日本地球惑星科学連合2019年大会

講演情報

[E] ポスター発表

セッション記号 A (大気水圏科学) » A-HW 水文・陸水・地下水学・水環境

[A-HW22] 流域の物質輸送と栄養塩循環-源流域から沿岸海域まで-

2019年5月30日(木) 17:15 〜 18:30 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:小林 政広(国立研究開発法人森林研究・整備機構 森林総合研究所)、吉川 省子(農業・食品産業技術総合研究機構 農業環境変動研究センター)、安元 純(琉球大学 農学部 地域農業工学科)、Adina Paytan(University of California Santa Cruz)

[AHW22-P11] Phosphate solubilizing bacteria as an indicator of sediment phosphorus in freshwater lakes

*Sreekumari Kurissery1Katelynn Crawford1Nandakumar Kanavillil1 (1.Lakehead University, Canada)

キーワード:Phosphate Solubilizing Bacteria, Freshwater Lakes , Sediment Phosphorus , Canada

It has been well documented that phosphorus pollution is one of the most significant factors impeding the overall health of freshwater lakes. Various measures are being taken to reduce phosphorus input into the lakes by anthropogenic activities and thus to maintain a healthy ecosystem. However, it is well known that bioavailable phosphorus tends to bind with substances such as ferric iron and calcium present in the water, become insoluble, and settles into the sediments. The presentstudy has been carried out to understand the relationship between the sediment phosphorus concentration and density of phosphate solubilizing bacteria (PSB) in two lakes in Ontario, Canada, namely, Lake Simcoe and Sparrow Lake. In September 2017, 20cm sediment cores were collected from the nearshore sites of these two lakes to determine the presence of PSB in relation to the sediment phosphorus concentration. PSB could potentially release phosphorus back into the water column through a process called internal phosphorus loading from the inorganic phosphates in the sediment when the right conditions are present. PSB were isolated from the sediment cores at 5 cm intervals by plating on to Pikovskaya’s agar. Five grams of sediment was used to analyze total reactive phosphorus in the sediment. In Lake Simcoe, PSB ranged from 3x101 to 1.1x101 cfu/g, and the amount of total reactive phosphorus ranged from 0.19 to 0.46 mg/g. In Sparrow Lake, PSB ranged from 4x100 to 3x101 cfu/g and the amount of total reactive phosphorus ranged from 0.21 to 0.39 mg/g. A linear regression was completed to determine the relationship between total reactive phosphorus and PSB for each core. The results showed a negative relationship between these two tested parameters (Lake Simcoe: r2=0.23, y = -35.34x + 30.811 p=0.5206, and Sparrow Lake: r2=0.87, y = -155.9x + 62.322, p=0.067). While PSB density decreased with core depth, the concentration of reactive phosphorus increased. This indicates that the density of PSB in lake sediment may indicate the concentration of total reactive phosphorus and thus the internal phosphorus loading. More study is recommended to confirm the results.