ANALISIS BENTUK MIKROPLASTIK PADA KERANG HIJAU (Perna viridis) DI ALUE NAGA KECAMATAN SYIAH KUALA KOTA BANDA ACEH

Kerang hijau (Perna viridis) merupakan salah hewan dari kelas bivalvia yang berhabitat di kawasan perairan estuari, teluk dan daerah mangrove. Kerang hijau termasuk kedalam kelompok suspension feeder yaitu memakan apa saja yang ada disekitarnya sehingga kerang hijau dapat mengakumulasi mikroplastik. Penelitian ini bertujuan untuk menganalisis bentuk mikroplastik yang ditemukan pada sampel kerang hijau (Perna viridis) di Alue Naga, Kecamatan Syiah Kuala, Kota Banda Aceh.Penelitian ini dilakukan pada bulan Mei-Juni 2021. Pengambilan data dengan menggunakan metode survei yang menggunakan teknik random sampling. Objek penelitian ini yaitu berupa kerang hijau (Perna viridis) yang diperoleh dari kawasan Alue Naga, Kecamatan Syiah Kuala, Kota Banda Aceh. Parameter yang diamati pada penelitian ini adalah bentuk mikroplastik yang terdapat pada kerang hijau (Perna viridis). Data dianalisis secara deskriptif yang ditampilkan dalam bentuk gambar dan tabel berdasarkan bentuk mikroplastiknya. Hasil penelitian diperoleh bahwa mikroplastik di kawasan Alue Naga ditemukan dalam 4 bentuk mikroplastik yaitu, bentuk fiber, fragmen, film, dan pelet.

Seasonal trends of the polyp expansion and nutritional condition of Alcyonium acaule (Octocorallia, Alcyonacea)

The ecological physiology of anthozoans, as well as their resistance to stressors, are strongly influenced by environmental factors and the availability of resources. The energy budget of anthozoans can vary seasonally in order to find an equilibrium between the available resources and respiration, polyp activity, growth, and reproduction processes. The variation in the biochemical composition of the animal tissues in these organisms results from a combination of the productivity processes of the water column coupled with the reproductive effort and potential starvation periods of the anthozoans. Here, the seasonal variation in the polyp activity of a slow-growing passive suspension feeder, the octocoral Alcyonium acaule, as well as their carbohydrate, protein and lipid contents, was investigated in a warm temperate environment using in-situ observations and biochemical analyses. Polyp activity exhibited a significant variability that was moderately dependent on season, while an aestivation phenomenon in A. acaule (i.e., a resting period in which the anthozoan is not capable of any polyp activity) during the warmer months is clearly observed. Carbohydrate concentrations in the coral species showed a significant increase in the late winter and spring seasons, and the lipid content increased during the spring. A higher abundance of lipids and carbohydrates coincided with a higher primary productivity in the water column, as well as with the octocoral reproduction period. In late autumn, there was a depletion of these biomolecules, with protein levels exhibiting great variability across sampling times. Complex alterations driven by climate change could affect the energy fluxes that depend on the dead or alive particles that are intercepted by marine animal forests. The obtained findings show a food shortage in late summer and autumn of the benthic suspension feeder A. acaule through the integrative descriptors of the ecophysiology of these anthozoans. This research contributes to the knowledge of energy storage capabilities in benthic suspension feeders in general, highlighting the importance of understanding the limits of resistance to starvation periods through these indicators.

The effect of external flow on the feeding currents of sessile microorganisms

Microscopic sessile suspension feeders live attached to surfaces and, by consuming bacteria-sized prey and by being consumed, they form an important part of aquatic ecosystems. Their environmental impact is mediated by their feeding rate, which depends on a self-generated feeding current. The feeding rate has been hypothesized to be limited by recirculating eddies that cause the organisms to feed from water that is depleted of food particles. However, those results considered organisms in still water, while ambient flow is often present in their natural habitats. We show, using a point-force model, that even very slow ambient flow, with speed several orders of magnitude less than that of the self-generated feeding current, is sufficient to disrupt the eddies around perpendicular suspension feeders, providing a constant supply of food-rich water. However, the feeding rate decreases in external flow at a range of non-perpendicular orientations due to the formation of recirculation structures not seen in still water. We quantify the feeding flow and observe such recirculation experimentally for the suspension feeder Vorticella convallaria in external flows typical of streams and rivers.

Macrophyte-derived detritus in shallow coastal waters contributes to suspended particulate organic matter and increases growth rates of Mytilus edulis

Benthic suspension feeders, such as bivalves, potentially have several different food sources, including plankton and resuspended detritus of benthic origin. We hypothesised that suspension feeders are likely to feed on detritus if it is present. This inference would be further strengthened if there was a correlation between δ13C of suspension feeder tissue and δ13C of particulate organic matter (POM). Since detritus is characterised by high particulate organic matter (POC):chl a ratios, we would also predict a positive correlation between POM δ13C and POC:chl a. We hypothesised that increasing depth and greater distance from shore would produce a greater nutritional reliance by experimentally transplanted blue mussels Mytilus edulis on plankton rather than macrophyte-derived detritus. After deployments of 3 mo duration in 2 different years at depths from 3 to 40 m, M. edulis sizes were positively correlated with POM concentrations. POC:chl a ratios and δ13C of POM and M. edulis gill tissue decreased with increasing depth (and greater distance from shore). δ13C of POM was correlated with δ13C of M. edulis. Our results suggest that detritus comprised a large proportion of POM at shallow depths (<15 m), that M. edulis ingested and assimilated carbon in proportion to its availability in POM, and that growth of M. edulis was higher where detritus was present and POM concentrations were higher.

IDENTIFIKASI KESESUAIAN LAHAN BUDIDAYA TERIPANG PASIR (Holothuria scabra) BERDASARKAN PARAMETER KIMIA MENGGUNAKAN SISTEM INFORMASI GEOGRAFIS DI PERAIRAN LOMBOK BARAT

Teripang merupakan kelompok hewan invertebrata dari filum Echinodermata kelas Holothurioidea. Teripang termasuk komponen penting dalam rantai makanan karena peranannya sebagai pemakan endapan (deposit feeder) dan pemakan materi tersuspensi (suspension feeder). Oleh karena itu diperlukan informasi yang memadai yang bisa dipakai untuk pengelolaan teripang secara berkelanjutan. Salah satu metode yang digunakan adalah dengan menggunakan sistem informasi geografis (SIG). Metode ini dapat digunakan untuk memudahkan dalam mengetahui lokasi penyebarannya, sehingga pengembangan dalam kegiatan budidaya teripang pasir (Holothuria scabra) dapat tercapai dengan optimal. Tujuan penelitian ini adalah menganalisis kesesuaian kawasan budidaya teripang menggunakan Aplikasi SIG yang disajikan dalam bentuk peta kesesuaian kawasan budidaya teripang pasir (H. scabra) di Perairan Lombok Barat. Penelitian ini dilaksanakan pada tanggal 17 Oktober 2016 – 27 November 2016 di Gili Asahan, Gili Layar dan Gili Gede Kecamatan Sekotong Barat Kabupaten Sekotong Barat Pulau Lombok Provinsi Nusa Tenggara Barat. Pengumpulan data dilakukan dengan metode survei, berupa data primer dan sekunder yang berkaitan langsung dengan hidup teripang. Berdasarkan parameter kimia hasil penelitian di Perairan Lombok Barat adalah: pH 6,82 – 7,50, salinitas 32 – 34 ppt dan DO 6,19 – 6,52 mg/L, lokasi kesesuaian lahan untuk kategori sangat sesuai terdapat di Gili Gede, kategori sesuai di Gili Asahan dan kategori tidak sesuai di Gili Layar.

Was the Devonian placoderm Titanichthys a suspension feeder?

Large nektonic suspension feeders have evolved multiple times. The apparent trend among apex predators for some evolving into feeding on small zooplankton is of interest for understanding the associated shifts in anatomy and behaviour, while the spatial and temporal distribution gives clues to an inherent relationship with ocean primary productivity and how past and future perturbations to these may impact on the different tiers of the food web. The evolution of large nektonic suspension feeders—‘gentle giants’—occurred four times among chondrichthyan fishes (e.g. whale sharks, basking sharks and manta rays), as well as in baleen whales (mysticetes), the Mesozoic pachycormid fishes and at least twice in radiodontan stem group arthropods (Anomalocaridids) during the Cambrian explosion. The Late Devonian placoderm Titanichthys has tentatively been considered to have been a megaplanktivore, primarily due to its gigantic size and narrow, edentulous jaws while no suspension-feeding apparatus have ever been reported. Here, the potential for microphagy and other feeding behaviours in Titanichthys is assessed via a comparative study of jaw mechanics in Titanichthys and other placoderms with presumably differing feeding habits (macrophagy and durophagy). Finite-element models of the lower jaws of Titanichthys termieri in comparison to Dunkleosteus terrelli and Tafilalichthys lavocati reveal considerably less resistance to von Mises stress in this taxon. Comparisons with a selection of large-bodied extant taxa of similar ecological diversity reveal similar disparities in jaw stress resistance. Our results, therefore, conform to the hypothesis that Titanichthys was a suspension feeder with jaws ill-suited for biting and crushing but well suited for gaping ram feeding.

Preferensi Habitat Spesies Kerang Laut (Moluska: Bivalvia) Di Ekosistem Intertidal Tanjung Bilik Taman Nasional Baluran

Kerang adalah jenis moluska yang hidup di substrat beberapa ekosistem perairan. Kerang merupakan komponen penting yang berperan sebagai pemakan sisa organik yang berada di perairan (deposit feeder) dan pemakan suspensi (suspension feeder) dalam rantai makanan. Beberapa spesies kerang juga dapat berperan dalam mengakumulasi (bioakumulator) logam berat. Di Taman Nasional Baluran, Jawa Timur, Indonesia, kerang sering digunakan oleh masyarakat setempat sebagai bahan dasar makanan dan cangkangnya dijual sebagai dekorasi kamar, perhiasan, dan peralatan rumah tangga. Akibat terjadinya eksploitasi terhadap kerang secara berlebihan, telah diduga bahwa kepadatan populasi dan keanekaragaman spesies kerang telah menurun. Penelitian ini dilakukan pada Oktober 2019 di Pantai Bilik di Taman Nasional Baluran untuk menentukan komposisi spesies dan preferensi habitat spesies kerang. Pengambilan sampel acak digunakan untuk mengukur komposisi spesies kerang di daerah penelitian. Hasil analisis menunjukkan bahwa terdapat adanya 6 ordo, 8 famili, 11 genera, dan 14 spesies. Nilai keanekaragaman spesies yang dihitung menggunakan indeks keanekaragaman jenis (H'). Hasil yang diperoleh menunjukkan telah ditemukan 2,109, yang menunjukkan keanekaragaman spesies tingkat sedang. Analisis kemerataan spesies menunjukkan nilai sebesar 0,79, yang berarti kemerataan spesies rendah. Habitat kerang di Pantai Bilik lebih terfokus pada bongkahan karang mati yang ditumbuhi alga. Moluska sering ditemukan bersama dengan karang dari keluarga Faviidae, terutama yang berasal dari genus Porites.

Scythes, sickles and other blades: defining the diversity of pectoral fin morphotypes in Pachycormiformes

The traditional terminology of ‘scythe’ or ‘sickle’ shaped is observed to be flawed as an effective descriptor for pectoral fin shape in pachycormids. The diversity of pachycormid pectoral fin shapes is assessed across the 14 recognised genera that preserve complete pectoral fins, and improved terms are defined to more effectively describe their form, supported by anatomical observation and aspect ratio analysis of individual fins, and corroborated by landmark analysis. Three clear and distinct pectoral fin structural morphotypes emerge (falceform, gladiform, falcataform), reflecting a diversity of pachycormid lifestyles throughout the Mesozoic, from agile pursuit predator to slow-cruising suspension feeder.