Substrate Effects on the Bioeroding Demosponge Cliona orientalis.2. Substrate Colonisation and Tissue Growth

Abstract Sponge bioerosion is a result of tissue expansion of endolithic sponges in calcium carbonate substrates. The efficiency of erosion by the sponges can be affected by substrate features, which are thus also likely to influence the way in which the sponge will grow. A field experiment was conducted, in which sponge tissue was grafted to biogenic blocks cut from the corals Goniopora tenuidens, massive Porites sp., Astreopora listeri, Favites halicora, Favia pallida, Goniastrea retiformis and Cyphastrea serailia, and the clam Tridacna squamosa, to investigate colonisation capabilities and growth patterns of Cliona orientalis Thiele, 1900 after 9 months of the experiment. C. orientalis is not substrate‐specific. It invaded > 90 % of the different substrate blocks and penetrated them to varying depths, but usually only down to slightly more than 1 cm. Lateral penetration clearly exceeded depth penetration. Enlargement of surface area versus restricted depth penetration benefits the symbiotic zooxanthellae located in the sponge's surface. Structural irregularities and barriers such as coral dissepiments temporarily deflected the direction of tissue growth and created characteristic tissue patch patterns in different substrates. Tissue growth may be more pronounced in substrates of higher density and lower pore volume, but evidence was only slight. Protection against predation is better in denser materials, which may stimulate the sponge's tissue growth especially in shallower substrate depth. In more porous substrates, favoured by grazers and corallivores, relatively more tissue was located in deeper layers.     

The crystallographic fabric and texture of siderite in concretions: implications for siderite nucleation and growth processes

The crystallographic fabric of siderite in siderite concretions has been determined for upper Carboniferous (Westphalian‐A) non‐marine concretions and lower Jurassic (Pliensbachian) marine concretions. Compositional zoning indicates that individual siderite crystals grew over a period of changing pore water chemistry, consistent with the concretions being initially a diffuse patch of cement, which grew progressively. The siderite crystallographic fabric was analysed using the anisotropy of magnetic susceptibility, which is carried by paramagnetic siderite. The siderite concretions from marine and non‐marine formations exhibit differences in fabric style, although both display increases in the degree of preferred siderite c‐axis orientation towards the concretion margins. The Westphalian non‐marine siderites show a preferred orientation of siderite c‐axes in the bedding plane, whereas the Pliensbachian marine siderites have a preferred orientation of c‐axes perpendicular to the bedding. In addition, a single marine concretion shows evidence of earlier formed, inclined girdle‐type fabrics, which are intergrown with later formed vertical c‐axis siderite fabrics. The marine and non‐marine fabrics are both apparently controlled by substrate processes at the site of nucleation, which was probably clay mineral surfaces. Siderite nucleation processes on the substrate were most probably controlled by the (bio?) chemistry of the pore waters, which altered the morphology and crystallographic orientation of the forming carbonate. The preferred crystallographic orientation of siderite results from the orientation of the nucleation substrate. Fabric changes across the concretions partially mimic the progressive compaction‐induced alignment of the clay substrates, while the concretion grew during burial.     

以醋酸为共代谢基质时四氯乙烯的生物降解初步研究

四氯乙烯（PCE）是一种广泛用于干洗和脱脂的有机溶剂,是地下水中常见的污染物.在本实验中,将某肉联厂厌氧污泥接种到土壤中,进行微生物培养.当系统中的微生物活性较高时,以醋酸为共代谢基质,进行驯化实验,当系统中的微生物适应浓度为120μg/L的PCE之后,对PCE在厌氧条件下的降解情况进行研究.研究结果表明,将厌氧污泥接种到土壤中培养的微生物,在以醋酸为共代谢基质的条件下,可以使PCE很快转化为三氯乙烯（TCE）,并可以进一步转化为二氯乙烯（DCEs）.PCE在天然地下水中的半衰期为108d,本实验PCE降解的半衰期为2.95d,反应速率常数为0.2342d^-1.     

Radiaxial fibrous calcites as low-magnesian calcite cement precipitated in a marine-meteoric mixing zone

Abstract Radiaxial fibrous calcite (RFC) has previously been interpreted as a marine or replacive cement. Study of the Dongjeom Formation (Early Ordovician), Korea, shows that RFC can form in marine‐meteoric mixing zones as a low‐magnesian calcite (LMC) cement. RFC in the shallow‐marine Dongjeom Formation occurs in arenaceous limestones at the top of a transgressive facies overlying a regressive facies. It shows well‐developed growth zonation, and lighter oxygen isotope values and more radiogenic strontium isotope ratios than those of Early Ordovician marine calcite. Such petrographic and chemical evidence indicates that the RFC was precipitated as a primary LMC cement in a marine and meteoric mixing zone. Owing to the unique environment of formation, the Dongjeom RFC is characterized by growth zonal fabric comprising alternating subzones, which may indicate precipitation from varying fluids. In addition, this study documents the importance of substrate for development of RFC. Early ‘nucleation’ for RFC occurred mainly on microcrystalline skeletal grains and internal sediments, whereas on homogeneously altered substrates, thin‐coated banding structure developed, ultimately forming coarse crystalline spar. This suggests that microcrystalline substrates are preferred sites for nucleation of RFC.     

Substrate damage and recovery after giant clam shell mining at remote coral reefs in the southern South China Sea

Giant clam shell mining(GCSM),a unique phenomenon occurring at remote coral reefs in the southern South China Sea(SCS),forms striking scars on the reef flats and damages the reef flat substrate.Through image analyses at three times(2004.02.02,2014.02.26,and 2019.04.10)and in situ surveys at Ximen Reef,a representative site that has experienced GCSM,we quantified the GCSM-generated substrate damage and the corre-sponding recovery.GCSM was estimated to have occurred sometime between 2012 and 2014,causing reduction in live coral subarea and formation of micro-relief as trenches and mounds.GCSM-generated damage was restricted to the reef flat.After GCSM,coral and algae subarea increased,and the trenches and mounds tended to be filled and eroded,rep-resenting a natural recovery of the substrate.The legal prohibition on human disturbances at the coral reefs contributed to substrate recovery at Ximen Reef.This case also implied that recovery of the other coral reefs that suffered from GCSM is possible.     

不同人工湿地系统中植物的生长特征及净化能力差异

以美人蕉、芦苇、香蒲、黄色鸢尾、水菖蒲、茭白为供试植物,以河沙和青砂为供试基质,通过模拟不同的人工湿地系统研究了植物生长特征及其人工湿地净化能力的变化.结果表明:与河沙处理相比,河沙+蚯蚓处理和河沙+青砂+蚯蚓处理中美人蕉的株高分别增加了42%和47%,叶长分别增加了36%和49%,株径分别增加了28%和20%;同样地,黄花鸢尾的株高分别增加了33%和23%,叶长分别增加了39%和29%,且水菖蒲的株高分别增加了53%和32%.与河沙处理相比,河沙+蚯蚓处理,河沙+青砂+蚯蚓处理中水菖蒲的SPAD值分别增加了20%和30%,黄花鸢尾的SPAD值分别增加了59%和65%,美人蕉的SPAD值分别增加了18%和11%.与对照人工湿地(CK)相比,人工湿地Ⅰ(河沙+植物)、人工湿地Ⅱ(河沙+植物+蚯蚓)和人工湿地Ⅲ(河沙+青砂+植物+蚯蚓)对COD的去除率分别增加了20%,24%和26%,对TP的去除率分别增加了14%,15%和19%,对NH₄-N的去除率分别增加了17%,23%和21%,对TN的去除率分别增加了5%,15%和12%.人工湿地Ⅱ中茭白、芦苇、水菖蒲和黄花鸢尾的密度高于人工湿地Ⅲ.粒径较小的河沙有利于植物的生长和氮的去除,而粒径较大的青砂对磷有较高的去除率.     

Benthic microbial biogeography along the continental shelf shaped by substrates from the Changjiang River plume

Coastal zones are active reactors of continental material including that transported by rivers via a series of microbiota-mediated reactions. Nevertheless, current knowledge of the ecology and functioning of the microbiota in coastal areas affected by large riverine inputs remains insufficient on a global scale. Here, an investigation on sediment microbial composition, including taxonomy and metabolic network, as well as their relationship with major benthic reaction substrates, namely carbon, n...     

Icebergs south‐East of New Zealand in 1967 (note)

Sightings of 85 icebergs south‐east of New Zealand in February and March 1967 are reported, with associated sea surface temperatures.     

Survey of New Zealand trout hatcheries for whirling disease caused by Myxosoma cerebralis

Fourteen hundred trout, mainly Salmo gairdneri, supplied by the four Government and nine Acclimatisation Society hatcheries in New Zealand were examined for the presence of spores of Myxosoma cerebralis (Hofer, 1903) (Protozoa: Myxosporida) in their head cartilage. The only positive result obtained was of a 24% infection rate in fish from the Otago Acclimatisation hatchery at Waitati, near Dunedin, which has since been closed down. Sixty fish were examined from Acclimatisation Societies hatcheries and 200 from Government Hatcheries to give a 95% chance of detecting infections of 5% and 1.5%, respectively, of the fish in these hatcheries. A formula is given for estimating sample sizes on the bases of probable infection rates and the degree of certainty of detection that is required.