Publications: Peer-reviewed journal articles (by staff)

Broad-scale patterns of tissue-delta N-15 and tissue-N indices in frondose Ulva spp.: Developing a national baseline indicator of nitrogen-loading for coastal New Zealand

1 January, 2013
CITATION

Barr NG, Dudley BD, Rogers KM, Cornelisen CD 2013. Broad-scale patterns of tissue-delta N-15 and tissue-N indices in frondose Ulva spp.; Developing a national baseline indicator of nitrogen-loading for coastal New Zealand. Marine Pollution Bulletin 67(1-2): 203-216.

ABSTRACT

A survey of tissue-delta N-15 and tissue-N values in the green macroalga, Ulva, was conducted around the coast of New Zealand to determine if these indices could be used as indicators of anthropogenic nutrient loading in coastal waters. In addition, data from four case studies showed temporal and spatial responses of tissue-delta N-15 and tissue-N in Ulva to significant terrestrial nutrient inputs. Tissue-delta N-15 in Ulva from 'natural' exposed coastal sites showed a relatively narrow baseline range of values (6.6 +/- 0.1-8.8 +/- 0.1 parts per thousand) in both summer and winter that was consistent throughout New Zealand. Departures in Ulva tissue-delta N-15 ratios outside this range, particularly when coupled with high (>3.1%) tissue-N values, indicate significant contributions of terrestrially-derived nitrogen to coastal seawater. We note that tissue-N content is also affected by exposure, light and season; however provided such factors are taken into account Ulva can be a cost-effective indicator of relative changes in both source and amount of nitrogen-loading. (c) 2012 Elsevier Ltd. All rights reserved.