Algal blooms modulate organic matter remineralization in freshwater sediments: A new insight on priming effect.

This study provides a novel insight into the degradation of sediment organic matter (SOM) regulated by algae-derived organic matter (AOM) based on priming effect. We tracked the dynamics of SOM mineralization products and pathways, together with priming effects (PE) using the compound-specific stable isotope (δC) technique following addition of low- and high-density algal debris in sediments. We found that algal debris increased the total carbon oxidation rate, and resulted in denitrification and methanogenesis-dominated SOM mineralization.

Abundant sediment organic matter potentially facilitates chemical iron reduction and surface water blackness in a Chinese deep lake.

Black bloom has become an increasingly severe environmental and ecological problem in lots of lakes. Ferrous monosulfide (FeS), which is closely related to chemical iron reduction (CIR), is considered the major cause for black water in shallow lakes, but few studies focus on the effect of organic matters (OM) content on iron and sulfate reduction and its contribution to the black bloom in deep lakes. Here, in Lake Fuxian, a Chinese deep lake which has also suffered from black bloom, FeS was identified responsible for the surface water blackness by using multiple microscopy and element analyses.

The establishment of preliminary safety threshold values for cyanobacteria based on periodic variations in different microcystin congeners in Lake Chaohu, China.

As harmful cyanobacterial proliferation threatens the safety of drinking water supplies worldwide, it is essential to establish a safety threshold (ST) for cyanobacteria to control cyanobacterial density effectively in water sources. For this purpose, cyanobacterial abundance, microcystin (MC) production, and environmental parameters were monitored monthly from September 2011 to August 2012 in one drinking water source of Lake Chaohu. The cyanobacterial density ranged from 1400 to 220 000 cells per mL with the succession of two dominant species Microcystis and Dolichospermum, which was determined by water temperature and nutrient loading.