Electronic Theses and Dissertation

ABSTRAK
Pencemaran logam berat tembaga di perairan dapat menimbulkan dampak toksik terhadap organisme akuatik, khususnya ikan kakap putih (Lates calcarifer), sehingga diperlukan upaya pengendalian yang ramah lingkungan melalui metode fitoremediasi. Penelitian ini bertujuan untuk mengetahui efektivitas makroalga Caulerpa taxifolia terhadap kelangsungan hidup dan respons histopatologis hati ikan kakap putih yang terpapar logam tembaga (Cu²⁺) dosis kronis sebesar 6,83 mg/L. Penelitian dilaksanakan selama 14 hari menggunakan Rancangan Acak Lengkap (RAL) dengan enam perlakuan dan tiga ulangan, yaitu P0 (tanpa paparan Cu²⁺ dan tanpa makroalga), P1 (tanpa makroalga), P2 (25 g), P3 (50 g), P4 (75 g), dan P5 (100 g). Parameter yang diamati meliputi kelangsungan hidup ikan, histopatologi hati, respirasi ikan, kualitas air, serta bioakumulasi logam tembaga, disertai pengamatan kondisi kloroplas makroalga. Hasil penelitian menunjukkan bahwa penambahan C. taxifolia mampu menurunkan dampak toksisitas Cu²⁺, yang ditandai dengan meningkatnya kelangsungan hidup ikan, membaiknya respirasi, serta berkurangnya tingkat kerusakan histopatologis hati dibandingkan perlakuan tanpa makroalga. Selain itu, keberadaan Caulerpa taxifolia turut memperbaiki perairan yang tercemar dan menekan bioakumulasi logam tembaga di media pemeliharaan. Dengan demikian, Caulerpa taxifolia efektif sebagai agen fitoremediasi yang ramah lingkungan di perairan maupun sistem akuakultur.

Kata kunci: Caulerpa taxifolia, Cu²⁺, fitoremediasi, ikan kakap putih, histopatologi hati, kelangsungan hidup.

ABSTRACT Copper heavy metal pollution in waters can cause toxic impacts on aquatic organisms, especially Asian sea bass (Lates calcarifer), so that environmentally friendly control efforts are needed through phytoremediation methods. This study aims to determine the effectiveness of macroalgae Caulerpa taxifolia on the survival and histopathological response of the liver of Asian sea bass exposed to chronic doses of copper metal (Cu²⁺) of 6.83 mg/L. The study was conducted for 14 days using a Completely Randomized Design (RAL) with six treatments and three replications, namely P0 (without Cu²⁺ exposure and without macroalgae), P1 (without macroalgae), P2 (25 g), P3 (50 g), P4 (75 g), and P5 (100 g). The parameters observed included fish survival, liver histopathology, fish respiration, water quality, and copper metal bioaccumulation, accompanied by observations of the condition of macroalgae chloroplasts. The results showed that the addition of C. taxifolia reduced the impact of Cu²⁺ toxicity, as indicated by increased fish survival, improved respiration, and reduced levels of histopathological liver damage compared to treatments without macroalgae. Furthermore, the presence of Caulerpa taxifolia improved polluted waters and suppressed the bioaccumulation of copper metal in the culture medium. Thus, Caulerpa taxifolia is effective as an environmentally friendly phytoremediation agent in water bodies and aquaculture systems. Keywords: Caulerpa taxifolia, Cu²⁺, phytoremediation, Asian sea bass (Lates calcarifer), liver histopathology, survival.