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International Journal on Algae
SJR: 0.219 SNIP: 0.261 CiteScore™: 0.24

ISSN Print: 1521-9429
ISSN Online: 1940-4328

International Journal on Algae

DOI: 10.1615/InterJAlgae.v11.i3.10
pages 199-210

Spatial and temporal response of scytonemin and photosynthetic pigments in calcareous algal mats from Southern Florida (USA)

Th. E. Smith
Ave Maria University, Ave Maria, FL 31142, USA

ABSTRACT

This study examines the spatial and temporal variability of 6 pigments (scytonemin, β-carotene, chl. a, phycoerythrin, phyocyanin, and allophycocyanin) within calcareous cyanobacterial mats from South Florida, USA. The total pigment concentrations within the cyanobacterial mats varied spatially with deth through the mat. β-carotene, chl. a, and allophycocyanin concentrations increased significantly with mat depth. The cyanobacterial mats upper layer (0.3 cm) had a 5.57-fold increase and the middle layer (0.6 cm) had a 4.24-fold increase from 0700 to 1200 hrs, while the largest increase was in the lower layer (1 cm) a 7.23-fold increase from 1000 to 1300 hrs. The community total pigment concentration from 0800 hrs and peaked at 1300 hrs varying from 7.61 mg·cm−3 to 21.06 mg·cm−3, a 2.77-fold increase, then decreasing at 1345 hrs. Scytonemin, which shields algae from UV-radiation, was abundant throughout the mats. β-carotene, scytonemin, and chl. a contributed over 97% of the total pigment concentration. All pigment concentrations increased with time of sampling, some as much as 3-fold, from 0800 to 1300 hrs and then declined. This may represent a diurnal cycle of resource allocation to optimize light harvesting and cell growth, which has implications for timing of sampling and estimating biomass with pigment concentration.