Changes in chlorophyll a and its response to nitrogen and phosphorus characteristics over the past three decades in Poyang Lake, China

Abstract

In this study, we explore the relationship between changes in chlorophyll a (Chl a) content, total nitrogen (TN) and total phosphorus (TP) characteristics from 1989 to 2018 in Poyang Lake, China, by applying Landsat Thematic Mapper/Enhanced Thematic Mapper (TM/ETM) image data in combination with in situ monitoring data. Results showed that the average Chl a content in water over this 30‐year period was 5.77 μg/L. Although the water quality status of the lake was generally healthy, proportional Chl a content >10 μg/L (E10) has gradually increased, and the water quality in some areas of the lake has subsequently deteriorated over the past 30 years. Additionally, E10 was significantly positively correlated to the TN/TP. Changes in Chl a content were significantly positively correlated to the ratio of TN flux to TP flux from tributaries into the lake, but negatively correlated to TP flux. Results indicated that Lake can be categorized as phosphorus‐sufficient and nitrogen limited.

Decadal shifts in Qingzang Plateau lake carbon dynamics (1970–2020): From predominant carbon sources to emerging sinks

“…Additionally, due to increased river runoff, QZP lakes receive more nutrient inputs, increasing aquatic plant and phytoplankton biomass. This lake area expansion has also decreased lake salinity levels, reducing aquatic plant and phytoplankton toxicity stress [ 57 ]. Moreover, aquatic plants and phytoplankton have absorbed more CO 2 from the atmosphere through photosynthesis to produce organic C, which has increased C fixation and decreased p CO 2 values, driving some lakes to shift from a C source to a C sink.…”

Pemodelan Status Trofik Danau Laut Tawar Aceh Tengah

“…Klorofil-a merupakan pigmen untuk fotosintesis yang mengindikasikan kadar biomassa alga dengan berat rata-rata 1% biomassa [5]. Pertumbuhan fitoplankton di perairan tergantung pada ketersediaan nutrien nitrogen dan fosfor [18]. Pertumbuhan fitoplankton secara berlebihan akan terjadi bila keberadaan senyawa N dan P berlebihan di perairan danau [19,20,21].…”

“…Walaupun nitrogen dan fosfor sebagai penentu pertumbuhan fitoplankton, namun fosfor lebih berperan [23], dimana fosfor menunjukkan persentase hubungan tertinggi dengan klorofil-a [24], dan konsentrasi klorofil-a dapat dikontrol dengan mengurangi konsentrasi TP [22]. Namun demikian rasio TN/TP menjadi faktor pembatas pertumbuhan fitoplankton [24,18], dimana ditemukan pola peningkatan klorofil-a dengan penurunan rasio TN/TP [20,25]. Selain faktor nutrien, peningkatan fitoplankton juga ditentukan oleh peningkatan cahaya [26].…”

“…Konsentrasi klorofil-a di Danau Laut Tawar dideskripsikan pada Gambar 5. Variasi konsentrasi klorofil-a tersebut dipengaruhi oleh ketersediaan nutrien di perairan [22,19,20,21,18], terutama nutrien fosfor (TP) [23,24].…”

Analisa Limbah Fosfor Kegiatan Keramba Jaring Apung di Danau Laut Tawar Aceh Tengah

“…Eutrofikasi perairan disebabkan oleh peningkatan nutrien, berupa dua nutrien utama yaitu N dan P [20,21]. Namun di perairan tawar, nutrien P memegang peranan penting sebagai nutrien pembatas pertumbuhan fitoplankton [22,23].…”