Plankton terbagi menjadi dua golongan yaitu fitoplankton dan zooplankton. Plankton di suatu perairan sangat penting dalam menentukan kesuburan perairan dan sebagai produsen primer. Tujuan dari penelitian ini yaitu untuk mengetahui kelimpahan plankton di Kelurahan Karang Anyar Pantai. Penelitian ini dilakukan pada bulan Desember 2018-Januari 2019 di Kelurahan Karang Anyar Pantai serta identifikasi plankton di lakukan di Laboratorium Nutrisi dan Pangan Fakultas Perikanan dan Ilmu Kelautan Universitas Borneo Tarakan. Kelimpahan fitoplankton berkisar 2-44 sel/L dan kelimpahan zooplankton berkisar 5-30 ind/L, indeks keanekaragaman fitoplankton berkisar 0,3250-1,8789 dan indeks keanekaragaman zooplankton bekisar 0.3926-0,6931. Kelimpahan plankton di perairan Kelurahan Karang Anyar Pantai tergolong kategori rendah dan keanekaragaman plankton termasuk dalam kestabilan komunitas sedang. Berdasarkan hasil kelimpahan dan keanekaragaman, yang menunjukkan kategori stabilitas air rendah dan komunitas sedang.
Kata kunci: Fitoplankton, Keanekaragaman, Kelimpahan, Kelurahan Karang Anyar Pantai, Zooplankton

Plankton is divided into two groups that phytoplankton and zooplankton. Plankton in waters is very important in determining the fertility of waters and as a primary producer. The purpose of this study is to determine the abundance of plankton in Karang Anyar Pantai Village. The research was conducted in December 2018 January 2019 in Karang Anyar Pantai Village and identification of plankton was carried out at the Nutrition and Food Laboratory and Marine Science Faculty, University of Borneo Tarakan, Phytoplankton abundance ranges from 2-44 cells/L and , zooplankton abundance ranges from 5-30 ind/L. Phytoplankton diversity index ranges from 0.3250 to1.8789 and zooplankton diversity index ranges from 0.3926 to 0.6931. Plankton abundance in the waters of Karang Anyar Pantai Village is classified as low and plankton diversity is included in the stability of the moderate community. Based on the results of abundance and diversity that the stability of running water and low abundance due to community activities. Based from abudance and diversity data, that show the water stability is low abundance and moderate community. Keywords: Phytoplankton, Diversity, Abundance, Kelurahan Karang Anyar Pantai, Zooplankton