新疆东天山图拉尔根大型铜镍矿床硫化物珠滴构造的特征及其对通道式成矿的指示

东天山图拉尔根岩浆铜镍硫化物矿床中产出一种不常见的硫化物珠滴状构造。这些硫化物珠滴粒度在5~20mm左右,是由磁黄铁矿、镍黄铁矿、黄铜矿等硫化物矿物组成的斑杂状硫化物集合体。野外观察发现硫化物珠滴具有各种几何形态,产出在稀疏浸染状硫化物和无矿化的辉石岩之间的部位。对图拉尔根杂岩体中发育的24个硫化物珠滴的统计结果显示,平缓厚层状矿化部位的硫化物珠滴呈水平方向拉长,陡倾薄层状矿化部位的硫化物珠滴呈陡倾拉长,珠滴的拉长方向和矿体的延伸方向一致。这表明在含矿母岩浆上升就位到中上地壳的过程中,硫化物珠滴受到熔浆流动的控制,因而其形态可以很好地指示通道式成矿硫化物熔体运动的方向。 硫化物珠滴的矿相学和电子探针数据表明其具有向地性特征,即磁黄铁矿和镍黄铁矿先结晶,沉淀在下部; 珠滴上部为后结晶的黄铜矿和其它富铜硫化物。这种元素分布可能对贯入块状硫化物矿石同样适用。碲化物和铋化物在硫化物珠滴中的含量明显高于其在早结晶的浸染状硫化物中的含量,表明富Te和Bi等元素及挥发份的熔体是在岩浆演化后期开始富集结晶的。     

On the ecology of oligochaetes: Monthly variation of community composition and environmental characteristics in two South Carolina tidal creeks

In the tidal creeks of the southeastern United States, the numerically and ecologically dominant macrobenthic organisms are typically oligochaetes. Due to their relatively small size and difficult taxonomy, little is known about the short-term and seasonal changes in the oligochaetes of tidal creeks. This study presents a report of the spatial and temporal changes of the oligochaete taxa within and between two tidal creeks in southern South Carolina, at monthly intervals over a 13-month period. These changes are framed within the reference of monthly changes in benthic chlorophylla, sediment composition, and porewater ammonia, as well as in the perspective of seasonal changes in the entire tidal creek macrobenthic community. The most abundant oligochaete found in this study was the tubificidMonopylephorus rubroniveus, followed by the naidParanais litoralis and the tubificidsTubificoides heterochaetus andT. brownae. All of the oligochaetes exhibited strong month-to-month and spatial changes, indicative of changes in water quality and sediment habitat characteristics (e.g., low dissolved oxygen, high benthic chlorophylla). There were significant correlations between the abundance of most species and either benthic chlorophylla concentration or the silt-clay fraction of the sediment. Looking at short-term changes in this rapidly changing component of the macrobenthic community provides insight not only into the ecology of the oligochaetes, but also into the changes in the tidal creek ecosystem and their potential effects on other biota.     

Relationships Between Meteorological and Water Quality Variables and Fisheries-Independent White Shrimp (<Emphasis Type="Italic">Litopenaeus setiferus</Emphasis>) Catch in the ACE Basin NERR,South Carolina

White shrimp (Litopenaeus setiferus) fisheries-independent and fisheries-dependent landings can be highly variable and may be related to environmental factors that influence growth, mortality, and survival. We used linear regression analysis to look for potential relationships between environmental and white shrimp catch-per-unit-effort (CPUE) data collected from the Ashepoo-Combahee-Edisto (ACE) Basin National Estuarine Research Reserve (NERR) for four critical months in the shrimp life cycle. This analysis used data from white shrimp fisheries-independent CPUE (2002 to 2014) and water quality and meteorological variables for August (juvenile), December (sub-adult), March (adult), and April (spawning adult). The results showed that shrimp CPUE was mainly correlated with water temperature, salinity, and dissolved oxygen concentration collected through the ACE Basin NERR’s System-Wide Monitoring Program (SWMP), but offshore wind, precipitation, and intra-annual CPUEs also partially explained the variability in monthly CPUEs. Black gill prevalence was correlated with water temperature and salinity. Additionally, our analysis found that winter water temperatures of ≤11 °C were correlated with reduced shrimp abundance the following spring. Ultimately, managers would like to successfully predict white shrimp stock abundance throughout fishing seasons based on environmental conditions. This study is a first step in identifying the environmental variables that may be useful in predicting white shrimp CPUE in the South Atlantic Bight. The techniques employed here can serve as a basis for predicting and managing other wild annual fisheries stocks.     

Fossil pigments as a guide to the paleolimnology of Browns Lake, Ohio

Some aspects of the paleolimnology of Browns Lake, Ohio, have been ascertained by a study of preserved sedimentary plant pigments and conductivity of interstitial water. Temporal changes in the sedimentary environment, especially redox conditions, along with changes in the flora of the lake and the development of peat in the basin have brought about differential sedimentation and preservation of pigments. Measurement of changes in total and relative concentration and diversity of chlorophyll derivatives and carotenoids has provided important clues to late-glacial and postglacial evolution of the lake. Laminated sediments, rich in fossil remains, near the base of the core indicate eutrophic conditions and meromixis for several thousand years beginning shortly after lake inception. As meromixis broke down, the lake evolved gradually to holomictic conditions when sapropel was deposited. An advancing complex of reed swamp and fen forest began during midpostglacial time, providing ever-increasing amounts of highly organic, peaty sediments and continues to the present. The pond is now dystrophic, and increasing deposition of inorganic sediment is apparent at the top of the core, concomitant with land clearance and agriculture. In the same interval, an increase of water conductivity reflects recent agricultural practices and industrialization in the region.     

Snapper (Chrysophrys auratus): a review of life history and key vulnerabilities in New Zealand

Snapper (Chrysophrys auratus) is an important coastal fish species in New Zealand for a variety of reasons, but the large amount of research conducted on snapper has not been reviewed. Here, we review life history information and potential threats for snapper in New Zealand. We present information on snapper life history, defining stages (eggs and larvae, juvenile and adult), and assess potential threats and knowledge gaps. Overall we identify six key points: 1. post-settlement snapper are highly associated with certain estuarine habitats that are under threat from land-based stressors. This may serve as a bottleneck for snapper populations; 2. the largest knowledge gaps relate to the eggs and larvae. Additional knowledge may help to anticipate the effects of climate change, which will likely have the greatest influence on these early life stages; 3. ocean acidification, from land-based sources and from climate change, may be an important threat to larval snapper; 4. a greater understanding of population connectivity would improve certainty around the sustainability of fishery exploitation; 5. the collateral effects of fishing are likely to be relevant to fishery productivity, ecosystem integrity and enduser value; 6. our understanding of the interrelationships between snapper and other ecosystem components is still deficient.     

Exploring impacts of development and climate change on stormwater runoff

Stormwater runoff is a leading cause of non‐point source pollution in urbanizing areas, and runoff effects will be exacerbated by climate's changing patterns of precipitation. To enhance understanding of impacts of development and climate change on stormwater runoff in small watersheds (< 6500 ha), we developed the Stormwater Runoff Modeling System (SWARM), a simple modeling system based on U.S. Department of Agriculture, Natural Resources Conservation Service curve number and unit hydrograph methods. The objective of this paper is to describe the applications possible with SWARM and to demonstrate its usefulness in exploring the impacts of development and climate change on runoff. Results encompass a range of impact scenarios. One development scenario shows that the amount of rainfall converted to runoff is 27% for an undeveloped area and 67% for a highly developed area. A climate scenario shows that the amount of rainfall converted to runoff in a medium developed area is 25% in drought conditions and 76% in wet conditions. User‐friendly templates make SWARM a good tool for scientific research, for resource management and decision making, and for community science education. The modeling system also supports the investigation of social and economic impacts to communities as they adapt to increased development and climate change. Although we calibrated SWARM specifically to the southeast coastal plain, it can be applied to other regions by recalibrating parameters and modifying calculation templates. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.     

Relative abundance of snapper (Chrysophrys auratus) across habitats within an estuarine system

Many fish species rely on estuarine nursery habitats as they transition to adult life stages. Quantifying nursery value, however, requires identification of the life stages (often small and short-lived) that utilise nursery habitats, and survey methods that provide comparable estimates across habitats. We focused our surveys on post-settlement snapper (Chrysophrys auratus) using video camera deployments across habitats within a northeastern New Zealand harbour. Post-settlement snapper abundance was higher among structured habitat types relative to bare sediments, with the type of structured habitat not influential. The exception appeared to be for reef habitat (although sampling was limited). Reef sites were structurally complex, but largely inhabited by older life stages (snapper and other fish species). Overall, nursery value for snapper appears to be connected to structure, rather than structure type. This result emphasises the importance of a broadened scope to coastal fishery management, one that incorporates not just fish extraction, but also habitat maintenance or restoration.     

Body and brood sizes of Tenagomysis spp. (Crustacea: Mysida) in southern estuaries in New Zealand

Mysids form a large biomass and mediate the benthic–pelagic coupling of numerous estuaries in southern New Zealand. An intra-annual (2011–2012) field survey in the breeding seasons (i.e. austral spring followed by summer) of mysids Tenagomysis chiltoni and Tenagomysis novaezealandiae, examining the body and brood sizes, was conducted. Samples were collected from six open and eight intermittently open/closed estuaries along the Otago coastline. Brood size of gravid females of T. chiltoni was not significantly related to their body size. Brood size of gravid females of T. novaezealandiae showed a significantly positive relationship with body size in spring but not in summer. It appears that brood size of gravid mysids do not always necessarily depend on body size, but may be influenced by breeding season (e.g. spring) and estuarine typology (e.g. intermittently open/closed).     

The great lakes clean-up

The Great Lakes are at last to be cleaned up. An agreement signed in Canada by President Nixon commits Canada and the US to spend 3,500 million dollars over five years de-polluting the immense lakes—Lake Erie is twice the size of Jamaica and Lake Ontario is twice the size of Cyprus. Currently, Erie has become known as the dead lake—but in a few years game fish could be back in it.     

Population trends of New Zealand fur seals in the Rakiura region based on long-term population surveys and traditional ecological knowledge

We estimated population abundance of New Zealand fur seal (Arctocephalus forsteri) pups on Bench Island off Stewart Island, New Zealand seven times between 1996 and 2012. Overall, there was a 29% increase in pup abundance from 1996 to 2012 at the Main Beach colony, corresponding to a mean annual growth rate of 1.6% and a doubling time of approximately 40 years. At the Sprat Point colony, there was an overall increase of 29% between 2003 and 2012 corresponding to a mean annual growth rate of 2.9% and a doubling time of approximately 25 years. The area occupied by both colonies has also increased. In 2006, we surveyed East Beach and counted a total of 201 pups. We obtained traditional ecological knowledge of fur seal distribution and breeding status from local Māori for 46 locations around Stewart Island, 36 of which have not been surveyed since Wilson in 1971–1974; this supports an expansion of fur seal presence and breeding areas in the region in the last 41 years.