Generalist dinoflagellate endosymbionts and host genotype diversity detected from mesophotic (67-100 m depths) coral Leptoseris

<p>Abstract</p> <p>Background</p> <p>Mesophotic corals (light-dependent corals in the deepest half of the photic zone at depths of 30 - 150 m) provide a unique opportunity to study the limits of the interactions between corals and endosymbiotic dinoflagellates in the genus <it>Symbiodinium</it>. We sampled <it>Leptoseris </it>spp. in Hawaii via manned submersibles across a depth range of 67 - 100 m. Both the host and <it>Symbiodinium </it>communities were genotyped, using a non-coding region of the mitochondrial ND5 intron (NAD5) and the nuclear ribosomal internal transcribed spacer region 2 (ITS2), respectively.</p> <p>Results</p> <p>Coral colonies harbored endosymbiotic communities dominated by previously identified shallow water <it>Symbiodinium </it>ITS2 types (C1_ AF333515, C1c_ AY239364, C27_ AY239379, and C1b_ AY239363) and exhibited genetic variability at mitochondrial NAD5.</p> <p>Conclusion</p> <p>This is one of the first studies to examine genetic diversity in corals and their endosymbiotic dinoflagellates sampled at the limits of the depth and light gradients for hermatypic corals. The results reveal that these corals associate with generalist endosymbiont types commonly found in shallow water corals and implies that the composition of the <it>Symbiodinium </it>community (based on ITS2) alone is not responsible for the dominance and broad depth distribution of <it>Leptoseris </it>spp. The level of genetic diversity detected in the coral NAD5 suggests that there is undescribed taxonomic diversity in the genus <it>Leptoseris </it>from Hawaii.</p

Distribution Modeling of Mesophotic Corals and Algae to Further Ecological Understanding and Resource Management of Hawaiian Coral Reefs.

Ph.D. Thesis. University of Hawaiʻi at Mānoa 2018

Polyphyly and hidden species among Hawaiʻi’s dominant mesophotic coral genera, Leptoseris and Pavona (Scleractinia: Agariciidae)

Widespread polyphyly in stony corals (order Scleractinia) has prompted efforts to revise their systematics through approaches that integrate molecular and micromorphological evidence. To date, these approaches have not been comprehensively applied to the dominant genera in mesophotic coral ecosystems (MCEs) because several species in these genera occur primarily at depths that are poorly explored and from which sample collections are limited. This study is the first integrated morphological and molecular systematic analysis of the genera Leptoseris and Pavona to examine material both from shallow-water reefs (<30 m) and from mid- to lower-MCEs (>60 m). Skeletal and tissue samples were collected throughout the Hawaiian Archipelago between 2–127 m. A novel mitochondrial marker (cox1-1-rRNA intron) was sequenced for 70 colonies, and the micromorphologies of 94 skeletons, plus selected type material, were analyzed. The cox1-1-rRNA intron resolved 8 clades, yet Leptoseris and Pavona were polyphyletic. Skeletal micromorphology, especially costal ornamentation, showed strong correspondence and discrete differences between mitochondrial groups. One putative new Leptoseris species was identified and the global depth range of the genus Pavona was extended to 89 m, suggesting that the diversity of mesophotic scleractinians has been underestimated. Examination of species’ depth distributions revealed a pattern of depth zonation: Species common in shallow-water were absent or rare >40 m, whereas others occurred only >60 m. These patterns emphasize the importance of integrated systematic analyses and more comprehensive sampling by depth in assessing the connectivity and diversity of MCEs

Stratigraphic distributions of genera and species of Neogene to Recent Caribbean reef corals

To document evolutionary patterns in late Cenozoic Caribbean reef corals, we compiled composite stratigraphic ranges of 49 genera and 175 species using Neogene occurrences in the Cibao Valley sequence of the northern Dominican Republic and faunal lists for 24 Miocene to Recent sites across the Caribbean region. This new compilation benefits in particular from increased sampling at late Miocene to early Pleistocene sites and from increased resolution and greater taxonomic consistency provided by the use of morphometric procedures in species recognition. Preliminary examination and quantitative analysis of origination and extinction patterns suggest that a major episode of turnover took place between 4 and 1 Ma during Plio-Pleistocene time. During the episode, extinctions were approximately simultaneous in species of all reef-building families, except the Mussidae. Most strongly affected were the Pocilloporidae (Stylophora and Pocillopora), Agariciidae (Pavona and Gardineroseris), and free-living members of the Faviidae and Meandrinidae. At the genus level, mono- and paucispecific as well as more speciose genera became regionally extinct. Many of the extinct genera live today in the Indo-Pacific region, and some are important components of modern eastern Pacific reefs. Global extinctions were concentrated in free-living genera. During the turnover episode, no new genera or higher taxa arose. Instead, new species originated within the surviving Caribbean genera at approximately the same time as the extinctions, including many dominant modern Caribbean reef-building corals (e.g., Acropora palmata and the Montastraea annularis complex). Excluding this episode, the taxonomic composition of the Caribbean reef-coral fauna remained relatively unchanged during the Neogene. Minor exceptions include: 1) high originations in the Agariciidae and free-living corals during late Miocene time; and 2) regional or global extinctions of several important Oligocene Caribbean reef builders during early to middle Miocene tim

Global Phylogenomic Assessment of \u3ci\u3eLeptoseris\u3c/i\u3e and \u3ci\u3eAgaricia\u3c/i\u3e Reveals Substantial Undescibed Diversity at Mesophotic Depths

Background: Mesophotic coral communities are increasingly gaining attention for the unique biological diversity they host, exemplified by the numerous mesophotic fish species that continue to be discovered. In contrast, many of the photosynthetic scleractinian corals observed at mesophotic depths are assumed to be depth-generalists, with very few species characterised as mesophotic-specialists. This presumed lack of a specialised community remains largely untested, as phylogenetic studies on corals have rarely included mesophotic samples and have long suffered from resolution issues associated with traditional sequence markers. Results: Here, we used reduced-representation genome sequencing to conduct a phylogenomic assessment of the two dominant mesophotic genera of plating corals in the Indo-Pacific and Western Atlantic, respectively, Leptoseris and Agaricia. While these genome-wide phylogenies broadly corroborated the morphological taxonomy, they also exposed deep divergences within the two genera and undescribed diversity across the current taxonomic species. Five of the eight focal species consisted of at least two sympatric and genetically distinct lineages, which were consistently detected across different methods. Conclusions: The repeated observation of genetically divergent lineages associated with mesophotic depths highlights that there may be many more mesophotic-specialist coral species than currently acknowledged and that an urgent assessment of this largely unstudied biological diversity is warranted

Komposisi Jenis Karang Keras (Scleractinia) di Perairan Pantai Utara Pulau Ambon

Terumbu karang merupakan ekosistem pesisir yang secara ekologi paling produktif dengan keanekaragaman tinggi. Penelitian ini bertujuan untuk mengetahui komposisi jenis karang keras (Scleractinia) di perairan pantai utara Pulau Ambon. Pengambilan data dilakukan dengan menggunakan metode sistematik sampling. Data karang yang diperoleh kemudian diidentifikasi, proses identifikasi dilakukan dengan teknik analisa visual menggunakan beberapa referensi Veron (2000), Veron (1986), Suharsono (2017), Coral Finder edisi ketiga, dan Website Corals of The World (http://www.coralsoftheworld.org) untuk melihat jenis-jenis apa saja yang ada pada lokasi penelitian. Hasil penelitian menunjukkan bahwa berdasarkan komposisi taksa jumlah genus terbanyak dari famili Fungidae, jumlah spesies terbanyak dari genus Porites dan jumlah koloni terbanyak dari spesies Porites lutea

Status survey of scleractinian corals at Long Island and adjoining areas of Middle Andaman Archipelago

1556-1566Long Island and its adjoining islands of Middle Andaman archipelago are mostly covered by mangrove habitat while the eastern coastal parts of the islands are with scattered fringing reef in the continental shelf region. A total of 253 species of scleractinian corals were recorded from four islands such as Long, Guitar, Round and North Passage with the average species diversity of 3.18 and live cover of 25.28 %. Globally recorded threatened 42 species of scleractinians were recorded from these study areas. The regional occurrence of the species revealed that 32.41 % scleractinian were common and 24.90 % corals were rare. Long Island harbors 29.42 % of scleractinian coral species of Andaman and Nicobar Islands with optimum diversity (H'=4.35) especially in the eastern and south-eastern coast. The present paper focused on the status survey of scleractinian corals from these areas to monitor the health status in Middle Andaman region of Andaman and Nicobar Islands

KEANEKARAGAMAN DAN PENUTUPAN TERUMBU KARANG DI PANTAI PASIR PUTIH SITUBONDO, JAWA TIMUR

Perairan Pantai Pasir Putih Situbondo masuk dalam kawasan pencadangan Taman Wisata Pasir Putih Kabupaten Situbondo berdasarkan PERBUB Situbondo No. 12 Tahun 2012. Sebagai tempat wisata air, terumbu karang merupakan salah satu aset penting dalam menarik wisatawan. Penting untuk mengetahui seberapa besar tutupan terumbu karang di daerah tersebut. Ada tiga tujuan dilakukannya penelitian di daerah tersebut yaitu, mengetahui persentase tutupan terumbu karang, mengetahui dominasi karang di perairan Pasir Putih Situbondo, dan mengetahui kondisi lingkungan di perairan tersebut. Penelitian dilakukan pada bulan Febuari 2016 pada 3 stasiun yang memiliki kondisi lingkungan berbeda. Stasiun pertama adalah Watu Lawang, stasiun kedua adalah Teluk Pelita dan Karang Mayit, stasiun ketiga adalah Karang Ponpon. Metode yang digunakan adalah UPT (Underwater Photo Transect). UPT merupakan metode yang memanfaatkan perkembangan teknologi kamera maupun komputer. Metode UPT dilakukan dengan mendokumentasikan terumbu karang di dalam frame sepanjang garis transect. Hasil dokumentasi dianalisis menggunakan program CPCe. Persentase tutupan terumbu karang pada daerah Watu Lawang sebesar 32,48%. Tutupan terumbu karang pada daerah Teluk Pelita dan Karang Mayit sebesar 23,30%. Tutupan terumbu karang pada daerah Karang Ponpon sebesar 27,47%. Tutupan terumbu karang di daerah Watu Lawang dan Karang Ponpon masuk dalam kategori sedang, sedangkan Teluk Pelita dan Karang Mayit tergolong buruk. Genus karang yang mendominasi di daerah Watu Lawang adalah Acropora, pada Teluk Pelita dan Karang Mayit adalah Leptoseris, Acropora dan Porites. Pada Karang ponpon adalah Porites dan Acropora. Kondisi substrat tiap stasiun bervariasi yaitu berpasir, berlumpur dan rubble. Sebagai kawasan pencadangan taman wisata air, banyak faktor yang dapat merusak terumbu karang. Faktor penyebab kerusakan terumbu karang antara lain faktor alam, sedimentasi dan sampah

Levels of autotrophy and heterotrophy in mesophotic corals near the end photic zone

Mesophotic corals live at ~30-150 m depth and can sustain metabolic processes under light-limited conditions by enhancing autotrophy through specialized photoadaptations or increasing heterotrophic nutrient acquisition. These acclimatory processes are often species-specific, however mesophotic ecosystems are largely unexplored and acclimation limits for most species are unknown. This study examined mesophotic coral ecosystems using a remotely operated vehicle (Ashmore Reef, Western Australia at 40 – 75m depth) to investigate the trophic ecology of five species of scleractinian coral (from genera Leptoseris, Pachyseris, and Craterastrea) using stable isotope analyses (δ13C and δ15N) of host and symbiont tissues and protein concentration. Trophic strategies were analyzed between species and between overall corals sampled above and below the end-photic point, where light is only 1% of surface irradiance. Results showed species-specific differences in resource use. Leptoseris hawaiiensis, L. scabra, and P. speciosa had similar Δ13C values (δ13C host - δ13C symbiont) approaching zero ( \u3c 0.5 ‰) which indicated greater dependence on symbiont autotrophy. In contrast, Leptoseris glabra and Craterastrea levis had higher Δ13C values (1.4 to 3.5 ‰) which indicated a greater reliance on external carbon sources. The latter two species also demonstrated tight nitrogen recycling within the holobiont, exhibiting low Δ15N values (host δ15N - symbiont δ15N = \u3c 0.5 ‰), compared to more autotrophic species (Δ15N = \u3e 1.2 ‰). Some species demonstrated the ability to maintain metabolic processes despite substantially reduced light availability (0.5 – 2% of surface irradiance). This research challenges our knowledge of acclimation limits for many scleractinian corals and contributes novel information for Ashmore Reef, the Western Australia region and mesophotic ecosystems in general, and critically examines common methods used to interpretate trophic ecology with bulk stable isotopes δ13C and δ15N

Topography, substratum and benthic macrofaunal relationships on a tropical mesophotic shelf margin, central Great Barrier Reef, Australia

Habitats and ecological communities occurring in the mesophotic region of the central Great Barrier Reef (GBR), Australia, were investigated using autonomous underwater vehicle (AUV) from 51 to 145 m. High-resolution multibeam bathymetry of the outer-shelf at Hydrographers Passage in the central GBR revealed submerged linear reefs with tops at 50, 55, 80, 90, 100 and 130 m separated by flat, sandy inter-reefal areas punctuated by limestone pinnacles. Cluster analysis of AUV images yielded five distinct site groups based on their benthic macrofauna, with rugosity and the presence of limestone reef identified as the most significant abiotic factors explaining the distribution of macrofaunal communities. Reef-associated macrofaunal communities occurred in three distinct depth zones: (1) a shallow (75 m). The effects of depth and microhabitat topography on irradiance most likely play a critical role in controlling vertical zonation on reef substrates. The lower depth limits of zooxanthellate corals are significantly shallower than that observed in many other mesophotic coral ecosystems. This may be a result of resuspension of sediments from the sand sheets by strong currents and/or a consequence of cold water upwelling