Pengaruh Siklus Pasang Surut dan Perbedaan Musim Terhadap Konsentrasi Nitrat (NO3) dan Fosfat (PO4) di Perairan Tegal Timur, Kota Tegal - Alfiatun Hasanah; Muhammad Zainuri; Bambang Yulianto (Buletin Oseanografi Marina, 2026)
Kawasan pesisir Tegal Timur memiliki peran krusial dalam ekologi pesisir dengan kompleksitasnya serta beragam aktivitas manusia yang menghasilkan limbah dan meningkatkan bahan organik. Di wilayah muara dan pesisir, siklus pasang surut dan variabilitas musim memengaruhi konsentrasi nitrat dan fosfat, yang berasal dari dekomposisi bahan organik serta aktivitas antropogenik. Penelitian ini bertujuan menganalisis dampak siklus pasang surut dan perbedaan musim terhadap konsentrasi nitrat dan fosfat di perairan Tegal Timur. Penelitian dilakukan di pesisir Kecamatan Tegal Timur, Kota Tegal, Jawa Tengah, dengan pengambilan sampel air di 7 titik (3 titik di muara dan 4 titik di laut). Data primer berupa konsentrasi nitrat dan fosfat, sedangkan data sekunder berasal dari pasang surut BIG (Badan Informasi Geospasial). Pengambilan sampel dilakukan pada Maret dan Agustus saat pasang tertinggi dan surut terendah. Hasil studi menunjukkan bahwa pada bulan Maret, konsentrasi nitrat tertinggi ditemukan saat pasang tertinggi, sedangkan pada bulan Agustus saat surut terendah. Pola berlawanan terjadi pada fosfat, dengan konsentrasi lebih tinggi saat surut pada bulan Maret dan lebih tinggi saat pasang tertinggi pada bulan Agustus. Musim penghujan menunjukkan konsentrasi nitrat dan fosfat lebih tinggi dibanding musim kemarau. Studi ini mengonfirmasi bahwa siklus pasang surut dan perbedaan musim memengaruhi distribusi nitrat dan fosfat di perairan Tegal Timur.  The coastal area of East Tegal plays a crucial role in coastal ecology due to its complexity and diverse human activities, which contribute to waste generation and increased organic matter input. In estuarine and coastal regions, tidal cycles and seasonal variability influence nitrate and phosphate concentrations, which originate from the decomposition of organic matter and anthropogenic activities. This study aims to analyze the impact of tidal cycles and seasonal differences on nitrate and phosphate concentrations in the waters of East Tegal. The study was conducted in the coastal area of East Tegal District, Tegal City, Central Java, with water sampling at 7 locations (3 in the estuary and 4 offshore). Primary data consist of nitrate and phosphate concentrations, while secondary data on tidal patterns were obtained from the Geospatial Information Agency (BIG). Sampling was carried out in March and August during the highest high tide and the lowest low tide conditions. The results indicate that in March, the highest nitrate concentration was observed during the highest high tide, whereas in August, it was found during the lowest low tide. An inverse pattern was observed for phosphate, with higher concentrations during low tide in March and during the highest high tide in August. The rainy season exhibited higher nitrate and phosphate concentrations compared to the dry season. This study confirms that tidal cycles and seasonal variations significantly influence the spatial distribution of nitrate and phosphate in the waters of East Tegal.