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DatoValore
TitleInfluence of lateral advection on phytoplankton size-structure and composition in a Mediterranean coastal area
AbstractPhytoplankton size is a significant functional trait affecting many ecological processes and influencing the carbon fate and the trophic regimes of the ecosystems. In this study, we examined the effect of the lateral advection of nutrient-rich Messina Mixed Waters on the phytoplankton size structure and community composition in the euphotic layer of the Gulf of Augusta (Western Ionian Sea) in early autumn. The chlorophyll a concentration ranged from 0.08 to 0.8 mg m and the phytoplankton abundances ranged from 21 × 10 to 245 × 10 cells L. The size structure of phytoplankton biomass, obtained by sequential filtration of water samples, suggested the dominance of micro-planktonic diatoms in an active Deep Chlorophyll Maximum (DCM) whereas smaller forms were mainly represented by phytoflagellates. A short-term tidal-induced variability of the assemblage structure was observed at a "sentinel" station located at the Gulf shelf-break where lateral advection due to meso-scale dynamics sustained most of the phytoplankton biomass. Our research shows that, in stratified conditions, nutrient enrichment by lateral advection at DCM modifies the size-structure of phytoplankton with respect to that expected from the reference baseline oceanic model validated in open ocean waters. In particular, while smaller fraction incidences reveal a surface oligotrophic system, an increase of the micro-sized fraction is triggered at DCM: this indicates the prevalence of "new production" processes which is a quite unusual condition for the Mediterranean DCM in early autumn, when trophic web is typically sustained by "regenerate production". Our observations suggest that both "microbial" and "herbivore" pathways could coexist and regulate the carbon flow in the Gulf in this season.
SourceContinental shelf research 209
KeywordsPhytoplankton size-structureDiatom associationsMediterranean gulfDCM
JournalContinental shelf research
EditorPergamon Press., Oxford;, Regno Unito
Year2020
TypeArticolo in rivista
DOI10.1016/j.csr.2020.104216
AuthorsDecembrini F.; Caroppo C.; Bergamasco A.
Text431973 2020 10.1016/j.csr.2020.104216 Scopus 2 s2.0 85090711490 Phytoplankton size structure Diatom associations Mediterranean gulf DCM Influence of lateral advection on phytoplankton size structure and composition in a Mediterranean coastal area Decembrini F.; Caroppo C.; Bergamasco A. CNR ISP Istituto di Scienze Polari, Spianata San Raineri, 86, Messina, 98122, Italy; CNR IRSA, Istituto di Ricerca Sulle Acque, Via Roma 3, Taranto, 74121, Italy; CNR ISMAR, Istituto di Scienze Marine, Arsenale Castello 2737/F, Venezia, 30122, Italy Phytoplankton size is a significant functional trait affecting many ecological processes and influencing the carbon fate and the trophic regimes of the ecosystems. In this study, we examined the effect of the lateral advection of nutrient rich Messina Mixed Waters on the phytoplankton size structure and community composition in the euphotic layer of the Gulf of Augusta Western Ionian Sea in early autumn. The chlorophyll a concentration ranged from 0.08 to 0.8 mg m and the phytoplankton abundances ranged from 21 × 10 to 245 × 10 cells L. The size structure of phytoplankton biomass, obtained by sequential filtration of water samples, suggested the dominance of micro planktonic diatoms in an active Deep Chlorophyll Maximum DCM whereas smaller forms were mainly represented by phytoflagellates. A short term tidal induced variability of the assemblage structure was observed at a sentinel station located at the Gulf shelf break where lateral advection due to meso scale dynamics sustained most of the phytoplankton biomass. Our research shows that, in stratified conditions, nutrient enrichment by lateral advection at DCM modifies the size structure of phytoplankton with respect to that expected from the reference baseline oceanic model validated in open ocean waters. In particular, while smaller fraction incidences reveal a surface oligotrophic system, an increase of the micro sized fraction is triggered at DCM this indicates the prevalence of new production processes which is a quite unusual condition for the Mediterranean DCM in early autumn, when trophic web is typically sustained by regenerate production . Our observations suggest that both microbial and herbivore pathways could coexist and regulate the carbon flow in the Gulf in this season. 209 Published version http //www.scopus.com/record/display.url eid=2 s2.0 85090711490 origin=inward Influence of lateral advection on phytoplankton size structure and composition in a Mediterranean coastal area Uncorrected_Proofs pagination_CSR_104216.pdf Articolo in rivista Pergamon Press. 0278 4343 Continental shelf research Continental shelf research Cont. shelf res. Continental shelf research. franco.decembrini DECEMBRINI FRANCO carmela.caroppo CAROPPO CARMELA alessandro.bergamasco BERGAMASCO ALESSANDRO