G. Hernandez-carmona et al., Effect of nutrient availability on Macrocystis pyrifera recruitment and survival near its southern limit off Baja California, BOTAN MARIN, 44(3), 2001, pp. 221-229
The effect of nutrient availability on Macrocystis pyrifera recruitment and
survival of juvenile sporophytes was examined at its southern limit off Ba
ja California, Mexico. Nitrate levels were inversely correlated with water
temperature (r(2) = 0.70) at the experimental location. Low concentrations
of nitrate occurred during most of 1998 (< 3 muM) except in spring (4.8-18.
8 muM). Experimental seeding with sporophylls and fertilizing the plants wi
th a slow-release inorganic fertilizer produced successful recruitment when
the water temperature was declining (18.7 degreesC). Survival of transplan
ted juveniles was significantly higher when fertilized during a period of p
articularly warm water and low nutrients in 1998 caused by El Nino. Analysi
s of tissue nitrogen suggests that plants were nutrient-limited during this
period, and possibly affected synergistically by temperature stress. The r
esults indicate that nutrients directly affect recruitment and survival of
giant kelp at its southern limit, particularly during El Nino conditions.