Recent anthropogenic impact in ancient Lake Ohrid (Macedonia/Albania): a palaeolimnological approach     

Julia Lorenschat  Xiaosen Zhang  Flavio S. Anselmetti  Jane M. Reed  Martin Wessels  Antje Schwalb 《Journal of Paleolimnology》2014,52(3):139-154

Ancient lakes, which are important centres of biodiversity and endemism, are threatened by a wide variety of human impacts. To assess environmental impact on ancient Lake Ohrid we have taken short sediment cores from two contrasting site locations, comprising a site of urban pollution and an apparently pristine area. Recent impacts on water quality and ecology were assessed using sediment, geochemical, ostracode, and diatom data derived from analysis of two ²¹⁰Pb-dated sediment cores spanning the period from 1918 to 2009. According to the index of geoaccumulation, sediments were often moderately contaminated with As. Fe and Ni concentrations often exceeded reported maximum limits above which harmful effects on sediment-dwelling organisms are expected. Productivity in the (pristine) south-eastern part of Lake Ohrid (Sveti Naum) is generally lower than in the north, probably due to the strong influence of spring discharge. Low ostracode and diatom concentrations, low abundance of the epilimnetic diatom Cyclotella ocellata, and low values of TOC and TIC indicate a lower productivity from the early 1920s to the late 1980s. Since the mid 1970s, increased relative abundance of C. ocellata and increasing diatom concentration indicate increasing productivity in the south-eastern part. Rising numbers of ostracode valves and higher TIC and TOC contents in both sediment cores indicate an increase in productivity during the late 1980s. A slight increase in productivity near Sveti Naum continued from the early 1990s until 2009, witnessed by rising TC, TIC, and TOC content and a generally high number of ostracode valves and ostracode diversity. The area near the City of Struga (site of urban pollution) is also characterized by rising TOC and TIC contents and, furthermore, by increasing Cu, Fe, Pb, and Zn concentrations since the early 1990s. The recent reduction in the number of ostracode valves and ostracode diversity is probably caused by a higher heavy metal load into the lake. This suggests that living conditions for the endemic species in Lake Ohrid have become less favourable in the northern part of the lake, which might threaten the unique flora and fauna of Lake Ohrid.  相似文献   

A Long-Term Study of Spawning Activity in a Florida Gulf Coast Population of Horseshoe Crabs (<Emphasis Type="BoldItalic">Limulus polyphemus</Emphasis>)     

H. Jane Brockmann  Sheri L. Johnson 《Estuaries and Coasts》2011,34(5):1049-1067

Populations of the American horseshoe crab (Limulus polyphemus) differ in broad areas of their biology. We observed a non-harvested, marked Florida Gulf coast population during their spring spawning (March–May) in 11 years across a 17-year period (1992–2009). Long-term changes occurred in the number of spawning pairs: the population was stable from 1992 to 2000 but increased markedly after 2000. Short-term variation in numbers of spawning pairs, unpaired females, unpaired males, and operational sex ratios was explained by changes over the season and during each week of spring tides and by differences in actual (not predicted) maximum high tide height. Wind direction strongly affected tidal inundation and the number of spawning horseshoe crabs. Tagging individuals revealed that females returned to the nesting beach less often than males and most females were re-sighted only within 1 week of spring tides. No animals were seen across more than 6 years. Implications for management are discussed.  相似文献   

Export and mesopelagic particle flux during a North Atlantic spring diatom bloom   总被引：2，自引：0，他引：2  

Patrick Martin  Richard S. LampittMary Jane Perry  Richard SandersCraig Lee  Eric D'Asaro 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(4):338-349

Spring diatom blooms are important for sequestering atmospheric CO₂ below the permanent thermocline in the form of particulate organic carbon (POC). We measured downward POC flux during a sub-polar North Atlantic spring bloom at 100 m using thorium-234 (²³⁴Th) disequilibria, and below 100 m using neutrally buoyant drifting sediment traps. The cruise followed a Lagrangian float, and a pronounced diatom bloom occurred in a 600 km² area around the float. Particle flux was low during the first three weeks of the bloom, between 10 and 30 mg POC m⁻² d⁻¹. Then, nearly 20 days after the bloom had started, export as diagnosed from ²³⁴Th rose to 360-620 mg POC m⁻² d⁻¹, co-incident with silicate depletion in the surface mixed layer. Sediment traps at 600 and 750 m depth collected 160 and 150 mg POC m⁻² d⁻¹, with a settled volume of particles of 1000-1500 mL m⁻² d⁻¹. This implies that 25-43% of the 100 m POC export sank below 750 m. The sinking particles were ungrazed diatom aggregates that contained transparent exopolymer particles (TEP). We conclude that diatom blooms can lead to substantial particle export that is transferred efficiently through the mesopelagic. We also present an improved method of calibrating the Alcian Blue solution against Gum Xanthan for TEP measurements.  相似文献   

Climate change adaptation in Australian mining communities: comparing mining company and local government views and activities   总被引：1，自引：0，他引：1  

Barton Loechel  Jane Hodgkinson  Kieren Moffat 《Climatic change》2013,119(2):465-477

Effective climate change adaptation in mining communities is reliant on action by both local authorities and mining operations. This article reports the findings of two surveys conducted in late 2010, with Australian mining companies and local government authorities respectively, investigating their perceptions and activities related to climate change adaptation. The research identified the main types of weather and climate-related impacts experienced in the past and expected under future climate conditions for the two groups. There were significantly differing levels of concern about weather and climate-related impacts between the two types of organisations. Mining company respondents reported lower levels of severity of impact from both past and (expected) future weather events, as well as lower levels of belief in climate change and of adaptation activities to prepare for it. Interestingly, mining companies generally reported less concern about future impacts than those experienced in the past, suggesting discounting of risks due to climate change scepticism. The article reports on a range of factors relevant to adaptation in mining communities, including perceived barriers, collaboration and further information needs. The research findings are discussed in the context of other recent research on climate change adaptation by Australian organisations and studies of mining industry adaptation in other countries.  相似文献   

J. P. Smol and E. F. Stoermer (eds): The diatoms: applications for the environmental and earth sciences     

Jane M. Reed 《Journal of Paleolimnology》2011,46(1):167-169

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Strategic priorities for assessing ecological impacts of marine renewable energy devices in the Pentland Firth (Scotland,UK)     

Mark A. Shields  Lora Jane Dillon  David K. Woolf  Alex T. Ford 《Marine Policy》2009

The Pentland Firth, located between the north coast of mainland Scotland (UK) and the Orkney Islands, is recognised as an excellent location for the utilisation of tidal stream technology. Potential ecological impacts associated with tidal stream technology may ultimately depend on device design, array size and deployment location. Available ecological data for the Pentland Firth is summarised and strategic priorities for assessing ecological impacts are provided. Baseline data on marine species and habitats in the Pentland Firth is severely lacking and consequently the integrity of any environmental impact assessment could be compromised by this lack of data.  相似文献   

On the detectability of lightcurves of Kuiper belt objects     

Pedro Lacerda  Jane Luu 《Icarus》2003,161(1):174-180

We present a statistical study of the detectability of lightcurves of Kuiper belt objects (KBOs). Some Kuiper belt objects display lightcurves that appear “flat”; i.e., there are no significant brightness variations within the photometric uncertainties. Under the assumption that KBO lightcurves are mainly due to shape, the lack of brightness variations may be due to (1) the objects having very nearly spherical shapes or (2) their rotation axes coinciding with the line of sight. We investigate the relative importance of these two effects and relate it to the observed fraction of “flat” lightcurves. This study suggests that the fraction of KBOs with detectable brightness variations may provide clues about the shape distribution of these objects. Although the current database of rotational properties of KBOs is still insufficient to draw any statistically meaningful conclusions, we expect that, with a larger dataset, this method will provide a useful test for candidate KBO shape distributions.  相似文献   

The nature of rainfall in the main drainage sub-basins of Uganda     

Francis W.N. Nsubuga  O.J. Botai  Jane M. Olwoch  C.J. deW Rautenbach  Yvette Bevis  Adebayo O. Adetunji 《水文科学杂志》2013,58(2):278-299

Abstract

A study of rainfall trends and temporal variations within seven sub-basins of Uganda spanning from 1940 to 2009 has been made. Rainfall climatologies are constructed from observational data, using 36 station records which reflect hydroclimatic conditions. Long-term changes in rainfall characteristics were determined by non-parametric tests (Mann-Kendall and Sen’s T tests), coefficient of variation (CV), precipitation concentration index and drought severity index. Magnitude of change was estimated by applying Sen’s estimator of slope. Decadal variability of rainfall with marked seasonal cycles is evident. Temporal variability of drought patterns is detected. Variations in annual rainfall are low with no significant trends observed in the main drainage sub-basins. Significant trends occur in October, November, December and January. A noticeable decrease in the annual total rainfall was observed mostly in northwestern and southwestern sub-basins. Rainfall trend in the second normal of June–July–August (JJA) was decreasing in all the main drainage sub-basins.

Editor Z.W. Kundzewicz; Associate editor S. Yue

Citation Nsubuga, F.W.N., Botai, O.J., Olwoch, J.M., Rautenbach, C.J.deW., Bevis, Y., and Adetunji, A.O., 2014. The nature of rainfall in the main drainage sub-basins of Uganda. Hydrological Sciences Journal, 59 (2), 278–299.  相似文献   

Erratum to: Seasonal and Inter-annual Patterns in Primary Production,Respiration, and Net Ecosystem Metabolism in Three Estuaries in the Northeast Gulf of Mexico     

Jane M. Caffrey  Michael C. Murrell  Kendra S. Amacker  Jennifer W. Harper  Scott Phipps  Mark S. Woodrey 《Estuaries and Coasts》2014,37(5):1312-1312

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Cytotoxic and genotoxic evaluation and chemical characterization of sewage treated using activated sludge and a floating emergent-macrophyte filter in a municipal wastewater treatment plant: a case study in Southern Brazil     

Angélica Goldoni  Camila Golfeto  Jane B. Teixeira  Gislaine Blumm  Camila M. Wilhelm  Franko Telöken  Eloisa Bianchi  Jairo L. Schmitt  Günther Gehlen  Marco Antonio S. Rodrigues  Luciano Basso da Silva 《Environmental Earth Sciences》2014,72(5):1503-1509

This study was conducted to evaluate the chemical parameters and the cytotoxic and genotoxic potential of raw domestic sewage and effluents from treatment with activated sludge and a floating emergent-macrophyte filter from a domestic wastewater treatment plant in the city of Novo Hamburgo, Rio Grande do Sul, Brazil. The physicochemical analysis revealed that both treatment systems achieved the legal emission pattern for biochemical oxygen demand, chemical oxygen demand, and suspended solids, but ammoniacal nitrogen and E. coli values were above the limits in the macrophyte treatment effluent. Phosphorous values were above the maximum permitted for both treatments. The results obtained from the Allium cepa test and the micronuclei test in fish did not demonstrate any significant differences in both cytotoxicity (mitotic index) and genotoxicity (chromosome aberration and micronucleus) endpoints between the negative control group and the exposed groups. However, the comet assay in fish revealed a DNA damage increase in animals exposed to the 30 % concentration of the macrophyte effluent and two concentrations of the activated sludge treatment effluent (10 and 75 %), which suggests that these two treatment systems may increase wastewater genotoxicity.  相似文献