Sergio Avaria

Variación temporal del fitoplancton entre 1993 y 1998 en una estación fija del seno Aysén, Chile (45º26'S 73º00'W)

Temporal distribution of the phytoplankton in a fixed station inside Aysen fjord is described using 130 qualitative phytoplankton samples and water surface temperature measurements taken every 15 days from February

Efectos microbiológicos producidos por un evento de surgencia costera en Chile central

An upwelling is an oceanographic phenomenon which produces a nutrients enrichment of euphotic zones resulting in a phytoplankton bloom crucial for productivity in many coastal zones in Chile. In this research we present information concerning the microbiological effect of an upwelling event. In regard to other studies performed in Chile, we include a novel variable: the changes in virus concentrations in relation with the upwelling and the abundances of phytoplankton and bacterioplankton. The samples were collected at Valparaiso bay (32o57S; 71o34W) during spring 2006. Species composition and high phytoplankton concentrations are according with an upwelling event. After the upwelling, phytoplankton, bacteria and virus increased 24, 6 and 15 times, respectively. Shortly after, phytoplankton and bacterioplankton declined but, in contrast, virus increased 5 more times. This latter is consistent with the idea that virus is important, at least, in the decline of the bacterioplankton

La familia Hemiaulaceae (Bacillariophyceae) de las aguas marinas chilenas

The Family Hemiaulaceae comprises four genera, all of which have been previously reported for coastal waters off Chile, and represented by the following taxa: Cerataulina pelagica (Cleve) Hendey, Hemiaulus sinensis Greville, H. membranaceus Cleve, Climacodium biconcavum Cleve, Eucampia antarctica (Castracane) Mangin, E. cornuta (Cleve) Grunow and E. zodiacus Ehrenberg. However, examination with light and electron microscopy of marine samples from along the Chilean coast and the Antarctic Peninsula (including those used in earlier publications) revealed that (1) the genus Cerataulina is represented by C. pelagica, and is distributed along the Chilean coast between Arica in the north and the Magellan Strait in the south, (2) the genus Eucampia comprises four taxa: E. zodiacus f. cylindrocornis Syvertsen (previously reported for Chile as E. zodiacus f. zodiacus), E. zodiacus f. recta Rivera, Avaria & Cruces (described here), E. cornuta and E. antarctica. The former three taxa occur in the central and northern coast of Chile, while E. antarctica lives in Antarctic waters south of the Magellan Strait, (3) earlier records of Hemialus membranaceus, H. sinensis and Climacodium biconcavum in Chilean waters are misidentifications of Eucampia zodiacus f. recta f. nov. A short description is included for each taxon, and photographs provide information about the main morphological characteristics.

PRIMER REGISTRO DE THALASSIONEMA PSEUDONITZSCHIOIDES (SCHUETTE & SCHRADER) HASLE (THALASSIONEMATACEAE, BACILLARIOPHYCEAE) EN EL PACIFICO SURORIENTAL FRENTE A LA COSTA DE CHILE

This note reports the finding of Thalassionema pseudonitzschioides (Schuette & Schrader) Hasle in samples collected in Iquique Bay (20°12S, 70°10W), in northern Chile. This is the first record of the species for the region. The taxon has been associated mainly with subtropical to temperate waters