Environ Earth Sci
DOI 10.1007/s12665-012-1578-2
ORIGINAL ARTICLE
Shell sand properties and vegetative distribution on shell ridges
of the Southwestern Coast of Bohai Bay
Wenjun Xie • Yanyun Zhao • Zhidong Zhang
Qing Liu • Jiangbao Xia • Jingkuan Sun •
Jiayi Tian • Tongqiu Sun
•
Received: 22 July 2010 / Accepted: 21 January 2012
Ó Springer-Verlag 2012
Abstract Little information is available about shell ridge
ecosystems. Vegetative distribution and shell sand properties were investigated on a shell ridge in the Binzhou
National Shell Ridge and Wetland Nature Reserve. 21 plant
species were observed in the study area and, according to
the Shannon–Weiner Index and species evenness, vegetative cover, and abundance varied significantly at different
sites (P \ 0.05). Sand percent, dissolved organic C, total
N, and available N concentrations were significantly higher
in the upper layers, while total and available P and K
concentrations were significantly higher in the lower profile. Plant species were divided into three groups based on
canonical correspondence analysis. Group A included 10
plant species, and was well correlated with high available
nutrient concentrations (dissolved organic C, and available
N, P, and K) and sand moisture. Groups B and C were well
correlated with total K, P and salinity. Thus shell sand
properties affected the spatial distribution of vegetation in
the study area. Due to the coarse texture, salinity was less
than 0.4% and much lower than in adjacent soils. Ten saltsensitive plant species were found, accounting for 48% of
the total plant species. Shell sand is therefore imperative to
W. Xie Y. Zhao Q. Liu J. Xia J. Sun J. Tian (&)
Shandong Key Laboratory of Eco-Environmental Science for the
Yellow River Delta, Binzhou University, No.391 5th Yellow
River Road, Binzhou 256603, Shandong, China
e-mail: [email protected]
Z. Zhang
Yantai Institute of Coastal Zone Research,
Chinese Academy of Sciences, Yantai 264003, China
T. Sun
Binzhou Institute of Fisheries Research, Binzhou 256600, China
shell ridge ecosystem sustainability, and shell sand mining
should be prohibited in the area.
Keywords Biodiversity Nutrient concentrations Salinity Shannon–Weiner Index
Introduction
Shell ridges are distinctive shell sand deposits lying on the
upper surface of tidal flats where shellfish grow in abundance and fresh water discharge is minimal (Liu et al.
2005). Occurrence of shell ridges have been reported in
China and Suriname (Meldahl 1995; Liu et al. 2005).
Research on shell ridges have previously focused on
coastal geomorphology, sea level and climate changes, and
coastal ecosystem evaluation (Saito et al. 2000).
The formation mechanisms and spatial distribution of
shell ridges have been studied, and results indicate that
they are more than 2000 years old (Saito et al. 2000; Liu
et al. 2005). Over time, shells fragment into shell sand,
which provide a unique habitat for plants and animals. Pan
et al. (2001) reported that more than 350 plant species, 85
aquatic animal species, 30 mollusk species, and 45 bird
species can be found in the Binzhou National Shell Ridge
and Wetland Nature Reserve. Biodiversity of shell ridges is
far higher than in nearby coastal silt zones, and many bird
species prefer shell ridges as migration stations.
The main inorganic shell constituent of shell ridges is
calcium carbonate (CaCO3) (95–99% by weight) and also
contains a small quantity of organic and other inorganic
constituents (Lorens and Bender 1980). Total N, P, and K
concentrations are about 0.76, 0.2, and 0.02%, respectively
(Marxen et al. 1998). Therefore, nutrients in shell sand may
facilitate plant growth. Interestingly, some salt-sensitive
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Environ Earth Sci
plant species, such as Periploca sepium Bunge, which do
not occur on neighboring soil, can be found on these shell
ridges. It is well known that soil properties affect vegetative distribution (El-Ghani and Amer 2003; Xu et al. 2008),
and we conclude that shell sand provides a unique habitat
for vegetation in the reserve.
Recently, the size of the Binzhou National Shell Ridge
and Wetland Nature Reserve shell ridge area is shrinking
and biodiversity is decreasing. To conserve this ecosystem,
it is crucial to understand the role of shell sand in the local
ecosystem (Maestre et al. 2006; Defeo et al. 2009), however, research is limited. Therefore, the physicochemical
properties of shell sand and vegetative distribution of a
shell ridge were investigated. The principal objectives of
this research were to discover the relationship between
shell sand properties and vegetative distribution as an
integral component of a larger understanding of the shell
ridge ecosystem.
Materials and methods
Fig. 1 Location shell ridges in the Binzhou National Shell Ridge and
Wetland Nature Reserve
Study site
The Binzhou National Shell Ridge and Wetland Nature
Reserve (38°100 –38°190 N; 117°510 –118°020 E) is on the
south-west coast of Bohai Bay in Shandong Province,
China. The reserve has four shell ridges with an average
thickness of 2–4 m. The shell ridge investigated is about
45 km long, 100–150 m wide, and 2–3 m thick, extending
from the north-west to the south-west, in accordance with
the average wave direction (Fig. 1).
Sampling design
In June, 2008, seven transects, proportionally distributed
along the shell ridge were selected. Each transect was 20 m
long and 5 (1 9 1 m) quadrants on a diagonal line were
chosen. Every plant species found was recorded and surveyed for abundance and coverage extent. Species
nomenclature followed the description of Lee (1996).
According to report from Zhang et al. (2007), sand profile
in the study area was divided into four layers, i.e., 0–25 cm
(white–yellow), 25–50 cm (deep white–yellow), 50–70 cm
(grayish-yellow, shell sand blended with silt), and
70–120 cm (light grayish-yellow, shell sand blended with
silt). In each quadrant, samples from each of these layers
were collected and stored in plastic bags.
method (Lu 2000). The semimicro-Kjeldahl method was
used to determine total sand nitrogen (TN) (Bremner 1996)
and available nitrogen (AN) was extracted with 2 M KCl
and analyzed with a segmented flow analyzer (Seal AA3)
(Mulvaney 1996). After wet digestion with H2SO4 plus
HClO4, total phosphorus (TP) was determined colorimetrically (Kuo 1996), and total potassium (TK) was determined by atomic absorption spectrometer (Shimadzu AAS
6800). Dissolved organic C (DOC) was extracted using
ultrapure water and measured with a TOC analyzer
(Elementar LiquiTOC II) after filtration through a 0.45 lm
filter (Martı́n-Olmedo and Rees 1999). Available phosphorus (AP) was extracted with sodium bicarbonate and
determination was conducted by spectrophotometry (Kuo
1996). Available potassium (AK) was extracted with
ammonium acetate (Helmke and Sparks 1996) and determination was conducted by atomic absorption
spectroscopy.
Data analysis
Plant diversity was determined using the Shannon-Weiner
Index (H0 ) [Eq. 1] and species evenness (J) [Eq. 2] (Krebs
1989).
S
X
Physicochemical properties analysis of shell sand
H0 ¼ Water content was determined by oven drying (Gardner
1996) and salinity was determined by the gravimetric
where S is the number of species and Pi is the species
frequency, calculated by dividing the individual number of
123
ðpi ln pi Þ
ð1Þ
i¼1
Environ Earth Sci
each plant species by the total individual number in each
quadrant.
J¼
H0
ln S
ð2Þ
Data from the five quadrants within each transect were
averaged to represent the sampling transect. The important
value (IV) of each plant species was calculated as
IV = (relative height ? relative coverage ? relative frequency)/3.
The mean values of shell sand properties and vegetation
data were calculated, and the significant differences among
them were determined. Canonical correspondence analysis
(CCA) of shell sand properties of the surface layer and IV
were used to determine the relationships between vegetation distribution and environmental variables. All analyses,
except CCA, were conducted using SPSS (12.0). CCA was
conducted using CANOCO (4.5). All significant differences, unless otherwise noted, are reported as P B 0.05.
Results
Characteristics of vegetation distribution
In the seven transects, 21 plant species were recorded. The
IV range of each plant species in study area was 0.01–0.25.
Phragmites australis (Cav.) Trin. ex Steud and Messerschmidia sibirica Linn. had the greatest IV, and were
0.25 and 0.19, respectively. Shannon-Weiner Index values
(H0 ), species evenness (J), and coverage extent are shown
in Table 1. Among the seven transects, significant differences were observed for H0 , J, and coverage extent. The
highest H0 and coverage extent were in the third transect,
and the highest J in the fourth.
Shell sand properties
Large shell fragments ([4 mm) were mainly in the surface
layer, and fine shell sand (\0.2 mm) in the four layers
accounted for [30% (Table 2). The ranges of shell sand
physicochemical properties in seven transects are shown in
Table 3. Within layers, no significant differences in properties were observed among seven transects (Table 3),
however, sand properties differed significantly among the
four layers (Table 4). Salinity was less than 0.4%,
increased with depth, and in the 50–70 and 70–120 cm
layers was significantly greater than in the two layers
above.
Sand moisture also increased with depth. In the 0–25
and 25–50 cm layers, water content was less than 4%, and
water content in the 70–120 cm layer was significantly
greater than in the three layers above.
Sand DOC, TN, and AN concentrations in the bottom
layer were significantly lower than those in the two layers
above. The highest TP, TK, and AK concentrations were in
the 70–120 cm layer and the highest AP was in the
50–70 cm layer, which were all significantly higher than
those in the two layers above. Correlation analysis showed
that TP was significantly correlated with TK and salinity in
the top layer (r = 0.772 and 0.925, respectively;
P B 0.01).
Correlation of vegetation and shell sand properties
Sampling
transects
H0
J
Coverage (%)
The successive decrease in the eigenvalues of the four
CCA axes indicated a well-structured data set in this study
(Table 5) (El-Ghani and Amer 2003). Nine sand properties
were well correlated with CCA axes, and the first two axes
explained 53.6% of the species–environment variance.
These results suggest a significant association between
vegetation and the measured sand properties (Jongman
et al. 1987). Axis 1 was well correlated with TN, TP, and
TK, and Axis 2 was well correlated with AP and AK.
The ordination diagram produced with the first two axes
is shown in Fig. 2. Three vegetation groups (A, B, and C)
were recognized. Group A involved 10 plant species,
linked with the relatively high TN, AN, AK, AP, DOC, and
1
0.65 ± 0.12 bc
0.28 ± 0.14 b
52.0 ± 7.2 c
Table 2 Shell sand texture of a shell ridge sand profile in the Bohai
Bay
Table 1 Plant diversity according to the Shannon–Weiner Index
(H0 ), species evenness (J), and coverage extent on a shell ridge ecosystem of the Bohai Bay
2
0.93 ± 0.16 a
0.42 ± 0.15 a
76.7 ± 5.5 ab
3
0.97 ± 0.10 a
0.42 ± 0.12 a
83.5 ± 6.5 a
4
0.49 ± 0.14 cd
0.44 ± 0.08 a
27.7 ± 3.7 de
5
0.70 ± 0.12 b
0.36 ± 0.13 ab
31.4 ± 4.0 d
6
7
0.42 ± 0.08 d
0.54 ± 0.11 c
0.30 ± 0.13 ab
0.30 ± 0.09 ab
21.7 ± 6.4 e
23.3 ± 2.4 e
Mean values ± SD (n = 5). Values within columns followed by the
same letter are not significantly different at P B 0.05
Profile
depth
(cm)
Sand texture (%)
[4 mm
2–4 mm
0.5–2 mm
0.2–0.5 mm \0.2 mm
0–25
4.16
6.62
36.57
21.78
30.87
25–50
0.66
4.11
39.09
23.24
32.91
50–70
0
1.02
11.43
28.67
58.87
70–120
0
1.03
30.49
36.31
32.71
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Environ Earth Sci
Table 3 Shell sand property ranges in seven transects on a shell ridge in the Bohai Bay
Profile
depth (cm)
Nutrient concentrations
Sand
moisture
AK (mg kg ) (%)
Salinity
(%)
pH
-1
TN
(g kg-1)
TP
(g kg-1)
TK
(g kg-1)
DOC
(mg kg-1)
AN
(mg kg-1)
AP
(mg kg-1)
0–25
0.44–0.81
0.13–0.18
0.47–0.95
7.71–11.94
3.66–7.88
4.74–6.34
69.67–101.15
0.77–4.18
0.07–0.17
7.12–7.62
25–50
0.51–0.76
0.12–0.19
0.68–1.39
7.71–12.17
3.88–7.26
4.72–7.61
78.46–107.05
1.23–5.97
0.07–0.16
7.25–7.59
50–70
70–120
0.41–0.62
0.41–0.57
0.13–0.21
0.22–0.29
0.81–1.77
1.49–2.49
6.60–8.63
4.23–6.83
3.94–5.98
3.22–5.06
8.81–12.75
6.66–12.06
82.64–139.09
131.27–195.99
2.09–7.04
6.49–11.39
0.18–0.28
0.23–0.39
7.51–7.92
7.37–7.81
TN total nitrogen, TP total phosphorus, TK total potassium, DOC dissolved organic carbon, AN available nitrogen, AP available phosphorus, AK
available potassium
Table 4 Shell sand property averages in seven transects on a shell ridge in the Bohai Bay
Profile depth
(cm)
Nutrient concentrations
TN
(g kg-1)
TP
(g kg-1)
TK
(g kg-1)
DOC
(mg kg-1)
AN
(mg kg-1)
0–25
0.63 a
0.15 b
0.61 d
8.84 ab
5.26 a
25–50
0.60 a
0.15 b
0.98 c
9.17 a
5.13 a
50–70
70–120
0.52 b
0.49 b
0.18 ab
0.27 a
1.24 b
1.99 a
7.57 c
5.61 d
4.75 ab
3.84 b
Sand moisture
(%)
Salinity
(%)
pH
82.48 b
2.74 c
0.14 b
7.38 a
5.77 c
98.79 ab
3.82 bc
0.15 b
7.40 a
10.07 a
7.62 ab
109.62 ab
140.23 a
4.93 b
7.22 a
0.24 a
0.29 a
7.85 a
7.42 a
AP
(mg kg-1)
AK
(mg kg-1)
5.85 c
Values within columns followed by the same letter are not significantly different at P B 0.05
TN total nitrogen, TP total phosphorus, TK total potassium, DOC dissolved organic carbon, AN available nitrogen, AP available phosphorus, AK
available potassium
Table 5 Correlation coefficients and eigenvalues of shell sand
properties of a shell ridge in the Bohai Bay
Discussion
Sand properties
Before the Binzhou National Shell Ridge and Wetland
Nature Reserve was established, shell sand was exploited by
local residents for carbonate materials, and vegetation suffered severe destruction. This was an important cause of
vegetation variation and abundance in the seven transects.
Álvarez-Rogel et al. (2007) showed that soil fertility
affected vegetation distribution in coastal ecosystems. In
the present study, three vegetation groups were recognized
and they inhabited shell ridge sites with different sand
properties. Group A grew in sand with relatively high
available nutrient concentrations and sand moisture, while
groups B and C had high salt tolerance and lower correlation with available nutrient concentrations and sand moisture. Hence, sand properties affected spatial distribution,
coverage extent, H0 , and J of vegetation in this study area.
Higher shell sand TK and lower shell sand TN in this
study compared with that of Marxen et al. (1998), especially
in the bottom layer, were caused by silt, which often entered
shell sand through sea tides. With the lapse of time, silt is
deposited under shell sand, and resulted in the higher TK
and lower TN. In the surface layer, variation of shell sand
properties was probably also a result of different silt percentages, which further influenced vegetation distribution.
Axes
1
2
3
4
Eigenvalues
0.56
0.48
0.36
0.24
AP
0.36
-0.43*
0.27
-0.30
TP
AN
-0.49*
0.24
-0.08
0.22
-0.47*
-0.41
-0.37
0.58*
0.39
0.27
TN
0.71**
0.02
AK
-0.09
0.58*
-0.25
TK
-0.52*
0.18
-0.50*
-0.46*
DOC
Salinity
0.19
-0.27
0.32
0.10
-0.42
-0.27
-0.68**
-0.38
0.33
0.02
0.65**
0.07
Moisture
0.47*
TN total nitrogen, TP total phosphorus, TK total potassium, DOC
dissolved organic carbon, AN available nitrogen, AP available phosphorus, AK available potassium
* Signifies P B 0.05
** Signifies P B 0.01
sand moisture. Group B and C included 10 plant species
and one plant species, respectively, and both were well
correlated with TK, TP, and salinity, but were not well
correlated with available nutrients and sand moisture.
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Environ Earth Sci
of shell ridge sand was coarse shell particles and fragments,
which caused water adsorption and capillary action to be
minimal. Hence, salt is not easily transported through shell
sand layers, even though the water table is shallow.
Therefore, the role of shell sand in shell ridge ecosystems
cannot be replaced by silt and other soil constituents.
However, compared to soil in agro-ecosystems, water and
nutrient concentrations in shell sand, especially bio-available forms, are low (Mowo et al. 2006). Decreasing suitability for habitation suggested that more attention should
be given to shell ridge ecosystem preservation.
Conclusions
Fig. 2 Canonical correspondence analysis ordination diagram for
vegetation species and shell sand properties of a shell ridge in Bohai
Bay. TN, total nitrogen; TP, total phosphorus; TK, total potassium;
DOC, dissolved organic carbon; AN, available nitrogen; AP, available
phosphorus; AK, available potassium; S, salinity; W, soil moisture;
arsa, Artemisia sacrorum Ledeb.; epsi, Ephedra Sinica Stapf; mesu,
Melilot suaveolens Ledeb.; zoma, Zoysia macrostachya Franch. Et
Sav.; cyth, Cynanchum thesioides (Freyn) K. Schum.; atce, Atriplex
centralasiatica Hjin.; libi, Limonium bicolor (Bunge) Kuntze; susa,
Suaeda salsa (L.) Pall.; soar, Sonchus arvensis Linn.; phau,
Phragmites australis (Cav.) Trin. ex Steud.; meja, Metaplexis
japonica (Thunb.) Makino; armo, Artemisia mongolica (Fisch. ex
Bess.) Nakai; ruco, Rubia cordifolia L.; arca, Artemisia carvifolia
Buch.-Ham. ex Roxb. mesi, Messerschmidia sibirica Linn.; asco,
Asparagus cochinchinensis (Lour.) Merr.; lecu, Lespedeza cuneata
(Dum.Cours.) G. Don; caja, Cayratia japonica (Thunb.) Gagnep.;
xasi, Xanthium sibiricum Patrin ex Widder; aeli, Aeluropus littoralis
(Gouan) Parl. Var. sinensis Debeaux; opus, Oplismenus var.
Submuticus
The most remarkable characteristic of shell ridge sand
was the relatively low salinity. The greatest shell sand
salinity was less than one third that of adjacent soil
(1.52%), and high soil salinity caused vegetation coverage
of adjacent soil to be less than 5%, dominated by halophytes. In coastal ecosystems, salinity is a key factor for
vegetation abundance and coverage extent (Bolduc and
Afton 2005; Badano and Marquet 2008). In this study, 10
salt-intolerant plant species inhabited the shell sand,
accounting for 48% of the total observed plant species.
Therefore, high vegetative abundance and coverage on
shell ridges was correlated with low salinity. Movement of
salt in the soil is driven by evaporation and capillary action
(Wallender et al. 2006; Lundmark and Olofsson 2007;
Volodina and Sokolova 2007). The dominant composition
This study contributed to a better understanding of the
ecological attributes of shell ridges in the coastal zone of
Bohai Bay in China. 21 plant species were observed on the
shell ridge and their distribution was affected by sand
properties. Dissolved organic C, TN, and available N concentrations were significantly higher in the upper layers,
while total and available P and K concentrations were
higher in the lower layers. Due to the coarse texture, salinity
was less than 0.4% and much lower than that in the adjacent
soils, which contributed to the biodiversity of shell ridge
ecosystems along the coastline. In shell ridge ecosystems,
the role of shell sand cannot be displaced by silt or other soil
constituents and shell mining should be prohibited.
Acknowledgments This work was financially supported by the
National Natural Science Foundation of China (31100468) and the
Natural Science Foundation of Shandong Province (Y2006D01,
ZR2009BL003).
References
Álvarez-Rogel J, Jiménez-Cárceles FJ, Roca MJ et al (2007) Changes
in soils and vegetation in a Mediterranean coastal salt marsh
impacted by human activities. Estuar Coastal Shelf S 73:
510–526
Badano EI, Marquet PA (2008) Ecosystem engineering affects
ecosystem functioning in high-Andean landscapes. Oecologia
155:821–829
Bolduc F, Afton AD (2005) Sediments in marsh ponds of the gulf
coast chenier plain: effects of structural marsh management and
salinity. Wetlands Ecol Manage 13:395–404
Defeo O, McLachlan A, Schoeman DS et al (2009) Threats to sandy
beach ecosystems: a review. Estuar Coast Shelf S 81:1–12
El-Ghani MMA, Amer WM (2003) Soil–vegetation relationships in a
coastal desert plain of southern Sinai, Egypt. J Arid Environ
55:607–628
Gardner WH (1996) Water content. In: Sparks DL (ed) Methods of
soil analysis. Part 1. Physical and mineralogical methods. SSSA,
Book Series no. 5. Madison, WI, USA, pp 493–544
Helmke PA, Sparks DL (1996) Lithim, sodium, potassium, rubidium,
and cesium. In: Sparks DL (ed) Methods of soil analysis. Part 3.
123
Environ Earth Sci
Chemical methods. SSSA, Book Series no. 5. Madison, WI.
pp 551–574
Jongman RH, ter Braak CJF, van Tongeren OFG (1987) Data analysis
in community and landscape ecology. Pudoc, Wageningen, The
Netherlands, p 299
Kuo S (1996) Phosphorus. In: Sparks DL (ed) Methods of soil
analysis. Part 3. Chemical methods. SSSA, Book Series no. 5.
Madison, WI, pp 869–919
Krebs CJ (1989) Ecological methodology. Harper and Row,
New York, p 654
Lee WT (1996) Standard illustrations of Korean plants. Academy
Publishing Co, Seoul
Liu ZJ, Zhuang ZY, Han DL et al (2005) The sedimentary
characteristics and formation mechanism of shell ridges along
the southwest coast of Bohai Bay. J Ocean Univ China
4(2):124–130
Lorens RB, Bender ML (1980) The impact of solution chemistry on
Mytilus edulis calcite and aragonite. Geochim Cosmochim Acta
44:1265–1278
Lu RK (2000) Soil agro-chemical analysis. Agricultural Science &
Technology Press, Beijing
Lundmark A, Olofsson B (2007) Chloride deposition and distribution
in soils along a deiced highway- assessment using difference
methods of measurement. Water Air Soil Poll 182:173–185
Maestre FT, Bradford MA, Reynolds JF (2006) Soil heterogeneity
and community composition jointly influence grasslands biomass. J Veg Sci 17(3):261–270
Martı́n-Olmedo P, Rees RM (1999) Short-term N availability in
response to dissolved-organic-carbon from poultry manure,
123
alone or in combination with cellulose. Biol Fertil Soils
29:386–393
Marxen JC, Hammer M, Gehrke T et al (1998) Carbohydrates of the
organic shell matrix and the shell-forming tissue of the snail
Biomphalaria glabrata (Say). Biol Bull 194:231–240
Meldahl KH (1995) Pleistocene shoreline ridges from tide-dominated
and wave-dominated coasts: northern gulf of California and
western Baja California, Mexico. Mar geol 123(1–2):61–72
Mowo JG, Janssen BH, Oenema O et al (2006) Soil fertility
evaluation and management by smallholder farmer communities
in northern Tanzania. Agr Ecosyst Environ 116(1–2):47–59
Pan HJ, Tian JY, Gu FT (2001) Seashell islands near the Yellow
River Delta and plant diversity protection. Marine Environ Sci
20(3):54–59 (in Chinese)
Saito Y, Wei H, Zhou Y et al (2000) Delta progradation and chenier
formation in the Huanghe (Yellow River) delta, China. J Asian
Earth Sci 18(4):489–497
Volodina IV, Sokolova TA (2007) Changes in the salt status of
meadow-chestnut soils under the impact of saline groundwater in
a model experiment. Eurasian Soil Sci 40(8):839–849
Wallender W, Tanji K, Gilley J et al (2006) Water flow and salt
transport in cracking clay soils of the Imperial Valley, California. Irrig Drain Syst 20(4):361–387
Xu XL, Ma KM, Fu BJ et al (2008) Relationships between vegetation
and soil and topography in a dry warm river valley, SW China.
Catena 75:138–145
Zhang HC, Chang FQ, Li B et al (2007) Branched aliphatic alkanes of
shell bar section in Qarhan Lake, Qaidam Basin and their
paleoclimate significance. Chinese Sci Bull 52(9):1248–1256