Spatiotemporal Associations of Reservoir Nutrient Characteristics and the Invasive, Harmful Alga Prymnesium parvum in West Texas

Abstract

Golden alga (Prymnesium parvum) is a harmful alga that has caused ecological and economic harm in freshwater and marine systems worldwide. In inland systems of North America, toxic blooms have nearly eliminated fish populations in some systems. Modifying nutrient profiles through alterations to land or water use may be a viable alternative for golden alga control in reservoirs. The main objective of this study was to improve our understanding of the nutrient dynamics that influence golden alga bloom formation and toxicity in west Texas reservoirs. We examined eight sites in the Upper Colorado River basin, Texas: three impacted reservoirs that have experienced repeated golden alga blooms; two reference reservoirs where golden alga is present but nontoxic; and three confluence sites downstream of the impacted and reference sites. Total, inorganic, and organic nitrogen and phosphorus and their ratios were quantified monthly along with golden alga abundance and ichthyotoxicity between December 2010 and July 2011. Blooms persisted for several months at the impacted sites, which were characterized by high organic nitrogen and low inorganic nitrogen. At impacted sites, abundance was positively associated with inorganic phosphorus and bloom termination coincided with increases in inorganic nitrogen and decreases in inorganic phosphorus in late spring. Management of both inorganic and organic forms of nutrients may create conditions in reservoirs unfavorable to golden alga. (KEY TERMS: algae; aquatic ecology; environmental impacts; nutrients.) VanLandeghem, Matthew M., Mukhtar Farooqi, Greg M. Southard, and Reynaldo Patiño, 2015. Spatiotemporal Associations of Reservoir Nutrient Characteristics and the Invasive, Harmful Alga Prymnesium parvum in West Texas.

Associations between Water Physicochemistry andPrymnesium parvumPresence, Abundance, and Toxicity in West Texas Reservoirs

“…The main objective of the present study is to improve our understanding of the environmental factors associated with golden alga in reservoirs, with an overall goal of providing information useful to the development of new options for the management of golden alga in these systems. Management options discussed focus on manipulation of physicochemical characteristics of reservoirs, especially salinity‐related variables, and are distinct from options for nutrient characteristics addressed in our companion article (VanLandeghem et al ., ). To accomplish this objective, we monitored water quality and golden alga variables at a total of eight sites in the Upper Colorado River basin (UCR) in Texas from January 2010 to July 2011.…”

Predicting the risk of toxic blooms of golden alga from cell abundance and environmental covariates

“…In the field, golden alga abundance and toxicity have been shown to be correlated (Roelke et al 2012;VanLandeghem et al 2015a), but exceptions to a monotonic relationship, such as high abundance and low toxicity, have been noted in several studies (Kurten et al 2007(Kurten et al , 2010Hambright et al 2010;VanLandeghem et al 2015b). Laboratory studies have also indicated that golden alga toxicity and abundance are poorly correlated (Baker et al 2007(Baker et al , 2009Brooks et al 2010).…”

“…These data were collected during standard water quality monitoring; a state‐wide golden alga survey conducted in Texas; and routine monitoring of golden alga‐impacted lakes and reservoirs. In addition, original abundance and toxicity data collected during previous projects (VanLandeghem et al 2015a,b) were included in the current analysis. In all cases, golden alga abundance was determined from hemocytometer counts following the methods of Southard (), and ichthyotoxicity was determined using a standard fathead minnow ( Pimephales promelas ) larva bioassay (Southard ).…”

“…Toxicity was also associated with pH in some (Prosser et al 2012;Roelke et al 2012) but not all (Patiño et al 2014) studies of the Brazos River basin, Texas. Some studies have indicated golden alga abundance and toxicity are positively correlated (Roelke et al 2012;VanLandeghem et al 2015a), whereas others have reported low toxicity associated with high golden alga abundance and vice versa (Hambright et al 2010;VanLandeghem et al 2015b). Thus, the relationship between abundance and toxicity in the field is not simply monotonic and is likely influenced by multiple environmental factors.…”

Climate-water quality relationships in Texas reservoirs

“…A number of studies have documented (but not attributed) observed trends in water quality in rivers and reservoirs of Texas. These include White Rock Lake (Brandbury and VanMetre, ; Van Metre and Callender, ), Trinity River (Van Metre and Callender, ), Rio Grande (DeYoe, ; Miyazono et al ., ), Broken Bow Lake (Carroll et al ., ), Brazos River and its reservoirs (Van Landeghem et al ., ), Colorado River and its reservoirs (Van Landeghem et al ., ,b), reservoirs in the Brazos and Colorado Rivers (Patiño et al ., 2014; Dawson et al ., in review), and streams from Northeast Texas (Taylor et al ., ). The impact of hydropower on water quality has been evaluated by Ashby et al .…”