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921.
Comparison of benthic and pelagic suspension feeding in shallow water habitats of the Northeastern Baltic Sea 总被引:1,自引:0,他引:1
Velda Lauringson Jonne Kotta Helen Orav-Kotta Ilmar Kotta Kristjan Herkül & Arno Põllumäe 《Marine Ecology》2009,30(S1):43-55
Combining field experiments with the biomass distribution data of dominant suspension feeders we compared the benthic and pelagic suspension feeding rates in shallow non-tidal brackish water coastal habitats. We found that pelagic grazing exceeded benthic grazing in almost all cases, on average from 14 to 4819 times depending on the site. Benthic grazing rates were related to site-specific environmental parameters and showed no relationship with water chlorophyl a (Chl a ) content, whereas pelagic grazing rates varied both spatially and temporally and were related to water Chl a content. Our results indicate that in several shallow coastal habitats, pelagic suspension feeding substantially exceeds benthic suspension feeding. This suggests that pelagic recycling is higher than the amounts of energy redirected from pelagic to benthic food webs by benthic suspension feeders. These results increase our knowledge of the energy flows in coastal ecosystems. 相似文献
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ABSTRACT Urban greening, the improvement or increase of green spaces in cities, has purported environmental, individual, social and cultural benefits. The extent and qualities of urban green spaces, and our opportunities to engage with them, reflect and shape human responses to those spaces. Planning scholars recognise the traditional role and obligation of planning to help reduce social problems and see the potential for the public to be leaders in defining responses. However, use of technical, scientific and economic approaches by urban land managers can limit recognition of diverse connections to urban green and advance narrow conceptions of nature. We sample people’s responses to different forms of urban green and greening in three case studies from Melbourne, Australia. We show that modern connections and expressions are personal, social and dynamic. Human experiences are embedded in nature and connections develop from interactions with and about nature, in formal and informal spaces. Diverse connections prompt responses to nature, and actions affecting nature itself. Accordingly, we propose ways to develop more receptive, responsive, inclusive and connected forms of urban greening. These include recognising diverse connections and expressions, encouraging dynamic relationships with nature, and providing varied ways of engaging with urban green spaces that foster stewardship. 相似文献
926.
Su Young Lee Yeong Bae Seong Lewis A. Owen Madhav K. Murari Hyoun Soo Lim Ho Il Yoon Kyu‐Cheul Yoo 《Boreas: An International Journal of Quaternary Research》2014,43(1):67-89
The late Quaternary glacial history of the Nun‐Kun massif, located on the boundary between the Greater Himalaya and the Zanskar range in northwestern India, was reconstructed. On the basis of morphostratigraphy and 10Be dating of glacial landforms (moraines and glacial trimlines), five glacial stages were recognized and defined, namely: (i) the Achambur glacial stage dated to Marine Oxygen Isotope Stage 3 to 4 (38.7–62.7 ka); (ii) the Tongul glacial stage dated to the early part of the Lateglacial (16.7–17.4 ka); (iii) the Amantick glacial stage dated to the later part of the Lateglacial (14.3 ka, 11.7–12.4 ka); (iv) the Lomp glacial stage dated to the Little Ice Age; and (v) the Tanak glacial stage, which has the youngest moraines, probably dating to the last few decades or so. Present and former equilibrium‐line altitudes (ELAs) were calculated using the standard area accumulation ratio method. The average present‐day ELA of ~4790 m above sea level in the Greater Himalaya is lower than those in the Ladakh and Zanskar ranges, namely 5380 and ~5900 m a.s.l., respectively. The ELA in the Zanskar range is higher than in the Ladakh range, possibly due to the higher peaks in the Ladakh range that are able to more effectively capture and store snow and ice. ELA depressions decrease towards the Ladakh range (i.e. inner Plateau). Peat beds interbedded with aeolian deposits that cap the terminal moraine of Tarangoz Glacier suggest millennial‐time‐scale climate change throughout the Holocene, with soil formation times at c. 1.5, c. 3.4 and c. 5.2 ka, probably coinciding with Holocene abrupt climate change events. Given the style and timing of glaciation in the study area, it is likely that climate in the Nun‐Kun region is linked to Northern Hemisphere climate oscillations with teleconnections via the mid‐latitude westerlies. 相似文献
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Peter Tan Leo Lymburner Medhavy Thankappan Adam Lewis 《Journal of the Indian Society of Remote Sensing》2011,39(3):365-372
The MODIS (Moderate Resolution Imaging Spectroradiometer) 250m EVI dataset provides a valuable ongoing means of characterising
and monitoring changes in land use and resource condition. However the multiple factors that influence a time series of greenness
data make the data difficult to analyse and interpret. Without prior knowledge, underlying models for time series in a given
remote sensing image are often heterogeneous. So while conventional time series analysis methods such as wavelet transform
and Fourier analysis may work well for part of the image, these models are either invalid or must be substantially re-parameterised
for other parts of the image. To overcome these challenges we propose a new approach to distil information from earth observation
time series data. The characteristics of a remote sensing time series are represented by a set of statistics (which we call
coefficients) selected to correspond to the dynamics of a natural system. To ensure the coefficients are robust and generic,
statistics are calculated independently by applying statistical models with less complexity on shorter segments within the
time series. An International Standards Organization (ISO) Land Cover classification (Jansen 2000) was generated for cropping regions in the Gwydir and Namoi catchments, in Australia. Areas identified in the classification
as irrigated and rain fed cropping were analysed using a tailored time series analysis tool. The crop analysis tool identifies
time series features such as the number and duration of fallow periods, crop timing, presence/absence of a crop during a year
for a specific growing season. This information is combined with paddock boundaries derived from Landsat imagery to provide
detailed year-by-year insight into cropping practices in the Gwydir and Namoi catchments. 相似文献