相比浅海暖水珊瑚礁，对深海的冷水珊瑚礁研究相对薄弱。近年来随着水下机器人和深潜器技术的进步，国际上兴起了深海珊瑚礁研究热潮。文章综述了：1）冷水石珊瑚的物种多样性及格局分布特征；2）冷水石珊瑚的生长特征及测量方法；3）冷水珊瑚礁的类型、形成机制与演化过程；4）海洋酸化对冷水珊瑚礁的影响；5）冷水石珊瑚对海洋古环境的记录等。最后提出中国南海冷水珊瑚礁研究展望，建议开展探测南海冷水珊瑚礁的分布，监测珊瑚礁区的生态环境，分析冷水石珊瑚群落特征，探讨冷水珊瑚礁对海洋酸化的响应机制，并利用南海冷水石珊瑚重建南海冷水珊瑚礁的发育历史及所记录的古海洋环境等研究工作。

Coral reefs are generally associated with shallow tropical seas; however, there are widespread and diverse coral ecosystems in deep waters on continental shelves, slopes, seamounts and ridges around the world. Cold-water corals have been known since the 18th century, but much fewer studies have been performed on deep-sea coral reefs compared with on tropical coral reefs. Along with the applications of modern submersibles and remotely operated vehicles (ROVs) to deep ocean exploration activities, more and more studies have been conducted and deep-sea coral reefs have become a research hotspot recently. This review includes: 1) the diversity and biogeographical distribution of cold-water corals; 2) the growth characteristics of corals and related environmental controls; 3) the initiation and development of deep-sea coral reefs; 4) the response of corals to ocean acidification; 5) corals as valuable archives for paleoceanographic reconstructions. It also highlights the future research directions of cold-water coral reefs in the South China Sea.

2018年在南海发现的深水珊瑚林，为底栖生物乃至碳循环研究弥补了重大空缺。受技术限制,以前深海底栖生物的研究主要局限在沉积覆盖的软基底,以为石质海底是一片贫瘠世界。1990年代中期，应用深潜技术首先在大西洋发现了深海珊瑚礁，为海洋科学开辟了新的研究方向。深海珊瑚包括两类：一类是属于六方珊瑚的石珊瑚，以其文石质的外骨骼形成珊瑚礁；另一类是以柳珊瑚为主的珊瑚林，柳珊瑚属于八方珊瑚,可以形成高镁方解石的骨骼。这些碳酸盐骨骼都能够记录深海的环境变化，是古海洋学研究的绝佳材料。太平洋由于文石补偿面过浅,不利于深水珊瑚礁发育，深水珊瑚林应当普遍发育,可惜至今尚未得到重视，绝大部分海域属于研究空白。通过对深水珊瑚礁和珊瑚林的组成以及分布的介绍，讨论深水珊瑚林在海洋生态学中的重要性及其在古海洋学再造中的意义。

The discovery of deep sea coral forests in the spring of 2018 filled a significant gap in the benthos research and even in carbon cycling in the South China Sea. Previously, the researches of deep-sea benthos were restricted to the sediment-covered soft bottom due to the technical limitations, and the rocky hard bottom was believed to be barren of life. Using submersible technique in the mid-1990s, deep-water coral reefs were first discovered in the Atlantic Ocean, which opened a new research direction in marine sciences. Two groups of deep sea corals have been recognized: scleractinian hexacorals and gorgonian octocorals. The aragonite skeleton of the former group build up deep sea coral reefs, while the latter make up deep sea coral forests with high-Mg calcite skeleton in many gorgonian corals. All kinds of carbonate coral skeletons can record environment changes of the deep sea and provide excellent material for high-resolution paleoceanography. Although the development of deep sea coral reefs in the Pacific Ocean is hampered by its extremely shallow aragonite compensation depth, deep sea coral forests are ubiquitous in the ocean. Up to now, most parts of the Pacific have not yet explored in this respect, and deep sea corals remain outside the research scope. The present paper is a literature review and calls for attention to the deep sea forests. It starts with the composition and distribution of deep sea coral reefs and forests, followed by discussions on the significance of deep sea coral forests in marine ecology and in paleoceanographic reconstructions.

广泛分布于海洋深部的竹节珊瑚，以其碳酸钙和蛋白质相间的“竹节状”骨骼而得名，且横向上具有“树轮状”生长纹层。利用竹节珊瑚进行古海洋学再造，可以填补传统方法在时间和空间上的空缺。着重介绍竹节珊瑚的无机地球化学指标方法，包括Mg/Ca温度计、Ba/Ca营养物浓度计和δ¹¹B-pH计，并简要描述了生命效应的潜在影响。最近在西太平洋海域新发现的深海竹节珊瑚林，开拓了竹节珊瑚古海洋学研究的新领域。

The strontium-to-calcium ratio (Sr/Ca) of reef coral skeleton is commonly used as a paleothermometer to estimate sea surface temperatures (SSTs) at crucial times in Earth's climate history. However, these estimates are disputed, because uptake of Sr into coral skeleton is thought to be affected by algal symbionts (zooxanthellae) living in the host tissue. Here, we show that significant distortion of the Sr/Ca temperature record in coral skeleton occurs in the presence of algal symbionts. Seasonally resolved Sr/Ca in coral without symbionts reflects local SSTs with a temperature sensitivity equivalent to that of laboratory aragonite precipitated at equilibrium and the nighttime skeletal deposits of symbiotic reef corals. However, up to 65% of the Sr/Ca variability in symbiotic skeleton is related to symbiont activity and does not reflect water temperature.

Corals are the ecosystem engineers of coral reefs, one of the most biodiverse marine ecosystems. The ability of corals to form reefs depends on the precipitation of calcium carbonate (CaCO3) under biological control. However, several mechanisms underlying coral biomineralization remain elusive, for example, whether corals employ different molecular machineries to deposit different CaCO3 polymorphs (i.e., aragonite or calcite). Here, we used tandem mass spectrometry (MS/MS) to compare the proteins occluded in the skeleton of three octocoral and one scleractinian species: Tubipora musica and Sinularia cf. cruciata (calcite sclerites), the blue coral Heliopora coerulea (aragonitic skeleton), and the scleractinian aragonitic Montipora digitata. Reciprocal Blast analysis revealed extremely low overlap between aragonitic and calcitic species, while a core set of proteins is shared between octocorals producing calcite sclerites. However, the carbonic anhydrase CruCA4 is present in the skeletons of both polymorphs. Phylogenetic analysis highlighted several possible instances of protein co-option in octocorals. These include acidic proteins and scleritin, which appear to have been secondarily recruited for calcification and likely derive from proteins playing different functions. Similarities between octocorals and scleractinians included presence of a galaxin-related protein, carbonic anhydrases, and one hephaestin-like protein. Although the first two appear to have been independently recruited, the third appear to share a common origin. This work represents the first attempt to identify and compare proteins associated with coral skeleton polymorph diversity, providing several new research targets and enabling both future functional and evolutionary studies aimed at elucidating the origin and evolution of coral biomineralization.© The Author(s) 2020. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Dissolved inorganic carbon (DIC) in ocean water is a major sink of fossil fuel derived CO2. Carbon isotopes in DIC serve as tracers for oceanic water masses, biogeochemical processes, and air-sea gas exchange. We present a timeseries of surface DIC δ13C and Δ14C values from 2011 to 2022 from Newport Beach, California. This is a continuation of previous timeseries (Hinger et al. 2010; Santos et al. 2011) that together provide an 18-year record. These data show that DIC Δ14C values have declined by 42‰ and that DIC δ13C values have declined by 0.4‰ since 2004. By 2020, DIC Δ14C values were within analytical error of nearby clean atmospheric CO2 Δ14C values. These long-term trends are likely the result of significant fossil fuel derived CO2 in surface DIC from air-sea gas exchange. Seasonally, Δ14C values varied by 3.4‰ between 2011 and 2022, where seasonal δ13C values varied by 0.7‰. The seasonal variation in Δ14C values is likely driven by variations in upwelling, surface eddies, and mixed layer depth. The variation in δ13C values appears to be driven by isotopic fractionation from marine primary producers. The DIC δ13C and Δ14C values record the influence of the drought that began in 2012, and a major upwelling event in 2016.

The Cedars ultramafic block hosts alkaline springs (pH > 11) in which calcium carbonate forms upon uptake of atmospheric CO2 and at times via mixing with surface water. These processes lead to distinct carbonate morphologies with ``floes" forming at the atmosphere-water interface, "snow" of fine particles accumulating at the bottom of pools and terraced constructions of travertine. Floe material is mainly composed of aragonite needles despite CaCO3 precipitation occurring in waters with low Mg/Ca (<0.01). Precipitation of aragonite is likely promoted by the high pH (11.5-12.0) of pool waters, in agreement with published experiments illustrating the effect of pH on calcium carbonate polymorph selection. The calcium carbonates exhibit an extreme range and approximately 1:1 covariation in delta C-13 (-9 to -28 parts per thousand VPDB) and delta(18) O (0 to -20 parts per thousand VPDB) that is characteristic of travertine formed in high pH waters. The large isotopic fractionations have previously been attributed to kinetic isotope effects accompanying CO2 hydroxylation but the controls on the delta C-13-delta O-18 endmembers and slope have not been fully resolved, limiting the use of travertine as a paleoenvironmental archive. The limited areal extent of the springs (similar to 0.5 km(2)) and the limited range of water sources and temperatures, combined with our sampling strategy, allow us to place tight constraints on the processes involved in generating the systematic C and O isotope variations. We develop an isotopic reaction-diffusion model and an isotopic box model for a CO2-fed solution that tracks the isotopic composition of each dissolved inorganic carbon (DIC) species and CaCO3. The box model includes four sources or sinks of DIC (atmospheric CO2, high pH spring water, fresh creek water, and CaCO3 precipitation). Model parameters are informed by new floe Delta Ca-44 data (similar to 0.75 +/- 0.07%), direct mineral growth rate measurements (4.8 to 8 x 10(-7) mol/m(2)/s) and by previously published elemental and isotopic data of local water and DIC sources. Model results suggest two processes control the extremes of the array: (1) the isotopically light end member is controlled by the isotopic composition of atmospheric CO2 and the kinetic isotope fractionation factor (KFF (%) = (alpha - 1) x 1000) accompanying CO2 hydroxylation, estimated here to be -17.1 +/- 0.8 parts per thousand (vs. CO2(aq)) for carbon and -7.1 +/- 1.1% (vs. 'CO2(aq)+ H2O') for oxygen at 17.4 +/- 1.0 degrees C. Combining our results with revised CO2 hydroxylation KFF values based on previous work suggests consistent KFF values of -17.0 +/- 0.3 parts per thousand (vs. CO2(aq)) for carbon and -6.8 +/- 0.8% for oxygen (vs. 'CO2(aq)+ H2O') over the 17-28 degrees C temperature range. (2) The isotopically heavy endmember of calcium carbonates at The Cedars reflects the composition of isotopically equilibrated DIC from creek or surface water (mostly HCO3-, pH = 7.8-8.7) that occasionally mixes with the high-pH spring water. The bulk carbonate delta C-13 and delta O-18 values of modern and ancient travertines therefore reflect the proportion of calcium carbonate formed by processes (1) and (2), with process (2) dominating the carbonate precipitation budget at The Cedars.