The Effect of Temperature on Algal Blooms Dr

The Effect of Temperature on Algal Blooms Dr. Scott Sowell Senior Seminar April 23, 2013

Introduction � Algal blooms are potentially dangerous events that can have negative environmental consequences � Happen more and more often � Can cause fish kills, human respiratory problems, and reduce water quality � Living near the St. Johns River, those of us in Jacksonville have an ethical responsibility to be aware of this problem.

Relevant Literature � Inorganic nutrients (N, P, and K) are limiting factors for plant growth (Albert, 1998; Smith, 2012; Thomas, 2009) � Anthropogenic sources (e. g. , agricultural runoff or municipal wastewater) unnaturally increase these nutrients (Johnson, 2002, Klein, 2004) � Plant populations increase (algal bloom) then die off, resulting in high rates of decomposition and dangerous hypoxic conditions (Newton, 2000; Marlow, 1999; Zeiler, 2000).

Relevant Literature � Cultural eutrophication of our local waterways can have both immediate and long-lasting effects (Dalonega, 2001; Ellington, 2002; Frazier, 2000) � Temperature and other abiotic factors have been known to slow down algal bloom (Conrad, 2000; Dutton, 2005; Hodges, 1999). � Temperature is one such abiotic factor that can affect algal blooms (Keys, 1999; Salmon, 2007) � Certain species of algae have different ranges of tolerance for temperature (Dalonega, 2001; Evans, 2008)

Methods �Grew 20 cultures of three different species of cyanobacteria (green algae) in separate containers �Each container was maintained at a certain temperature (2 at each of ten temperatures 20 C : 20, 22, 26, 28, 30, 32, 34, 36, 38, 40 �Microscopic counts were taken of each culture every day for 30 days

Algae Cultures & Counts Counting Algae on Microscope Algae Culture Bottles

Results

Results �The majority of algal cells demonstrated a range of tolerance of 24 -32 C �All temperatures below 24 C or above 32 C resulted in minimal or no algae growth �This was true for all species except for C. laticeps that had a higher range of tolerance into the upper temperatures

Discussion �To mitigate the effects of an algal bloom, temperatures should be regulated below 24 C or above 23 C �This would not be true for C. laticeps that demonstrated an extended range of tolerance into the upper temperatures �This also points to warnings that springtime local temperatures are most conducive to algal blooms