Seasonal variations of nutrients and phytoplankton in the coastal SW Adriatic Sea (1995-1997)

Citation
C. Caroppo et al., Seasonal variations of nutrients and phytoplankton in the coastal SW Adriatic Sea (1995-1997), BOTAN MARIN, 42(4), 1999, pp. 389-400
Citations number
48
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Aquatic Sciences
Journal title
BOTANICA MARINA
ISSN journal
0006-8055 → ACNP
Volume
42
Issue
4
Year of publication
1999
Pages
389 - 400
Database
ISI
SICI code
0006-8055(199907)42:4<389:SVONAP>2.0.ZU;2-9
Abstract
Monitoring cruises were carried out on four coastal transects of the southe rn Adriatic Sea over two years to investigate the effects of the hydrodynam ic regime on environmental factors and phytoplankton species composition an d succession. The concentration of nutrient salts is usually low except for the winter months. Biomass levels tin terms of chlorophyll a) proved to be very low, with values ranging between 0.05 and 1.25 mu g Chl a L-1. Phytop lankton densities showed specific oligotrophic water values and varied in a wide range from 9 x 10(3) to 2.9 x 10(6) cells L-1; the maximum values wer e reached in January-February mainly because of a bloom of the diatom Skele tonema costatum. Diatoms were present throughout the year and represented t he majority of the population (44.3%) together with phytoflagellates (39.6% ), while dinoflagellates and coccolithophorids reached, respectively, 10.3 % and 5.8 %. During the year, diatoms were dominant with high cell densitie s in winter time, while phytoflagellates had a larger distribution over tim e and reached the highest Values in spring and summer. Species diversity va lues were typical of temperate coastal areas (H-' = 2.79 +/- 0.73). The type of circulation determined the distribution of thermohaline charact eristics, abundance and biomass, as well as species composition and success ion of phytoplankton in time. However, no great spatial variations were obs erved.