Ari Atoll Research Articles

The occurrence of an Acanthaster planci outbreak in Ari Atoll, Maldives

The corallivorous crown-of-thorns starfish Acanthaster planci (COTS) is recognized as a major cause of coral reef degradation throughout much of the Indo-Pacific region (Fabricius 2013). In this study, we report a localised outbreak of COTS at Mama Ghiri, Ari Atoll, Republic of Maldives in June 2014 (3°44′40′′ N; 72°49′13′′ E) (Fig. 1a-c). Belt transects (approximately 9×100 m) were used to record COTS density in the shallows (0–5m depth). An average density of 120±51 COTS per transect (mean ± SD; n=6), with a maximum of 222, was recorded around Mama Ghiri. Moreover, coral mortality of approximately 70 % including complete or partial death of nearly 100 % of tabular Acropora (mainly belonging to the species A. cytherea, A. clathrata, and A. hyacinthus), was estimated (Fig. 1c). These data are comparable with those of COTS outbreaks recently reported in other Indo-Pacific regions (Baird et al. 2013). Although A. planci outbreaks were previously observed in the Maldives (Ciarapica and Passeri 1993), this event was more intense in terms of COTS density. As in many other parts of the world, Maldivian reefs are subjected to increasing pressure from natural and direct anthropogenic disturbances (Jaleel 2013). Considering that A. planci outbreaks may represent a significant threat to coral reef health and biodiversity, we stress the urgent need to explore other Maldivian reefs to document the extent of this phenomenon and its effect on corals and their associated fauna.

Whale shark economics: a valuation of wildlife tourism in South Ari Atoll, Maldives.

Whale sharks attract large numbers of tourists, divers and snorkelers each year to South Ari Atoll in the Republic of Maldives. Yet without information regarding the use and economic extent of the attraction, it is difficult to prioritize conservation or implement effective management plans. We used empirical recreational data and generalized mixed statistical models to conduct the first economic valuation (with direct spend as the primary proxy) of whale shark tourism in Maldives. We estimated that direct expenditures for whale shark focused tourism in the South Ari Marine Protected Area for 2012 and 2013 accounted for US$7.6 and $9.4 million respectively. These expenditures are based on an estimate of 72,000–78,000 tourists who are involved in whale shark excursions annually. That substantial amount of income to resort owners and operators, and tourism businesses in a relatively small area highlights the need to implement regulations and management that safeguard the sustainability of the industry through ensuring guest satisfaction and whale shark conservation.

Modern foraminiferal distribution and diversity in two atolls from the Maldives, Indian Ocean

Abstract Foraminifera from the coral-reef lagoons of two atolls are used to investigate the distribution and diversity of assemblages in the central Indian Ocean. Eight assemblages and 270 species of foraminifera are identified. Three assemblages are reefal and dominated by Amphistegina and Calcarina. Only one lagoon assemblage is present in both atolls, which is characterized by abundant Ammonia sp. 1 and smaller miliolid foraminifera. In Ari Atoll, abundant Amphistegina sp. 1, Operculina ammonoides, Amphistegina radiata and Nummulites venosa characterize one lagoon assemblage and abundant Neoeponides bradyi and Textularia cf. T. cushmani characterize the other. In Rasdhoo Atoll, abundant Textularia gr. foliacea and Spiroloculina nummiformis characterize one lagoon assemblage and abundant Textularia cf. T. cushmani and Textularia sp. 5 characterize the other. The assemblages compare well with sedimentological characteristics, which is also reflected in their distributions. Species diversity in the Maldives appears to be higher than the western Indian Ocean region due to the stronger influence of central Indo-Pacific faunas. It is not however, as high as the central Indo-Pacific region, which may be due to lower habitat diversity.

Analysis of whale shark Rhincodon typus aggregations near South Ari Atoll, Maldives Archipelago

AB Aquatic Biology Contact the journal Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AB 8:145-150 (2010) - DOI: https://doi.org/10.3354/ab00215 Analysis of whale shark Rhincodon typus aggregations near South Ari Atoll, Maldives Archipelago Morgan J. Riley*, Michelle S. Hale, Adam Harman, Richard G. Rees School of Earth & Environmental Sciences, University of Portsmouth, Burnaby Road, Portsmouth, PO1 3QL, UK *Email: morgan@whalesharkresearch.co.uk ABSTRACT: We made surveys for whale sharks Rhincodon typus on a total of 99 d from April through June each year from 2006 to 2008 along the southern fringe of the South Ari Atoll, Maldives Archipelago. We recorded the length and sex of each shark observed and made photographs to facilitate repeated identification from their spot patterns using pattern-recognition software. We identified 64 whale sharks from digital photographs taken during 220 sightings over 3 yr. Approx. 87% of those sharks were immature males. The average length of recognisable sharks was 5.98 m (range 2.5 to 10.5 m), significantly shorter than that reported for whale sharks in other aggregations in the Indian Ocean. Our findings suggest that these sharks are either a small proportion of a local population or perhaps an even smaller component of a regional population in the western Indian Ocean. We applied a Lincoln-Petersen closed-population mark-recapture model and a Jolly-Seber open-population model to estimate population size, but found that neither model provided reliable results because key assumptions of each were not met. KEY WORDS: Whale shark · Rhincodon typus · Maldives Archipelago · Mark-recapture · Photo-identification Full text in pdf format PreviousNextCite this article as: Riley MJ, Hale MS, Harman A, Rees RG (2010) Analysis of whale shark Rhincodon typus aggregations near South Ari Atoll, Maldives Archipelago. Aquat Biol 8:145-150. https://doi.org/10.3354/ab00215 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AB Vol. 8, No. 2. Online publication date: January 20, 2010 Print ISSN: 1864-7782; Online ISSN: 1864-7790 Copyright © 2010 Inter-Research.

Sedimentation on Rasdhoo and Ari Atolls, Maldives, Indian Ocean

A first systematic study of composition, texture, and distribution of modern sediments in two Maldivian atolls reveals the predominance of skeletal carbonates. Fragments of corals, calcareous algae, mollusks, benthic foraminifera, and echinoderms are identified in the grain-size fraction >125 μm. Non-skeletal grains such as cemented fecal pellets and aggregate grains only occur in small percentages. Fragments of skeletal grains, aragonite needles, and nanograins (<1 μm) are found in the grain-size fraction <125 μm. Needles and nanograins are interpreted to be largely of skeletal origin. Five sedimentary facies are distinguished (1–5), for which the Dunham-classification is applied. Fore reef, reef, back reef, as well as lagoonal patch reef and faro areas in both atolls are characterized by the occurrence of coral grainstones (1), which also contain fragments of red coralline algae, the codiacean alga Halimeda, and mollusks. On reef islands, coral-rich sediment is cemented to form intertidal beachrock and supratidal cayrock. Skeletal grains in atoll-interior lagoons are mainly mollusks and foraminifera. The lagoon of Rasdhoo Atoll is covered in the west by mudstones (2), in the center by mollusk packstones (3) and mollusk wackestones (4), and by hard bottoms with corals in the east adjacent to channels through the atoll reef margin. The interior lagoon of Ari Atoll contains mollusk wackestones (4) in the center and mollusk-foraminifer packstones (5). Marginal lagoon areas are characterized by hard bottoms with corals. Facies distribution appears to be an expression of depositional energy, which decreases from the atoll margin towards the center in Ari Atoll, and towards the west in Rasdhoo Atoll. Predominant sediment mineralogies include aragonite and high-magnesium calcite. Mean aragonite content decreases from 90% in coral grainstone to 70–80% in mollusk packstone, mollusk wackestone, and mudstone, and to 50% in mollusk-foraminifer packstone. Stable isotopes of oxygen and carbon in bulk samples range from −3 to −1.5 (δ18O) and from +0.4 to +3.2 (δ13C). It is not possible to delineate facies based on O- and C-isotopes.

Human Orc2 localizes to centrosomes, centromeres and heterochromatin during chromosome inheritance

Corrigendum17 February 2005free access Human Orc2 localizes to centrosomes, centromeres and heterochromatin during chromosome inheritance Supriya G Prasanth Supriya G Prasanth Search for more papers by this author Kannanganattu V Prasanth Kannanganattu V Prasanth Search for more papers by this author Khalid Siddiqui Khalid Siddiqui Search for more papers by this author David L Spector David L Spector Search for more papers by this author Bruce Stillman Bruce Stillman Search for more papers by this author Supriya G Prasanth Supriya G Prasanth Search for more papers by this author Kannanganattu V Prasanth Kannanganattu V Prasanth Search for more papers by this author Khalid Siddiqui Khalid Siddiqui Search for more papers by this author David L Spector David L Spector Search for more papers by this author Bruce Stillman Bruce Stillman Search for more papers by this author Author Information Supriya G Prasanth, Kannanganattu V Prasanth, Khalid Siddiqui, David L Spector and Bruce Stillman The EMBO Journal (2005)24:1092-1093https://doi.org/10.1038/sj.emboj.7600624 This article corrects the following: Cullin-based ubiquitin ligases: Cul3–BTB complexes join the family08 April 2004 PDFDownload PDF of article text and main figures. ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InMendeleyWechatReddit Figures & Info Correction to: The EMBO Journal (2004) 23, 1681–1687. doi:10.1038/sj.emboj.7600186 Due to an author error, the X-axis in Figure 3D was mislabelled as INA instead of DNA. The correct figure is reproduced below. Figure 1.Orc2 depletion has dual execution points. (A) Immunoblot of whole-cell extract from cells transfected with Orc2 siRNA duplex or control luciferase siRNA and harvested at different time points. Cells were transfected at 0, 24 and 48 h at about 20% starting confluence. Efficacy of RNAi was assessed by immunoblotting to detect Orc2. a-Tubulin levels were used as loading controls. Orc3 levels were also modulated and, with the reappearance of Orc2 in the cells at 144 h, the levels of Orc3 also increased. (B) Orc2 depletion at 72 h post siRNA shows morphologically two distinct populations of cells: the flat adherent cells and the rounded mitotic cells. (C) DNA content of control and Orc2 siRNA-treated cells at 48 h was determined by flow cytometry. Note a broader S phase and an increase in G2/M in Orc2 siRNA-treated cells. (D) Two-dimensional FACS to assess BrdU incorporation (10 min pulse) and DNA content by propidium iodide (PI) was assessed by flow cytometry in control and Orc2-depleted cells at 72 h. Note an increase in G2/M and accumulation of cells in S phase without incorporation of BrdU (see arrow) in Orc2-depleted cells. (E) Histogram showing the percentage of cells incorporating BrdU during a 24 h label at different time points after transfection, with Orc2 (gray bars) or luciferase control (white bars) siRNA duplexes. BrdU incorporation was allowed for 24 h to ensure that all cells had a chance to pass through at least one S phase. Download figure Download PowerPoint The authors apologize for this error. Previous ArticleNext Article Read MoreAbout the coverClose modalView large imageVolume 24,Issue 5,March 9, 2005Crinoids - also called Feather Stars, appear as a dense mass of arms hidden in the smallest crevices, holes or other hiding places of tropical reefs during daytime. The picture was captured at Ellaidhoo, a small Maldive island of the Ari atoll (Indo-Pacific Ocean) with a Nikonos RS/50mm macro lens on Kodak Elitechrome 100 ASA colour slide film. The photographer, Wolfgang Seifarth, is a molecular biologist at the University of Heidelberg, Germany, where he studies the importance of endogenous retroviral elements (HERV) in the human genome. Wolfgang Seifarth also has a strong interest in marine biology field research and taxonomy, and underwater photography. His image of the crinoids was selected as the winner of the EMBO Journal Cover Contest 2005. Volume 24Issue 59 March 2005In this issue FiguresRelatedDetailsLoading ...

Tethya (Porifera, Demosponglae) Species Coexisting in a Maldivian Coral Reef Lagoon: Taxonomical, Genetic and Ecological Data

Abstract. Tethya microstella, T. orphei, T. robusta, and T. seychellensis live in sympatry in a Maldivian coral reef lagoon (Gangehi Island, Ari Atoll). A morphological, morphometric, and electrophoretical study of these species show that their Maldivian populations are well separated morphologically and genetically. The genetic distances and the other data are more consistent with an immigration than with a local speciation hypothesis. Their coexistence may be explained by a differentiation in ecological requirements. The four species inhabit the shallow water biotope of the lagoon among the rubble of dead corals. Our data show that T. orphei and T. seychellensis occupy the upper rubble layer, T. microstella and T. robusta the lower one. This distinction agrees with the different morpho‐functional features of the two pairs of species.