Modes of iron-manganese mineralization on the bottom of Lake Baikal

The investigation of the bottom of Lake Baikal carried out during the 2008 summer season by means of Mir manned deep-submergence vehicles resulted in the recovery of a series of sediments, ferruginous crusts, and peculiar mineralized tubes several centimeters high and up to 2–6 cm in diameter. According to the scanning electron investigation, these formations consist mainly of the enclosing sediment particles and biogcnie silica cemented by iron and minor manganese hydroxides. The chemical composition of the tubes is similar to both that of the enclosing sediments and slightly ferruginous crusts and nodules, but the tubes and crusts are somewhat richer relative to the sediments in some microelements, namely, arsenic, cadmium, and uranium. In general, the structure and composition of these tubes reminds one of the worm tubes common in the sediments of a number of seas. The investigation of the rare earth elements in some samples or ferruginous formations and sediments revealed a positive europium anomaly, which might be related to either the composition of the surrounding continental magmatic rocks or to the influence of hypothetical hydrothermal solutions.     

Inorganic and organic nitrogen cycling in the Southern California Bight

On the basis of mass balance calculations performed for nitrogen (N) uptake experiments in the Southern California Bight (SCB), it has been suggested that a significant portion of dissolved inorganic N (DIN) uptake results in the production of dissolved organic N (DON). To investigate this process, the fate of ammonium (NH₄⁺) and nitrate (NO₃⁻) uptake was quantified within the euphotic zone at three coastal stations in the SCB using ¹⁵N tracer techniques. Several trends in the fate of DIN and the production of DON were observed. First, production of particulate N (PN), from both NH₄⁺ and NO₃⁻, was quantitatively more important in near surface waters, while DON release dominated within the nitracline. Second, the percentage of gross N uptake released as DON was generally higher when NO₃⁻, rather than NH₄⁺, was the substrate. Third, the percentage of N released as DON was higher at night, relative to the day. Fourth, rates of DON release were significantly correlated to NH₄⁺ regeneration, suggesting that similar mechanisms are responsible for both processes—presumably grazing. The results of this study indicate that the DON pool is a sink for DIN uptake on the time scale of hours. One implication of this finding is that new production estimates based on ¹⁵NO₃⁻ uptake rates will likely underestimate particle flux out of the surface layer because the rate of NO₃⁻ uptake is underestimated due to loss of DO¹⁵N during the incubation. On time scales of months to years, however, the N that is taken up as NO₃⁻ and released as DON will likely contribute to export flux via incorporation of the dissolved phase during seasonal mixing into sinking particles or transport. The export of DON on these time scales argues for the use of gross uptake rates to calculate f-ratios.     

Characterisation of domestic and industrial sewage in Southern California coastal sediments using nitrogen,carbon, sulphur and uranium tracers

A degradation-mixing model has been developed to aid in the interpretation of geochemical processes occurring in sewage-contaminated marine sediment near San Pedro, California. The nitrogen isotope ratio (${}^{15}{}^{14}\text{N}$) is shown to be an effective tracer of sewage discharge-on the San Pedro Shelf. Isotopic fractionation of ${}^{15}\text{N}{}^{14}\text{N}$ during release of amino compounds or ammonia (as a consequence of bacterial degradation of organic detritus) appears to be negligible. The nitrogen isotope ratio, therefore, may be considered a conservative component for tracing the source of organic matter deposited in marine sediment.Uranium enrichment from seawater is shown not to occur in the highly reducing sewage-contaminated sediments. The content of uranium in the effluent particulates (18 ppm) is large compared with the content in the uncontaminated sediment (3 to 5 ppm). This allows the content of uranium to also be used as a tool for tracing the deposition of sewage particles in marine sediment. Uranium and nitrogen are shown to be incorporated in the organic fraction of sewage effluent and are released during bacterial degradation of the organic matter. Cadmium and sulphur are shown not to be mobilised during sewage deposition and degradation. The stable isotope ratio of sulphur (${}^{34}\text{S}{}^{32}\text{S}$) is used to demonstrate that sulphur enrichment occurs in the sediment by in situ reduction of seawater sulphate. The data summarised by Morel et al. (1975) are presented and discussed in accordance with the above model.     

Organic carbon and nitrogen in the northern California current system: comparison of offshore, river plume, and coastally upwelled waters

During the first year of the Northeast Pacific GLOBEC program we examined the spatial distributions of dissolved and particulate organic carbon and nitrogen in the surface waters off the Oregon and Washington coasts of North America. Eleven east–west transects were sampled from nearshore waters to 190 km offshore. Hydrographic data and the distribution of inorganic nutrients were used to characterize three distinct water sources: oligotrophic offshore water, the Columbia River plume, and the coastal upwelling region inshore of the California Current. Warm, high salinity offshore water had very low levels of inorganic nutrients, particulate organic carbon (POC) and dissolved organic carbon (DOC). Warm, low salinity water in the Columbia River plume was relatively low in nitrate, but showed a strong negative correlation between salinity and silicate. The river plume water had the highest levels of total organic carbon (TOC) (up to 180 μM) and DOC (up to 150 μM) observed anywhere in the sampling area. Cold, high salinity coastal waters had high nutrient levels, moderate to high levels of POC and particulate organic nitrogen (PON), and low to moderate levels of DOC and dissolved organic nitrogen (DON). Each of these regions has characteristic C:N ratios for particulate and dissolved organic material. The results are compared to concentrations and partitioning of particulate and dissolved organic carbon and nitrogen in other regions of the North Pacific and North Atlantic Oceans.     

The past, present and future evolution of Hurst Castle spit, Hampshire

Previous models of the evolution of Hurst Castle Spit over-emphasised longshore growth at the expense of other processes, particularly rise in sea-level. Initially, a Pleistocene valley system was submerged creating a tidal strait, the West Solent, between Christchurch Bay and the East Solent. This almost certainly caused a major hydrodynamic change, transforming much of Christchurch Bay and the West Solent from a low to a high tidal energy environment. Hurst Castle Spit and the Shingles Bank then began to form due to a combination of an easterly littoral drift, offshore gravel movement due to the high tidal energy, a rising sea-level, the transgression of Hurst Beach due to overwashing and the formation of recurves due to waves in the West Solent. The growth of the Shingles Bank due to offshore sediment movement from Hurst Castle Spit was of particular importance because of its influence on the wave energy along Hurst Beach. Significant local supplies of shingle in the vicinity of Hurst Castle Spit, reworked from Quatenary deposits, were also of importance. Thus, it is not a classic multi-recurved spit and the transgressive segment, Hurst Beach, has much in common with barrier coastlines.The same processes are continuing to shape Hurst Castle Spit at present, with the additional effects of human interference in the coastal sediment system. The construction of sea defences at Milford-on-Sea in the period 1936 to 1968 has modified the sediment budget and Hurst Castle Spit is experiencing a phase of rapid evolution: maximum recession rates have increased from 1.5m a⁻¹ (1867–1968) to 3.5m a⁻¹ (1968–1982). It is difficult to quantify the exact role of sea-level rise in the present evolution of Hurst Castle Spit.The future evolution of Hurst Castle Spit will depend largely on man. If there is no further interference, which is highly unlikely, the beach volume will continue to decline, resulting in a further increase in the rate of recession. Ultimately, a true tidal breach will probably form, marking a new phase in the evolution of Hurst Castle Spit and its environs. However, shingle renourishment, or another coastal engineering solution will probably be undertaken. The future rate of sea-level rise will have important long-term influences on all these options.     

Evidence for storm-dominated early progradation of Castle Neck barrier, Massachusetts, USA

Washovers, dune scarps and flattened beach profiles with concentrations of coarse-grained sediment or heavy minerals are the diagnostic geological signatures of large storms on barriers today. It is clear that storms are a major force driving transgressive barriers onshore, but what is not as well understood is the role these powerful erosive events play in the evolution of prograding barriers. Application of ground-penetrating radar (GPR) and a combination of coring techniques have significantly improved our ability to image barrier architecture. Results of these studies reveal a more complex evolution than previously recognized. It is now possible to precisely locate and map storm deposits within prograded barrier lithosomes.

A comprehensive study of northern Castle Neck, Massachusetts was performed using 15 km of GPR surveys, a 120-m-long seismic line, 11 cores, and several radiocarbon dates. Storm-related layers are the most prominent horizons contained in the barrier stratigraphy. The geometry and sedimentology of these layers closely resembles those of a present-day post-storm beach. Twenty closely spaced, curvilinear heavy mineral layers imaged in the landward portion of the barrier suggest that the Castle Neck barrier was heavily influenced by storms during its initial phase of progradation beginning 4000 years BP. Approximately 1800 years BP, two intense storms impacted the coast depositing two extensive coarse-grained units. These layers mimic the flat-lying sand and gravel deposits that occur in front of a nearby eroding till outcrop following major storms. The great number of storm deposits in the early history of Castle Neck is related to either a period of greater storm activity and/or a slow rate of barrier progradation. The occurrence and preservation of these earlier storm layers are likely a product of the exposure of nearby drumlins resulting in greater availability of iron oxide and ferromagnesian sands. The supply of heavy-mineral sands has gradually diminished as the barrier prograded and the proximal drumlin source was buried by beach and dune sands.     

Heterotrophic euglenids from marine sediments of cape tribulation, tropical australia

This paper presents new data on free-living heterotrophic euglenids (Euglenozoa, Protista) that occurred in the marine sediments at Cape Tribulation, Queensland, Australia. Twenty-nine species from 9 genera are described with uninterpreted records based on light microscopy, including one new taxon:Notosolenus capetribulationi n. sp. There was little evidence for endemism because the majority of heterotrophic euglenid species encountered here have been reported or were found from other habitats.     

异养细菌在海洋生态系统中的作用

概述异养细菌的分布、生物学特点、对物质矿化分解的作用以及在海洋生态系统物质循环和能量流动中的作用 ;海洋细菌生物量和生产力的研究方法 ;异养细菌在铁限制大洋生态系中的作用 ;国内外对底栖异养细菌生态功能研究的现状 ;最后提出该领域今后应加强研究的内容     

卡德藻自养、异养与兼养培养的比较研究

本文对卡德藻在自养、异养和兼养培养条件下的比生长速率、细胞密度、细胞色素组成及脂肪酸组成等方面进行了比较研究。兼养卡德藻的细胞密度大于自养条件和异养条件下细胞密度之和。兼养培养的卡德藻比生长速率是自养的 2倍 ,异养的 1.3倍。兼养和异养生长的对数期较自养的长。光合自养培养卡德藻最适光强为 10 0 0 0 lx,而兼养培养最适光强范围为 10 0 0～ 2 0 0 0 lx。在自养和兼养培养时亚油酸的含量很高 ,自养和兼养状态下分别为 16 .6 %和 17.4 9%。 EPA合成的量较低。异养藻的多不饱和脂肪酸的产量较自养藻和兼养藻要低。兼养藻细胞光合色素组成和含量与自养藻细胞的基本一致 ,但在异养条件下藻细胞色素组成发生明显改变。     

Tracing flocculent industrial and domestic sewage transport on San Pedro Shelf,Southern California,by nitrogen and sulphur isotope ratios

Domestic and industrial sewage is discharged at a depth of 60 m near Whites Point on the San Pedro Shelf, Southern California borderland. A density-stratified thermocline, above the outfall at a depth of 20 to 30 m, is thought to prevent most effluent particles from reaching shallower depths and recreational facilities. In this investigation, measurement of the natural abundance of nitrogen isotopes (${}^{15}\text{N}{}^{14}\text{N}$) is used to determine the level of sewage contribution to flocculent suspended material persisting at water depths of 7, 13 and 20 m. Organic nitrogen at 20 m depth was shown to be predominantly of sewage-origin and at 7 m, predominantly of marine origin. Organic nitrogen at 13 m depth and within 3 km of the outfall pipes is predominantly sewage in origin.Stable isotope composition of sulphur (${}^{32}\text{S}{}^{34}\text{S}$) in the flocculent material indicates that the effluent particles contain metabolic sulphur, incorporated from dissolved seawater, as well as bacterially produced mineral sulphide.     

The amino acid composition of estuarine colloidal material

Amino acids were determined in estuarine colloidal and particulate material from near surface waters ranging from fresh to brackish water (12 g kg^?1 salinity). The hydrolizable amino acids and associated ammonia account for an average of 80% of the nitrogen present in colloidal samples, and approximately 75% of the nitrogen from particulate fractions of the same samples. The relative proportions of these amino acids are similar to those of a cultured estuarine diatom. There are no significant amounts of D amino acids, or non-protein amino acids characteristic of bacteria in sediments and soil. A single deep-water sample (25 m) shows some evidence of bottom mud resuspension by the presence of a possible aspartic acid-hydroxyproline dimer.     

Inhibition of essential amino acid absorption in marine fishes by mercury

In polluted coastal waters marine fish can concentrate heavy metals in the intestine two or more orders of magnitude above those found in the water column and several-fold higher than the sediment level. These accumulations are primarily due to ingestion of contaminated food and drink. Relatively long residence time of gut content, low permeability coefficient of divalent cations through the lipid bilayers of membranes and profuse binding to the negative charge sites on the mucosal side of the gut, all combine to increase the concentration of heavy metals in the lumen. Do these high levels of heavy metals interfere with the normal processes of nutrient absorption? We have measured the effect of HgCl₂ and CH₃HgCl on the absorption of the essential amino acids, l-leucine, l-isoleucine, l-lysine and l-methionine, by the intestine of Fundulus and toadfish in vitro and in vivo. At concentrations expected in the gut, HgCl₂ can inhibit 20–80% of the leucine absorption; CH₃HgCl is less potent in this respect. While the action of Hg²⁺ appears to be limited to the luminal side, the more lipophilic CH₃Hg⁺ rapidly penetrates the epithelial cell layer and can inhibit the intracellular energy production needed for transport. The implications of these findings for growth and survival of marine fishes are discussed.     

Biota of a subalpine springbrook in the Southern Alps

The flora and fauna of a subalpine springbrook at Cass in the Southern Alps of New Zealand was studied from April 1975 to January 1976. Spring water was moderately hard (30.0 g.m.^‐3), with high concentrations of dissolved oxygen (> 90% saturation) and carbon dioxide (5–14 g.m^‐3) and a temperature of 6.0–6.5°C. Three mosses covered much of the stream bed and formed distinct zones. Fissidens rigidulus inhabited torrential, water near the middle of the channel, Pterygophyllum quadrijarium. grew in the water‐saturated inner spray zone, and Cratoneuropsis relaxa inhabited the outer spray zone. In moss samples, 44 species of invertebrates were collected, mainly immature stages of insects. Zelandoperla jenestrata (Plecoptera), Zelolessica cheira (Trichoptera) a species of Empididae (Diptera) and several species of Chironomidae were most abundant in Fissidens; Austroperla cyrene (Plecoptera), a species of Helodidae (Coleoptera) and a triclad, Neppia montana, were most abundant in Pterygophyllum; an isopod, Styloniscus otakensis, was the only common animal on Cratoneuropsis. It is suggested that animal microdistribution patterns reflect differences in water saturation, flow rates, and detritus trapping ability within the moss zones.     

Seasonal occurrence of larval fishes in the nearshore Southern California Bight off San Onofre,California

Larval fishes were sampled from the nearshore region of the Southern California Bight off San Onofre for 29 months and analyzed with a Curtis-Bray Cluster Analysis to determine temporal assemblages and species associations. Two major assemblages of larvae were found: members of the winter-spring (December-May) assemblage were most abundant from January to May; members of the summer-fall (June-November) assemblage were most abundant from July to September. The winter-spring assemblage was composed primarily of Engraulis mordax, Genyonemus lineatus, Sebastes spp. and Paralichthys californicus; some abundant taxa in the summer-fall assemblage were Seriphus politus, Paralabrax spp., and Hypsoblennius spp., although E. mordax again predominated. Demersal spawners tended to have spawning seasons of longer duration than pelagic spawners; winter-spring spawners generally had longer spawning seasons than summer-fall spawners.We suggest that temperature is an important determinant in the seasonal pattern of larval fish occurrence. The annual ocean temperature cycle near San Onofre was a good indicator of the seasonal occurrence of fish larvae in this area. Larvae found in the cooler months were generally offspring of adults whose northern ranges extend to Canada. Warm-water larvae were offspring of adults whose northern ranges extend to Point Conception or northern California.     

渤海湾海域浮游细菌的生态研究

研究了2004年8月份和10月份渤海湾水体中异养浮游细菌数量分布及其与生态环境因子的关系。结果显示,8月份异养浮游细菌的数量在(5.7~150)×106cfu/L,最高值出现在海河口附近的6号站位,次高值出现在11站位,此季节细菌总体分布是近岸略高,调查范围的南部比北部高;10月份异养浮游细菌的数量在(3~121)×106cfu/L,最高值和次高值出现在海河口附近的5,6号站位,此季节异养浮游细菌总体分布情况是近岸比远岸高,调查范围的南部比北部高。8月份异养细菌数与溶氧量有明显的相关性;10月份异养细菌数与溶氧量有高度明显的相关性,与生化需氧量、氨氮都有较明显的相关性。     

Foraminiferal distribution in one bed,Monterey Formation,California

All 146,039 foraminifera obtained from twenty-four 5-ml replicate samples taken 10-cm apart along one 8-cm thick bed in the Monterey Formation were identified and counted. Replicates 1 through 19 and 20 through 24 differ taxonomically and, very significantly, numerically. Differences probably reflect postmortem transport, small-scale ecological variations, and possibly other phenomena. Such foraminiferal distributions can assist both the determination of sampling adequacy and sedimentation processes themselves.     

坛紫菜氨基酸提取工艺影响条件的优化与分析

以坛紫菜（Porphyra haitanensis）为实验材料,采用盐酸水解法和浸提法,以日立L-8900型高速全自动氨基酸分析仪为测定仪器,分别研究了坛紫菜总氨基酸（TAA）和游离氨基酸（FAA）在提取过程中各条件的不同水平对提取结果的影响.实验结果表明：（1）利用正交设计L9（34）对影响TAA提取的4个条件（藻体质量、稀释倍数、干燥温度、空白值）在3个水平上进行优化实验,藻体质量、稀释倍数对测定结果影响显著,干燥温度影响不显著;通过实验筛选出各条件的最佳水平为：藻体质量为0.050 0g,稀释3倍,干燥温度为60℃.（2）利用正交设计L16（45）对影响FAA测定的5个条件（藻体质量、提取液、提取温度、提取时间、空白值）在4个水平上进行优化实验,结果表明藻体质量、提取液、提取温度、提取时间的不同水平对测定结果均有显著影响,其中藻体质量对结果的影响最大;通过实验筛选出各条件的最佳水平为：藻体质量为0.010 0 g,提取液为去离子水,提取温度为60℃,提取时间为4 h.     

The nitrogen cycle of an East Coast,U.K., saltmarsh: I. Nitrogen assimilation during primary production; Detrital mineralization

Nitrogen assimilation during primary production by the association of Puccinellia maritima/Halimione portulacoides which dominates the surface of the Colne Point saltmarsh, Essex, U.K., was measured. Nitrogen assimilated annually was 1·159 moles N m⁻² year⁻¹, of which assimilation by P. maritima accounted for 90%. Mineralization of organic-N from plant detritus was also measured at five sites representing the different marsh habitats. The annual amount of organic-N mineralized on the marsh surface almost exactly balanced the annual assimilation by P. maritima/H. portulacoides, suggesting that the nitrogen cycle of the marsh was balanced between production and decay. Mineralization of detrital organic-N within the sediments varied seasonally because of seasonal changes of environmental temperature, but was also shown to be influenced by seasonal variations in the amounts of mineralizable organic-N present in the sediments.     

南黄海溶解态氨基酸组成特征及DON生物可利用性研究

生物可利用性有机氮(BDON)在海洋生态系统氮循环中起着关键作用, 氨基酸是BDON的重要组成部分, 也是DON生物可利用性的重要指示物。本研究阐述2021年春、夏季南黄海水体中总溶解氨基酸(THAA)组成和时空分布特征, 并对南黄海DON生物可利用性进行分析。南黄海DON物质的量的浓度(下文简称浓度)分布呈现近岸高、远岸低的特征, 夏季THAA水平分布上呈现北高南低的特征。夏季南黄海THAA的平均浓度(1.11±0.34μmol/L)略高于春季(0.98±0.28 μmol/L) 而DON平均浓度春季(8.17±5.06 μmol/L)明显高于夏季(5.72±2.82 μmol/L)。南黄海氨基酸主要由丝氨酸、甘氨酸+苏氨酸、谷氨酸、精氨酸、丙氨酸等构成, 其占总氨基酸的比例春季(61.51%)略低于夏季(65.69%)。南黄海以硅藻为主的浮游植物群落是水体氨基酸的重要来源, 浒苔绿潮暴发显著影响了水体氨基酸的组成。夏初浒苔绿潮进入消亡和降解阶段, 这可能是南黄海35°N以北海域DON具有很高的生物可利用性的重要原因。     

两种黄海潮间带海绵的元素与氨基酸成分分析

应用能量色散X射线荧光光谱(EDXRF)分析了黄海潮间带繁茂膜海绵(Hymeniacidon perleve)和肾指海绵(Reniochalina sp.)的无机元素,其中硅是两种海绵中最多的无机元素。繁茂膜海绵较肾指海绵的锌含量高,参照文献数据推测这可能是该属海绵的特性。测定了2种海绵的含水量,有机碳、氮、氢元素和氯基酸在海绵干质量中的比例。分析了繁茂膜海绵在2002年8月到11月中主要无机元素的变化,发现繁茂膜海绵中的硅含量在降低。繁茂膜海绵的氨基酸总量远高于肾指海绵,2种海绵中含量较高的氨基酸是甘氨酸、谷氨酸、天冬氨酸、亮氨酸、缬氨酸、赖氨酸等。元素与氨基酸分析将对海绵细胞培养基开发有帮助。