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1.
黑河中游不同土地利用类型下土壤碳储量及其空间变化 总被引：6，自引：1，他引：5
通过黑河中游不同土地利用类型下土壤碳密度、碳储量的研究表明:总有机碳(TOC)、活性有机碳(AOC)、非活性有机碳(NOC)碳密度、碳储量从小到大呈不同的变化趋势。其中,NOC与TOC碳密度从大到小的空间分布基本一致,而AOC与NOC、TOC的分布存在差异,说明土地利用类型变化对三类有机碳的影响不同。经计算得到,1m深度TOC、AOC、DOC碳库总量分别为94.72、45.12、49.60Tg,DOC碳库占TOC碳库的比例略高于AOC占TOC碳库的比例。分析发现,引入AOC和NOC指标,更能真实反映出有机碳与影响因素间关系。 相似文献
2.
西安高陵近代河漫滩沉积与洪水变化 总被引：3，自引：1，他引：3
根据高陵渭河河漫滩沉积剖面中105个样品的颗粒与有机质分析,Hg与CaCO3含量测定和史书记载的年代资料,研究了西安高陵渭河距今约120 a来河漫滩沉积指示的洪水变化。结果表明,高陵渭河约120 a来至少发生了16次大洪水, 洪水规模存在一定差别, 各次洪水一般代表了当年降水量的明显增加; 高陵渭河河漫滩沉积中有机碳浓度、金属汞的含量、CaCO3含量变化显著,它们与颗粒大小之间有明显的相关性,沉积物粒度越细,其有机碳和重金属汞的含量越高,CaCO3含量越少。有机碳和重金属汞的含量变化能够间接指示洪水动力强弱变化和短暂降水量增加。汞含量变化表明,渭河汞污染发生时间相当晚。 相似文献
3.
互花米草引种对苏北潮滩湿地TOC、TN和TP分布的影响 总被引：5，自引：0，他引：5
分析了TOC、TN和TP在苏北潮滩湿地不同生态带沉积物和植被中的分布状况,结果表明:TOC和TN的水平和垂向平均含量以互花米草滩为最高,其次分别为盐蒿滩、芦苇滩和光滩。TP的平均含量以光滩为最高,依次由海向陆逐渐减小。在生物量最大期间(秋季),单位面积上互花米草体内TOC、TN和TP的累积量远大于盐蒿和芦苇。互花米草主要通过以下4个方面对研究区潮滩湿地TOC、TN和TP的分布产生影响:(1)互花米草滩面较高的沉积速率;(2)互花米草对整个潮滩湿地不同植被分布格局的改变;(3)互花米草有着高生产力以及巨大的地下生物量;(4)互花米草的生长特性使其在生长过程中对磷的需求量很大。 相似文献
4.
This study tests the hypothesis that Fourier-transform infrared spectroscopy (FTIRS) of lake sediments can be used to infer
past changes in tree-line position and total organic carbon (TOC) content of lake water. A training set of 100 lakes from
northern Sweden spanning a broad altitudinal and TOC gradient from 0.7 to 14.9 mg/l was used to assess whether vegetation
zones and TOC can be modelled from FTIR spectra of surface sediments (0–1 cm) using principal component analysis (PCA) and
partial least squares (PLS) regression. Preliminary results show that FTIRS of lake sediments can be used to reconstruct past
changes in tree line and the TOC content of lake water, which is hardly surprising since FTIRS registers the properties of
organic and minerogenic material derived from the water mass and the drainage area. The FTIRS model for TOC gives a root mean
squared error (RMSECV) of calibration of 1.4 mg/l (10% of the gradient) assessed by internal cross-validation (CV) yielding
an Rcv2 of 0.64. This should be compared with a near-infrared spectroscopy (NIRS) and diatom transfer function for TOC from the same
set of lakes, which have a Rcv2 of 0.61 and 0.31, and RMSECV of 1.6 and 2.3 mg/l, respectively. The FTIRS-TOC model was applied to a Holocene sediment core
from a tree-line lake and the results show similar trends as inferences from NIRS and pollen from the same core. Overall,
the results indicate that changes in FTIR spectra from lake sediments reflect differences in catchment vegetation and TOC,
and that FTIRS-models based on surface-sediment samples can be applied to sediment cores for retrospective analysis. 相似文献
5.
通过北冰洋西部楚科奇海盆M03孔晚第四纪以来生源沉积物,有孔虫丰度和冰筏碎屑(Ice．Rafted Detritus,IRD)的综合研究表明,海洋氧同位素(Marine Isotope Stage,MIS)7期以来,碳酸钙(CaCO )含量和浮游有孔虫丰度在间冰期的增加和冰期的降低,分别指示大西洋水输入的加强和减弱。而有机碳(TOC)和生源蛋白石(Biogenic Opa1)含量的变化可能主要与输入到海底的TOC降解和Opal溶解作用与底层水中的溶解氧有关。间冰期低的TOC和Opal含量可能反映楚
科奇海盆海冰覆盖减少,营养盐供给多,表层生产力增加,通气作用好,底层水富氧,降解和溶解作用增强,保存在沉积物中的TOC和Opal减少;而冰期相对高的TOC和Opal含量可能反映楚科奇海盆海冰覆盖时间较长,营养盐供给少,表层生产力较低,通气作用差,底层水少氧,降解和溶解作用减弱,保存在沉积物中的TOC和Opal增多。 相似文献
科奇海盆海冰覆盖减少,营养盐供给多,表层生产力增加,通气作用好,底层水富氧,降解和溶解作用增强,保存在沉积物中的TOC和Opal减少;而冰期相对高的TOC和Opal含量可能反映楚科奇海盆海冰覆盖时间较长,营养盐供给少,表层生产力较低,通气作用差,底层水少氧,降解和溶解作用减弱,保存在沉积物中的TOC和Opal增多。 相似文献
6.
Lake Baikal, an ancient pristine lake in Siberia, has accumulated sediment deposits that span 25 million years. These deposits
have the potential to provide a long-term record of climate changes and their interaction with the ecology of the lake. In
order to investigate whether sedimentary phytoplankton pigments could be used to reconstruct past changes in total phytoplankton
abundance and productivity, we compared the spatial variability in sedimentary pigment distributions in Holocene cores from
three separate regions of the lake; Vidrino in the south, Posolski on Selenga Delta and Continent Ridge in the north. Furthermore,
we present the first continuous sedimentary pigment and organic carbon sequence of the Kazantsevo interglacial (roughly a
time equivalent to the European Eemian, and Marine Isotopic Stage MIS5e) at a resolution of approximately 150 years. Results
of the spatial study showed marked differences in the sediment pigment deposition. Lowest chlorophyll a plus its degradation products versus organic carbon ratios (Chlas/TOC) indicating lowest production, but highest variability with time (indicating strongest climatic oscillations) were found
at Continent Ridge. The study of sedimentary pigments deposited during the last two interglacial periods at Continent Ridge
showed Chlas/TOC ratios 50–1000 times higher during the Kazantsevo Interglacial compared to the glacial periods, whereas the TOC content
was only five times higher, thus indicating the significance of the Chlas/TOC ratio for the reconstruction of the phytoplankton abundance and productivity. Strong oscillations occurred during the
Kazantsevo Interglacial within centennial time scales. Chlorophyllb plus its degradation products provided additional information on the past development of Chlorophyceae. Highest Chlas/TOC ratios were found during the early Holocene at approximately 9 kyr BP. Indications of short phytoplankton production
maxima were also found during the late Atlantic (6 kyr BP) and at the Subboreal/Subatlantic transition (3 kyr BP). From this
we conclude that sedimentary chlorophyll a is a reliable indicator of phytoplanktonic response to climate changes and may serve for␣validation of future climate scenarios
in continental regions. 相似文献
7.
黄河泥沙是黄河下游陆地地貌类型形成的物质来源,泥沙沉积改变了地表土壤结构和有机碳含量水平。基于室内外实验和空间地统计分析方法,文中对开封—周口土壤有机碳组分的空间特征和影响因素进行了分析。在0~100 cm土壤中TOC、AOC、NOC的含量分别为0.05~30.03 g/kg、0.01~8.86 g/kg和0.02~23.36 g/kg,表层0~20 cm的TOC、AOC、NOC高于下层,同一土层中TOC的变化幅度和含量差异性最大,AOC最小,NOC介于二者之间。NOC的含量对TOC的贡献大于AOC。空间地统计学研究显示,TOC、AOC、NOC的块金系数在0.50~0.67之间,具有中等程度的空间相关性,TOC、AOC、NOC的含量受结构因素和随机因素的共同作用,且二者的作用强度接近。空间上,自表层向下层,土壤TOC、AOC和NOC的整体变化趋势较为一致,高值区与低值区之间过渡明显,NOC和AOC的含量及空间变化能较好地反映TOC的空间变化和碳积累区域。分析发现,黄河泥沙冲/沉积区分布、农业耕作过程和耕作历史是影响区内土壤有机碳及其组成含量和空间分布的主要因素,而有机物的输入量、土壤颗粒物组成及二者的动态关系是影响土壤结构体形成和有机碳含量的关键因素,提高有机物的含量和改善土壤结构是提升土壤质量、实现区内农业持续发展的有效途径。 相似文献
8.
在放射性核素137Cs和210Pb精确计年的基础上,建立了长江中游网湖近代沉积物年代序列。通过对沉积物中TOC、TN、TP、孢粉、重金属元素、粒度等指标的测定,结合相关文献资料,分析了百年来网湖沉积物中营养元素的分布特征,物源变化以及主控因子。结果表明:百年来网湖沉积物中TN和TOC含量显著相关,呈不断上升趋势,存在2个明显的演化阶段,主控因子为流域人类活动强度,气候波动对其有影响,但影响不大。TP的变化与TN和TOC明显不同,波动较大,规律不明显,主要受人类活动强度以及径流侵蚀输移入湖物质变化两大因子控制。 相似文献
9.
Peter Roseacute;n Roland Hall Tom Korsman Ingemar Renberg 《Journal of Paleolimnology》2000,24(2):109-123
The relationships between diatoms (Bacillariophyceae) in surface sediments of lakes and summer air temperature, pH and total organic carbon concentration (TOC) were explored along a steep climatic gradient in northern Sweden to provide a tool to infer past climate conditions from sediment cores. The study sites are in an area with low human impact and range from boreal forest to alpine tundra. Canonical correspondence analysis (CCA) constrained to mean July air temperature and pH clearly showed that diatom community composition was different between lakes situated in conifer-, mountain birch- and alpine-vegetation zones. As a consequence, diatoms and multivariate ordination methods can be used to infer past changes in treeline position and dominant forest type. Quantitative inference models were developed to estimate mean July air temperature, pH and TOC from sedimentary diatom assemblages using weighted averaging (WA) and weighted averaging partial least squares (WA-PLS) regression. Relationships between diatoms and mean July air temperature were independent of lake-water pH, TOC, alkalinity and maximum depth. The results demonstrated that diatoms in lake sediments can provide useful and independent quantitative information for estimating past changes in mean July air temperature (R2
jack = 0.62, RMSEP = 0.86 °C; R2 and root mean squared error of prediction (RMSEP) based on jack-knifing), pH (R2
jack = 0.61, RMSEP = 0.30) and TOC (R2
jack = 0.49, RMSEP = 1.33 mg l-1). The paper focuses mainly on the relationship between diatom community composition and mean July air temperature, but the relationships to pH and TOC are also discussed. 相似文献
10.
湖泊沉积物有机地化指标在古气候解释中具有复杂性和多解性。TOC、C/N和δ^13Corg作为3种常用的有机地化指标,现已广泛运用于东、中亚全新世气候变化研究中。以这3种指标为例综述了东、中亚全新世湖泊沉积有机地化指标的变化机制及影响因素。根据数据的综合分析与对比,大部分湖泊全新世沉积物TOC百分含量较高时,C／N比值也较高。这与沉积物有机质的来源有关,因两者TOC和C／N作用机制不同,也存在少数湖泊,其两者对应关系不明显;同一湖泊δ^13Corg与TOC及δ^13Corg与C／N对应关系相似;由于不同区域影响有机地化指标的因素不同,TOC、C／N和δ1^3Corg间的关系存在区域差异,据此可将研究区分为中纬度地区、青藏高原区和低纬度季风区。上述区域规律存在于研究中所选的大部分湖泊,由于有机地化指标作用机理的复杂性,也存在不符合这种规律的湖泊,因而上述结论有待于进一步讨论。 相似文献
11.
长江中游网湖近代沉积环境演变及其对人类活动的响应 总被引：5，自引：2，他引：3
采用放射性核素210Pb和137Cs计年方法,建立了长江中游网湖近代沉积物的年代序列,并对网湖沉积物的粒度组成、磁性参数、重金属元素、花粉组合以及营养盐含量等指标进行了分析。根据沉积指标垂直分布的综合特征,结合湖区史料,重建了网湖100年来沉积环境的演变过程。通过对沉积指标与湖区人口变化、工农业产值等数据的比对,发现中华人民共和国成立以后沉积物中TOC和TN浓度与人口变化存在较高的相关性,相关系数分别达到0.8892和0.8928(P<0.001);沉积物中重金属元素富集序列、营养盐富集序列与孢粉含量的变化序列与湖区人类活动具有较好的耦合性。表明网湖沉积指标可以敏感地反映湖区的人类活动。 相似文献
12.
河北坝上地区湖泊沉积物记录的中全新世干旱气候 总被引：13，自引：10，他引：3
根据位于典型草原带的河北坝上地区白诺尔及毗邻的内蒙古乌兰诺尔湖泊沉积物的K、Na、Ca、Mg等化学元素组成、总有机碳(TOC)与氧同位素(δ18O)的分析,以(K+Na+Ca+Mg)/(Fe+Mn)值指示干旱度,1δ8O值指示夏季风的强弱,TOC值指示湖区植被状况,探讨了该地区14C测年9.8~5.3 ka B.P.以来的气候变化与环境变迁。结果表明:两个剖面所记录的气候变化趋势相近,14C测年7.0~5.7 ka B.P.为偏干期。反映夏季风强弱的氧同位素指标与干旱程度的变化没有明显的对应关系,说明夏季风引起的降水量变化不是气候干湿变化的主要影响因子,温度升高导致的蒸发加强可能对气候干旱化的影响更加明显。 相似文献
13.
猪野泽沉积物有机地球化学指标与花粉组合的关系及其对环境变化的响应 总被引：1，自引：0，他引：1
探讨晚冰期以来猪野泽沉积物中的总有机碳（TOC）、碳氮比（C/N）、有机碳同位素（δ13C）3种有机地球化学指标与花粉组合之间的相互关系。结果表明,猪野泽沉积物中有机地球化学指标和孢粉组合对环境变化的响应程度不同,3种有机地球化学指标对环境变化的整体趋势反应敏感,孢粉组合适于对细节变化的分析。猪野泽沉积物整个剖面中（除~13.0 cal ka BP之前的底部砂层沉积段外）TOC和C/N较低值,δ13C较高值,对应总花粉浓度较低时期;TOC和C/N较高值,δ13C较低值,对应总花粉浓度较高时期。 相似文献
14.
15.
吉林省不同水系的高锰酸盐指数、化学需氧量和总有机碳的相关关系比较 总被引：1，自引：0，他引：1
通过对吉林省四大水系的主要河流在2005~2006年内采样,测其高锰酸盐指数(PV)、化学需氧量(COD)和总有机碳(TOC),用最小二乘法对PV—TOC、COD—TOC和COD—PV进行线性回归,并进行相关关系的显著性检验,建立吉林省四大水系主要河流PV—TOC、COD—TOC和COD—PV的定量关系模型。结果表明,吉林省四大水系主要河流中PV—TOC、COD—TOC和COD—PV之间均具有显著的线性相关关系,不同水系的线性相关关系之间存在一定的差异。 相似文献
16.
A decade of widespread increases in surface water concentrations of total organic carbon (TOC) in some regions has raised
questions about longer term patterns in this important constituent of water chemistry. This study uses near-infrared spectroscopy
(NIRS) to infer lake water TOC far beyond the decade or two of observational data generally available. An expanded calibration
dataset of 140 lakes across Sweden covering a TOC gradient from 0.7 to 24.7 mg L−1 was used to establish a relationship between the NIRS signal from surface sediments (0–0.5 cm) and the TOC concentration
of the water mass. Internal cross-validation of the model resulted in an R
2 of 0.72 with a root mean squared error of calibration (RMSECV) of 2.6 mg L−1. The TOC concentrations reconstructed from surface sediments in four Swedish lakes were typically within the range of concentrations
observed in the monitoring data during the period represented by each sediment layer. TOC reconstructions from the full sediment
cores of four lakes indicated that TOC concentrations were approximately twice as high a century ago. 相似文献
17.
Andrew S. Carr Arnoud Boom Brian M. Chase David L. Roberts Zoë E. Roberts 《Journal of Paleolimnology》2010,44(4):947-961
Pyrolysis–gas chromatography mass spectrometry (py-GC/MS) allows the characterisation of complex macromolecular organic matter.
In lakes and wetlands this can potentially be used to assess the preservation/diagenesis and provenance of sediment organic
matter. It can complement palaeoenvironmental investigations utilising ‘bulk’ sediment variables such as total organic carbon
(TOC) and TOC/total nitrogen ratios. We applied py-GC/MS analyses to a ~32,000-year sediment record from the southern Cape
coastline of South Africa. We used the results to evaluate the sources and extent of degradation of organic matter in this
semi-arid environment. Marked down-core changes in the relative abundance of multiple pyrolysis products were observed. Correspondence
analysis revealed that the major driver of this down-core variability in OM composition was selective preservation/degradation.
Samples comprising highly degraded OM are primarily confined to the lower half of the core, older than ~12,000 years, and
are characterised by suites of low-molecular-weight aromatic pyrolysis products. Samples rich in organic matter, e.g. surface
sediments, are characterised by products derived from fresh emergent or terrestrial vegetation, which include lignin monomers,
plant-derived fatty acids and long-chain n-alkanes. Pyrolysates from the late glacial-early Holocene period, approximately mid-way down the core are characterised by
distinct suites of long-chain n-alkene/n-alkane doublets, which may reflect the selective preservation of recalcitrant aliphatic macromolecules and/or enhanced inputs
of the algal macromolecule algaenan/polymerised algal lipids. Increased TOC, lower δ13C and increased abundance of more labile lignin and fatty acid products at the same depths suggest this period was associated
with increased lake primary productivity and enhanced inputs of terrestrial OM. TOC is the only ‘bulk’ parameter correlated
with the correspondence analysis axes extracted from the py-GC/MS data. Distinct fluctuations in TOC/total nitrogen ratio
are not explained by variation in organo-nitrogen pyrolysis products. Notwithstanding, the study suggests that py-GC/MS has
potential to complement palaeolimnological investigations, particularly in regions such as southern Africa, where other paleoenvironmental
proxy variables in sediments may be lacking or equivocal. 相似文献
18.
Yuko Soma Yukinori Tani Mitsuyuki Soma Hideo Mitake Ryo Kurihara Shinya Hashomoto Takahiro Watanabe Toshio Nakamura 《Journal of Paleolimnology》2007,37(2):163-175
Detailed depth profiles of photosynthetic pigments in a sediment core (G-12) collected at the BDP93 site, the Buguldeika saddle,
of south Lake Baikal, along with depth profiles of total organic carbon (TOC) and biogenic silica, were studied to elucidate
the temporal changes of phytoplankton assemblages in the lake during the past 28 kyr. In addition to the quantification of
carotenoids by high-performance liquid chromatography with photodiode-array detection (HPLC-PDA), steryl chlorin esters (SCEs)
were analyzed by HPLC-PDA, HPLC-mass spectrometry (LC-MS) and sterols in SCEs by gas chromatography–mass spectrometry (GC–MS)
to enrich the taxonomical information on the phytoplankton composition. Allochthonous input of organic matter from the Selenga
River resulted in the higher TOC contents in core G-12 than in a previously reported core (G-6) collected at another site
from the southern basin. The poorer correlation in core G-12 than in G-6 between TOC and chlorophyll-a-originating pigments, which are indicative of autochthonous production, also indicated a significant allochthonous input
at the site. The abundance of lutein among the carotenoids detected, and the good correlation of total chlorophyll a and b shows that green algae represented a significant portion of the phytoplankton, accompanying the diatoms at the G-12 site,
after the last glacial period. The presence of cryptomonads and cyanobacteria were confirmed from marker carotenoids in the
sediment core. GC–MS analysis of sterols in SCEs detected marker sterols of diatoms, green algae, chrysophytes and dinoflagellates.
The depth profiles of the measured indicators gave consistent features for temporal changes in phytoplankton assemblage at
the G-12 site of Lake Baikal after the last glacial maximum.
Notably, the profile of a chrysophyte-specific sterol in SCEs was consistent with the reported distribution of chrysophyte
cysts during the Holocene. The presence of phytoplankton, such as green algae, diatoms and chrysophytes, in Lake Baikal during
the late last glacial period was indicated by the analysis of sterols in SCEs.
Sedimentary carotenoids and sterols in SCEs were found to give complementary information about phytoplankton composition.
These molecular indicators allow us to reconstruct past lake phytoplankton assemblages responding to environmental changes
with a time resolution as high as age–depth relationship in sediments attainable at present. 相似文献
19.
Svetislav S. Krsti? Wolfgang Zech Igor Obreht Zorica Svir?ev Slobodan B. Markovi? 《Journal of Paleolimnology》2012,47(1):113-124
This study presents changes in diatom flora assemblage composition, TOC, TOC/N and biogenic opal in a 450 cm core of Lake
Panch Pokhari, Central Nepal (4,050 m asl), indicating Late Quaternary environmental fluctuations. Four Diatom Zones (DZ) were detected, with two major changes. The first one was found in ~430 cm depth (~14.8 cal. kyr BP), where the original
flora characterized by Navicula digitulus Hustedt, Pinnularia rhombarea Krammer, P. aff. viridiformis var. minor Krammer, Encyonema silesiacum (Bleisch) D. G. Mann, Cymbopleura naviculiformis (Auerswald) Krammer and Nitzschia sp. was fully replaced by an assemblage consisting of Aulacoseira alpigena (Grunow) Krammer, Diatoma hyemalis (Roth) Heib., Tabellaria flocculosa (Ehrenberg) Kützing, Brachysira brebissonii Ross and Pinnularia subgibba Krammer, creating a stable diatom assemblage for ~8 kyr (DZ3). The second change was found at ~70 cm (~2.1 cal. kyr BP) when
increased nutrient inputs lead to emergence of new taxa such as Fragilaria construens var. subsalina Hustedt, F. tenera (W. Smith) Lange-Bertalot, Eunotia cf. pseudopapilio Lange-Bertalot and M. N?rpel-Schempp and Gomphonema subclavatum Grunow. In order to evaluate the past environmental conditions in the Lake Panch Pokhari, the detected diatom taxa were subjected
to analyses of their autecological preferences and dominance within the specific assemblage. We also assumed that TOC/N ratios
>10 indicate accelerated erosion due to the strengthening of the Summer Monsoon starting at ~14.8 and between 13.7 and 12.8 cal.
kyr BP. Monsoon intensity was most pronounced during the Early Holocene and at the beginning of the Late Holocene. The fluctuations
of TOC and TOC/N in the Late Glacial sediments seem to correlate temporally and climatically with oscillations in the Northern
Atlantic region. 相似文献
20.
Postglacial marine environmental changes in Maxwell Bay, King George Island, West Antarctica 总被引：3，自引：0，他引：3
Sediment textural properties and total organic carbon (TOC) contents of three sediment cores from Maxwell Bay, King George Island, West Antarctica, record changes in Holocene glaciomarine sedimentary environments. The lower sedimentary unit is mostly composed of TOC-poor diamictons, indicating advanced coastal glacier margins and rapid iceberg discharge in proximal glaciomarine settings with limited productivity and meltwater supply. Fine-grained, TOC-rich sediments in the upper lithologic unit suggest more open water and warm conditions, leading to enhanced biological productivity due to increased nutrient-rich meltwater supply into the bay. The relationship between TOC and total sulfur (TS) indicates that the additional sulfur within the sediment has not originated from in situ pyrite formation under the reducing condition, but rather may be attributed to the detrital supply of sand-sized pyrite from the hydrothermal-origin, quartz-pyrite rocks widely distributed in King George Island. The evolution of bottom-water hydrography after deglaciation was recorded in the benthic foraminiferal stable-isotopic composition, corroborated by the TOC and lithologic changes. The Ø18 O values indicate that bottom-water in Maxwell Bay was probably mixed gradually with intruding 18 O-rich seawater from Bransfield Strait. In addition, the Ø13 C values reflect a spatial variability in the carbon isotope distribution in Maxwell Bay, depending on marine productivity as well as terrestrial carbon fluxes by meltwater discharge. The distinct lithologic transition, dated to approximately 8000 yr BP (uncorrected) and characterized by textural and geochemical contrasts, highlights the postglacial environmental change by a major coastal glacier retreat in Maxwell Bay. 相似文献