Rapid coral reef assessment using 3D modelling and acoustics: acoustic indices correlate to fish abundance, diversity and environmental indicators in West Papua, Indonesia

Background Providing coral reef systems with the greatest chance of survival requires effective assessment and monitoring to guide management at a range of scales from community to government. The development of rapid monitoring approaches amenable to collection at community level, yet recognised by policymakers, remains a challenge. Technologies can increase the scope of data collection. Two promising visual and audio approaches are (i) 3D habitat models, generated through photogrammetry from video footage, providing assessment of coral cover structural metrics and (ii) audio, from which acoustic indices shown to correlate to vertebrate and invertebrate diversity, can be extracted. Methods We collected audio and video imagery using low cost underwater cameras (GoPro Hero7™) from 34 reef samples from West Papua (Indonesia). Using photogrammetry one camera was used to generate 3D models of 4 m2 reef, the other was used to estimate fish abundance and collect audio to generate acoustic indices. We investigated relationships between acoustic metrics, fish abundance/diversity/functional groups, live coral cover and reef structural metrics. Results Generalized linear modelling identified significant but weak correlations between live coral cover and structural metrics extracted from 3D models and stronger relationships between live coral and fish abundance. Acoustic indices correlated to fish abundance, species richness and reef functional metrics associated with overfishing and algal control. Acoustic Evenness (1,200–11,000 Hz) and Root Mean Square RMS (100–1,200 Hz) were the best individual predictors overall suggesting traditional bioacoustic indices, providing information on sound energy and the variability in sound levels in specific frequency bands, can contribute to reef assessment. Conclusion Acoustics and 3D modelling contribute to low-cost, rapid reef assessment tools, amenable to community-level data collection, and generate information for coral reef management. Future work should explore whether 3D models of standardised transects and acoustic indices generated from low cost underwater cameras can replicate or support ‘gold standard’ reef assessment methodologies recognised by policy makers in marine management

INDUKSI KALUS DAN PENGHASILAN CAPSAICIN PADA VARIASI KADAR NUTRIEN MS DAN KOMBINASI ZAT PENGATUR TUMBUH

Capsaicin merupakan salah satu metabolit sekunder tanaman cabai yang memberikan rasa pedas pada buah cabai dan bersifat iritan. Modifikasi komposisi medium pada kultur in vitro dapat digunakan untuk meningkatkan penghasilan capsaicin. Salah satu cara untuk meningkatkan penghasilan capsaicin adalah dengan meningkatkan kadar garam dan sukrosa medium yang berakibat menurunnya potensial air medium (stres air). Penelitian bertujuan untuk mendapatkan kadar nutrien MS dan kombinasi zat pengatur tumbuh yang optimal dalam penghasilan capsaicin secara kuantitatif melalui induksi kalus dari eksplan hipokotil cabai rawit (Capsicum frutescens) putih. Penelitian menggunakan Rancangan Acak Lengkap Faktorial dengan dua faktor perlakuan, yaitu kadar nutrien MS (½ resep medium MS, ¾ resep medium MS, 1 resep medium MS, 1¼ resep medium MS, dan 1½ resep medium MS ) dan kombinasi auksin-sitokinin (1 mg/L 2,4-D + 2 mg/L BAP, 2 mg/L 2,4-D + 0,5 mg/L Kin, 0,04 mg/L IAA + 2 mg/L BAP). Penelitian ini menghasilkan data kuantitatif yang meliputi waktu inisiasi kalus, persentase pertumbuhan kalus, berat basah kalus, kandungan senyawa capsaicin; dan data kualitatif yang meliputi morfologi kalus (warna dan tekstur kalus). Hasil penelitian menunjukkan bahwa medium 1 MS dengan penambahan IAA + BAP dapat menginisiasi kalus tercepat (5,67 hari), berat basah kalus terbesar (0,67 g), dan dapat menginduksi eksplan (100%). Tingginya kadar nutrien medium MS dan penambahan kombinasi ZPT cenderung meningkatkan kandungan capsaicin. Medium 1½ MS dengan penambahan 2,4-D + Kin atau IAA + BAP dapat meningkatkan kandungan capsaicin 1,2 kali dibandingkan dengan medium 1 MS + 2,4-D + Kin atau 1 MS + IAA + BAP dan dapat meningkatkan kandungan capsaicin 1,4 kali dibandingkan dengan medium 1½ MS kontrol