Biogeographic variability in the physiological response of the cold‐water coral Lophelia pertusa to ocean acidification

While ocean acidification is a global issue, the severity of ecosystem effects is likely to vary considerably at regional scales. The lack of understanding of how biogeographically separated populations will respond to acidification hampers our ability to predict the future of vital ecosystems. Cold‐water corals are important drivers of biodiversity in ocean basins across the world and are considered one of the most vulnerable ecosystems to ocean acidification. We tested the short‐term physiological response of the cold‐water coral Lophelia pertusa to three pH treatments (pH = 7.9, 7.75 and 7.6) for Gulf of Mexico (USA) and Tisler Reef (Norway) populations, and found that reductions in seawater pH elicited contrasting responses. Gulf of Mexico corals exhibited reductions in net calcification, respiration and prey capture rates with decreasing pH. In contrast, Tisler Reef corals showed only slight reductions in net calcification rates under decreased pH conditions while significantly elevating respiration and capture rates. These differences are likely the result of environmental differences (depth, pH, food supply) between the two regions, invoking the potential for local adaptation or acclimatization to alter their response to global change. However, it is also possible that variations in the methodology used in the experiments contributed to the observed differences. Regardless, these results provide insights into the resilience of L. pertusa to ocean acidification as well as the potential influence of regional differences on the viability of species in future oceans.     

Experimental bleaching of a tropical sea anemone in situ

Bleaching (whitening) of cnidarians such as corals and sea anemones has caused widespread degradation of coral reefs around the world and is therefore an urgent issue for coral reef science and conservation. Although cnidarians often bleach in aquaria, methods for experimental induction of bleaching in wild cnidarians are lacking, which impedes scientists’ ability to understand the ultimate effects of bleaching on the broader ecosystem. In this study, we investigated the utility of an in situ method for experimental induction of bleaching in the tropical sea anemone Heteractis crispa. Healthy, wild anemones were covered with opaque black plastic sheets, mesh cages or left undisturbed (controls) and tentacle colour and body size were monitored with a colour reference card and flexible tape, respectively, every 1–3 days for 15 days. Caged and control anemones remained unchanged for the duration of the experiment, but covered anemones commenced whitening after 4–6 days and were completely white after 7–14 days (mean time to bleaching ± SE = 10.1 ± 0.7 days). Experimental bleaching occurred without reduction in anemone body size and was visibly similar to natural bleaching seen previously in H. crispa. We hypothesize that light‐deprivation, reduced water flow, physical contact or some combination of these factors caused the bleaching. This study provides the basis for a simple and rapid method of inducing bleaching in situ, which releases scientists’ dependence on sporadic natural bleaching events or artificial aquarium experiments, and provides a means to investigate the effects of bleaching on other ecosystem components such as fishes.     

Temporal dynamics and persistence of sponge assemblages in a Central Pacific atoll lagoon

Sponges are important components of coral reef fauna, although little is known of their temporal dynamics. Sponges dominate the lagoon system at Palmyra Atoll in the Central Pacific, which may not be its natural state. Here we examined the temporal variability and recruitment rates of these sponge assemblages to determine if they are stable and examined the evidence that a recent transition has occurred from a coral‐ to sponge‐dominated system. We found 24 sponge species in permanent quadrats in the lagoon between 2009 and 2011, and 11 species on our recruitment panels. The sponge assemblage composition and abundance did not vary significantly between years and appear stable. Many sponge recruits were found in both years that the panels were examined although higher rates were recorded in the second year of the study. While it seems very possible that a change to a sponge‐dominated lagoon is associated with declining environmental quality at Palmyra as a result of modifications over 70 years ago, without pre‐modification data on reef assemblage composition this remains speculative. Our observations of short‐term temporal stability in the sponge assemblages at Palmyra highlight the potential for sponge‐dominated reef states to be maintained in degraded reef environments that are seemingly unsuitable for coral survival.     

Spatial and ecologic distribution of neglected microinvertebrate communities across endangered ecosystems: meiofauna in Bali (Indonesia)

Biodiversity estimations, particularly in vulnerable tropical regions, are essential to understanding ecosystem structure, function and conservation. While threats to marine and terrestrial ecosystems have fueled increased interest in biodiversity research, information on meiofauna, a key trophic and ecologic community of microscopic organisms that lives within sediments, is still lacking. Here we report the results of a faunistic investigation conducted in Bali, Indonesia. The results reveal that the biodiversity of marine meiofauna in Bali is very high. Meiofauna from coral reefs, sand flats and seagrass beds differed significantly in abundance and diversity. Nonetheless, overall community compositions show that meiofauna communities are affected by environmental variables. The high meiofaunal diversity observed in Bali, a low diversity region of the Coral Triangle, indicates the importance of further meiofaunal research across this region and across a broader diversity of habitats. The data presented provide an important baseline for future studies on biodiversity conservation in the face of environmental changes due to anthropogenic impacts and/or natural events.     

阳江核电站水库振冲碎石桩试验研究

通过对碎石桩和桩间土进行多种物理力学特性试验,揭示振冲碎石桩的力学特性和复合地基的加固处理效果,为业主、设计和施工单位提供了可靠的技术资料,对工程的合理设计、顺利施工起到了关键作用。试验结果可供类似地基的碎石桩复合地基设计作参考。     

路南石林喀斯特流域水文特征初探

本文运用水文地貌系统耦合分析的方法,对路南石林喀斯特流域水文特征进行了探讨,对喀斯特完全入渗式流域和完全漏渗式流域的特性进行了初步研究,揭示了侵蚀基面的变化对流域地表地下水系结构的影响,认为石林发育区水文特征有其自身的特点。      

High‐grade localized metasomatic alteration of the granitic gneiss surrounding a clinopyroxene‐rich pegmatoid dyke: Söndrum stenhuggeriet,Halmstad, SW Sweden

The Söndrum stone quarry (Halmstad, SW Sweden) exposes a transition from migmatized granitic gneissic country rock into a foliated clinopyroxene‐free granitic gneiss, and then a central pegmatoid dyke dominated by clinopyroxene megacrysts. This transition zone represents a fracture‐controlled, fluid‐alteration zone that developed under conditions of 650–700 °C and 790 MPa. Mineral chemical trends in F, Cl, Fe, Ti, Mn and Y are interpreted as documenting a fluid infiltration event associated with the formation of the pegmatoid dyke. Fluid inclusions from the pegmatoid dyke are CO₂ dominant, whereas in the surrounding country rock they are dominated by H₂O‐NaCl‐CaCl₂. Fluid inclusions from the intermediate foliated clinopyroxene‐free granitic gneiss are a mixture of the two types. The pegmatoid dyke appears to have originated from a high Ca activity, Fe‐Mg enriched, fluid‐rich granitic melt with a CO₂ component, which was emplaced along a tectonic fracture in a regionally migmatized granitic gneiss in the lower crust. This was accompanied by limited partial melting of the surrounding granitic gneiss. The Ca activity of the melt was high enough to allow for the formation of clinopyroxene megacrysts as opposed to orthopyroxene. H₂O‐enriched fluids expelled from the crystallizing pegmatoid dyke, which retained the majority of the CO₂ helping to stabilize the clinopyroxene. The expelled fluids coarsened and chemically affected the surrounding country rock resulting in trends in the mineral and fluid inclusion chemistry seen today in the foliated and regional granitic gneiss.     

Pliocene‐Quaternary history of Futuna Island,south Vanuatu,southwest Pacific

U‐series ages from thermal ionisation mass spectrometry are reported here for the raised coral reefs of Futuna Island, which lies adjacent to the eastern margin of the backarc Futuna Trough in south Vanuatu, southwest Pacific. U‐series ages from coral from the lowest raised reef indicate that its upper part is most likely to be ca 210 ka, whereas the most elevated raised reef has a likely age of ca 520 ka (range 600–440 ka). The inferred Pliocene‐Quaternary history for Futuna Island and the adjacent Futuna Trough is: (i) formation of the Pliocene—Early Quaternary basaltic‐andesite cone in a southeast part of the Vanuatu Island Arc; (ii) inception of the Futuna Trough (adjacent to the west margin of Futuna Island) since 1.8 Ma; (iii) subsequent uplift of the volcanic cone above sea‐level caused ～500 m of its upper part to be removed by marine erosion; (iv) the island then subsided and at least 160 m of limestone was deposited on the truncated cone; and (v) during the period 520 ka to ca 210 ka seven fringing reefs formed at the margin of the cone as the island was uplifted. Since ca 210 ka Futuna further subsided and, as a result, the post ca 210 ka history of the island is obscure.     

The human impact on natural rock reserves using basalt,anorthosite, and carbonates as raw materials in insulation products

Typical crustal rocks such as basalt, limestone, and anorthosite are used in stone wool insulation products. The raw materials for stone wool production are not specific to any rare mineral source but depend upon the mixture of materials having the correct chemical composition, exemplified by 40 wt% basalt, 20 wt% anorthosite, and 40 wt% cement-bonded renewable materials. This study provides an overview of the natural cycle of these resources, including their abundances in nature, and sets the consumption by the stone wool industry and other human activities in perspective.

Basalt, anorthosite, and carbonates are widespread on all continents. Although basaltic rocks cover most of the ocean floor, these reserves are hidden below several kilometres of water and therefore are regarded as inaccessible. Instead, large igneous provinces on land constitute major basaltic reserves useful for human rock exploration. Globally, anorthositic provinces comprise smaller volumes than do limestone or basalt, but still occur in sufficient amounts to supply for the production of insulation materials indefinitely. An evaluation of the modern consumption rates and reserves shows that the crustal inventories of these rock types are so large that they could supply current human demand for millions of years.

The natural degradation of surface rocks occurs by physical and chemical weathering creating sediment that is transported along rivers and deposited in the ocean. Sediments are either obducted with continental lithosphere or subducted with oceanic crust and recycled through the mantle by plate tectonics. Insulation products have a chemical composition similar to average crustal rocks and participate in the natural rock cycle. However, these products need not accumulate in nature, inasmuch as old insulation materials serve as excellent source materials for new products. Moreover, current production lines exploit more than 30 natural and 20–30 synthetic source materials that circumvent regional depletion and contribute to the recycling of other industrial materials.     

Petrographical and geochemical characterization of Comblanchien limestone (Bourgogne,France): A fingerprint of the building stone provenance

The Comblanchien limestone is a well-known building stone that deserves a quantitative characterization in order to be able to certify its origin. We compare petrographical and geochemical characteristics of limestones commercialized under the name of Comblanchien to those of one of their competitors (VATC, a Portuguese coated grain-bearing limestone). From macroscopic and microscopic observations, the distinction is somehow difficult but the coated grain-bearing Comblanchien samples have δ¹³C values (from +1.75 to +2.25‰) different from those of the VATC sample (negative δ¹³C value). As an example of application of these results, three samples from a building site near Paris are also studied in order to verify their provenance. We conclude that they do not come from quarries from the Comblanchien area, but likely from Portugal. The study shows that a detailed analysis of building limestones may provide a robust tool for discriminating between currently mined stones of different provenances, and thus open the possibility to attach to a given limestone a fingerprint, an identity card, and if required a commercial label.