Carmen E. Morales

ABSTRACT Zooplankton production is a critical issue for understanding marine ecosystem structure and dynamics, however, its time-space variations are mostly unknown in most systems. In this study, estimates of copepod growth and production (CP) in the coastal upwelling and coastal transition zones off central-southern Chile (∼35–37° S) were obtained from annual cycles during a 3 year time series (2004, 2005, and 2006) at a fixed shelf station and from spring–summer surveys during the same years. C-specific growth rates (g) varied extensively among species and under variable environmental conditions; however, g values were not correlated to either near surface temperature or copepod size. Copepod biomass (CB) and CP were higher within the coastal upwelling zone (

ABSTRACT The annual cycle and phenology of phytoplankton (satellite-derived chlorophyll-a, Chl-a) in the coastal upwelling region off central-southern Chile, their time-space variation, and the extent of their coupling with those of wind-driven upwelling (as Zonal Ekman Transport, ZET), Sea Surface Temperature (SST), and Photosynthetically Active Radiation (PAR), were analyzed using a ∼10 y satellite time series (2002-2012). Wavelet analysis (WA) was applied to extract the dominant frequencies of variability and their recurrence, to derive the phenological indexes, and to assess the extent of the coupling between Chl-a and environmental forcing in the annual frequency. Index estimates were obtained from minimum and maximum accumulated values in two different frequency bands, annual (WA-ANF) and all except the synoptic (WA-ALF). The annual frequency was dominant in all the variables, however, the annual cycle and phenology of Chl-a displayed higher submeso- and mesoscale variability. The mean onset date of Chl-a was similar to those of PAR and ZET with WA-ALF and cross-WA indicated that, for the most part, their annual cycles were coupled or coherent. Few interannual changes in Chl-a phenology were detected, including a ∼1 month longer duration (WA-ALF) during La Niña 2010-2011. The mean anomalies in the magnitudes of Chl-a and ZET during the upwelling season showed a slight but significant trend, negative for Chl-a and positive for ZET, while SST remained relatively constant. This pattern was unexpected since three La Niña-related conditions were identified during the 2007-2012 period. This article is protected by copyright. All rights reserved.

... Author Contact Information , E-mail The Corresponding Author , Carmen E. Morales a , Laura Farías a , Marcela Cornejo a , Michelle Graco b ... more important in terms of carbon transfer during wintertime ([Böttjer and Morales, 2005], [Böttjer and Morales, 2007] and [Vargas et al ...

In the Humboldt Current System, the region off central-southern Chile has relatively high eddy kinetic energy, generating an extensive coastal transition zone (∼600km offshore) in which coastally derived eddies are recurrent features. This energy might promote strong exchanges of water, biogeochemical properties, and plankton between the coastal upwelling band and the adjacent oceanic zone. In this study, the mesoscale structure

... Daniela Böttjer • Carmen E. Morales • Ulrich Bathmann ... nauplii are a relatively stable component in this coastal area (Torres 2006), together with picoplankton (Alarcon 2008) and nanoplankton (Böttjer and Morales 2007), we hypothesize that they exert a relatively high grazing ...

ABSTRACT Diet selection of the Chilean stone crab Homolaspis plana (Milne-Edwards, 1834) was studied using the optimal foraging theory to explain its feeding strategy. The hypothesis that H. plana prefers prey species of the highest prey (energy) value was experimentally tested on adult crabs during 1980–1981. Food value was defined as the ratio between caloric content and consumption time, according to energy maximization as the criterion to optimize diet selection. Diet composition of adult crabs from the littoral of Valparaso (Chile) and ingestion under laboratory conditions were studied to determine type, size and quantity of food to be offered in experiments on prey-type preference. Porcellanid crabs, barnacles and bivalves were the most frequently occurring items in stomachs from in situ conditions. In the aquaria, daily ingestion rates were quite variable among crabs and among days. H. plana showed no size preference for molluscs (Tegula atra, Semimytilus algosus) but preferred larger sizes of porcellanids. The order of preference for prey type was S. algosus>T. atra> porcellanids. However, no differences between their energy values were found and, therefore, the optimal foraging hypothesis was rejected. By extension, the energy maximization criterion alone may not explain the diet selection of H. plana under experimental conditions.

Abstract. The North Atlantic was the site for the 1989 JGOFS Pilot Study, an international study of ocean fluxes in relation to the carbon cycle. In this paper we present preliminary estimates of the grazing pressure by copepod assemblages at four stations' 60, 56, 52 and 47°N, ...