Autonomous zooplankton profiler reveals high-Arctic zooplankton dynamics during transition to polar night

<p>With rapid sea-ice decline, ocean warming and increasing Atlantic inflow, the ecosystem of the Central Arctic Ocean (CAO) is experiencing an unprecedented, potentially disruptive transformation. While this transformation is affecting the biodiversity of marine communities and the ecosystem functions they fulfil, major knowledge gaps about the distribution of pelagic macrofauna (zooplankton and fish) complicate the assessment of the impact of this transformation on biodiversity and marine resources. The largest blind spot remains in the central Arctic Basin, which has been difficult to sample with large sampling gear such as fishing nets due to a year-round ice coverage. However, in the face of increasing human activities and international efforts to implement marine management in the CAO, it becomes important to monitor pelagic fauna in this remote area. One possibility to enable a better sampling of pelagic macrofauna is to use sea-ice thethered autonomous observatories. Within the British/German project EcoLight, we developed a new autonomous sea-ice observatory comprising an ASL Acoustic Zooplankton and Fish Profiler (AZFP). The device has 4 frequencies targeting different size classes of animals. It samples automatically at predefined intervals and transmits the data to a server in Europe via Iridium. It is possible to change the sampling parameters via a remote connection at any time. The AZFP buoy was deployed in the CAO in September 2020, shortly before the end of the MOSAiC expedition. Since then, the buoy has been recording the vertical zooplankton distribution in the water column under the ice. First data show a light-induced change of the vertical distribution of scatterers, transitioning from deep distribution during the polar day, through a short period of diel vertical migration during the twilight period, to a constant presence of scatterers in the surface layer in the polar night. Furthermore, AZFP data suggest an enhancement of zooplankton between the upper pycnocline and ~50 m depth during in an eddie transition. The data collected by the EcoLight AZFP buoy constitute the first hydroacoustic record of zooplankton distribution near the North Pole sampled with a fully autonomous system in the absence of disturbing light sources. They demonstrate the feasibility of year-round automated monitoring of macrofauna in the CAO in relation to environmental properties. Similar autonomous devices may serve as key elements in the future monitoring of biological resources in the CAO and other inaccessible areas.</p>

Distribusi Horizontal Zooplankton Berdasarkan Salinitas Di Perairan Bonang Kabupaten Demak Indonesia

ABSTRAK: Zooplankton merupakan salah satu biota yang sensitif akan perubahan karakteristik perairan. Zooplankton sering dijadikan indikator terhadap kondisi ekologis suatu perairan. Tujuan dalam penelitian ini yaitu untuk mengetahui Distribusi zooplankton dan pengaruh perbedaan salinitas pada distribusi zooplankton di Perairan Bonang Kabupaten Demak. Lokasi penelitian dibagi menjadi tiga stasiun yaitu Stasiun A (Sungai), Stasiun B (Muara), Stasiun C (Laut). Sampel diambil dengan plankton net di ketiga stasiun tersebut dengan tiga kali pengulangan dan tiga waktu pengulangan di setiap stasiunnya. Hasil penelitian ini ditemukan 20 genus zooplankton yaitu Corycaeus sp, Muggiaea sp, Mysis sp, Penaeus sp, Macrobrachium sp, Anisomysis sp, Pleuromamma sp, Thysanopoda sp, Euterpina sp, Undinula sp, Acartia sp, Arcella sp, Acrocalanus sp, Centropages sp, Candacia sp, Halopthilus sp, Paracalanus sp, Metridia sp, Pseudocalanus sp, Emplectonema sp yang termasuk ke dalam 6 Kelas, Keenam kelas tersebut terdiri dari Hydrozoa, Malascostraca, Maxillopoda, Tubulinea, dan Hexanaulipa. Hasilnya nilai P yaitu 0,00008 < 0,5 yang berarti salinitas memberi dampak pada distribusi horizontal zooplankton berdasarkan Uji Anova. ABSTRACT: Zooplankton is one of the sensitive biota to respond environmental aquatic of changes. Zooplankton is frequently used as an indicator of the ecological conditions of waters. The purpose of this study is to determine the distribution of zooplankton and the effect of differences in salinity on zooplankton distribution in the coastal waters of Bonang Demak Regency. The research location is divided into three stations namely Station A (River), Station B (Estuary), Station C (Marine). Samples were taken with a plankton net at the three stations with three repetitions and three repetitions at each station. The results of this study found 20 genera zooplankton namely Corycaeus sp, Muggiaea sp, Mysis sp, Penaeus sp, Macrobrachium sp, Anisomysis sp, Pleuromamma sp, Thysanopoda sp, Euterpina sp, Undinula sp, Acartia sp, Arcella sp, Acrocalanus sp, Centropages sp, Candacia sp, Halopthilus sp, Paracalanus sp, Metridia sp, Pseudocalanus sp, Emplectonema sp included in 6 Classes, The six classes consist of Hydrozoa, Malascostraca, Maxillopoda, Tubulinea, and Hexanaulipa. The result is P value P = 0,00008 < 0,5 that meansthe zooplankton distribution is influenced by salinity based on the Anova Test