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Study area:
A: Map of Chile;
B & C: Carelmapu
locality, Region of Los
Lagos
Sporophylls
(n=6)
Adult sporophyte
(n=7)
Meiospores
Pool
Effects of pH, temperature and light on carbon metabolism in Macrocystis pyrifera
gametophytes
Barbara S. Labbe1,2, Pamela A. Fernández3,4, July Z. Florez4,5 and Alejandro H. Buschmann2,3,4
1Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, TAS, Australia
2Master in Science, Postgrade Direction, University of Los Lagos, Puerto Montt, Chile
3i~mar Centre, University of Los Lagos, Puerto Montt, Chile
4MASH, Marine Agronomy of Seaweed Holobionts, Chile
5Depto de Cs y Geografía, Fac. de Cs Naturales y Exactas y HUB Ambiental, Universidad de Playa Ancha, Valparaíso, Chile
Ocean Acidification (OA)
(Boyd & Law, 2011)
BACKGROUND
HCO3-
CO2
Ci sources
(DIC)
Photosynthesis
91%
1%
Current
Oceans
Different strategies for
capturing Ci at different
stages of the life cycle
Carbon Concentrating Mechanisms (CCM)
(Modified from Fernández et al. 2014)
METHODS
Effect of
inhibitors of
photosynthesis
-AZ (Acetazolamide) (CAEXT)
-EZ (Etoxizolamide) (CAEXT /
CAINT)
-DIDS (4,4´-
diisothiocyanatosilbene-
2,3´-disulfonate)(HCO3-via
AE)
O2Evolution by
Lineal regresion
Post-inhibitor
injection
(Modified from Fernández et al. 2015)
3 ways-ANOVA
Tukey (P<0.05)
Software R(4.0.2)
2 pH levels
-pH Amb (∿8.2)
-pH OA (∿7.8)
- Light Amb
(40-50 µmol m-2s-1)
- Light CCG
(10-20 µmol m-2s-1)
(Amb: ambient; CCG: Climate
Global Change)
Experiment 1
(pH-Light)
Experiment 2
(pH-Temp)
-pH Amb (∿8.2)
-pH OA (∿7.8)
- Temp Amb (12°C)
- Temp CCG (16°C)
2 pH levels
2 light levels 2 temp levels
AIM: Effect of OA and
climate global change
on CCM of M. pyrifera
gametophytes
RESULTS
Extracellular conversion of HCO3-to CO2by carbonic anhydrase is
the main CCM in gametophytes of M. pyrifera under these
experimental conditions
CONCLUSIONS
Experiment 2
(pH-Temp)
Extracellular conversion of HCO3-to CO2by carbonic anhydrase is
the main CCM in gametophytes of M. pyrifera under these
experimental conditions.
The gametophytes of M. pyrifera, like the sporophytes of M. pyrifera, use HCO3- to carry
out photosynthesis, however their main CCM is the external conversion of HCO3- to CO2,
a process mediated by the enzyme CA(EXT)
This is contrary to what has been described in adult sporophytes of M. pyrifera where
the main CCM is the direct consumption of HCO3- via AE
This study determined for
the first time CCM in early
stages in M. pyrifera
Questions? Contact me: Barbara.Labbe@utas.edu.au
Macrocystis pyrifera “Key Specie”
Carbon
Concentrating
Mechanisms
(CCM)
(Diagram by Elise Hore)
Experiment 1
(pH-Light)