Air selalu menjadi kebutuhan penting dalam memenuhi segala aspek kehidupan bagi semua makhluk hidup. Keberadaan sumber daya perairan harus didukung dengan kuantitas yang tercukupi serta kualitas yang baik. Salah satu sumber daya perairan yang sering dimanfaatkan oleh makhluk hidup adalah sungai, terutama aliran sungai yang berasal dari air terjun (coban). Tujuan penelitian ini untuk mengetahui keanekaragaman jenis diatom epilitik serta potensinya sebagai organisme indikator penentu kualitas perairan sungai di Coban Tarzan Kabupaten Malang. Pengambilan sampel diatom epilitik dilakukan dengan metode terpilih (purposive sampling) pada tiga stasiun di perairan sungai Coban Tarzan. Sampel diatom epilitik diambil dari substrat batuan yang terendam air dan tidak lebih dari kedalaman 20 cm. Parameter yang diamati dan diukur antara lain Kepadatan (K), Indeks Keanekaragaman Shannon Wiener (H'), Indeks Dominansi Simpson (C) dan Indeks Tropik Diatom Epilitik. Hasil pengamatan menunjukkan bahwa kepadatan total diatom epilitik yang ditemukan di Coban Tarzan selama penelitian adalah 152.669 ind/cm 2 , yang terdiri delapan genus (Amphora, Cocconeis, Cymbella, Fragilaria, Gomphonema, Navicula, Nitzschia dan Rhoicosphenia). Sementara itu nilai H' diatom epilitik di sungai Coban Tarzan menunjukkan tingkat keanekaragaman yang sedang (H'=1,52), sedangkan untuk nilai C menunjukkan tidak ada spesies diatom epilitik yang mendominasi di perairan tersebut (C=0,25). Hasil indeks tropik diatom epilitik menunjukkan perairan sungai Coban Tarzan tergolong memiliki kualitas perairan dengan kategori sedang (mesotrofik).

The purpose of this research is to know the ability of polyculture macrophyte ( Fimbristylis globulosa and Vetiveria zizanoides) and the combination of both with consortium of indigenous denitrifying bacteria from Sutami reservoir that was added by Microcystis spp. or not to reduce the concentration of nitrate, dissolved phosphate and the carrying capacity of Microcystis spp. The experiment was done in a medium filled up with Sutami reservoir water enriched with 16 ppm of nitrate and 0.4 ppm of phosphate. The denitrifying bacteria used in this research were DR-14, DU-27-1, DU-30-1, DU-30-2, TA-8 and DU-27-4 isolated from Sutami reservoir. The treatments were incubated within 15 days. Microcystis spp. abundance was calculated every day, but the measurement of the concentration of nitrate and dissolved phosphate was done every six days. The results showed that both treatment and the combination of both macrophytes with a consortium of denitrifying indigenous bacteria were added or not either Microcystis able to reduce nitrate at 99% and 93-99% orthophosphoric. The combination of macrophytes with denitrifying indigenous bacterial consortium from Sutami reservoir was able to inhibit the carrying capacity of Microcystis spp. highest up to 47.87%. They could also significantly reduce the abundance of Microcystis from 10 7 cells/mL in earlier days of the treatment into 0.35x10 4 cells/mL after fifteen days of incubation.

One of the biggest threats from human activities to rivers is the increasing number of residential areas around or even just above the river flow. This condition is certainly very threatening the sustainability of rivers in the region. One of the biggest threats is that the garbage produced by the community will be directly disposed of in the river flow. One way that can be done to reduce waste disposal in the river is by utilizing river flow, so that many rivers are now increasingly being developed as a vehicle for habitat conservation, because the river is considered important for various aquatic plants, migratory and sedentary fishes, and aquaculture ponds, birds and several types of mammals. In this case, the concept of river management must be based on environmental, ecological, economic and social aspects according to the characteristics of the surrounding community. The purpose of this community service is to utilize river flow for tilapia fish farming. The method used in the service is the PAR by way of lectures and direct practice in aquaculture with karamba by utilizing river flow. From the results of community service including partners showed that some respondents know how to fish with karamba, but do not know that river flow can also be used for fish farming with the karamba system. As well as the results of fish farming practices with the karamba system most of the respondents agreed agree (73%) if the fish culture using the karamba system is used as an alternative business idea related to river flow utilization and 60% of respondents agree the use of river flow for fish cultivation can reduce waste disposal in the river.

Pruning tea leaves not only improve the productivity of the tea leaves but ecologically improve soil arthropods, which have very important role in the food chain. This study aimed to identify and analyse the diversity of soil arthropods in the tea plantation of PTPN XII Bantaran Blitar with pruning system. Observation of soil arthropods was performed by using hand sorted method on tea land with 25, 25 and 30 cm of each length, width and depth, respectively. Observations were performed at three stations, namely Pruning Year (PY) I, PY II and PY III, at which each station contains 10 observation point. The data were analysed by PAST program 3.06 version. This study found soil arthropods about 45 specimens, consisting of 15 orders, and 33 families. The most abundant order is Coleoptera, as well  the role of common soil arthropods are predator.  Family Formicidae is the most common family found in tea plantation. In addition, the highest of soil arthropods diversity index is in PY III, i.e. 2,58.