Distribution and diversity of aquatic macrophytes and the assessment of physico-chemical parameters of Dakatia beel in Khulna district, Bangladesh

The physico-chemical characteristics of water and aquatic macrophytes from Dakatia Beel under Khulna district in Bangladesh were studied within January, 2020 to February, 2021. Twenty three species of aquatic macrophytes belonging to 15 families have been recorded. The aquatic macrophytes in Dakatia Beel collected from several sites belonging to 23 genera and 15 families (Lemnaceae, Pontederiaceae, Araceae, Convolvulaceae, Amaranthaceae, Asteraceae, Fabaceae, Polygonaceae, Ceratophyllaceae, Onagraceae, Parkeriaceae, Cyperaceae, Poaceae, Euphorbiacee, Nymphaceae). We also observed the different plant groups which comprises 6 species of floating, 10 species of emergent and only 2 species of submerged aquatic macrophytes. Dissolved oxygen ranged between 1.78 to 2.2 mg/L with a mean value 1.95 mg/L. The study area showed maximum total dissolved solid 588 ppm and the minimum in 482 ppm with a mean value of 534 ppm. Maximum value of phosphate was noted in 1029 μg/L and minimum 988 μg/L with a mean value of 1005 μg/L. Asian J. Med. Biol. Res. 2021, 7 (2), 118-125

Invertebrates and microbiota associated with aquatic macrophyte degradation in a shallow lake in southern Brazil

Aquatic macrophytes are the main producers of organic matter in shallow aquatic ecosystems. They are also food sources for many herbivores. When macrophytes die, they enter the debris chain, are conditioned by microbial action and colonized by benthic invertebrates which remobilize nutrients from their biomass. In subtropical aquatic systems, the participation of shredder invertebrates has been questioned, highlighting the participation of fungi and bacteria in the degradation of organic matter. This study evaluated the degradation of two submerged aquatic macrophytes, Mayaca fluviatilis and Stuckenia pectinata, determining the quality of debris and microbiota and invertebrate trophic group density throughout the degradation process. Our results indicated that plants with lower polyphenol concentrations had higher degradation speeds. The shredders invertebrates had reduced abundance in both macrophytes, emphasizing the importance of bacteria and fungi in the nutrient cycling process in subtropical shallow lakes.

ECOLOGICAL STUDY OF EPIPHYTIC DIATOMS ON TWO SUBMERGED AQUATIC MACROPHYTES IN TIGRIS RIVER, IRAQ

This study was aimed to provide the baseline information of epiphytic diatom communities in the Tigris river within Wasit Province to fill the information gap on the algal distribution. This investigation was conducted on epiphytic diatoms from two macrophytes (Ceratophyllum demersum and Myriophyllum alterniflorum) and related physicochemical parameters of the river from June 2015 to May 2016. Three sites were selected along the river (Al-Aziziyah, Zubaidiyah, and Numaniyah). Qualitative and quantitative study of epiphytic diatoms was investigated. A total of 277 species of epiphytic diatoms were identified on both macrophytes, these diatoms belonged to 27 genera for C. demersum and 28 genra for M. alterniflorum. A total number of diatom species were ranged from 801.8× 104 cell.g-1 at site 3 to 1159.72 ×104 cell.g-1 at 1for C. demersum, while on M. alterniflorum were ranged (87.24 × 104 -545.68×104 cell.g-1) at site1. The study revealed that diatoms were abundant, reflecting the quality of water and determine the extent of pollution and polluted type.

Sediment Facilitates Microbial Degradation of the Herbicides Endothall Monoamine Salt and Endothall Dipotassium Salt in an Aquatic Environment

Endothall dipotassium salt and monoamine salt are herbicide formulations used for controlling submerged aquatic macrophytes and algae in aquatic ecosystems. Microbial activity is the primary degradation pathway for endothall. To better understand what influences endothall degradation, we conducted a mesocosm experiment to (1) evaluate the effects of different water and sediment sources on degradation, and (2) determine if degradation was faster in the presence of a microbial community previously exposed to endothall. Endothall residues were determined with LC-MS at intervals to 21 days after endothall application. Two endothall isomers were detected. Isomer-1 was abundant in both endothall formulations, while isomer-2 was only abundant in the monoamine endothall formulation and was more persistent. Degradation did not occur in the absence of sediment. In the presence of sediment, degradation of isomer-1 began after a lag phase of 5–11 days and was almost complete by 14 days. Onset of degradation occurred 2–4 days sooner when the microbial population was previously exposed to endothall. We provide direct evidence that the presence and characteristics of sediment are of key importance in the degradation of endothall in an aquatic environment, and that monoamine endothall has two separate isomers that have different degradation characteristics.

Sediment Facilitates Microbial Degradation of The Herbicides Endothall Monoamine Salt and Endothall Dipotassium Salt in an Aquatic Environment

Endothall dipotassium salt and monoamine salt are herbicide formulations used for controlling submerged aquatic macrophytes and algae in aquatic ecosystems. Microbial activity is the primary degradation pathway for endothall. To better understand what influences endothall degradation, we conducted a mesocosm experiment to 1) evaluate the effects of different water and sediment sources on degradation, and 2) determine if degradation was faster in the presence of a microbial community previously exposed to endothall. Endothall residues were determined with LC-MS at intervals to 21 days after endothall application. Two endothall isomers were detected. Isomer-1 was abundant in both endothall formulations, while isomer-2 was only abundant in the monoamine endothall formulation and was more persistent. Degradation did not occur in the absence of sediment. In the presence of sediment degradation if isomer-1 began after a lag phase of 5-11 days and was almost complete by 14 days. Onset of degradation occurred 2-4 days sooner when the microbial population was previously exposed to endothall. We provide direct evidence that the presence and characteristics of sediment are of key importance in the degradation of endothall in an aquatic environment, and that monoamine endothall has two separate isomers that have different degradation characteristics.