VNU Journal of Science Earth and Environmental Sciences, Vol 37, No 2 (2021) 13 23 13 Original Article Environmental Factors Influencing Chlorophyll a Concentration in Tri An Reservoir, Vietnam Tran Thi Hoang Yen1, Tran Thanh Thai1, Nguyen Van Tu1,2, Ngo Xuan Quang1,2, Pham Thanh Luu1,2,* 1Institute of Tropical Biology, Vietnam Academy of Science and Technology, 85 Tran Quoc Toan, District 3, Ho Chi Minh City, Vietnam 2Graduate University of Science and Technology, Vietnam Academy of Science and[.]