Reef Boulders Research Articles

Paleo-Typhoon Events as Indicated by Coral Reef Boulder Deposits on the Southern Coast of Hainan Island, China

The southern coast of Hainan Island, China, is one of the most frequently hit areas of tropical cyclones in the Northwest Pacific regions. Although some of the extreme typhoon events were known in historical times, quantitative information on the timing and magnitude of paleo-typhoon events in this coastal area remains rare. In the present study, a large number of coral reef boulders were found on the Xiaodonghai reef platform, on the south coast of Hainan Island. Morphometric analysis of the boulders shows an exponentially fining landward trend, indicating a storm origin; a wave-induced current velocity of 2.41–5.71 m/s during the storm events is required to transport the boulders that were originally situated outside the reef edge. Based on the U/Th and 14C dating for the age-indicating samples taken from the boulders, seven major periods with intense typhoon activities were identified for the last 4,000 years, i.e., 1800–1500 BCE, 1200–900 BCE, 50–120 CE, 550–800 CE, 900–1000 CE, 1350–1900 CE, and 1910–2000 CE. A comparison with the regional typhoon records in terms of climatic parameters in the northwestern Pacific and the South China Sea regions indicates that the longitudinal variations of intense typhoon frequency were mainly controlled by El Niño-Southern Oscillation (ENSO), dominantly modulated by the Intertropical Convergence Zone. Because of the future warming climate, there will be a trend of enhanced typhoon risk for the southern Hainan Island coasts.

Multi‐species restoration accelerates recovery of extinguished oyster reefs

AbstractA multi‐species approach to habitat restoration may boost the key processes (e.g. recruitment) that enable foundation species to overcome barriers to recovery. Natural systems tend to be formed by co‐occurring foundation species whose synergy drives ecological productivity and resilience beyond that of single foundation species. Yet, restoration remains primarily a single‐species focus enterprise where positive interactions are seldom incorporated into planning. A multi‐species approach that prioritizes species combinations that create emergent properties for their persistence may accelerate habitat recovery and the success of restoration programmes.On the largest oyster reef restoration project in the Southern Hemisphere, we experimentally established canopy‐forming kelp to test whether they could accelerate the natural recruitment of oysters to substrata monopolized by turf‐forming algae. To understand whether facilitation of oysters was a function of the kelp themselves (biological facilitation) or the physical environment they create (physical facilitation), we compared recruitment to the understorey of living kelp and synthetic kelp mimics.Despite observing high density oyster recruitment to the turf‐free underside of reef boulders (8,300 oysters/m2), turf algae appeared to inhibit oyster recruitment to the exposed surfaces of the reef, limiting their capacity to grow and form complex, three‐dimensional habitat.Transplanted kelp, whether living or synthetic kelp mimics, effectively reduced the biomass of turf and enhanced oyster recruitment, creating turf‐free substrata on the upper reef surfaces with up to 26 times the oyster recruitment than turf‐covered substrata.Synthesis and applications. Our results provide proof‐of‐concept that incorporating the transplant of canopy‐forming kelp to reefs constructed to restore oysters is not only achievable, but may be imperative to successfully restore oyster reefs in turf‐dominated systems. Kelp transplants suppressed the turf algae that otherwise excluded oysters from the reef surface, effectively shifting the competitive advantage toward oyster recovery by maintaining bare substrata for oyster recruitment. By demonstrating that a multi‐species approach to restoration accelerates the recovery of a restored habitat, we emphasize the value of incorporating the multi‐species concept into restoration planning.

Millennial scale maximum intensities of typhoon and storm wave in the northwestern Pacific Ocean inferred from storm deposited reef boulders

Typhoons and associated storm waves in the northwestern Pacific Ocean commonly cause coastal disasters. The possibility remains that an even stronger typhoon than the strongest one observed to date might have occurred before. The development of a method to estimate a maximum intensity of past typhoons over thousands of years is important for paleoclimatology, paleoceanography and disaster prevention. Numerous storm wave boulders exist on reefs in the Ryukyu Islands, Japan, which have been deposited to their present position by the cumulative effects of the past storm waves. These boulders can be used as proxies for the hydrodynamic conditions of the largest waves from past events. Here, we present numerical computations for storm waves and boulder transport with the boulder distribution as a constraint factor to estimate the maximum intensities of storm waves and their causative typhoon events over the past 3500 years. Though the intensities of the maximum estimated waves and associated typhoon events were slightly stronger than those recorded over the past ~70 years in the Ryukyu Islands, our results suggest that no abnormally intense typhoon has struck the Ryukyu Islands in the past 3500 years. The potential impact from tsunamis remains uncertain; however, our results are meteorologically reasonable.

Three-dimensional structure of coral reef boulders transported by stormy waves using the very high resolution WorldView-2 satellite

ABSTRACT Collin, A., Etienne, S. and Jeanson, M., 2016. Three-dimensional structure of coral reef boulders transported by stormy waves using the very high resolution WorldView-2 satellite. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 572–576. Coconut Creek (Florida), ISSN 0749-0208. Coral reef boulders have been showed to reliably characterize the amount of wave energy related to cyclone, storm or tsunami events. The wave height and current velocity have been successfully explained by the variability in the boulder individual (morphology) and population (distribution) spatial patterns. Even if a single boulder may include a substantial amount of information, it may be highly challenging to characterize it given the access difficulty at the local and regional scales. Moreover, a boulder population is meaningful to robustly and continuously depic...

Potential for timing high-energy marine inundation events in the recent geological past through age-dating of reef boulders in Fiji

Transported coastal boulders have increasingly come to represent a valuable element of investigations within the broader framework of multi-proxy approaches applied to coastal hazard studies. Through a case study on Taveuni Island in Fiji, this paper outlines some approaches and hindrances to effective timing of prehistorical high-energy marine inundation events (storms and tsunamis) on tropical coastlines from the evidence of reef-platform carbonate boulders. Various sources of errors are outlined that investigators must consider when attempting to use carbonate boulder ages as a surrogate for timing past events. On Taveuni, uranium : thorium dates with a high level of precision (1–7 years) suggest that major inundation events have a return period of approximately 40–45 years since 1650 AD. Of particular importance, considerably different age dates are provided by coral samples sourced from the top and bottom (i.e. opposite faces) of individual boulders, so highlighting interpretation biases that must be avoided.

Bicoelia corticifera, a new inozoid sponge from the Upper Triassic (Norian) reef boulders of the Central Taurids (southern Turkey)

Upper Triassic Norian reef boulders, exposed in a locality in the Central Taurids, southern Turkey, yielded a high number of hypercalcified sponges, including Sphinctozoans, Inozoans, Spongiomorphids, and Chaetetids. The reef boulders are exposed near the fountain Tavuk Çeşme, located at the road leading from the town of Aksu to Yenişarbademli. Geologically this locality belongs to the Anamas Akseki Autochthon. In this paper a new inozoan sponge, Bicoelia corticifera nov. sp., is described from Tavuk Çeşme. It is a cylindrical and unbranched sponge, found in several thin sections. The sponge is characterized by 2 axial spongocoels, and the sponge wall is composed of fine reticulate fiber skeleton and a distinct outer wall. Usually several specimens grow closely side by side.

Hypercalcified segmented sponges (“sphinctozoans”) from the Upper Triassic (Norian) reef boulders of Taurus Mountains (southern Turkey)

Upper Triassic Norian reef boulders, exposed in a locality near the fountain “Tavuk Cesme” (“Chicken Fountain”) in Taurus Mountains, southern Turkey yielded a large number of hypercalcified sponges, including “sphinctozoans”, “inozoans”, “spongiomorphids”, and “chaetetids”. The sphinctozoans from this locality are described in this paper. Geologically, this locality belongs to the Anamas-Akseki autochthonous. The reef boulders of this locality are exposed near the “Tavuk Cesme” fountain, located at the road, leading from the town of Aksu to Yenisarbademli. The following taxa are described: Amblysiphonella taurica nov. sp., Anthalythalamia riedeli Senowbari-Daryan, Calabrisiphonella sphaerica nov. sp., Calabrisiphonellacuifi nov. sp., Cinnabaria minima Senowbari-Daryan, Colospongia recta nov. sp., Colospongia sp. 1, Colospongia sp. 2, Colospongia sp. 3, Cryptocoeliacompacta nov. sp., Cryptocoelia? sp., Deningeriacrassireticulata Senowbari-Daryan, Zuhlke, Bechstadt and Flugel, Discosiphonella minima Senowbari-Daryan and Link, Gigantothalamia ovoidalis Senowbari-Daryan, Hajarispongiadipoyrazensis nov. sp., Hajarispongia cortexifera nov. sp., Kashanella irregularis Senowbari-Daryan, Kashanella cylindrica nov. sp., Parauvanella ferdowsensis Senowbari-Daryan, Parastylothalamia cylindrica nov. gen., nov. sp., Asiphothalamia polyosculata nov. gen, nov. sp., Sollasia norica nov. sp., and Thaumastocoelia sphaeroida Senowbari-Daryan. The most abundant sponge is Amblysiphonella taurica nov. sp. followed by Hajarispongia dipoyrazensis nov. sp., Colospongia and Discosiphonellaminima Senowbari-Daryan and Link are also relatively abundant. The stylothalamid sponge Parastylothalamia nov. gen. is an abundant sponge genus in other Norian reefs of the Taurus Mountains, but is rare at the “Tavuk Cesme” locality.

Aggtecella, a new genus of Corallinales (Rhodophyta) from the Anisian of the Aggtelek-Rudabánya Mountains, NE Hungary

A description is given of the new Corallinales (Rhodophycean) alga Aggtecella hungarica from the Anisian reef limestones of the Aggtelek-Rudabanya Mountains, NE Hungary. Aggtecella is an encrusting nodular alga similar to Lithoporella melobesoides (Foslie) known from Tertiary deposits. A. hungarica occurs, in addition to the type locality (Anisian), also in the Ladinian-Carnian Wetterstein reef limestones in the Southern Alps and in Carnian reef boulders in Sicily.

Calcareous algae from the Triassic (Anisian reef boulders and Norian reef limestones) of Karaburun, western Turkey

Invertebrate Anisian and Norian reef boulders were found in the Gerence and Guvercinlik Formations, respectively, exposed in northeastern part of the Karaburun Peninsula, western Turkey. Halimedacean green algae and solenoporacean red algae, usually associated with other reef building organisms are described in this paper. The following taxa were determinated: halimedaceans: Egericodium hungaricum Flugel, Velledits, Senowbari-Daryan and Riedel, Aternasus irregularis n. gen., n. sp.; solenoporaceans: Solenopora cf. alcicornis Ott, Solenopora triasina Vinassa de Regny, Solenopora vachardi n. sp., Solenopora concentrica n. sp., Solenopora paraconcentrica n. sp., Tauristorea parallela Senowbari-Daryan and Link, Tauristorea discursa n. sp., and Parachaetetes cassianus (Flugel). The monospecific genus Aternasus n. gen. is the most abundant alga within the Anisian reef boulders. The solenoporaceans are represented by several taxa but the individual species are less abundant. E. hungaricum, T. parallela Senowbari-Daryan and Link, and S. triasina Vinassa de Regny are described from the Norian reef limestones embedded in Guvercinlik Formation, all other taxa from the Anisian reef boulders embedded in the Gerence Formation.

Filograna (colonial serpulid worm tubes) from Upper Triassic (Norian) reef boulders of Taurus Mts. (southern Turkey)

Two colonial serpulid worm tubes—Filograna taurica n. sp. and Filograna serialis n. sp.—from the Upper Triassic (Norian) reef boulders occurring in Taurus Mts. (south Turkey) are described. As bafflers, both species of Filograna build microbioherms reaching dimensions of up to 15 cm. Both species were not known either in Turkey or in any other Triassic localities of the Tethyan realm.

Upper Triassic (Norian-Rhaetian) new thalamid sponges from northern Calabria (southern Italy)

Two new sphinctozoan sponges, Calabrisiphonella labyrinthica nov. gen., nov. sp. and Calabrispongia globosa nov. gen., nov. sp., are described from reef boulders derived from Triassic dolomites (Dolomia principale) of the Argentino valley in Northern Calabria (Southern Italy). Calabrisiphonella is an Amblysiphonella-type sponge charac- terized by having a complicated canal system (labyrinth-like) within the chamber walls. The structure of Calabrispongia is similar to some Paleozoic or Jurassic Stromatoporoidea, which are attributed to the sponges. The systemtic position of both sponges, described here, is discussed. The age of the sponge-bearing reefs represented in the boulders is Norian-Rhaetian. Key word: Sponge, Sphinctozoa, Reef, Upper Triassic (Norian-Rhaetian), Northern Calabria, Italy.

Fish feeding guilds along a gradient of bay biotopes and coral reef depth zones

The study of fish feeding guild structure is a useful method to compare fish communities of complex marine ecosystems. Guild structure was determined in four coral reef depth zones, viz. the fringing reef at depths of 2, 5, 10, and 15 m, as well as in seven shallow-water biotopes within a single bay, viz. notches in fossil reef rock, mangroves, fossil reef boulders, seagrass beds, algal beds at a depth of 2 m, algal beds at a depth of 5 m, and the channel. The study was done in an inland bay on the Caribbean island of Curacao, using a visual census technique. Total fish densities within the different feeding guilds varied considerably between the biotopes, and were generally higher in the reef biotopes and on the boulders than in the remaining bay biotopes. Cluster analysis revealed that the greatest dissimilarity in guild structures in terms of fish densities was that between the algal beds and all other biotopes, followed by that between the reef depth zones and other bay biotopes (notches, mangroves, seagrass beds, channel). The species composition of the guilds also differed considerably among the various biotopes. Species richness within the various guilds showed much smaller differences between the biotopes, but was generally somewhat higher in the reef biotopes. Cluster analysis of guild structures in terms of species richness revealed little dissimilarity among the various biotopes. The coral reef was dominated by omnivores and zooplanktivores, whereas the bay was dominated by zoobenthivores and herbivores. Differences in guild structure between the bay and the adjacent reef indicate differences in food availability.

Day-night shifts of fishes between shallow-water biotopes of a Caribbean bay, with emphasis on the nocturnal feeding of Haemulidae and Lutjanidae

Day-night changes in fish communities were quantified in 6 associated shallow-water biotopes within a single bay: mangroves, seagrass beds, algal beds, channel, fossil reef boulders, and notches in fossil reef rock. All biotopes, except the algal beds, showed a strong reduction in fish density and species richness at night, caused by absence of diurnally active fishes and migrations of Haemulidae and Lutjanidae to the seagrass beds. The fish fauna of the different biotopes showed a relatively high dissimilarity between day and night. This dissimilarity is largely caused by absence of Acanthuridae, Chaetodontidae, Labridae, Pomacentridae, Scaridae and Sparidae at night. These fishes seek shelter at night in, amongst others, the channel, notches and boulders. The balloonfish Diodon holocanthus utilised almost all biotopes as shelter as well as feeding sites. The wide distribution of its preferred food (molluscs) probably explains its distribution in most biotopes at night. The nocturnally active Haemulidae and Lutjanidae, on the other hand, migrated from their daytime shelter sites to the seagrass beds at night to feed. Some of these fishes also migrated to the algal beds to feed. The preference of Haemulidae and Lutjanidae for the seagrass bed as a feeding biotope, instead of other bay biotopes, appears to be related to the relatively high availability of their preferred food (Tanaidacea and Decapoda) as determined by digestive tract analysis. Other bay biotopes showed much lower densities of such food items compared to the seagrass beds.

Importance of shallow-water biotopes of a Caribbean bay for juvenile coral reef fishes: patterns in biotope association, community structure and spatial distribution

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 202:175-192 (2000) - doi:10.3354/meps202175 Importance of shallow-water biotopes of a Caribbean bay for juvenile coral reef fishes: patterns in biotope association, community structure and spatial distribution I. Nagelkerken1,2, M. Dorenbosch2, W. C. E. P. Verberk2, E. Cocheret de la Morinière2, G. van der Velde2,* 1Carmabi Foundation, PO Box 2090, Piscaderabaai z/n, Curaçao, Netherlands Antilles 2Laboratory of Aquatic Ecology, Aquatic Animal Ecology Section, University of Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands *Corresponding author. E-mail: gerardv@sci.kun.nl ABSTRACT: Fish community structure of a non-estuarine inland bay on the Caribbean island of Curaçao was determined in the mangroves, seagrass beds, algal beds, channel, fossil reef boulders, notches in fossil reef rock, and on the adjacent coral reef, using visual censuses in belt transects. Fish communities varied among biotopes, but some overlap was present. Fish density and species richness were highest at the boulders and on the coral reef, and extremely low on the algal beds, whereas the total number of individuals calculated for the entire bay was highest on the seagrass beds. Differences in fish densities between biotopes were related to differences in structural complexity and amount of shelter. Fishes in the bay largely consisted of 17 (mainly commercially important) reef fish species, which used the bay biotopes only as a nursery during the juvenile part of their life cycle. Small juveniles of these species were most often found in the mangroves, whereas at intermediate sizes some were found in the channel. Large individuals and adults were found on the reef, and densities of several of these species were higher on the reef near the bay than on reefs located farther down-current. Fishes which spent their entire life cycles in either the bay or on the coral reef were also found, and the latter group showed a strong decrease in abundance with increasing distance into the bay. The density distribution of individual fish species was not homogeneous within the bay. In the mangroves and seagrass beds, spatial distribution of fishes was correlated with distance to the mouth of the bay, water transparency, amount of shelter, and the structural complexity of the biotope. Juveniles of 3 reef species showed an increase in size on the seagrass beds with distance from the mouth into the bay, whereas 1 bay species showed a decrease in size with this distance. KEY WORDS: Mangroves · Seagrass beds · Coral reef fish · Nursery · Habitat association · Community structure · Habitat complexity Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 202. Online publication date: August 28, 2000 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2000 Inter-Research.

High diversity of tropical intertidal zone sponges in temperature, salinity and current extremes

The wide intertidal zone of the Quirimba Archipelago (Mozambique, East Africa) encompasses many different habitats, which all experience wide environmental variation. Large daily fluctuations in temperature occur when standing water is heated up at low tide to >10°C above ambient. Salinity may be high in the dry season and periodically almost fresh in the wet season. Very high current velocities (≈3 ms−1) may occur and the direction of water flow is often complex. Sponges were a major component of the fauna (and dominate the sessile forms) in most of the eight habitats studied: exposed reef, sheltered reef, sand‐rock, cave, reef boulders, boulders on sand, mangrove swamp and seagrass meadows. The highest number of sponge species occurred in the two reef habitats: from mean values of between ≈2.5 and ≈0.5 species/m2 (upper and lower shore, respectively). The diversity of species present yielded a high Shannon index value of H=2.95 for the total of 33 species. A rank‐abundance plot of the data showed a high level of equitability (J=0.84). Community similarity measurement using Bray–Curtis index showed two clusters; the exposed habitats of the reefs and sand‐rock and the refugia of cave, reef and sand boulders.

Barbafera carnica Senowbari-Daryan, 1980: A Triassic worm-tube

Barbafera carnicaSenowbari-Daryan (1980), a Carnian reef fossil of uncertain systematic position, is redescribed based on extraordinarily preserved material from Carnian reef boulders of the Cassian Formation of the Southern Alps (Dolomites/Italy).Barbafera is interpreted as a worm tube characterized by a complicated wall structure.Barbafera may belong to the family SerpulidaeRafinesque.