Wednesday, June 6, 2007 - 11:45 AM
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Algal Responses to the Minerotrophication of the Everglades: A Mechanistic Perspective

Scot Hagerthey and Sue Newman. Everglades Division, South Florida Water Management District, 3301 Gun Club Road, West Palm Beach, FL 33416-4680

Minerotrophication, the increase in the total salinity of a water body, can be caused by a variety of natural or anthropogenic processes.  Within the Everglades, a vast array of canals and pump stations were constructed for the purposes of water management.  We studied the minerotrophication of the Everglades impoundment, Water Conservation Area-1, which occurs when relatively higher saline canal water (580 mg/L) penetrates into the low saline marsh (75 mg/L).  Periphytic desmid and diatom temporal and spatial distributions were negatively affected by increases in salinity associated with canal water intrusion events.  Desmid relative abundances declined exponentially from 20% to < 5% when salinity exceeded 100 mg/L.  Moreover, species specific responses showed a greater sensitivity and range of responses.  Unlike nutrient enrichment, which tends to change assemblage composition through increased growth due to reduction in nutrient limitation, salinity increases likely caused the decline in desmid and diatom species by altering osmotic balances or cell turgor pressures.  These physiological responses occur rapidly thus suggesting that short-term pulsed events may significantly affect algal dynamics.  However, desmid assemblages recovered when lower salinities were reestablished; thus, indicating that an active management strategy could maintain a low salinity environment or minimize canal intrusion impacts.

See more of Special Session - Everglades Water Quality: On the Critical Path to Restoration II
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