Many coral reefs worldwide are rapidly declining, but efficient restoration techniques are not yet available. Here, we evaluate methodologies for reef restoration based on the “gardening concept”. A floating mid-water prototype nursery was placed at 6 m depth (14 m above sea-bottom) within the nutrient-enriched environment of a fish farm (Eilat, Red Sea). Ten colonies from five branching coral species provided 6,813 fragments (0.5–3 cm height). The fragments, each attached to a plastic pin, were inserted into plastic nets that were tied to a rope-net floating nursery. After 144 nursery days, only 13.1% of the fragments died and 21.2% were detached by mechanical forces. Small colonies ready for transplantation developed within 144–200 days. Ramets’ ecological volumes increased 13–46 folds and their heights by a factor of 3.5. After 306 days, the ecological volumes of the colonies increased 147–163 fold as compared to original volumes (revealing a daily growth rate constant of 1.67% during the first 5–10 months) and height values by a factor of six. Building and maintenance costs of the nursery were low. This nursery prototype demonstrates the feasibility of the coral “gardening concept” by fulfilling several important needs, namely, mass production of coral colonies at low costs, high survivorship, fast growth, short nursery phase and improved methodologies for handling farmed colonies. 相似文献
A full account for carbon dioxide (CO2) and other greenhouse gas balance is presented for the Dutch forest and nature areas for 1990–2002 at a Tier 2.5 level. The
paper outlines how complex guidelines can be turned into a practical system, appropriate for a small country, making use of
the best knowledge and data available. The net total sink of all processes of the forest and other nature terrains balance
is very stable through time around an average of 1.74 million tonnes of CO2 per year. The sink is to a large extent determined by the growth of forest remaining forest, and the harvest taking place
in there. Newly added processes in this new National System are significant as well, but they compensate each other. The sources
from deforestation and nitrous oxide (N2O) emissions (around 900 ktonne CO2) are for two thirds compensated by the sinks from afforestation, dead wood, soil C changes due to land use changes, and trees
outside the forest. The land use changes between 1990 and 2000 showed that The Netherlands has an annual deforestation of
2504 ha (0.7% of the forest area) and an afforestation of 3124 ha. Deforestation led in total over the 13 years of 1990–2002
to an emission of 11.2 million tonne CO2 compensated by only 1.9 million tonne CO2 due to afforestation.
A gnotobiotic multi-species study was designed to consist of a food-web of soil-dwelling animals. The food-web was exposed to five concentrations copper (Cu) spiked soil for three exposure durations i.e. 28, 56 and 84 days. Based on multivariate analysis the food-web was significantly affected by Cu exposure at and above 300 mg Cu kg(-1) soil (lowest tested concentration). The number of animals present in the 2500 mg Cu kg(-1) (highest tested concentration) was at all sampling occasions below the starting point level. Based on analysis of the individual species the lowest 10% effect concentration (EC10) observed was 50 mg Cu kg(-1) soil, for Enchytraeus crypticus. Using the EC10 for the individual species the HC5 (Hazard Concentration at the 5% level) was estimated to be between 25 and 36 mg Cu kg(-1) soil, depending on the exposure duration. A similar experiment but using a reduced design was performed employing soil contaminated with Cu in the field more than 80 years ago. The trend in the field-contaminated soil was similar to that observed for the spiked soil. 相似文献
We compared membrane thickness of fully developed eggs with those of non-developed eggs in different endangered falcon taxa.
To our knowledge, membrane thickness variation during development has never been examined before in falcons or any other wild
bird. Yet, the egg membrane constitutes an important protective barrier for the developing embryo. Because eggshell thinning
is a general process that occurs during bird development, caused by calcium uptake by the embryo, eggs are expected to be
less protected and vulnerable to breakage near the end of development. Thus, egg membranes could play an important protective
role in the later stages of development by getting relatively thicker. We used linear mixed models to explore the variation
in membrane thickness (n = 378 eggs) in relation to developmental stage, taxon, female age, mass and identity (73 females), egg-laying sequence (105
clutches) and the study zone. Our results are consistent with the prediction that egg membranes are thicker in fully developed
eggs than in non-developed eggs, suggesting that the increase in membrane thickness during development may compensate for
eggshell thinning. In addition, our data shown that thicker membranes are associated with larger, heavier and relatively wider
eggs, as well as with eggs that had thinner eggshells. Egg-laying sequence, female age and the study zone did not explain
the observed variation of membrane thickness in the falcon taxa studied. As we provide quantitative data on membrane thickness
variation during development in falcons not subjected to contamination or food limitation (i.e. bred under captive conditions),
our data may be used as a reference for studies on eggs from natural populations. Considering the large variation in membrane
thickness and the multiple factors affecting on it and its importance in the protection of the embryo, we encourage other
researchers to include measurements on membranes in studies exploring eggshell thickness variation. 相似文献
The journey of the European eel to the spawning area in the Sargasso Sea is still a mystery. Several trials have been carried
out to follow migrating eels with pop-up satellite tags (PSATs), without much success. As eels are very efficient swimmers,
tags likely interfere with their high swimming efficiency. Here we report a more than twofold increase in swimming cost caused
by a regular small satellite tag. The impact was determined at a range of swimming speeds with and without tag in a 2-m swimming
tunnel. These results help to explain why the previous use of PSATs to identify spawning sites in the Sargasso Sea was thus
far unsuccessful. 相似文献
The effect of the integration of Solid Oxide Fuel Cell (SOFC) technology in a sugar-ethanol factory on the environmental profile/footprint of the products (sugar, ethanol, electricity) is evaluated. The sugarcane is the primary feedstock and sugar, ethanol and electricity are the main products of the system, where the functional unit is defined as 9.86 ton/h of sugar, 2.195 ton/h of hydrated ethanol (96% w/w) and 847 kWh of electricity. A detailed set of material and energy inputs and outputs was obtained from a local factory and was completed using simulation data by Aspen Plus®.The environmental impacts (greenhouse gases and air pollution), exergy efficiency and a renewability parameter have been considered as indicators for the comparative assessment with conventional sugar, ethanol and electricity production technologies. The results show that the use of a SOFC technology involves a reduction of greenhouse gas emissions (52-55%) and non-renewable resources (60-64%) when compared with the conventional integrated sugar and ethanol plant. The higher renewability index (0.93) and exergy efficiency (38%) are noticed for the Solid Oxide Fuel Cell technology integrated in the sugar-ethanol factory than conventional sugar-ethanol plant. 相似文献
The FloodProBE project started as a FP7 research project in November 2009.Floods, together with wind related storms, are considered the major natural hazard in the EU in terms of risk to people and assets. In order to adapt urban areas (in river and coastal zones) to prevent flooding or to be better prepared for floods, decision makers need to determine how to upgrade flood defences and increasing flood resilience of protected buildings and critical infrastructure (power supplies, communications, water, transport, etc.) and assess the expected risk reduction from these measures.The aim of the FloodProBE-project is to improve knowledge on flood resilience and flood protection performance for balancing investments in flood risk management in urban areas. To this end, technologies, methods and tools for assessment purposes and for the adaptation of new and existing buildings and critical infrastructure are developed, tested and disseminated.Three priority areas are addressed by FloodProBE. These are: (i) vulnerability of critical infrastructure and high-density value assets including direct and indirect damage, (ii) the assessment and reliability of urban flood defences including the use of geophysical methods and remote sensing techniques and (iii) concepts and technologies for upgrading weak links in flood defences as well as construction technologies for flood proofing buildings and infrastructure networks to increase the flood resilience of the urban system.The primary impact of FloodProBE in advancing knowledge in these areas is an increase in the cost-effectiveness (i.e. performance) of new and existing flood protection structures and flood resilience measures. 相似文献
Environmental Chemistry Letters - Because many engineered nanoparticles are toxic, there is a need for methods to fabricate safe nanoparticles such as plant-based nanoparticles. Indeed, plant... 相似文献
Covid-19 lockdowns have improved the ambient air quality across the world via reduced air pollutant levels. This article aims to investigate the effect of the partial lockdown on the main ambient air pollutants and their elemental concentrations bound to PM2.5 in Hanoi. In addition to the PM2.5 samples collected at three urban sites in Hanoi, the daily PM2.5, NO2, O3, and SO2 levels were collected from the automatic ambient air quality monitoring station at Nguyen Van Cu street to analyze the pollution level before (March 10th–March 31st) and during the partial lockdown (April 1st–April 22nd) with “current” data obtained in 2020 and “historical” data obtained in 2014, 2016, and 2017. The results showed that NO2, PM2.5, O3, and SO2 concentrations obtained from the automatic ambient air quality monitoring station were reduced by 75.8, 55.9, 21.4, and 60.7%, respectively, compared with historical data. Besides, the concentration of PM2.5 at sampling sites declined by 41.8% during the partial lockdown. Furthermore, there was a drastic negative relationship between the boundary layer height (BLH) and the daily mean PM2.5 in Hanoi. The concentrations of Cd, Se, As, Sr, Ba, Cu, Mn, Pb, K, Zn, Ca, Al, and Mg during the partial lockdown were lower than those before the partial lockdown. The results of enrichment factor (EF) values and principal component analysis (PCA) concluded that trace elements in PM2.5 before the partial lockdown were more affected by industrial activities than those during the partial lockdown.