. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. PHYCOERYTHRIN 1- 0) T3 O) ' A 1- 400 800 Nitrogen load (kgha-1 y1) 0 I 500 1500 Irradiance (//mole photon m'2 s~1) increased (Fig. IE), even though this pigment is known to function as a nitrogen reserve (11). C. tikvahiae may not be nitrogen- limited in these estuaries, an inference that we base on both the relatively low response of chlorophyll a (Fig. 1A) and carotenoid (Fig. IB) concentrations, and the lack of response of phycoerythrin Figure 1. Milligrams dry weigh! of pigments per gram dry weight of macroalgae are show
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. PHYCOERYTHRIN 1- 0) T3 O) ' A 1- 400 800 Nitrogen load (kgha-1 y1) 0 I 500 1500 Irradiance (//mole photon m'2 s~1) increased (Fig. IE), even though this pigment is known to function as a nitrogen reserve (11). C. tikvahiae may not be nitrogen- limited in these estuaries, an inference that we base on both the relatively low response of chlorophyll a (Fig. 1A) and carotenoid (Fig. IB) concentrations, and the lack of response of phycoerythrin Figure 1. Milligrams dry weigh! of pigments per gram dry weight of macroalgae are shown versus nitrogen load (left column) and versus irradiance (right column). (A) Chlorophyll a (C. vagabunda. F = P < : G. tikvahiae, F = P < ). (B) carotenoid (C. vagabunda. F = P < ; G. tikvahiae, F = P < ), and (C) phycoerythrin (ns) concentrations versus nitrogen load. The dotted lines show published (5) pigment concentrations ranges for macroalgae in nitrogen-poor waters (lower dotted lines) and nitrogen-rich water (upper dotted lines). (D) Chlorophyll a (C. vagabunda, F = , P < ; G. tikvahiae. F = , P < ). (E) carotenoids (C. vagabunda, F = P < ; G. tikvahiae, F = , P < ) and (F) phycoerythrin (ns) concentrations versus irradiance. concentrations (Fig. 1C) to nitrogen load. We also measured concentrations of chlorophyll /;. which showed a positive response to nitrogen load (data not shown). Curiously, concentrations of chlorophyll b responded more strongly to increased nitrogen sup- ply than did chlorophyll a concentrations (Fig. 2A). We have no explanation for this response. Concentrations of chlorophyll a (Fig. ID) and carotenoids (Fig. IE) in both species of algae decreased similarly and significantly at lower irradiance. These results suggest that the mechanism of response to irradiance is similar for both species of algae. Phyco- erythrin concentrations (Fig. IF) did
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
