title: Growth and metal removal potential of a Phormidium bigranulatum-dominated mat following long-term exposure to elevated levels of copper.
abstract: The present study explores the tolerance and metal removal response of a well-developed 2-week-old Phormidium mat after long-term exposure to Cu(2+)-enriched medium. Cu(2+) enrichment inhibited increase in mat biomass in a concentration-dependent manner. Mat area and the number of entrapped air bubbles decreased as Cu(2+) concentration increased in the medium. Decrease in number of air bubbles obviously reflects the adverse effect of Cu(2+) on photosynthetic performance of the mat. Metal enrichment did not substantially alter the amount of pigments, such as chlorophyll a, chlorophyll b, carotenoids, and phycocyanin, in the mat. Enhancement of Cu(2+) concentration in the medium led to changes in species composition of the test mat; however, Phormidium bigranulatum always remained the dominant organism. Relative share of green algae and some cyanobacterial taxa, namely, Lyngbya sp. and Oscillatoria tenuis, in the mat were increased by Cu(2+) enrichment. The mat successfully removed 80 to 94 % Cu(2+) from the growth medium containing 10 to 100 μM Cu(2+). Extracellular polysaccharides, whose share increased in the mat community after metal addition, seem to have contributed substantially to metal binding by the mat biomass.
authors.affiliation: Department of Botany, School of Life Sciences, H.N.B. Garhwal University, Srinagar, Garhwal, 246 174, India, drdkumar83@gmail.com.
authors.forename: Dhananjay
authors.initials: D
authors.lastname: Kumar
authors.forename: J P
authors.initials: JP
authors.lastname: Gaur
mesh_terms: D001673:Biodegradation, Environmental; D018533:Biomass; D002734:Chlorophyll / Q000031:analogs & derivatives; D000077194:Chlorophyll A; D000460:Chlorophyta; D003300:Copper / Q000378:metabolism* / Q000633:toxicity*; D000458:Cyanobacteria / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism*; D008670:Metals / Q000378:metabolism; D010788:Photosynthesis / Q000187:drug effects; D036401:Toxicity Tests, Chronic
chemical_list: D008670:Metals; D002734:Chlorophyll; C085815:chlorophyll a'; C037184:chlorophyll b; D003300:Copper; D000077194:Chlorophyll A