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Trophic resources are an important control governing carbonate production. Though this importance has long been recognized, no calibration exists to quantitatively compare biogenic assemblages within trophic resource fields. This study presents a field calibration of carbonate producers in a range of settings against high-resolution in situ measurements of nutrients, temperature and salinity. With its latitudinal extent from 30°to 23°N, the Gulf of California, Mexico, spans the warm-temperate realm and encompasses nutrient regimes from oligo-mesotrophic in the south to eutrophic in the north. Accordingly, from south to north carbonates are characterized by: (i) coral-dominated shallow carbonate factories (5-20 m water depth) with average sea-surface temperatures of 25°C (min. 18°C, max. 31°C), average salinities of 35AE06& and average chlorophyll a levels, which are a proxy for nutrients, of 0AE25 mg Chl a m )3 (max. 0AE48, min. 0AE1). (ii) Red algal-dominated subtidal to inner-shelf carbonate formation (10-25 m) in the central Gulf of California exhibiting average temperatures of 23°C (min. 18°C, max. 30°C), average salinities of 35AE25&, and average Chl a levels of 0AE71 Chl a m )3 (max. 5AE62, min. 0). (iii) Molluskan bryozoan-rich inner to outer shelf factories in the northern Gulf of California (20-50 m) with average sea surface temperatures of only 20°C (min. 13°C, max 29°C), average salinities of 35AE01&, and average contents of 2AE2 mg Chl a m )3 (max. 8AE38, min. 0). By calibrating sedimentological data with in situ measured oceanographic information in different environments, the response of carbonate producers to environmental parameters was established and extrapolated to carbonates on a global scale. The results demonstrate the importance of recognizing and quantifying trophic resources as a dominant control determining the biogenic composition and facies character of both modern and fossil carbonates.

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ABSTRACT. Using satellite derived data from 1997-2010, sea surface temperature (SST), chlorophyll a (Chl) and primary productivity (PP) variations are described at different temporal and spatial scales in the Gulf of California. Interannual signals of El Niño (EN) and La Niña (LN) were more evident at the entrance to the gulf. Once EN or LN events were over, there was a delayed response of three to six months for the reestablishment of "normal" phytoplankton activity levels. Phytoplankton response to high concentrations of nutrients due to LN was not immediate. At regional scale, EN significantly decreased the Chl mean with regard to "normal" conditions at the entrance, central gulf, and Midriff Islands region (MIR); however, PP under EN conditions decreased significantly only at the entrance. The increase in Chl and PP due to LN relative to "normal" conditions was significant only at the entrance. SST, Chl, and PP annual signals are the main source of variation, particularly for the central gulf and entrance, but in the MIR, "winter" PP (1.96 g C m ). Highest PP was found in the central gulf and MIR, where inferences of production attributable to new production were estimated at more than 60% of PP. At the gulf entrance, primary productivity was mainly attributable to regenerated production, particularly during summer and autumn.Key words: Gulf of California, chlorophyll a, primary productivity, remote sensing, El Niño. RESUMEN.Con datos satelitales de 1997 a 2010, se describe la variación de temperatura superficial del mar (TSM), clorofila a (Chl) y productividad primaria (PP) a diferentes escalas temporales y espaciales en el golfo de California. Las señales interanuales El Niño (EN) y La Niña (LN) fueron más evidentes en la boca del golfo. Existió una respuesta desfasada de tres a seis meses para el restablecimiento de las condiciones "normales" de la actividad fitoplanctónica una vez que cesaba un evento EN o LN. La respuesta fitoplanctónica ante las mayores concentraciones de nutrientes que supone el evento LN no fue inmediata. En la escala regional, la condición EN redujo significativamente el promedio de Chl respecto a condiciones "normales" en la boca, el centro y la región de las islas grandes (RIG) del golfo; sin embargo, la PP bajo la condición EN sólo se redujo significativamente en la boca. El incremento de Chl y PP por LN con relación a condiciones "normales" sólo fue significativo en la boca. Se confirma que la señal anual de TSM, Chl y PP es la componente mayor de la variación, sobre todo para las regiones de la boca y centro. Sin embargo, en la RIG, la PP de "invierno" (1.96 g C m ). La PP más alta se encontró en la RIG y en el centro del golfo, en donde las inferencias de producción atribuible a la producción nueva se calcularon en más del 60% de PP. En la boca del golfo, la productividad primaria fue principalmente atribuible a la producción regenerada, particularmente durante verano y otoño.Palabras clave: golfo de California, clorofila a, productividad primaria, percepción remota, El Niño.

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