The San Lázaro Basin (SLB) sediment record is highly sensitive to the El Niño-Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) due to its location vertically underlying the dynamic boundary between the northern, cooler and fresher waters of the California Current System (CCS) and the southern, warmer and saltier surface waters from the subtropics and tropics. Warm sea surface temperatures (SSTs) and the ensuing stratified surface water column favor carbonate productivity, mostly dominated by the export of coccolithophorids as observed during El Niño events, while cool SSTs and a less stratified water column favor a relatively higher export of organic carbon. Here we show how during the last two millennia, the mechanisms that drive the organic carbon and carbonate export depend on the time scale considered. The organic carbon and carbonate records show opposite trends for the past 2000 years. On multicentennial periodicities, their variability is probably a result of precessional forcing and associated decreasing Northern Hemisphere insolation, which has been shown to affect the migration of the Intertropical Convergence Zone and the polar jet stream. On shorter time scales, interannual to centennial, the SLB records exhibit an ENSO-like variability; similarly, decadal to multidecadal variability is correlated with instrumental and reconstructed PDO records. We further show how interannual variance seems to have increased during the Little Ice Age, most likely related to large ENSO events, in contrast with an apparent reduction in this type of variability between 400 and 1350 Common Era, suggesting a changing sensitivity of the ENSO teleconnection in the southern CCS for the past two millennia. ABELLA-GUTIÉRREZ AND HERGUERA CARBON PALEOPRODUCTIVITY IN THE SOUTHERN CCS 953PUBLICATIONS Paleoceanography
Growth and reproductive cycle of the prawn, Palaemon adspersus were studied in Fornells Bay from April 2002 to March 2003. Samples caught using a lift net showed that abundance is markedly seasonal, with peaks in autumn and winter. P. adspersus showed distinct sexual dimorphism, the females being larger than the males. The K coefficient of the VBGF (Von Bertalanffy Growth Formula) was higher in the females (2.065 year −1 for females and 1.076 year −1 for males) and the same applies to L ∞ coefficient of the VBGF (47.8 mm in females and 34.14 mm in males). Ovigerous females were found from March to August. However, the low percentage of ovigerous females found in the study area suggests that reproduction and incubation do not occur at the study site. Also, as the ovary shows activity during the whole year cycle, it is not possible to distinguish a discrete reproductive period. RESUMENEl crecimiento y el ciclo reproductor de Palaemon adspersus fueron estudiados en la bahía de Fornells entre Abril de 2002 y Marzo de 2003. Las muestras obtenidas con una red por elevación indican una marcada variación estacional, con mayores abundancias en otoño e invierno. P. adspersus presenta dimorfismo sexual, siendo de mayor talla las hembras. Los parámetros de crecimiento calculados fueron superiores en hembras. El valor del coeficiente K de la VBGF (Fórmula de crecimiento de Von Bertalanffy fue 2.065 año −1 para las hembras y 1.076 año −1 para los machos. En el caso de L ∞ , fueron 47.8 mm en hembras y 34.14 mm en machos. Se han encontrado hembras ovígeras entre Marzo y Agosto. En cualquier caso, el bajo porcentaje de hembras ovígeras encontradas sugiere que la reproducción e incubación no se desarrollan en el área de estudio. Esto unido a que la actividad del ovario se mantiene durante todo el año no permite discernir un periodo reproductor claro.
Variability of North Pacific sea surface temperatures (SSTs) on multidecadal timescales plays an important role in modulating global climate and regional hydroclimate. The principle modern phenomenon associated with this variability is the Pacific Decadal Oscillation (PDO); however, our understanding of the PDO and multidecadal SST variability more broadly is limited to SST observations from the historical era and land-based proxy reconstructions. Here, we reconstruct multidecadal Pacific Ocean SST variability with an 1,800-year, continuous, high-resolution alkenone-derived SST reconstruction from Baja California, a region sensitive to changes in the PDO, and compare the record with a reconstruction of Southwestern North American hydroclimate. Our SST reconstruction displays persistent multicentennial and discontinuous intervals of multidecadal variability with periodicities similar to instrumental PDO observations. The most severe droughts in Southwestern North America during the last two millennia are coeval with strong multidecadal variability, suggesting that multidecadal SST variability plays an important role in regional megadroughts.Plain Language Summary The distribution of heat in the ocean's surface plays a profound role in global and regional climate on timescales of seasons to millennia. The observational record of ocean temperatures only spans the last 150 years, requiring us to use paleoclimate archives to understand the mechanisms of climate variations on multidecadal and longer timescales. Here, for the first time, we reconstruct changes in ocean temperature off Baja California in the Eastern Subtropical Pacific Ocean during the last two millennia. We find that so-called "megadroughts" that occurred in Southwestern North America during the last millennium coincide with time intervals that have the strongest variations in ocean temperatures. The combined alterations to atmospheric circulation and Pacific temperature caused by the Pacific Decadal Oscillation together likely played an important role in the development of Southwestern North American megadroughts.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.