Submerged Macrophytes Exhibit Different Phosphorus Stoichiometric Homeostasis

Abstract

Phosphorus (P) is a limiting element in many aquatic ecosystems. Excessive P input often leads to cyanobacterial bloom, thus triggering ecological imbalances and a series of environmental problems. Submerged macrophytes have a strong ability to absorb P and play important roles in maintaining aquatic ecosystem functions. However, the degree to which submerged macrophytes maintain their tissue P contents in various nutrient levels and the corresponding influencing factors are still not very clear. In this study, the stoichiometric characteristics and stoichiometric homeostasis of P in the aboveground and belowground parts of three submerged macrophytes, Vallisneria natans (Lour.) Hara, Hydrilla verticillata (L.f.) Royle, and Ceratophyllum demersum (L.), with great differences in growth forms, were studied under different growth times and nutrient levels via laboratory experiments. The results showed that the water conductivity, turbidity, and chlorophyll content increased significantly with the increasing nutrient levels. The variation of species, organ, growth time, and nutrient level could significantly affect the P contents of submerged macrophytes. Among these factors, the variance contribution rates caused by the differences of nutrient levels in water column were the highest at more than 50%. The P stoichiometric homeostasis index (HP) in the belowground parts of the three submerged macrophytes was higher than that of the aboveground parts. The HP decreased by the growth time; the HP of V. natans was significantly higher than those of H. verticillata and C. demersum. In summary, the P stoichiometric homeostasis in submerged macrophytes could reflect their responses to environmental changes, and the P content of submerged macrophytes was an indicator of the bioavailability of external P. H. verticillata exhibited a high growth rate and a high accumulation of P content, making it the most suitable species in this study for removing large amounts of P from water in a short term.

Shallow lakes at risk: Nutrient enrichment enhances top‐down control of macrophytes by invasive herbivorous snails

“…In our experiment, moderate nutrient treatment significantly increased the N and P contents of V. natans leaves as compared to treatment with low nutrient concentrations, which is consistent with other laboratory and field investigations on this species (He et al., 2015; Li et al., 2018; Su et al., 2019). A correlation between plant N content, and often also P content, and the respective nutrient availability in the environment has also been observed in many other macrophyte species (Cao et al., 2011; Center et al., 2014; Cronin & Lodge, 2003; Demars & Edwards, 2007; Velthuis et al., 2017).…”

Temperature influences swine wastewater treatment by aquatic plants

“…The presence of plants in humid areas results in more stable temperatures, which may promote the removal of pollutants (Hill and Payton, 2000). Some studies indicate a relationship between N and P contents in water and aquatic plants (Li et al, 2018;Nogueira et al, 1996;Petracco, 1997). The high N and P contents in the wastewater are much higher than the values allowed by Res.357/05 -MMA (2005), which establishes values of 2.18 mg L -1 for N and 0.1 mg L -1 for P, when released in lotic environments.…”

“…Phosphorus can also act as a limiting factor in the primary production of aquatic ecosystems, leading to eutrophication. This fact may lead to changes in the physical, chemical, and biological properties of the environment, causing losses in productivity and biodiversity (Li et al, 2018;Mees et al, 2009). The wastewater used in this research had high TN and TP contents, which are highly polluting if released directly into the environment.…”

Carbon, Nitrogen, and Phosphorus Allocation Strategy Among Organs in Submerged Macrophytes Is Altered by Eutrophication

“…Sediment nutrients and water TP might be potential drivers for plant nutrient allocation strategies changing with ambient environment, considering their prominent participation in shaping ecological stoichiometric characteristics of plants (Li et al, 2018;Su et al, 2018). However, we found that the relationships of scaling exponents to sediment nutrients or water TP were all statistically non-significant ( Supplementary Figure 1).…”