This research investigated the production of biodegradable plastic films made from a blend of carrageenan and corn starch biopolymers. The procedure included producing bioplastic resin pellets using a single screw extrusion at a 110 degrees C temperature, followed by hot compression at a temperature of 160 degrees C to form a biodegradable plastic film. The project aimed to develop a continuous biodegradable plastic production method, particularly made from carrageenan, which is more adaptable for commercial-scale production. The carrageenan/corn starch films were prepared with various compositions, ranging from formulations dominated by carrageenan (56:14% w/w) to those dominated by corn starch (14:56% w/w), with the addition of a constant amount of glycerol (30% w/w) as a plasticizer. After the films were obtained, each of the samples was evaluated for their physico-mechanical properties, chemical structure, water sensitivity, and soil biodegradability. In general, an increase in corn starch content within the film matrix led to an enhancement of the overall properties of the resulting film. The film with the highest corn starch content exhibited tensile strength and elongation at break values that were 49% and 163% higher, respectively, compared to the film with the lowest corn starch content. Additionally, these samples demonstrated improved thermal stability, with a 12% increase in the thermal decomposition temperature, and enhanced barrier properties, as evidenced by a 6% reduction in water vapor permeability and a 72% decrease in water uptake. This is mainly due to the inherent molecular structure of corn starch, particularly due to its long straight-glucose chains. On the other hand, carrageenan increased the biodegradability rate of the films. These findings demonstrate the potential of carrageenan/corn starch blends as promising candidates for future packaging materials.

对青藏高原的积雪和湖泊资源进行监测和保护是当前研究的热点问题。以青藏高原内流流域为研究区,基于Google Earth Engine（GEE）平台和Landsat 8 OLI影像,合成年际长时序卫星影像,提取研究区2013—2023年间积雪与湖泊的面积,探讨其时空变化规律,通过回归分析,建立积雪和湖泊面积与气象因子、地形因子的关系式。结果表明:1)2013至2023年,青藏高原内流区永久积雪的总面积减少了493 km2,降幅达5.98%;湖泊面积增加了1 638 km2,增幅达4.84%;2)积雪面积在11 a间呈现周期性波动,经历下降、上升、骤降与再上升,且变化幅度逐年扩大;而湖泊面积总体保持稳定,呈现缓慢的上升趋势;3)研究区内积雪面积的主要影响因素是温度、降水、高程、坡度、坡向;湖泊面积受到积雪消融的影响,但其主要影响因素是温度、降水、高程、坡度。研究结果可以更好地帮助理解气候变化对高原生态系统的影响,了解未来气候条件下积雪和湖泊的动态变化规律,并且为决策提供支持。

对青藏高原的积雪和湖泊资源进行监测和保护是当前研究的热点问题。以青藏高原内流流域为研究区,基于Google Earth Engine（GEE）平台和Landsat 8 OLI影像,合成年际长时序卫星影像,提取研究区2013—2023年间积雪与湖泊的面积,探讨其时空变化规律,通过回归分析,建立积雪和湖泊面积与气象因子、地形因子的关系式。结果表明:1)2013至2023年,青藏高原内流区永久积雪的总面积减少了493 km2,降幅达5.98%;湖泊面积增加了1 638 km2,增幅达4.84%;2)积雪面积在11 a间呈现周期性波动,经历下降、上升、骤降与再上升,且变化幅度逐年扩大;而湖泊面积总体保持稳定,呈现缓慢的上升趋势;3)研究区内积雪面积的主要影响因素是温度、降水、高程、坡度、坡向;湖泊面积受到积雪消融的影响,但其主要影响因素是温度、降水、高程、坡度。研究结果可以更好地帮助理解气候变化对高原生态系统的影响,了解未来气候条件下积雪和湖泊的动态变化规律,并且为决策提供支持。

对青藏高原的积雪和湖泊资源进行监测和保护是当前研究的热点问题。以青藏高原内流流域为研究区,基于Google Earth Engine（GEE）平台和Landsat 8 OLI影像,合成年际长时序卫星影像,提取研究区2013—2023年间积雪与湖泊的面积,探讨其时空变化规律,通过回归分析,建立积雪和湖泊面积与气象因子、地形因子的关系式。结果表明:1)2013至2023年,青藏高原内流区永久积雪的总面积减少了493 km2,降幅达5.98%;湖泊面积增加了1 638 km2,增幅达4.84%;2)积雪面积在11 a间呈现周期性波动,经历下降、上升、骤降与再上升,且变化幅度逐年扩大;而湖泊面积总体保持稳定,呈现缓慢的上升趋势;3)研究区内积雪面积的主要影响因素是温度、降水、高程、坡度、坡向;湖泊面积受到积雪消融的影响,但其主要影响因素是温度、降水、高程、坡度。研究结果可以更好地帮助理解气候变化对高原生态系统的影响,了解未来气候条件下积雪和湖泊的动态变化规律,并且为决策提供支持。

Environmental changes, such as climate warming and higher herbivory pressure, are altering the carbon balance of Arctic ecosystems; yet, how these drivers modify the carbon balance among different habitats remains uncertain. This hampers our ability to predict changes in the carbon sink strength of tundra ecosystems. We investigated how spring goose grubbing and summer warming-two key environmental-change drivers in the Arctic-alter CO2 fluxes in three tundra habitats varying in soil moisture and plant-community composition. In a full-factorial experiment in high-Arctic Svalbard, we simulated grubbing and warming over two years and determined summer net ecosystem exchange (NEE) alongside its components: gross ecosystem productivity (GEP) and ecosystem respiration (ER). After two years, we found net CO2 uptake to be suppressed by both drivers depending on habitat. CO2 uptake was reduced by warming in mesic habitats, by warming and grubbing in moist habitats, and by grubbing in wet habitats. In mesic habitats, warming stimulated ER (+75%) more than GEP (+30%), leading to a 7.5-fold increase in their CO2 source strength. In moist habitats, grubbing decreased GEP and ER by similar to 55%, while warming increased them by similar to 35%, with no changes in summer-long NEE. Nevertheless, grubbing offset peak summer CO2 uptake and warming led to a twofold increase in late summer CO2 source strength. In wet habitats, grubbing reduced GEP (-40%) more than ER (-30%), weakening their CO2 sink strength by 70%. One-year CO2-flux responses were similar to two-year responses, and the effect of simulated grubbing was consistent with that of natural grubbing. CO2-flux rates were positively related to aboveground net primary productivity and temperature. Net ecosystem CO2 uptake started occurring above similar to 70% soil moisture content, primarily due to a decline in ER. Herein, we reveal that key environmental-change drivers-goose grubbing by decreasing GEP more than ER and warming by enhancing ER more than GEP-consistently suppress net tundra CO2 uptake, although their relative strength differs among habitats. By identifying how and where grubbing and higher temperatures alter CO2 fluxes across the heterogeneous Arctic landscape, our results have implications for predicting the tundra carbon balance under increasing numbers of geese in a warmer Arctic.

Seaweeds are a rich source of various bioactive compounds and metabolites. In this study, sulfated polysaccharide, kappa-carrageenan has been isolated from red algae, Hypnea valentiae, and developed biodegradable film with the addition of plasticizers, sorbitol and polyethylene glycol (PEG 4000) at varying concentrations of carrageenan (1%, 5% and 7% Carr). The biodegradable film exhibited excellent mechanical properties with increasing carrageenan concentration. The 5% Carr film showed improved water barrier properties, high water contact angle (hydrophobicity), high tensile strength (11.38 MPa) and elongation at break (23.27%) which imparts rigidity and flexibility to the film. The results of FTIR and SEM images revealed that the plasticizers and polysaccharides have been blended properly. Since seaweeds are natural antioxidants the kappa-carrageenan based biodegradable films displayed strong radical scavenging activity. The 7% Carr film exhibited 86% of radical scavenging activity in ABTS assay and 5% Carr showed 80% of scavenging activity. The biodegradable films displayed efficient antibacterial activity against gram-negative bacteria, E. coli and gram-positive bacteria, B. subtilis. The developed films exhibited excellent biodegradability, the films samples degraded completely within 84 days of soil burial. The kappa-carrageenan based biodegradable film (5% Carr) from red algae, H. valentiae better serves as a versatile food packaging material.

冰湖面积变化是全球气候变化的指示器。天山地形复杂，冰湖分布广泛，其变化特征和对气候变化的响应机制还需要进一步探究。基于Google Earth Engine（GEE）平台研究天山近20 a的冰湖变化情况，同时结合降水和温度进行驱动力分析。结果表明：（1）2020年天山共有冰湖1532个，冰湖面积164.02 km2；天山冰湖分布呈现西多东少的特点，东、西2个部分冰湖面积年平均增长率分别为3.47%和0.63%。（2）天山海拔低于3600 m范围内的冰湖普遍呈扩增趋势，面积<0.1 km2的冰湖变化更为明显。（3）地理探测器结果表明，温度和冰川是影响天山冰湖变化的主要驱动因子。2000—2020年天山东部降水明显增加，温度呈不显著降低趋势，该区域冰湖面积在稳定充足的冰川融水与径流补给下持续扩张。研究结果可以为天山水资源的合理开发以及冰湖溃决灾害风险评估提供科学依据。

冰湖面积变化是全球气候变化的指示器。天山地形复杂，冰湖分布广泛，其变化特征和对气候变化的响应机制还需要进一步探究。基于Google Earth Engine（GEE）平台研究天山近20 a的冰湖变化情况，同时结合降水和温度进行驱动力分析。结果表明：（1）2020年天山共有冰湖1532个，冰湖面积164.02 km2；天山冰湖分布呈现西多东少的特点，东、西2个部分冰湖面积年平均增长率分别为3.47%和0.63%。（2）天山海拔低于3600 m范围内的冰湖普遍呈扩增趋势，面积<0.1 km2的冰湖变化更为明显。（3）地理探测器结果表明，温度和冰川是影响天山冰湖变化的主要驱动因子。2000—2020年天山东部降水明显增加，温度呈不显著降低趋势，该区域冰湖面积在稳定充足的冰川融水与径流补给下持续扩张。研究结果可以为天山水资源的合理开发以及冰湖溃决灾害风险评估提供科学依据。

The employment of novel biopolymers offers geotechnical engineers a diverse range of materials to choose from, depending on the specific requirements of different projects. Regarding the promotion of environmentally friendly materials in the construction industry, this study introduces carrageenan as a novel biopolymer for soil improvement. The research also includes a comparative study of carrageenan's performance with xanthan which is the most commonly used biopolymer in geotechnical engineering. Unconfined compressive tests (UCS) were conducted to evaluate the performance of biopolymer-treated soil samples over a variety of effective parameters including biopolymer content, moisture content, curing time, soil particle size, and durability under wet-dry cycles. In order to explore the soil size effect, kaolinite silt and sand were combined in various proportions and treated with different biopolymer ratios to enhance strength development. The optimal mix of each biopolymer-treated soil was then exposed to five cycles of wetting and drying. Carrageenan improved the compressive strength of untreated soils in all cases, for example 3.4 times for 0.5% (wb/ws) of biopolymer. In higher proportions of kaolinite, carrageenan performed considerably better than xanthan gum in terms of compressive and shear strength. In addition, with an emphasis on confining pressures, static triaxial experiments were conducted to examine the effectiveness of carrageenan, by which it was shown that carrageenan out-performs xanthan in terms of shear strength especially in the fine-grained soil. The mechanism and chemical interaction behind the significant performance of carrageenan in binding soil grains, increasing mechanical strength and improving durability of the soil was also studied through FTIR analysis and scanning electron microscopy (SEM) images. It can be concluded that carrageenan can be considered as a sustainable alternative to conventional materials such as cement and lime.

探究昆仑山冰湖变化特征对区域生态环境和发展至关重要。基于Google Earth Engine(GEE)遥感云平台进行监督分类，研究昆仑山近20 a的冰湖分布面积和数量变化情况，并结合气温、降水和冰川面积进行驱动力分析。结果表明：（1）2000—2020年昆仑山地区冰湖数量增加39.25%，面积增加81.35%，呈西多东少的分布特征。（2）昆仑山地区面积小于0.1 km2的冰湖对气候变化更敏感，增长速度最快；昆仑山冰湖主要集中在海拔4600～5600m，冰湖数量和面积分别占总量的71.58%和70.51%。（3）2000—2020年昆仑山地区气温降低3.45%，降水减少6.27%，冰川面积减少了21.15%，冰川融化产生的冰川融水是冰湖增长的主要原因。研究结果可为干旱区水资源的保护和利用、灾害预警等方面提供科学支撑。