On the behaviour of dumped dredger spoil

Observations carried out on the dredger dumping grounds at Lowestoft have shown that fine particulate dredger spoil consists of two phases, one semi-fluid and the other a solid. Once introduced into the marine environment these two phases behave differently. The solid phase falls directly to the bed where it forms a persistent deposit with a localized effect while the semifluid phase is carried by the prevailing currents in the form of a turbid cloud. The possible significance of this twin-phase behaviour is discussed.     

Trace element distribution in mineral separates of the Allende inclusions and their genetic implications

Concentrations of the REE, Sc, Co, Fe, Zn, Ir, Na and Cr were determined by instrumental neutron activation and mass spectrometric isotope dilution analysis for mineral separates of the coarseand fine-grained types (group I and II of Martin and Mason's classification) of the Allende inclusions.These data, combined with data on mineral/liquid partition coefficients, oxygen isotope distributions and diffusion calculations, suggest the following: (1) Minerals in the coarse-grained inclusions (group I) crystallized in a closed system with respect to refractory elements. On the other hand, differences in oxygen isotope distributions among minerals preclude a totally molten stage in the history of the inclusion. Group I inclusions were formed by rapid condensation (either to liquid or solid) in a supercooled solar nebula; extrasolar pyroxene and spinel dust were included but not melted in the condensing inclusions, thus preserving their extrasolar oxygen isotope composition. REE were distributed by diffusion during the subsequent heating at subsolidus temperatures; because oxygen diffuses much more slowly at these temperatures, the oxygen isotope anomalies were preserved. (2) The fine-grained (group II) inclusions were also formed by condensation from a super-cooled nebular gas; however, REE-rich clinopyroxene and spinel were formed early and REE-poor sodalite and nepheline were formed later and mechanically mixed with clinopyroxene and spinel to form the inclusions. The REE patterns of the bulk inclusions and the mineral separates are fractionated, indicating that REE abundances in the gaseous phase were already fractionated at the time of condensation of the minerals. (3) Pre-existing Mg isotope anomalies in the coarse-grained inclusions must have been erased during the heating stage thus resetting the ²⁶Al-²⁶Mg chronometer.     

Hydrologic,geomorphic and climatic processes controlling willow establishment in a montane ecosystem

Willow communities dominate mid‐elevation riparian areas throughout the Rocky Mountains of North America. However, many willow stands are rapidly declining in aerial cover and individual plants in stature. A poor understanding of the processes that control willow establishment hinders identifying the causes of this decline. We analysed the processes that have facilitated or limited willow establishment over the last half of the 20th century on two large floodplains in Rocky Mountain National Park in Colorado by addressing two questions: (1) How does hydrologic regime control willow establishment on different fluvial landforms? (2) How might climate‐driven variations in hydrologic regime affect future willow establishment? We precisely aged willows on the three most common fluvial landforms, stream point bars, drained beaver ponds, and abandoned channels, and statistically related establishment dates to patterns of annual stream peak flow. The role of peak flow on willow establishment varied significantly by landform. Willow recruitment had occurred nearly every year on point bars. In former beaver complexes, most willows had established following dam breaches, whereas willows had established on abandoned channels for several years following channel avulsion. Establishment on point bars and abandoned channels was driven by peak flows of 2‐ to 5‐year return intervals, whereas in abandoned beaver ponds most establishment was associated with flow events of >5‐year return interval. Models of climate change suggest that temperatures will increase and precipitation seasonality will shift over the coming decades in the Rocky Mountains, leading to earlier spring runoff, lower summer and fall flows, decreased snowpack and decreased soil moisture. Such changes are likely to diminish opportunities for willow establishment. Copyright © 2005 John Wiley & Sons, Ltd.     

Stratigraphic evidence for anthropogenically induced coastal environmental change from Oaxaca, Mexico

Previous interdisciplinary paleoenvironmental and archaeological research along the Río Verde Valley of Oaxaca, Mexico, showed that Holocene erosion in the highland valleys of the upper drainage basin triggered geomorphic changes in the river's coastal floodplain. This article uses stratigraphic data from sediment cores extracted from Laguna Pastoría, an estuary in the lower Río Verde Valley, to examine changes in coastal geomorphology potentially triggered by highland erosion. Coastal lagoon sediments contain a stratigraphically and chronologically distinct record of major hurricane strikes during late Holocene times. Three distinct storm facies are identified from sediment cores obtained from Laguna Pastoría, which indicate that profound coastal environmental changes occurred within the region and are correlated with increased sediment supplied from highland erosion. The Chione/Laevicardium facies was deposited in an open bay while the Mytella/barnacle facies and sand facies were deposited in an enclosed lagoon following bay barrier formation. We argue that highland erosion triggered major geomorphic changes in the lowlands including bay barrier formation by 2500 cal yr B.P. These environmental changes may have had significant effects on human populations in the region. The lagoon stratigraphy further indicates an increase in mid–late Holocene hurricane activity, possibly caused by increased El Niño frequencies.     

Testing GISS-MM5 physics configurations for use in regional impacts studies

The Mesoscale Modeling System Version 5 (MM5) was one-way nested to the Goddard Institute for Space Studies global climate model (GISS GCM), which provided the boundary conditions for present (1990s) and future (IPCC SRES A2 scenario, 2050s) five-summer “time-slice” simulations over the continental and eastern United States. Five configurations for planetary boundary layer, cumulus parameterization, and radiation scheme were tested, and one set was selected for use in the New York City Climate and Health Project—a multi-disciplinary study investigating the effects of climate change and land-use change on human health in the New York metropolitan region. Although hourly and daily data were used in the health project, in this paper we focus on long-term current and projected mean climate change. The GISS-MM5 was very sensitive to the choice of cumulus parameterization and planetary boundary layer scheme, leading to significantly different temperature and precipitation outcomes for the 1990s. These differences can be linked to precipitation type (convective vs. non-convective), to their effect on solar radiation received at the ground, and ultimately to surface temperature. The projected changes in climate (2050s minus 1990s) were not as sensitive to choice of model physics combination. The range of the projected surface temperature changes at a given grid point among the model versions was much less than the mean change for all five model configurations, indicating relative consensus for simulating surface temperature changes among the different model projections. The MM5 versions, however, offer less consensus regarding 1990s to 2050s changes in precipitation amounts. All of the projected 2050s temperature changes were found to be significant at the 95th percent confidence interval, while the majority of the precipitation changes were not.     

Seasonal warm-water refuge and sanctuary usage by the Florida manatee (Trichechus manatus latirostris) in Kings Bay,Citrus County,Florida

The largest Florida manatee (Trichechus manatus latirostris) aggregation at a natural warm-water site occurs in Kings Bay, Crystal River, FL. In accordance with the Manatee Recovery Plan, manatee protection areas within Kings Bay have been created by the United States Fish and Wildlife Service (USFWS) and the State of Florida including a year-round refuge designation and seven Federal manatee sanctuaries during the winter manatee season (15 November–31 March). Over the last 30 years, an increase in manatee counts has been observed in Kings Bay which has prompted the need to review existing manatee protection measures. Aerial survey data collected between 1983 and 2012 were used to examine the seasonal change in manatee distribution within Kings Bay to assess the effectiveness of current sanctuary sizes and locations. Regression analysis suggested a significant change in manatee abundance among the winter seasons (p < 0.05). The average winter manatee counts increased by 4.81 animals per year over the 30-year period. Spatially explicit maps using geographic information system (GIS) analysis revealed a strong correlation between high manatee density and artesian springs in Kings Bay during the winter seasons. Highest abundances were identified at three locations: King Spring, Three Sisters Springs, and Magnolia Springs, which coincide with preexisting sanctuary designations. Additional coverage is advocated to support the overflow of manatees outside of sanctuary boundaries. As density patterns were not uniform across summer periods, a consideration of additional boat speed regulations is recommended.     

Adaptation and poverty reduction in Mozambique: an opportunity for developing countries to lead§

Climate change disproportionately impacts the world’s poorest countries. A recent World Bank report highlighted that over 100 million people are at risk of falling into extreme poverty as a result of climate change. There is currently a lack of information about how to simultaneously address climate change and poverty. Climate change challenges provide an opportunity for those impacted most to come up with new and innovative technologies and solutions. This article uses an example from Mozambique where local and international partners are working side-by-side, to show how developing countries can simultaneously address climate change and poverty reduction using an ecosystem-based adaptation approach. Using ecosystem-based adaptation, a technique that uses the natural environment to help societies adapt to climate change, developing countries can lead the way to improve climate adaptation globally. This paradigm shift would help developing countries become leaders in ecosystem-based adaptation and green infrastructure techniques and has implications for climate policy worldwide.

POLICY RELEVANCE

The Paris Agreement resulting from the United Nations Framework Convention on Climate Change (UNFCCC) 21st Conference of Parties (COP 21) in December 2015 was rightly lauded for its global commitment to cut greenhouse gas emissions. However, COP 21 was also historic because of its call for non-party stakeholders to address climate change, inclusion of a global goal of ‘enhancing adaptive capacity, strengthening resilience and reducing vulnerability’, and the United States’ commitment of $800 million to adaptation funding. The combination of recognizing the need for new stakeholders to commit to climate change adaptation, the large impact climate change will have on the developing world, and providing access to funds for climate change adaptation creates a unique opportunity for developing countries to pave the way in adaptation policies in practices. Currently, developing countries are creating National Adaptation Plans (NAPs) for the UNFCCC. Through including a strong component of ecosystem-based adaptation in NAPs, developing countries can shape their countries’ policies, improve local institutions and governments, and facilitate a new generation of innovative leaders. Lessons learned in places like Mozambique can help lead the way in other regions facing similar climatic risks.     

Predicting long-term urban growth in Beijing (China) with new factors and constraints of environmental change under integrated stochastic and fuzzy uncertainties

Numerous studies related to the simulation and prediction of urban growth to address land-use and land-cover (LULC) changes have been conducted in recent years, but very few have considered the impact of climate change, flooding impact, government relocation, corridor cities, and long-term rainfall variations simultaneously. To bridge the gap, this study predicts possible future LULC changes for 2030 and 2050 in Beijing (China), since Beijing is one of the fastest-growing megacities in the world. The proposed integrated modeling analysis covers four key scenarios to reflect the influences of different factors and constraints on LULC changes, in which cellular automata, Markov chain, and multi-criteria evaluation are fully coupled. While fuzzy membership function was used to address the uncertainty associated with the decision analysis, Markov chain, which is regarded as a stochastic process, was applied to predict future urban growth pathways. In addition, a statistical downscaling model driven by possible climate change scenarios was employed to address long-term rainfall variations in Beijing, China. This study differs from previous ones for Beijing in terms of not only the effects of climate change and flooding impact but also the newly-developed economic free trade zone in Xiong’an and the central government’s plan to relocate to the Tongzhou district. Findings indicate that there is no marked difference in LULC over the four key scenarios. Compared to the baseline LULC in 2010, the predicted results indicate that urban expansion is expected to increase more than 6 and 11% in 2030 and 2050, respectively.