Elevated alkalinity and sulfate adversely affect the aquatic macrophyte Lobelia dortmanna

Abstract

The increase in alkalinity and SO 4 2-in softwater lakes can negatively affect pristine isoetid population because the increase in alkalinity and SO 4 2-can stimulate sediment mineralization and consequently cause anoxia. The consequences of increased sediment mineralization depend on the ability of isoetids such as Lobelia dortmanna to oxidize the rhizosphere via radial O 2 loss. To study how alkalinity and SO 4 2-affect the isoetid L. dortmanna, and if negative effects could be alleviated by neighboring plants, three densities of L. dortmanna (''Low'' = 64 plants m -2 , ''Medium'' = 256 plants m -2 and ''High'' = 1,024 plants m -2 ) were exposed to elevated alkalinity in the water column, or a combination of both elevated alkalinity and SO 4 2-, and compared to a control situation. The combination of SO 4 2-and alkalinity significantly increased mortality, lowered areal biomass and reduced actual photosynthetic efficiency. Plant density did not significantly alleviate the negative effects caused by SO 4 2-and alkalinity. However, actual photosynthetic efficiency was significantly positively correlated to redox potential in the sediment, indicating a positive relationship between plant performance and sediment oxidation. The negative effects on L. dortmanna were probably caused by long periods of tissue anoxia by itself or in combination with H 2 S intrusion. Therefore, increase in both SO 4 2-and alkalinity surface water can dramatically affect L. dortmanna populations, causing reduction or even disappearance of this icon species.

Predicting aquatic macrophyte occurrence in soft-water oligotrophic lakes (Pyrenees mountain range)

“…Sulphate can enter the system by atmospheric deposition , but most chemical variance in the studied area is related to bedrock weathering . Sulphate can lead to sulphide toxicity in lakes with high oxygen demand in their sediments (Pulido et al, 2012a) and can also acidify the system, compromising soft-water vegetation (Arts, 2002). Thus, high concentrations of sulphate appear to prevent the development of macrophytes, yet within the range found in lakes with aquatic vegetation, sulphate does not seem to impose any constraints, as this variable is never a significant predictor of the presence of individual species.…”

Changes in physico-chemical conditions and macrophyte abundance in a shallow soft-water lake mediated by a Great Cormorant roosting colony

“…Changes in the water chemistry of such ecosystems can lead to simultaneous alterations of macro-N o n -c o m m e r c i a l u s e o n l y phyte community composition including the disappearance of isoetids such as Isoetes lacustris L., Littorella uniflora (L.) Asch. and Lobelia dortmanna L. (Arts, 2002;Pulido et al, 2012).…”

Grouping and clustering of maize Lancaster germplasm inbreds according to the results of SNP-analysis

“…В России это растение спорадически встречается в северных областях Европейской части; в Средней России отмечено лишь в некоторых озерах Тверской области (Gubanov et al, 2004), где считалось единственным представителем атлантических видов (Nevskiy, 1956). Этот вид относится к группе так называемых «изоэтидов»специфических погруженных растений с низкими трофическими требованиями (Lamentowicz and Milecka, 2004;Sand-Jensen et al, 2005;Pulido et al, 2012). Морфологические характеристики этих растений сопряжены с ростом в бедных углеродом олиготрофных озерах и характеризуются розеткой коротких листьев (<10 см), плотной, хорошо развитой корневой системой, обширными воздушными внутренними лакунами в листьях и корнях и хлоропластами вблизи лакун (Raven et al, 1988цит.…”