Our new Biological Assessment is out - Klamath Basin Crisis

Klamath Project Operations Biological Assessment
Endangered Suckers: Environmental Baseline for Suckers
becomes the limiting nutrient. When light, nutrients, or other conditions for algae
become unfavorable, the production of the algal bloom will cease or rapidly
decline, resulting in an algal “crash.”
The massive blooms of AFA and the subsequent rapid decline (crash) can cause
extremes in water quality including elevated pH, low DO concentrations
(hypoxia), and elevated levels of un-ionized ammonia, which can be toxic to fish
(Kann and Smith 1993; Kann and Smith 1999; Perkins et al. 2000 Water Quality;
Walker 2001; Welch and Burke 2001; Wood et al. 2006; Kuwabara et al. 2007;
Morace 2007). In the process of rapid growth, algal biomass can form extremely
dense blooms, which can vary in magnitude depending on the availability of
growth-promoting conditions (Kann and Smith 1993; Kann and Smith 1999;
Perkins et al. 2000 Water Quality). During the same bloom conditions and
following a bloom crash, particularly when coupled with high rates of nighttime
respiration, DO can drop to levels that restrict fish growth and that can be lethal
(Kann and Smith 1993; Kann and Smith 1999; Perkins et al. 2000 Water Quality).
In addition, when dense algae blooms die off, the microbiological decomposition
of the algae and organic matter in the bed sediment can further deplete DO and
produce increased concentrations of ammonia (Kann and Smith 1993; Risley and
Laenen 1999; Kann and Smith 1999; Perkins et al. 2000 Water Quality; Walker
2001; Welch and Burke 2001; Wood et al. 2006; Kuwabara et al. 2007; Morace
2007). The potential for low DO concentration increases later in the growing
season (July-September) when the algae blooms have crashed and considerable
organic matter has accumulated in the sediments. During this same period,
increased water temperature increases water column oxygen depletion rates as
decomposition and respiration take place at a faster rate, and oxygen
concentration in the water column tends to be lower because solubility of oxygen
decreases as water temperature increases.
Nutrient Input Algal GrowthWater Quality ChangesFish Survival and
Propagation
Wetlands may affect water quality through production and release of
decomposition products, particularly dissolved humic 1 substances that appear to
inhibit AFA growth (Geiger et al. 2005). Figure 2-12 shows how humic
substances from wetlands may inhibit AFA growth (Geiger et al. 2005). The
absence or reduction of this algae species just downstream, at or within marsh
environments has been noted at Hanks Marsh (Forbes et al. 1998) and Upper
Klamath National Wildlife Refuge (Sartoris and Sisneros 1993, cited by Campbell
1993a). Perdue et al. (1981) noted the absence of AFA in UKL at a location
1 From humus, which are dark organic material in soils, produced by the decomposition of
vegetable or animal matter and essential to the fertility of the earth.
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