Academic literature on the topic 'Megabentos'

Seagrass bed are one of the ecosistems in shallow waters that can support the biodiversity of marine organisms. Megabenthos as benthic organisms that usually live in association in seagrass beds, have an important role in the food web in their habitat. This study aims to analyse the diversity of megabenthos associated with their habitat characteristics in seagrass waters in Bandengan, Teluk Awur and Panjang Island Jepara. This research was conducted using a descriptive field method, and megabenthos data collecting was carried out using the line transect method. Thr result showed that 158 individuals from 8 species of megabenthos were found (from 2 phyla: Echinodermata and Molluska) from three observation locations. Condition factors that influence the abundance and diversity of megabenthos are the substrat type and seagrass cover. Padang lamun sebagai salah satu ekosistem di perairan laut dangkal dapat menopang keanekaragaman hayati organisme laut. Megabentos yang termasuk dalam organisme bentik merupakan organisme yang biasa hidup berasosiasi di padang lamun, mempunyai peranan penting dalam jaring-jaring makanan di habitatnya. Penelitian ini bertujuan untuk menganalisa keanekaragaman megabentos dikaitkan dengan karakteristik habitatnya di perairan padang lamun di Bandengan, Teluk Awur dan Pulau Panjang Jepara. Penelitian ini dilakukan dengan metoda deskriptif lapangan, dan pengambilan data megabentos dilakukan dengan metoda line transek. Hasil pengamatan menunjukkan ditemukan 158 individu dari 8 spesies megabentos (dari 2 filum: Echinodermata dan Molluska) dari ketiga lokasi pengamatan. Faktor kondisi yang berpengaruh terhadap kelimpahan dan keanekaragaman megabentos adalah jenis substrat dasar dan tutupan lamun.

Perairan Pulau Buton dan sekitarnya dengan wilayah terumbu karang yang cukup luas, kaya keanekaragaman hayati laut dan nilai estetika yang tinggi. Terumbu karang bermanfaat banyak bagi manusia dalam berbagai aspek ekonomi, sosial, dan budaya. Penelitian megabentos pada ekosistem terumbu karang ini telah dilakukan pada 2016 (April), 2017 (Juni) dan 2018 (Mei). Pengamatan dilakukan pada 15 stasiun yang tersebar pada pulau-pulau besar dan kecil dari timur hingga barat. Tujuan penelitian ini untuk mengetahui sebaran dan kepadatan megabentos serta kemiripan spesies antar stasiun pada perairan tersebut. Pengambilan data dilakukan dengan menggunakan metode Reef Check Benthos (RCB). Hasil pengamatan menunjukkan ada delapan spesies megabentos, diantaranya Drupella cornus menyebar secara luas (100%), dan memiliki nilai total kelimpahan individu tertinggi, berkisar antara 35,7 – 57,9%, (472 – 704 individu). Sedangkan Acanthaster planci memiliki sebaran yang terbatas dengan kelimpahan individu yang rendah (0,3 – 1,0%). Kepadatan individu megabentos pada pengamatan April berkisar antara 0,16 – 2,31 individu/140m2, pada Juni berkisar antara 0,11 – 1,47 individu/140m2 dan 0,11 – 1,24 individu/140m2 pada Mei. Dari tiga tahun pengamatan (2016 – 2018) kelimpahan rata-rata individu megabentos tidak ditemukan adanya perbedaan yang signifikan. Hasil analisa klaster menunjukkan bahwa kehadiran setiap spesies megabentos antar stasiun pengamatan dipengaruhi oleh kemiripan tipe substrat dan habitat.The waters of Buton Island and its surrounding, has a large coral reef area with high species biodiversity and has an aesthetics value and beneficial for human being in many aspects such as economics, social and culture. Researches on megabenthos in coral reef ecosystems have been conducted in 2016 (April), 2017 (June) and 2018 (May) at 15 stations around large and small islands scattered from east to west. The aims of this study were to know the distribution and abundance of megabenthos and similarity of species between stations in these waters. Data collection is conducted using the Reef Check Benthos (RCB) method. The results shows that eight megabenthos was found, where Drupella cornus has a wide distribution (100%), and has the highest total value of individual abundance, ranging from 35.7 - 57.9%, (472 - 704 individuals). Whereas Acanthaster planci has a limited distribution with a low abundance of individuals (0.3 - 1.0%). The abundance of megabenthos in April’s observations ranged from 0.16 - 2.31 individuals/140m2, in June it ranged from 0.11 - 1.47 individuals/140m2 and 0.11 - 1.24 individuals/140m2 in May. In three years of observation (2016 - 2018) the average abundance of megabenthos individuals is not significantly different. The results of cluster analysis showed that the similarity of megabenthos species between observation stations was influenced by similarities in substrate type and habitat.

Ekosistem terumbu karang adalah ekosistem laut yang sangat rentan oleh kerusakan lingkungan. Terumbu karang di perairan Bilik, Taman Nasional Baluran merupakan contoh ekosistem terumbu karang yang mengalami ancaman kerusakan lingkungan akibat perubahan iklim dan aktivitas manusia. Salah satu metode yang dapat digunakan untuk memonitor kesehatan terumbu karang adalah dengan melihat kelimpahan megabentos dalam ekosistem terumbu karang. Oleh karena itu, penelitian ini memiliki tujuan untuk mengetahui kesehatan ekosistem terumbu karang dengan melihat kelimpahan megabentos di perairan Bilik, Taman Nasional Baluran. Metode yang digunakan dalam inventarisasi megabentos adalah dengan Benthos Belt Transect dan analisis video di Blok Sijile dan Blok Jeding di Perairan Bilik. Hasil pengamatan menunjukkan bahwa di Blok Sijile tidak ditemukan ekosistem terumbu karang dan megabentos. Sementara itu di Blok Jeding ditemukan ekosistem terumbu karang dengan megabentos berupa bulu babi dan bintang laut biru. Kelimpahan bulu babi di dan bintang laut biru adalah 0-0,14 individu/m2. Kondisi tersebut menunjukkan bahwa kesehatan ekosistem terumbu karang di Blok Jeding perairan Bilik Sijile masih baik, namun perlu mendapat perhatian khusus karena sebagian area terumbu karang mengalami pemutihan akibat aktivitas perikanan yang tidak ramah lingkungan.MEGABENTHOS ABUNDANCE AS CORAL HEALTH INDICATORS IN BILIK WATERS, BALURAN NATIONAL PARK, INDONESIA. Coral reef ecosystems are marine ecosystems that are prone to environmental damage. Coral reefs in Bilik waters, Baluran National Park, are examples of coral reef ecosystems that are threatened by environmental damage due to climate change and human activities. One of the methods for health monitoring of coral reefs is by looking at the abundance of megabenthos in coral reef ecosystems. Therefore, this study aims to determine the health of coral reef ecosystems by looking at the abundance of megabenthos in Bilik waters, Baluran National Park. We used Benthos Belt Transect and video analysis to identify the spatial distribution and number of megabenthos in Sijile Block and Jeding Block, Bilik waters. The results showed that in Sijile Block, there were no coral reef neither megabenthos ecosystems. Meanwhile, in Jeding Block, there was a coral reefs ecosystem with megabenthos in the form of sea urchins and blue starfish. The abundance of sea urchins and the blue sea star in Jeding Block was about 0-0.14 individual/m2. These conditions indicate that the health of the coral reef ecosystem in Jeding Block, Bilik waters was still in good condition, even though it still needs special attention related to coral bleaching as a consequence of fisheries activities that are not environmentally friendly.

Terumbu karang merupakan ekosistem yang subur dan kaya akan makanan. Megabentos merupakan salah satu komunitas hewan bentik yang berasosiasi dengan terumbu karang. Tujuan penelitian ini yaitu untuk mengetahui kepadatan megabentos (bulu babi, bintang laut, teripang, lola, kima, lobster, siput drupella, dan bintang laut berduri), mengetahui kelimpahan relatif karang hidup serta hubungan kelimpahan relatif karang hidup dengan kepadatan megabentos di Perairan Waworaha Provinsi Sulawesi Tenggara. Pengambilan data kondisi karang dan fauna megabentos dilakukan dengan menggunakan metode Belt Transect yang ditarik sejajar garis pantai dengan luasan 350 m². Hasil penelitian yang didapatkan pada tiap stasiun adalah persentase kelimpahan relatif karang hidup di perairan waworaha termasuk tinggi dengan rata-rata persentase kelimpahan relatif karang hidup sebesar 70,28%. Nilai rata-rata kepadatan megabentos adalah 0,070 ind/m² dengan kepadatan tertinggi terdapat pada stasiun 3 yaitu 0,096 ind/m², dan kepadatan megabentos terendah terdapat pada stasiun 1 yaitu 0,030 ind/m². Perhitungan nilai hubungan kelimpahan relatif karang hidup dengan kepadatan megabentos didapatkan nilai r sebesar 0.929 bernilai positif yang artinya kelimpahan relatif karang hidup dan kepadatan megabentos memiliki hubungan yang sangat kuat.Kata kunci: Karang, Kepadatan, Megabentos, Waworaha

Bulu babi, bintang laut biru, teripang, kima, lola, siput drupella, lobster, dan bintang laut berduri merupakan organisme megabentos yang berasosiasi dengan terumbu karang. Terumbu karang adalah habitat bagi ribuan biota, baik yang hidup sementara maupun menetap selamanya. Penelitian ini bertujuan untuk mengetahui kepadatan dan keanekaragaman megabentos serta untuk mengetahui hubungan persentase tutupan karang dengan kepadatan dan keanekaragaman jenis megabentos di Perairan Desa Buton, Sulawesi Tengah. Penelitian ini dilaksanakan pada bulan Januari-April 2019, yang meliputi pengambilan data dan pengolahan data. Pengambilan data megabentos dilakukan dengan menggunakan metode Belt Transect yang ditarik sejajar garis pantai dengan luasan 150 m2. Untuk pengambilan data persentase tutupan karang menggunakan metode Line Intercept Transect (LIT) dengan menarik transek sejajar garis pantai sepanjang 60 m2. Nilai kepadatan megabentos yang tertinggi dengan nilai 2,37 ind/m2berada pada kondisi karang yang baik dengan nilai tutupan persentase 73,03% dan yang terendah dengan nilai 2,13 ind/m2berada pada kondisi karang yang sedang dengan nilai tutupan persentase 48,32%. Hasil indeks keanekaragaman jenis megabentos pada kondisi karang yang baik diperoleh 1,73, untuk kategori kondisi karang yang sedang diperoleh nilai 1,59, danuntuk kategori karang yang buruk diperoleh nilai 1,32. Hasil perhitungan korelasi kepadatan megabentos dengan persentase tutupan karang diperoleh nilai r = 0,57 dengan kategori hubungan sedang, sedangkan untuk hubungan keanekaragaman jenis dengan persentase tutupan karang sangat kuat diperoleh nilai r = 0,99.Kata Kunci: Megabentos, Kepadatan, Keanekaragaman, Desa Buton

Berbagai upaya telah dilakukan untuk mengatasi masalah abrasi di wilayah pesisir pantai Desa Banyuurip, Gresik. Upaya yang dilakukan salah satunya adalah reboisasi mangrove, namun upaya tersebut belum efektif, sehingga salah satu solusinya adalah dengan dipasangnya geosyntheticbag (geobag), yang merupakan kantong ramah lingkungan berisi pasir yang disusun dan dapat berfungsi sebagai perangkap sedimen dan pelindung pantai. Tujuan dari penelitian ini adalah untuk mengetahui pada bulan ke berapa biota dapat tumbuh pada geosintetik dan struktur komunitas biota yang tumbuh menggunakan metode random transek. Hasil penelitian menunjukkan bahwa megabentos epifauna dapat tumbuh pada geobag pada bulan ke-4 setelah pemasangan, yang terdiri dari 3 spesies yaitu Metopograpsus sp., Ostrea edulis, dan Fistulobalanus albicostatus. Kelimpahan jenis megabentos pada bulan ke-4 rata-rata mencapai 198 individu/m2, sedangkan kelimpahan pada bulan ke-5 mencapai 259 individu/m2. Hasil perhitungan indeks struktur komunitas megabentos pada bulan ke-4 dan ke-5 secara berurutan meliputi indeks keanekaragaman (H’) bernilai 0,10 dan 0,11; indeks keseragaman (c) bernilai 0,09 dan 0,10; dan indeks dominansi bernilai 0,96 dan 0,96. Berdasarkan penelitian ini, dapat disimpulkan bahwa geobag berfungsi sebagai pencegah abrasi serta sekaligus dapat menyatu dengan media di sekitarnya sehingga diklaim ramah lingkungan, karena dapat ditumbuhi biota yang tidak mengganggu atau merubah struktur komunitas biota di wilayah tersebut. Various attempts have been made to solve the abrasion in the coastal area of Banyuurip Village, Gresik. To overcome this problem, the community planted the mangroves, but these have not been effective. One solution to this problem is to install a geosynthetic bag (geobag), which is an environmentally friendly bag that is arranged and can be function as a sediment trap. The purpose of this study was to determine when the megabenthos can grow in the geosynthetic and how the community structure grow using the quadrant random transect method. The result showed that epifaunal megabenthos could grow on geobag at the fourth month after installation, which consisted of 3 species. The abundance of megabenthos at the 4th month averaged 198 individuals/m2, while the abundance at the 5th month reached 259 individuals/m2. The structure index (H’) in January and February were 0.10 and 0.11, respectively. The similarity index (C) were 0.09 and 0.10, and while the dominance index was 0.96 and 0.96. This study is suggested that the geobag can be function both as a deterrent to abrasion and simultaneously integrate with the surrounding media and be claim as environmentally friendly, because it can be overgrown with biota that does not disturb or change the structure of the biota community in the area.

This study aims to analyze the density of megabenthos in coral reef ecosystems in the waters of Perlang Village. This research was conducted in November 2019 in the waters of Perlang Village with the megabentos data collection method using the Bentos Belt Transect (BBT) method based on COREMAP CTI LIPI (2017) with 5 data collection stations. The results found 603 individuals consisting of 9 species from 4 megabenthos families in coral reef ecosystems. Species found at the study site are Diadema setosum, Diadema antillarium (Familli Deadematidae), Drupella cornus, Drupella rugosa (Family Murcidae), Trochus sp, Trochus conus, Tectus pyramis (Family Trochidae), Tridacna gigas, and Tridacna maxima (Family Tridacnidae) . The highest attendance percentage of all stations was obtained by Diadema setosum of 47.93% (289 people). Percentage of live coral cover from 5 observation stations ranged from 57.44% - 91.78%. Observation pensions that received the highest percentage of cover values ​​were at pension 2 with 91.78% in the very good category.

The coral reef was a habitat for several groups of biota that live in this ecosystem. Some species or group species of benthic fauna are known to be ecologically important and others are economically important so that they can be used as indicators to assess reef health. Research on megabenthic fauna in Ternate and its surrounding waters, North Maluku, was carried out in 2012, 2015, 2016, 2017 and 2018 at fourteen permanent stations. The purpose of this study was to determine the fluctuations in several megabenthic faunae temporarily. Data were collected using the modified Belt Transect Method, namely Benthos Belt Transek method. Eight species or groups of megabenthic fauna in the coral reef have been observed. The highest distribution and abundance of megabenthic fauna was coral polyps eating-snail of Drupella spp. The species wealth index decreased from 2012 to 2017 (1.17 to 1.05) but experienced an increase in 2018 (to 1.29). The relatively high dominance found in the megabenthic fauna community was observed in 2015, 2016 and 2017, while in 2012 and 2018 it had relatively low dominance. The megabenthic fauna community observed in 2012 and 2018 has relatively high diversity, whereas in 2015, 2016 and 2017, the diversity is relatively low. The megabenthic fauna community observed in 2012 and 2018 has spread evenly, while in 2015, 2016 and 2017, the relative prevalence of fauna is relatively uneven. Terumbu karang merupakan habitat bagi beberapa kelompok biota yang hidup di dalamnya. Beberapa spesies atau kelompok spesies bentos diketahui bernilai ekologis pentingdan yang lainnya bernilai ekonomis penting sehingga dapat dijadikan sebagai indikator untuk menilai kesehatan terumbu. Penelitian fauna megabentos di perairan Ternate dan sekitarnya, Maluku Utara dilakukan pada tahun 2012, 2015, 2016, 2017 dan 2018 pada empat belas stasiun permanen. Tujuan penelitian ini adalah untuk mengetahui fluktuasi beberapa indeks ekologi megabentos dari tahun ke tahun. Pengambilan data menggunakan metode Benthos Belt Transect yang dimodifikasi dari Belt Transect Method. Sebanyak delapan kelompok jenis atau kelompok jenis megabentos pada perairan terumbu karang telah diamati. Sebaran dan kelimpahan megabentos tertinggi adalah siput pemakan polip karang Drupella spp. Indeks kekayaan spesies mengalami penurunan tahun 2012 hingga 2017 (1,17 menjadi 1,05), namun mengalami peningkatan pada tahun 2018 (menjadi 1,29). Dominansi yang relatif tinggi dijumpai pada komunitas megabentos yang teramati pada tahun 2015, 2016 dan 2017, sedangkan pada tahun 2012 dan 2018 memiliki dominansi yang relatif rendah. Komunitas megabentos yang teramati pada tahun 2012 dan 2018 memiliki keanekaragaman yang relatif tinggi, sedangkan pada tahun 2015, 2016 dan 2017 berkeanekaragaman relatif rendah. Komunitas megabentos yang teramati pada tahun 2012 dan 2018 memiliki kemerataan fauna yang relatif merata, sedangkan pada tahun 2015, 2016 dan 2017 memiliki kemerataan fauna yang relatif tidak merata.

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Da a conocer las especies que integran el megabentos asociado al fondo submareal rocoso de las Islas San Lorenzo (Alfajes) y Palomino en el Callao; los cambios de los principales parámetros comunitarios y su asociación con la temperatura superficial del mar (TSM) durante un intervalo de tiempo coincidente con la ocurrencia del evento El Niño 1997-98. La metodología utilizada está dada sobre la base de un muestreo al azar simple. En cada estación, se toman seis réplicas, adoptando como unidad de muestreo un cuadrante metálico de 0,25m². En el laboratorio, los especímenes se separan, identifican y cuantifican al menor taxón. El rango de temperatura superficial del agua de mar, fluctua entre 15,11°C en enero de 1997 y 21,87°C en enero de 1998. En total se encontran 84 especies en la estación Palomino y 70 en la estación Alfajes. Los valores máximos de diversidad son de 3,65 bits/individuo en Palomino en diciembre de 1997 y de 3,31 bits/individuo en Alfajes durante enero de 1997, los más bajos se registran en junio de 1998 con 2,69 bits/individuo en Palomino y en Alfajes en septiembre de 1997 con 2,51 bits/individuo.
Tesis

The study of the non-crustacean invertebrates dwelling on the deep Mediterranean Sea is of interest for different marine science disciplines, being the diversity of species and their distributions largely unexplored. In fact, the present Thesis conducted an effort in order to increase valid scientific information not only at taxonomical level, but also at the level of community composition and distribution. Detailed data on the reproductive biology and ethology was required for some group of ecological relevance in order to solve some relevant gaps of information. Ten multidisciplinary oceanographic cruises were conducted between October 2008 and April 2013 to sample the deep seafloor of the western Mediterranean Sea. The sampling areas included the Blanes Canyon and its adjacent open slope, the Palamós (also named La Fonera) and Cap de Creus Canyons, sea hills in the Gulf of Valencia and Eivissa Channel, and landslides on the Eivissa Channel. A total of 223 benthic trawls were completed resulting in a total swept area of 10.3 km². Samples were also observed by means of two ROV’s. Resulting from these ten cruises, this work evidenced and updated species bathymetrical and geographical distributions ranges of non-crustacean invertebrate species by different methodologies (i.e. traditional and technologically advanced sampling). As a result of that effort, new faunistic reports were described: two first records (i.e. Gracilechinus elegans (Düben & Koren, 1844) Dicopia antirrhinum C. Monniot, 1972), three rare species (i.e. Hedingia mediterranea (Bartolini Baldelli, 1914), Penilpidia ludwigi (von Marenzeller, 1893) and Phascolosoma (Phascolosoma) turnerae (Rice, 1985), and eleven extensions of maximum depth range of distribution. This new record for Dicopia antirrhinum increased the lower depth limit of this genus in the Mediterranean Sea from 500 to 1100m depth. This finding contributes to the knowledge of the poorly investigated Mediterranean deep ascidian fauna, in sharp contrast with the relatively well-known shallow-water Mediterranean ascidians. We also observed that densities and biomass of non-crustacean invertebrates were pointed to be significantly higher in submarine canyons than in surrounding open slopes. These findings suggest submarine canyon habitats of the north-western Mediterranean Sea as hotspots of benthic megafauna communities. The most abundant group in terms of density was the Phylum Echinodermata. A Phylum largely undescribed in deep Mediterranean waters, when compared with the faunistic data already available for the Atlantic. All specimen sampled of this Phylum were classified, described and their bathymetrical ranges re-defined. These results were compared and extended with the previous published literature, checking, validating (or discarding) all available information. The reproductive pattern of the most abundant species of Asteroidea in the present study, Ceramaster grenadensis was studied. The size pattern distribution of show a depth related trend showing smaller sizes at greater depths (dwarfism), as observed in other species of Atlantic Ocean. Additionally, juveniles were sampled at the deepest range of distribution of the species (i.e. 2250 m). Histological analysis of C. grenadensis gonads, revealed a semicontinous reproductive patterns, with a maximum of reproductive activity in autumn (maximum values of Gonadal Index). This finding coincides with some already published study for other deep-sea Mediterranean Echinoderm species such as B. lyrifera. The in situ faunal sampling with video technologies (i.e. Remotely Operated Vehicles; ROVs) showed the occurrence of different species assemblage compositions in different geomorphological habitats such as, submarine canyons, sea hills and landslides. Benthic cnidarian communities were observed in seamount rocky areas while submarine landslides fauna were mainly composed by vagil fauna as fishes and crustaceans. The description of characteristics seascape units might help to estimate taxonomical group in other similar but presently unexplored deep-sea areas. Finally, this study suggests that an increasing effort combining traditional and technologically-new sampling methods is advisable in order to obtain a more complete overview of species inhabiting the different deep-sea continental margins.
En el estudio de la presente tesis se pretende realizar una exhaustiva clasificación taxonómica de las especies de invertebrados no-crustáceos muestreados en el margen catalán profundo, así como determinar sus patrones de distribución y su composición faunística. El material utilizado fue recopilado a lo largo de 10 campañas oceanográficas realizadas entre octubre 2008 y abril 2013 en el Mediterráneo occidental en el marco de los Proyecto Nacionales y Europeos PROMETEO, DOSMARES, BIOFUN, PROMARES y EUROLEON. Las áreas de muestreo incluyeron el Cañón de Blanes y su talud adyacente, los cañones de la Fonera y Cap de Creus, dos montañas submarinas ubicadas en el Golfo de Valencia y el Canal de Ibiza, y dos deslizamientos submarinos del Canal de Ibiza. Adicionalmente se realizó una campaña transmediterránea en la cual se muestrearon tres áreas del Mediterráneo, oeste, central y este. Se utilizaron para la recolección de muestras tanto métodos de muestreos tradicionales (artes de arrastre) como nuevas tecnologías de muestreo visual (ROV). Las profundidades muestreadas mediante ROV fueron de entre los 60 m y los 1100 m de profundidad; y entre los 850 m y los 2850 m mediante muestreos tradicionales. Se obtuvieron 5877 individuos distribuidos en 8 Filos, 18 Clases y 69 especies. En la presente Tesis se describe por primera vez en el Mediterráneo la presencia de dos especies: el equinoideo regular Gracilechinus elegans (Düben & Koren, 1844) y la ascidia carnívora Dicopia antirrhinum C. Monniot, 1972. Igualmente se describió la presencia de tres especies consideradas ‘raras’: las holoturias endémicas Hedingia mediterranea (Bartolini Baldelli, 1914) y Penilpidia ludwigi (von Marenzeller, 1893) así como el sipúnculido Phascolosoma (Phascolosoma) turnerae Rice, 1985. Asimismo se amplió el rango de distribución batimétrica de 11 especies. Los datos se analizaron además de a nivel puramente taxonómico, a nivel poblacional, revelando mayores densidades (individuos • km -2) y biomasas (kg • km -2) en zonas de cañones submarinos. También se observó que a nivel faunístico el grupo más abundante fueron los equinodermos, representando el 57% del total de especímenes recolectados. Si pasamos a considerar los datos obtenido mediante imágenes de ROV, se recopilaron un total de 4520 observaciones faunísticas de los tres hábitats geomorfológicos descritos (un cañón, dos montes y dos deslizamientos submarinos) y entre los cuales se describieron similitudes en cuanto a comunidades faunísticas en función de parámetros tales como la profundidad, geomorfología y tipo de substrato.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
Crustacea is mentioned as a dominant group in almost all continental shelf environments around the Brazilian coast and the taxonomic group with more studies. However, the carcinofauna of some Brazilian shelfs are poorly known, such as Sergipe state. The aim of this study is contribute for the knowledge of Crustacea, components of benthic megafauna from continental shelf of Sergipe and understand how populations communities vary spatially and temporally. The crustaceans were collected with otter trawl in two different seasonal periods, 18 stations between 36°32'W 10°36'S e 37°05’W 11°21’S distributed in 6 transects and in 10, 20 and 30 m isobaths, for a total of 72 stations sampled, between the years 1999 and 2000. Environmental parameters from water and sediment were collect in each station. In laboratory, the organisms were identified to species level and analyzed in terms of richness, abundance and biomass, and the community in terms of diversity indices, equitativity, frequency of occurrence and relative importance indices. The Crustacea was represented by 62749 individuals, distributed in 71 taxa, 199.97 kg of biomass and 77.81km² of density. The collected organisms are representatives of 2 orders, 4 infraorders, 25 families, 46 genus and 64 species. Brachyura presented the greatest number of taxa with 39, followed by Caridea with 12, Dendrobranchiata with 9, Anomura with 7, Stomatopoda with 2 and Achelata with 1. The community was abundant and displayed considerable richness; however, diversity and equitability were low, showing the dominance of the species X. kroyeri, N. schmitti, L. schmitti, F. schmitti and C. ornatus. The fauna varied in space and time and the main abiotic parameters that explain these variations were depth, temperature and the bottom type, especially coarser sediments with high levels of sand and gravel. Six species of Crustacea were recorded for the first time from Sergipe continental shelf, 3 Brachyura (Allactaea lithostrota, Coryrhynchus riisei e Ericerodes minusculus), 2 Caridea (Alpheus armillatus, A. cf. packardii e A. intrisecus) e 1 Stomatopoda (Squilla brasiliensis).
Os crustáceos são citados como grupo dominante em quase todos os ambientes de plataforma ao longo do litoral brasileiro, sendo também o grupo com maior volume de trabalhos realizados. No entanto, algumas plataformas brasileiras ainda têm sua carcinofauna precariamente desconhecida, como é o caso de Sergipe. Nesse sentido, esse trabalho visa contribuir para o conhecimento dos Crustacea, componentes da megafauna bêntica, da plataforma continental de Sergipe, bem como entender como as populações que compõe essa comunidade se distribuem espacial e temporalmente ao longo da plataforma. Os crustáceos foram coletados a partir de arrastos duplos com rede de arrasto pesqueiro em quatro campanhas amostrais entre 1999 e 2000, em 18 estações entre 36°32'W 10°36'S e 37°05’W 11°21’S distribuídas em seis transectos, nas isóbatas de 10, 20 e 30 m, totalizando 72 estações amostradas. Também foram coletados os parâmetros ambientais da água e do sedimento para cada estação. Os organismos foram identificados até o nível de espécie, utilizando literatura taxonômica específica, e analisados em termos de riqueza, abundância e biomassa e, a comunidade foi analisada a partir dos índices de diversidade, equitatividade, frequência de ocorrência e índice de importância relativa. A fauna de Crustacea esteve representada por 62749 indivíduos distribuídos em 71 táxons que somaram 199.97 kg de biomassa úmida e uma densidade de 77.81 ind./km². Os organismos coletados são representantes de 2 ordens, 4 infraordens, 25 famílias, 46 gêneros e 64 espécies. Dos grupos principais de Crustacea, Brachyura apresentou maior número de táxons com 39, seguido de Caridea com 12, Dendrobranchiata com 9, Anomura com 7, Stomatopoda com 2 e Achelata com 1. A comunidade estudada foi abundante e com uma riqueza considerável, mas a diversidade e equitatividade da fauna foram baixas, evidenciando a dominância das espécies X. kroyeri, N. schmitti, L. schmitti, F. schmitti e C. ornatus para a fauna de Crustacea da plataforma continental. A fauna variou em função do tempo e do espaço e os principais parâmetros abióticos que explicaram essas variações foram a profundidade, a temperatura e o tipo de fundo, principalmente os sedimentos mais grossos com altos teores de areia e cascalho. Dentre os Crustacea identificados, foram registrados pela primeira vez para a plataforma continental de Sergipe seis espécies, sendo 3 Brachyura (Allactaea lithostrota, Coryrhynchus riisei e Ericerodes minusculus), 2 Caridea (A. cf. packardii e A. intrisecus) e 1 Stomatopoda (Squilla brasiliensis).

Polar deep water environments are poorly studied. This thesis investigates fundamental questions as to the nature of controlling factors on megabenthic communities as well as the diversity, densities and distributions of organisms present. The deep (1000-1660m) Faroe-Shetland Channel harbours an Arctic fauna owing to cold deepwater intrusions from the Norwegian Sea. Despite the relatively low species richness of the megabenthos, variation in faunal composition with depth is apparent. Two distinct communities were identified in the north and south of the channel. Epibenthic megafauna in the south are dominantly filter feeders and in the north deposit feeders. Megabenthic diversity and density decreased to the northeast of the channel. Lebensspuren number and area increase northwards in the Channel. The increase in bioturbation and deposit feeder abundance is concurrent with an increase in fine sediment quantity. The response of a deep, Arctic benthic community to physical disturbance was investigated in the Faroe-Shetland Channel. High levels of physical disturbance, characterised by smothering of the seabed resulted in significant but variable reductions in megafaunal abundance (up to 92.3%). Reductions in diversity, particularly in species richness, were apparent between disturbed (ES(500) = 12.9) and undisturbed areas (ES(500) = 20.6). The implications of selective removal of taxa on ecosystem function and recovery are discussed. Low level disturbance had comparatively little effect on the communities. The effects varied in nature depending on motility and functional group (e.g. motile scavenger abundances were maximal at intermediate distances from disturbance). Effects of physical factors on the megabenthos of Kangerdlugssuaq Fjord mouth in Arctic Greenland were investigated. Large reductions in faunal density (1881 to 60,132 individuals ha-1) and increases in diversity (H´ = 0.93-2.54), through increases in richness (ES(220) = 7.6-18.8) and reductions in dominance (Berger-Parker Index = 0.77-0.38), were found from 270 to 720m depth. Distinct shallow, intermediate and deep communities were identified. Shallower stations had high levels of iceberg disturbance, directly reducing diversity and creating a complex, patchy environment. Responses to disturbance were taxa specific (e.g. mobile suspension feeders aggregate on disturbed areas), but the shallow area has higher densities of suspension feeding epifauna. Deeper areas experience small scale disturbance from deposition of drop stones but its relatively low frequency and magnitude allows increased diversity. Deposit feeding epifaunal and infaunal taxa increase with depth indicated by increased Lebensspuren. Density decreases result from decreased food supply with depth. Benthic megafauna were investigated from the NE Weddell Sea (250 to 500m depth), close to the Fimbul Ice Shelf. Faunal density decreased with depth; diversity was variable but not related to depth. Two distinct communities were found, a shallow community with dense patches of suspension feeders in undisturbed areas and a deep community where these were not present. Disturbance from icebergs was very important in controlling faunal distribution. In shallow waters direct effects of disturbance were observed. In deeper waters habitat changes, caused by past disturbance, controlled faunal distributions. Ice ploughing created a mosaic landscape of fine and coarse sediments. Megafaunal density was highest in coarse sediment and diversity highest in intermediate areas. Quantitative data on benthic megafaunal abundance and diversity obtained using the same method allowed valid comparisons to be made between these polar areas. Megafaunal abundance was comparable between the Arctic and Antarctic stations, although in both areas abundance decreased with increased depth. Diversity was higher in the Antarctic stations, but species richness and evenness in both areas changed with depth. Iceberg disturbance was found to be very important in structuring megabenthic communities, particularly in the Antarctic. The results of this study are used to assess the utility of towed camera sleds, remotely operated vehicles and autonomous underwater vehicles as a method for obtaining ecological information in remote environments.

<strong><em>Abstract. </em></strong>Seafloor habitats of the Canadian part of Georges Bank were assessed and mapped following the habitat template theory (Southwood 1988). The approach considers the primary selective forces (habitat disturbance and adversity of the environment) that have shaped the existing communities of benthic species and that have defined the life history traits of species found in different habitats. The disturbance axis of the template is modeled based on the information on sediment, currents, and bathymetry. The adversity axis is modeled based on chlorophyll concentration, bottom water temperature, salinity, and seasonal variability in temperature. A preliminary sediment map needed for assessment of the natural disturbance rate was developed from high-resolution multibeam backscatter groundtruthed with archive and current sediment sample data. The distribution of megabenthos assemblages identified from underwater photography was found to follow gradients in disturbance and adversity on the bank. We suggest that application of the habitat template theory is useful for ocean managers in defining areas that are more or less likely to suffer from adverse human impacts. If natural rates of habitat disturbance are high, then risk of harmful habitat alteration and degradation is lower than in naturally stable areas. Similarly, if the natural adversity of the environment is high, then adding additional stressors will further reduce the scope for growth of organisms, which makes natural populations in adverse environments less likely to recover than populations in benign environments.