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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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This study analyzed monthly and inter-annual variability of mesoscale phenomena, including the El Niño Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO) climate indexes and wind intensity considering their influence on sea surface temperature (SST) and chlorophyll a (Chl-a). These analyses were performed to determine the effects, if any, of climate indexes and oceanographic and environmental variability on the central and southern coastal ecosystem of Sonora in the Gulf of California (GC). Monthly satellite images of SST ( • C) and Chl-a concentration were used with a 1-km resolution for oceanographic and environmental description, as well as monthly data of the climate indexes and wind intensity from 2002-2015. Significant differences (p > 0.05) were observed while analyzing the monthly variability results of mesoscale phenomena, SST and Chl-a, where the greatest percentage of anti-cyclonic gyres and filaments was correlated with a greater Chl-a concentration in the area of study, low temperatures and, thus, greater productivity. Moreover, the greatest percentage of intrusion was correlated with the increase in temperature and cyclonic gyres and a strong decrease of Chl-a concentration values, causing oligotrophic conditions in the ecosystem and a decrease in upwelling and filament occurrence. As for the analysis of the interannual variability of mesoscales phenomena, SST, Chl-a and winds, the variability between years was not significant (p > 0.05), so no correlation was observed between variabilities or phenomena. The results of the monthly analyses of climate indexes, environmental variables and wind intensity did not show significant differences for the ENSO and PDO indexes (p > 0.05). Nonetheless, an important correlation could be observed between the months of negative anomalies of the ENSO with high Chl-a concentration values and intense winds, as well as with low SST values. The months with positive ENSO anomalies were correlated with high SST values, low Chl-a concentration and moderate winds. Significant inter-annual differences were observed for climate indexes where the years with high SST values were related to the greatest positive anomaly of ENSO, of which 2002 and 2009 stood out, characterized as moderate Niño years, and 2015 as a strong El Niño year. The years with the negative ENSO anomaly were related to the years of lower SST values, of which 2007SST values, of which -2008SST values, of which and 2010SST values, of which -2011 stood out, characterized as moderate Niñas. Thus, variability associated with mesoscale oceanographic phenomena and seasonal and inter-annual variations of climate indexes had a great influence on the environmental conditions of the coastal ecosystem of Sonora in the Gulf of California.

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