Estimating primary productivity of marine macroalgae in East Antarctica using in situ fluorometry

Figures & data

Fig. 1. Map of the Windmill Islands showing relevant locations. Codes are as follows: BB, Brown Bay; LI, Lilienthal Island; MI, Molholm Island; PC, Powell Cove; SI, Shirley Island; SB, Sparkes Bay; WK, Wilkes. The map was provided by the Australian Antarctic Data Centre.

Fig. 2. Annual photon dose at different depths in near-shore waters at Casey. Values for different numbers of ice free days are presented; there were 84 days at the time of the study. Panel B (inset) shows a crossing over at approximately 30 m: the annual photon dose in shallow waters increases with an increase in the number of ice-free days, whereas at depths below 30 m the annual photon dose decreases with an increase in the number of ice-free days.

Fig. 3. Diel changes in photosynthetic parameters of Iridaea sp. and irradiance in a low light ice-covered environment derived from light response curves conducted every 90 min, where ETR_max represents the maximum rate of electron transport, α represents the initial slope of the PE curve, and represents the effective quantum yield of PSII energy conversion. Irradiance was less than 1 µmol photons m⁻² s⁻¹. Error bars are standard deviations.

Fig. 4. Diel changes in photosynthetic parameters of Iridaea sp. and irradiance in a high light ice-free environment derived from light response curves conducted every 90 min, where ETR_max represents the maximum rate of electron transport, α represents the initial slope of the PE curve, and represents the effective quantum yield of PSII energy conversion. Error bars are standard deviations.

Fig. 5. Oxygen evolution–electron transport rate curves derived from simultaneous in vivo measurements of ambient irradiance, ETR and oxygen concentration. Closed circles represent measurements; open circles represent the best fit line according to the model predictions.

Table 1. Parameters used to describe the empirical non-linear relation between ETR (electrons m⁻² s⁻¹, abscissa) and O₂ evolution (µmol O₂ m⁻² s⁻¹, ordinate) for Antarctic macroalgae. Data are estimates derived from a single curve fit of four pooled replicate experiments ± SD; R² represents the coefficient of determination, ** denotes significance at 99%. Data used in these calculations from fig. 6 of Runcie & Riddle (2006).

	O2max	Initial slope	O2min	R^2
Iridaea cordata	2.75 ± 0.4	1.00 ± 0.4	−0.79 ± 0.4	0.63**
Himantothalllus grandifolius	4.49 ± 0.4	0.26 ± 0.1	−0.49 ± 0.3	0.81**
Desmarestia menziesii	1.97 ± 0.4	0.49 ± 0.3	−0.12 ± 0.3	0.44**

Table 2. In vivo- and in situ-derived rates of oxygen evolution and consumption, and carbon fixation rate estimates of Antarctic macroalgae. Algae were either measured at (in situ) or obtained from (in vivo) depths as defined. Values of P_max were measured in vivo, productivity and production values were derived from in vivo or in situ measurements. E_max represents maximum irradiance during a 24-h interval at the location of collection or in situ measurement. ND = no data.

Species	depth		Pmax	In situ productivity	Production	Emax	Photon dose	Reference
	(m)	n	(µmolO2 g^−1FWh^−1)	(µmolO2 g^−1FWh^−1)	(mgCg^−1FWh^−1)	(µmolphotonsm^−2s^−1)	molm^−2d^−1
Iridaea sp. (Brown Bay)	10	1	ND	−5.22 to −5.00	−1.47 ± 0.05	1	0.1	this study
Iridaea sp. (aquarium)	<1	1	ND	−5.63 to −4.96	−1.53 ± 0.00	2	0.1	this study
Iridaea sp. (Molholm Is.)	4	1	ND	−6.45 to 0.64	−1.14 ± 0.11	22	0.7	this study
Iridaea sp. (Shirley Is.)	4	1	ND	−5.71 to 0.24	−0.97 ± 0.04	12	0.6	this study
Iridaea sp.	6	4	ND	−8.22 to 2.51	−1.19 ± 0.04	5	0.2	this study
Iridaea sp.	7	3	ND	−5.75 to 20.29	3.58 ± 0.03	299	6.5	this study
Iridaea sp.	6	4	ND	−8.02 to −7.97	−2.30 ± 0.00	0.1	0.009	this study
Iridaea sp.	4	3	ND	−5.94 to 20.27	3.65 ± 0.23	363	10.1	this study
Himantothallus grandifolius	6	4	ND	−2.56 to 10.45	0.88 ± 0.09	38	2.9	this study
Himantothallus grandifolius	6	3	ND	−2.66 to 7.49	0.58 ± 0.04	33	1.3	this study
Himantothallus grandifolius	6	2	ND	−2.04 to 18.42	2.36 ± 0.05	299	9.0	this study
Himantothallus grandifolius	6	4	ND	−2.41 to −2.41	−0.70 ± 0.00	0.1	0.009	this study
Himantothallus grandifolius	6	2	ND	−1.10 to 18.93	2.60 ± 0.03	567	6.1	this study
Desmarestia menziesii	6	3	ND	−1.07 to 15.50	2.42 ± 0.00	350	7.3	this study
Desmarestia menziesii	6	4	ND	2.31 to 15.49	3.53 ± 0.00	567	6.1	this study
Gigartina skottsbergii	10^A	4	15 ± 2	ND	1.74 ± 0.31	146–400	6.7	Gómez et al. (1997)
Himantothallus grandifolius	10^A	4	8 ± 2	ND	0.66 ± 0.21	146–400	6.7	Gómez et al. (1997)
Desmarestia anceps	10^A	4	23 ± 5	ND	0.65 ± 0.62	146–400	6.7	Gómez et al. (1997)
Kallymenia antarctica	10^A	4	14 ± 2	ND	1.96 ± 0.22	146–400	6.7	Gómez et al. (1997)
Palmaria decipiens	10^A	4	26 ± 5	ND	2.45 ± 0.56	146–400	6.7	Gómez et al. (1997)
Phyllophora antarctica	10^A	6	10.0 ± 2.1	ND	0.03	∼2	∼0.1	Schwarz et al. (2003)
Desmarestia menziesii	<1^A	5	24.09 ± 1.7	ND	ND	< 30	< 2.6	Runcie & Riddle (2006)
Himantothallus grandifolius	<1^A	4	21.59 ± 1.45	ND	ND	< 30	< 2.6	Runcie & Riddle (2006)
Iridaea cordata	<1^A	4	17.12 ± 1.96	ND	ND	< 30	< 2.6	Runcie &Riddle (2006)
Iridaea cordata	<1^A	3 or 4	19	ND	ND	ND	ND	Weykam et al. (1996)
Desmarestia menziesii	<1^A	3 or 4	∼8	ND	ND	ND	ND	Weykam et al. (1996)
Himantothallus grandifolius	<1^A	3 or 4	7	ND	ND	ND	ND	Weykam et al. (1996)
^Adenotes in vivo measurements made on samples collected from the field.

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