Phản ứng của carbon đất trung gian sắt đối với sự suy giảm mực nước trong một đất ngập nước trên núi
Tóm tắt
Kho dự trữ carbon hữu cơ trong đất (SOC) ở các vùng đất ngập nước đang bị đe dọa bởi sự suy giảm mực nước (WTD) trên toàn cầu. Tuy nhiên, phản ứng của SOC đối với WTD vẫn còn rất không chắc chắn. Ở đây, chúng tôi khảo sát vai trò chưa được nghiên cứu đầy đủ của sắt (Fe) trong việc trung gian hóa hoạt động enzyme trong đất và sự ổn định lignin trong một thí nghiệm WTD mesocosm tại một vùng đất ngập nước trên núi. Trái ngược với lý thuyết 'khóa enzyme' cổ điển, hoạt động oxy hóa phenol chủ yếu được kiểm soát bởi sắt hóa trị hai [Fe(II)] và giảm dần với WTD, dẫn đến sự tích tụ của các hợp chất thơm có thể hòa tan và giảm hoạt động của enzyme thủy phân. Hơn nữa, việc sử dụng dithionite để loại bỏ oxit sắt cho thấy sự gia tăng đáng kể các phenol lignin được bảo vệ bởi sắt trong đất tiếp xúc với không khí. Oxid hóa sắt do đó hoạt động như một 'cánh cổng sắt' chống lại 'khóa enzyme' trong việc điều tiết động lực học SOC của đất ngập nước dưới sự tiếp xúc với oxy. Cơ chế mới được công nhận này có thể là chìa khóa để dự đoán sự lưu trữ carbon trong đất ngập nước với sự gia tăng của WTD trong bối cảnh khí hậu thay đổi.
Từ khóa
#carbon hữu cơ trong đất #suy giảm mực nước #sắt #enzyme #lignin #đất ngập nướcTài liệu tham khảo
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