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Photophysiological responses of intertidal benthic microalgal communities to in situ light environments: Methodological considerations
Author(s) -
Pinckney J.,
Zingmark R. G.
Publication year - 1993
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1993.38.7.1373
Subject(s) - benthic zone , spartina , biomass (ecology) , intertidal zone , spartina alterniflora , irradiance , environmental science , photosynthesis , sediment , oceanography , biology , ecology , botany , wetland , marsh , geology , physics , quantum mechanics , paleontology
Photosynthesis vs. irradiance ( P‐I ) curves usually express production in terms of production per unit biomass. However, for benthic microalgal communities, the depth of the sediment photic zone as well as the amount of biomass exposed to light varies as a function of incident irradiance. We examined the photosynthetic responses of intertidal benthic microalgal communities from different light environments with traditional depth‐integrated methods as well as the percent P max and fixed‐depth interval methods. P‐I curve parameters ( α, I k , I m ) change depending on the method used. With the depth‐integrated biomass‐specific method, microalgae in unshaded mudflats have a higher α (0.261±0.016) than microalgae in shaded tall Spartina habitats (0.161±0.014), suggesting that mudflat microalgae are more shade‐acclimated than tall Spartina microalgae. However, if curves are constructed with measurements obtained at a fixed depth (surface) in the sediment, tall Spartina microalgae exhibit a significantly higher α (0.260±0.020) than mudflat microalgac (0.175±0.006). With the latter method, tall Spartina surface microalgae appear more shade‐acclimated than mudflat surface microalgae. We conclude that the fixed‐depth interval method provides a more realistic representation of the photophysiological responses of benthic microalgal communities.