Chara: The Rooted Alga with a Competitive Edge

Habitat

Chara can be an early indicator of lake eutrophication and the switch from clear water to algae dominance. Of the 300 different species of Chara found worldwide, most will be found in low to mildly eutrophic lakes. As the lake becomes more eutrophic, Chara abundance will often decline. Chara vulgaris is a common species in the US, inhabiting shallow, mildly eutrophic lakes and ponds. Hard waters, represented by high alkalinity, are required for all Chara species to proliferate and form dense canopies (Kufel and Kufel 2002). Hardwater lakes are abundant in calcium cations, which are usually accompanied by bicarbonate anions (HCO₃^–), the primary inorganic carbon source for aquatic plants and macroalgae. Charophytes have a higher affinity to bicarbonate than aquatic plants, allowing for a competitive advantage over them. In dense Chara beds, so much bicarbonate is depleted that calcite encrustation will form on Chara (up to 60% dry weight of charophytes is calcium carbonate (CaCO₃); Kufel and Kufel 2002; Hidding et al. 2010). Chara has been found to grow best on muddy substrates with the rhizoid (root-like structure) attached to the bottom (Kufel and Kufel 2002).

While controlling Chara with pesticides is cost-effective and immediate, it comes with drawbacks. As mentioned before, there is an enormous amount of nutrients bound within Chara. When treated, most of these nutrients will be released back into the water, which will fuel the regrowth of Chara, leading to a perpetual need to re-treat. All in all, this leads to an acceleration of the lake eutrophication process. To stop the regrowth and ensure ecological resilience, it is best to incorporate products like Summer Slam, Nature’s Blend, or MetaFloc to address the nutrient release and stop regrowth after such treatments.

Another new eco-friendly approach to keep Chara biomass in check is to focus on sediment nutrients and muck. This is because 1) Chara loves mucky substrates as outlined earlier, and 2) Chara’s sediment phosphorus uptake is entirely from the mobile sediment pool in the surface sediments (~10cm; Kufel and Kufel 2002). MuckBiotics is a highly effective probiotic (beneficial bacteria) tablet that can digest organic matter (muck/sludge), while boosting biological nutrient removal and improving water quality. Add MetaFloc with MuckBiotics to address all mobile P in the sediment, and it’s a one-two punch for long-term success. New sediment P fractionation testing can determine exact dosing rates for both products.