Dating Methods of Cold-water Corals and Their Application in Reconstructing Carbon-reservoir Ages of Intermediate and Deep Oceans

Establishing a precise chorology is a critical issue when employing cold-water coral as paleoenvironmental archives. Currently, U-Th, ¹⁴C and ²¹⁰Pb dating techniques are the most frequently used methods. The high-magnesium calcite skeleton of bamboo coral has clear growth bands, which is appropriate for ¹⁴C and ²¹⁰Pb dating methods and holds a great potential to be high-resolution archives of mid-to-deep ocean evolution. Aragonitic stony coral is appropriate for both U-Th and ¹⁴C dating methods, which is valuable in paleoceanographic research. Because the U-Th method can provide the absolute chronology of coral samples, it can further be used to calculate the ¹⁴C age of ocean carbon reservoirs. Therefore, U-Th and ¹⁴C dating results of stony coral are currently the most reliable data for exploring the evolution of ocean carbon reservoirs through the Last Glacial Maximum to the present. It has been found that the ¹⁴C ventilation ages of intermediate water masses of the equatorial Atlantic and Southern Ocean significantly decreased at the end of the Heinrich Stadial 1. This suggests a massive carbon transfer from deep oceans to the atmosphere, or the Atlantic intermediate depths were ventilated by the southern- and the northern-sourced water masses, respectively, before and after the Heinrich Stadial 1.     

贵州边阳地区中三叠世的六射珊瑚化石

本文描述了贵州边阳地区中三叠统拉丁尼克期的六射珊瑚4属6种，其中1个已知种，1个亲近种，2个新种和2个未定种：Pinacophyllum spizzensis(Tornquist)，P．aff．yunnanense Wu，P．bianyangense sp．nov，Retiophyllia bianyangensis sp．nov．，Procydolites sp．，Margarosmilia sp．，丰富了世界中三叠世六射珊瑚研究的资料。迄今全世界缺乏早三叠世珊瑚，研究中三叠世珊瑚，对探讨中生代开始出现的六射珊瑚的发生和系统演化，古生代四射珊瑚与中生代珊瑚之间存在的关系，都有很重要的意义。     

Response of the soft coral Heteroxenia fuscescens to ultraviolet radiation regimes as reflected by mycosporine-like amino acid biosynthesis

The variation in mycosporine‐like amino acid (MAA) concentration in the soft coral Heteroxenia fuscescens in relation to changes in ultraviolet radiation (UVR) regimes was investigated at the Gulf of Eilat, northern Red Sea. Solar radiation (300–700 nm) was measured for different depths and seasons. The UVR irradiance was measured to a depth of 25 m on the reef. The mean attenuation coefficient for UV‐B measured in winter was twofold that of the summer value. Separation of H. fuscescens extracts by reverse‐phase isocratic high‐performance liquid chromatography revealed a single MAA compound, palythine (λ_max = 320 nm). Possible seasonal changes in MAAs in colonies of H. fuscescens along a depth gradient were examined on different dates. Palythine concentrations in the colonies were significantly higher in summer than in the other seasons particularly in shallow water. Possible changes in MAA content in colonies of H. fuscescens as a result of UVR protection, were determined by experiments conducted for periods of 1 week, 1 month and 3 months, at a depth of 5 m. In these experiments colonies were removed from the natural substrate and placed underwater, protected from UVR by a PVC filter. Significant differences between UV‐exposed and protected colonies of H. fuscescens were found only in the 3‐month experiment conducted during the summer. These findings demonstrate that UVR is an important environmental factor regulating MAA biosynthesis in the soft coral H. fuscescens.     

台湾北部四种软珊瑚体内十八种金属累积于共肉组织与中轴骨骼的特性

分别检测采自台湾北部和平岛沿岸海域及淡水河出海口海域的侧扁软柳珊瑚(Subergorgia suberosa)、扁刺柳珊瑚(Echinogorgia complexa)、网刺柳珊瑚(Echinogorgia reticulata)和1未定种柳珊瑚4种软珊瑚样品体内18种金属元素。比较同株珊瑚中金属累积于共内组织与中轴骨骼含量的特性．研究结果显示铜(Cu)及钒(V)于4种珊瑚中累积于中轴骨骼的量高于共内组织，Zn、Fe、Mn、Ca、Cd、Ni、Pb及Se则恰相反，Al、As、Co、Cr及Sn累积部位没有规则，Ag,Au及Ba因有ND值(未检出值)无法归纳其累积倾向，但若忽略ND值，则Ag与Ba累积于共肉组织较高，Au累积于中轴骨骼较高．此研究结果显示环境中金属倾向累积于软珊瑚共肉组织或中轴骨骼可能有一定之脉络可循．     

Microhabitat type determines the composition of nematode communities associated with sediment-clogged cold-water coral framework in the Porcupine Seabight (NE Atlantic)

The nematofauna associated with a cold-water coral degradation zone in the Porcupine Seabight (NE Atlantic) was investigated. This is the first comprehensive study of nematodes associated with cold-water corals. This research mainly aimed to investigate the influence of microhabitat type on nematode community structure. Three distinct microhabitats for nematodes were distinguished: dead coral fragments, glass sponge skeletons and the underlying sediment. The nematode assemblages associated with these three microhabitats were significantly different from each other. Coral and sponge substrata lie relatively unprotected on the seafloor and are consequently more subjected to strong currents than the underlying sediment. As a result, both large biogenic substrata were characterized by higher abundances of taxa that are less vulnerable and more adapted to physical disturbance, whereas the underlying sediment yielded more slender, sediment-dwelling taxa. Typically epifaunal taxa, such as Epsilonematidae and Draconematidae, were especially abundant on dead coral fragments, where they are thought to feed on the microbial biofilm which covers the coral surface. Several epifaunal genera showed significant preferences for this microhabitat, and Epsilonema (Epsilonematidae) was dominant here. Sponge skeletons are thought to act as efficient sediment traps, resulting in a lower abundance of epifaunal taxa compared to coral fragments. The underlying sediment was dominated by taxa typical for slope sediments. The considerable degree of overlap between the communities of each microhabitat is attributed to sediment infill between the coral branches and sponge spicules. It is assumed that the nematofauna associated with large biogenic substrata is composed of a typical sediment-dwelling background community, supplemented with taxa adapted to an epifaunal life strategy. The extent to which these taxa contribute to the community depends on the type of the substratum. Selective deposit feeders were dominant on sponge skeletons and in the underlying sediment, whereas coral fragments were dominated by epistratum feeders. The presence of a microbial biofilm on the coral fragments is proposed as an explanation for the significant preference of epistratum feeders for this microhabitat. Densities in the underlying sediment were low in comparison with other studies, but biodiversity was higher here than on the coral and sponge fragments, a difference which is attributed to lower disturbance. Nevertheless, the large biogenic substrata provide a microhabitat for rare, epifaunal taxa, and fragments of both substrata within the sediment increase habitat complexity and hence biodiversity.     

DARWIN'S Coral Reef Research - a Review and Tribute

Abstract. In rememberance of the death of CHARLES DARWIN 100 years ago, a review is given on his coral reef research from the point of view of present knowledge. Although during DARWIN'S time no one was aware of the changing level of the glacial sea or of the important function of the symbiotic zooxanthellae in the life of hermatypic corals, his observations and considerations on the ecology of corals and on the formation of coral reefs are relevant to this day. But of course his ideas need new causal interpretations. The origin of the different reef types can no longer be explained by subsidence alone, but by different modes biologists and geologists described during the following century. To summarize all the many existing theories, the all enclosing "theory of compensation" is put forward here in honour of this great man.     

Distribution and population structure of deep‐dwelling red coral in the Northwest Mediterranean

Commercially harvested since ancient times, the highly valuable red coral Corallium rubrum (Linnaeus, 1758) is an octocoral endemic to the Mediterranean Sea and adjacent Eastern Atlantic Ocean, where it occurs on rocky bottoms over a wide bathymetric range. Current knowledge is restricted to its shallow populations (15–50 m depth), with comparably little attention given to the deeper populations (50–200 m) that are nowadays the main target of exploitation. In this study, red coral distribution and population structure were assessed in three historically exploited areas (Amalfi, Ischia Island and Elba Island) in the Tyrrhenian Sea (Western Mediterranean Sea) between 50 and 130 m depth by means of ROV during a cruise carried out in the summer of 2010. Red coral populations showed a maximum patch frequency of 0.20 ± 0.04 SD patches·m^?1 and a density ranging between 28 and 204 colonies·m^?2, with a fairly continuous bathymetric distribution. The highest red coral densities in the investigated areas were found on cliffs and boulders mainly exposed to the east, at the greatest depth, and characterized by medium percentage sediment cover. The study populations contained a high percentage (46% on average) of harvestable colonies (>7 mm basal diameter). Moreover, some colonies with fifth‐order branches were also observed, highlighting the probable older age of some components of these populations. The Ischia population showed the highest colony occupancy, density and size, suggesting a better conservation status than the populations at the other study locations. These results indicate that deep dwelling red coral populations in non‐stressed or less‐harvested areas may diverge from the inverse size‐density relationship previously observed in red coral populations with increasing depth.     

Population genetics of cold‐water coral associated Pleustidae (Crustacea,Amphipoda) reveals cryptic diversity and recent expansion off Iceland

Amphipoda are a diverse and important faunal component of deep‐sea habitats worldwide. However, relatively little is known about species that are associated with cold‐water corals, in particular concerning their genetic diversity, population genetic processes, population differentiation, and potential host specificity. We exemplarily investigate these questions studying three pleustid species—Stenopleustes aff. malmgreni (Boeck, 1871), Stenopleustes aff. nodifera (Sars, 1883) and Neopleustes aff. boecki (Hansen, 1888)—that are associated with cold‐water corals and polychaete assemblages along the Reykjanes Ridge southwest of Iceland. We sequenced mitochondrial COI and performed ddRAD to study thousands of nuclear loci. These species and a pair of morphologically cryptic species within Stenopleustes aff. nodifera were consistently delimited by COI and ddRAD. We conclude that all of our studied species are new to science, raising the number of pleustids reported from cold‐water corals to six. Two species were collected only once, and these species exhibited high levels of inbreeding, suggesting little exchange with other populations, which might be a result of strong host specificity. The other two species were wider distributed, with very low differentiation among populations, even between populations separated by 130 km. These species showed signs of recent population expansions, possibly in relation to changes in the cold‐water coral associated ecosystem (e.g., due to glacial cycles and/or volcanic or geothermal activities). They had lower levels of inbreeding and were each associated with three different host coral species, which might facilitate dispersal and gene flow. Our results show divergent population genetic patterns for the studied pleustid species. These might be attributed to the species’ host specificity and highlight important differences among species with seemingly similar life‐styles. Species diversities appear to be greatly underestimated, limiting our abilities to truly assess the vulnerability of the fauna living in these threatened cold‐water coral habitats.     

An overview of cold-water coral protection on the high seas: The Hatton bank (NE Atlantic)—A case study

The present paper provides an overview of cold-water corals protection in the Hatton Bank deep-water fisheries through the implementation of the United Nations General Assembly resolution 61/105. The methodology and scientific evidence used to propose protection of cold-water coral ecosystems in the high seas (∼16,000 km²) are briefly summarised. The role of international agents and importance of interdisciplinary research for making management decisions are furthermore described. Implementation was slow because (i) of scarce initial scientific knowledge, (ii) research on the high seas was difficult and expensive, (iii) there were several international interests at stake, (iv) agreement from a number of agents was needed, and (v) international advisory and decision making processes were quite slow. Some lessons learned are also discussed since these may help to increase protection efficiency of deep-sea vulnerable marine ecosystems in the high seas.