Details

Autor(en) / Beteiligte

• Schnetzer, A
• Schaffner, R A
• Stauffer, BA
• Miller, P E
• Jones, A
• Cetinic, I
• Jones, B
• Weisberg, S B
• Caron, DA

Titel

Toxic Blooms of the Diatom Pseudo-nitzschia spp. and Urban River Discharge Into Southern California Coastal Waters

Ist Teil von

• Eos (Washington, D.C.), 2006-09, Vol.87 (36)

Erscheinungsjahr

2006

Link zum Volltext

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• The Los Angeles area of the Southern California Bight is the focal point of a field-oriented ECOHAB research program to investigate the relationship between freshwater inputs from a highly urbanized coastal region and blooms of the toxic diatom Pseudo-nitzschia. Our study encompasses a 400 km super(2) area including the Los Angeles Harbor area and adjacent coastal ocean (from the Palos Verdes peninsula to Newport Beach) that is periodically influenced by runoff from 3 major rivers (Los Angeles River, San Gabriel River and Santa Ana River). We conducted multiple surveys (weekly to monthly) throughout 2005, a record rainfall year for Southern California, to examine the spatial and temporal relationship between river discharge, Pseudo-nitzschia abundance, domoic acid production and pertinent chemical / physical (temperature, PO sub(4), NO sub(3)+NO sub(2), Si(OH) sub(4)) parameters. We discuss differences in environmental conditions among non-bloom months with those during bloom periods. The latter include a mixed diatom bloom that was co-dominated by Pseudo-nitzschia spp. in mid- April. Domoic acid concentrations at that time peaked at 9.7 mu g particulate DA per liter south of the Los Angeles harbor (mean = 1.2 mu g DA per liter). Toxic species of Pseudo-nitzschia present in spring of 2005 included P. delicatissima, P. fraudulenta and P. pungens. A bloom that was solely dominated by P. delicatissima was observed inside the inner breakwater of the LA harbor at the beginning of July. Although cell abundances reached 6 x10 super(6) cells per liter, particulate domoic acid during this highly localized event did not exceed 0.01 mu g per liter. Ongoing analysis on relationships of nutrient concentration, nutrient ratios and physical parameters will be discussed.