water samples and wind blown inputs

The amount of nitrogen in the biotic (flora and fauna) and abiotic (soils, ice and snow) systems at Cape Bird was determined by taking water from melt streams, snow or ice, acidifying and evaporating down to 50mls samples. About 10L of water was evaporated per day and the 50 samples created per day (~1400 in total) were tested for total mineral N, NH4, NO3, NO2 and pH using the steam distillation method. Samples were collected from ice cap ice (top and bottom), freshly fallen snow, snowbank snow (1 year old), Keble Valley (top, middle and bottom), a penguin colony (top, middle and bottom), soil above Keble Valley and ornithogenic soil. Water flows were determined from streams in the study area using a V-notch weir and from these results the volume of water per day could be calculated and the amount of nutrients in meltwater. The weight of ice in one hectare of the ice cap to 1m depth was calculated from volume, density measurements. The weights of soils per hectare to 5 or 10 cms depth were calculated from bulk density measurements. Strong winds could potentially redistribute material originating from penguin colonies and therefore represent additional nitrogen inputs. Dust collecting boxes were installed in Keble Valley and left for the winter to be examined the following season for input of windblown organic debris, particularly nitrogen, from Northern Rookery into Keble Valley. Two boxes were positioned, one north facing and the other south facing. The contents were weighed and then analysed for nitrogen content.