The Prediction of Waters Trophic Status Based on the Contents of Nutrient and Chlorophyll-a Through the Trophic Index at the Estuary of Ketingan River, Sidoarjo

Abstract

Eutrophication is a process of abundant increasing of nutrient contents (nitrate and phosphate) in waters which can stimulate the process of algae blooming and can decrease the quality of waters. This research aims to know the trophic status based on the contents of nutrient and chlorophyll-a at the eastuary of Ketingan river, Sidoarjo on March 2018. The main parameter that was measured in this research is dissolved inorganic nitrogen and dissolve inorganic phosphate, chlorophyll-a and the dissolved oxygen that as main component to predict the fertility status by using the TRIX method. The trophic status that was got at the estuary of Ketingan river, Sidoarjo using the TRIX method shows the value of 1.21 to 2.30, means, it is included in oligotrophic waters category. KEY WORDS Eutrophication, estuary, chlorophyll-a, trophic index, waters.

Komposisi Kelimpahan Dan Struktur Komunitas Fitoplankton Di Kawasan Pantai Sekotong, Nusa Tenggara Barat

“…Hal tersebut juga didukung dengan tidak ditemukannya satu genus pun dari divisi Cyanophyta pada stasiun 3. Hal itu sesuai dengan pendapat Diniariwisan et al (2018), bahwa pada wilayah perairan laut umumnya banyak didominasi fitoplankton dari divisi Chrysophyta.…”

“…Konsentrasi kandungan nitrat lebih dari 0,2 mg/l dapat memicu eutrofikasi yang tentunya dengan dukungan nilai kualitas air yang lain. Nilai fosfat 0,031 sampai 0,1 mg/l termasuk kategori eutrofik (Diniariwisan et al, 2018). Walaupun nilai nitrat dan fosfat cukup tinggi, namun kondisi kelimpahan fitoplankton masuk kategori oligotrofik.…”