Penelitian mengenai struktur komunitas meiofauna di substrat padang lamun Pulau Pari, Kepulauan Seribu telah dilakukan pada bulan November tahun 2011. Penelitian bertujuan untuk mengetahui hubungan antara struktur komunitas meiofauna interstisial dengan substrat padang lamun yang berbeda. Sampel diambil secara purposive random sampling pada 2 stasiun, 15 titik di padang lamun bagian utara dan barat daya Pulau Pari. Berdasarkan hasil penelitian diperoleh 8 takson yang berasal 6 filum yakni Nemathelminthes, Annelida, Platyhelminthes, Arthropoda, Protozoa dan Gnathostomulida. Kelimpahan jenis meiofauna interstisial berkisar antara 109.000 -- 194.000 individu / m2. Kelimpahan tertinggi dimiliki oleh kelompok Nematoda jenis Daptonema sp. sedangkan terendah ada pada kelompok Foraminifera. Komposisi butiran sedimen memengaruhi komposisi kehadiran jenis meiofauna yang hidup di antara rongga interstisialnya. Berdasarkan data parameter abiotiknya, padang lamun Pulau Pari memiliki kondisi lingkungan yang sesuai untuk kehidupan meiofauna.

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Research on the community structure of the interstitial meiofauna in substrate of seagrass bed in Pari Island was conducted on November 2011. The objective of this study was to determine the relationship between interstitial meiofauna community structure and the different substrate of different sea grass community. Samples were taken by purposive random sampling methods in 2 stations, 15 sites in north side and south west side seagrass bed in Pari Island. The identification on the interstitial meiofauna obtained 8 taxons from 6 phyla, they are Nemathelminthes, Annelida, Platyhelminthes, Arthropoda, Protozoa and Gnathostomulida. The abundance of the interstitial meiofauna was between 109.000 - 194.000 individual/m2. The highest abundance belonged to the group of nematode class Daptonema sp. while the lowest belonged to the group of Foraminifera. The grain size composition influences the composition of meiofauna who lived in the interstitial space of its substrates. Based on abiotic parameters data, the waters of Pari Island still have the appropriate environmental condition for the optimal growth of meiofauna.