Variabilidad en la tasa de producción de oxígeno en tres especies fitoplanctónicas marinas circulando dentro de una capa superficial de mezcla simulada.

BARBIERI, E.S.; VILLAFAÑE, V.E.; HELBLING, E.W.

Viña del Mar, Chile

Congreso; XI Congreso Latinoamericano de Ciencias del Mar; 2005

&lt;!-- /* Font Definitions */ @font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-1610611985 1107304683 0 0 159 0;} @font-face {font-family:Calibri; panose-1:2 15 5 2 2 2 4 3 2 4; mso-font-charset:0; mso-generic-font-family:swiss; mso-font-pitch:variable; mso-font-signature:-1610611985 1073750139 0 0 159 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-qformat:yes; mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; text-align:justify; text-indent:9.05pt; line-height:150%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi; mso-fareast-language:EN-US;} .MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; font-family:"Times","serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:Calibri; mso-bidi-theme-font:minor-latin; mso-fareast-language:EN-US;} .MsoPapDefault {mso-style-type:export-only; text-align:justify; text-indent:9.05pt; line-height:150%;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --&gt; Oxygen dynamics in three phytoplankton species (20 - 25 µm in effective diameter) - Dunaliella salina (Chlorophyceae), Thalassiosira weissflogii (Bacillariophyceae) and Heterocapsa triquetra (Dinophyceae) - was experimentally determined when cells circulated within a simulated upper mixed layer (UML).  Samples were exposed to three radiation treatments receiving: a) Full solar radiation (PAB, 280 - 700 nm), b) PAR+UV-A (PA, 320-700 nm), and c) Only PAR (P, 400-700 nm).  Two pathways were simulated (i.e., as if the cells started to circulate from the surface or from the bottom of the UML): 1) “Downward” circulation (i.e., from 100% to 9 % irradiance and back to 100%), and 2) “Upward” circulation (i.e., from 9% to 100% irradiance and back to 9%).  There were no significant differences among radiation treatments (p < 0.05), and photosynthetic inhibition was only due to PAR.  We found important inter-specific differences in O2 rates when cells circulated within the simulated UML: D. salina was affected by both high and low irradiances whereas T. weissflogii was only inhibited by high irradiances.  On the other hand, H. triquetra showed the least variability and it benefited by fluctuating radiation regimes.  We also determined differences in the depth integrated O2 production when species performed a complete rotation within the simulated UML, with the highest values in H. triquetra and the lowest in D. salina.  Our findings may have important implications for the assessment of primary productivity in areas exposed to changing meteorological conditions throughout the year, and hence with variable UMLs.