title: Can stormwater be detected by algae in an urban reef in Hawai'i?
abstract: Nitrogen (N) enrichment of tropical reefs can result in the dominance of invasive algae. The invasive alga Acanthophora spicifera and the native alga Laurencia nidifica are part of a diverse reef assemblage in 'Ewa Beach, O'ahu. Their N contents and δ(15)N values were investigated to determine if N was enriched and to evaluate potential nitrogenous sources near and removed from storm-drain outlets. δ(15)N values of algae (3.8-17.7‰) were within and above the range for algae around the island (1.9-11.9‰). Elevated algae N isotope values (δ(15)N>+7‰, [N]>1.6%) and seawater nitrate+nitrite levels (0.59-7.93 μM) indicated a mixed, high nutrient environment. The overlap in δ(15)N values with multiple nitrogenous sources precluded identification. However, spatial and temporal patterns did not support stormwater as the dominant, nitrogenous source. Patterns were congruent with algal incorporation of terrestrial derived N, subjected to a high degree of biogeochemical cycling.
authors: University of Hawai'i, Department of Botany, 3190 Maile Way, Room 101, Honolulu, HI 96822, USA. erincox@hawaii.edu
authors: T
authors: T
authors: Erin Cox
authors: Celia M
authors: CM
authors: Smith
authors: Brian N
authors: BN
authors: Popp
authors: Michael S
authors: MS
authors: Foster
authors: Isabella A
authors: IA
authors: Abbott
mesh_terms: D002947:Cities; D057894:Coral Reefs; D004323:Drainage, Sanitary; D004784:Environmental Monitoring; D006254:Hawaii; D058865:Introduced Species; D058086:Microalgae / Q000502:physiology*; D009584:Nitrogen / Q000032:analysis; D062065:Wastewater / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D009584:Nitrogen; D062065:Wastewater; D014874:Water Pollutants, Chemical