红树林湿地沉积速率对于气候变化的响应*
作者简介:刘涛(1980—), 男, 山东省滨州市人, 副研究员, 博士, 主要从事海洋沉积学研究。E-mail: salanitana@sina.com
收稿日期: 2016-05-12
要求修回日期: 2016-11-07
网络出版日期: 2017-04-06
基金资助
国家自然科学基金项目(41306075)
广西自然科学基金项目(2014GXNSFBA118222)
广西科学院基本业务经费项目(12YJ25HS16)
Response of mangrove swamp sedimentation rate to climate change
Received date: 2016-05-12
Request revised date: 2016-11-07
Online published: 2017-04-06
Supported by
National Natural Science Foundation (41306075)
Natural Science Foundation of Guangxi (2014GXNSFBA118222)
Fundamental Research Funds of the Guangxi Academy of Sciences (12YJ25HS16)
Copyright
红树林湿地对维持热带-亚热带地区海岸带生态平衡具有重要作用, 并在全球碳循环中扮演重要角色。以广西北海市红树林湿地作为研究对象, 对该地区两处湿地钻孔沉积物的粒度、沉积速率进行了综合研究, 并结合当地近30余年的降雨量和台风登陆频率的变化特征, 分析了红树林沉积物中风暴沉积的粒度组分、含量以及影响风暴沉积输入量的主要因素以及红树林沉积速率对于气候变化的响应特征。研究表明: 1) 正常天气状况下由潮流输入的泥沙粒级均为粉砂-黏土组分, 红树林沉积中的砂粒级组分为台风期间的暴风浪输入。风暴沉积在南流江口红树林沉积物中所占的比重超过56%, 在大冠沙红树林沉积物中所占比重超过73%。2) 近30年来, 两处红树林湿地的沉积速率对于台风登陆频率增加有明显正响应, 而对降雨量变化则无明显响应。3) 在径流来沙量较少的大冠沙红树林湿地, 由于岸线开敞、潮间带和红树林带宽度较小, 导致台风期间暴风浪入射能量较强, 风暴沉积输入量较高, 其沉积速率反而高于径流来沙量充足的河口区。
刘涛 , 刘莹 , 乐远福 . 红树林湿地沉积速率对于气候变化的响应*[J]. 热带海洋学报, 2017 , 36(2) : 40 -47 . DOI: 10.11978/2016052
Mangrove swamp plays an important role in the maintenance of ecological balance in tropical-subtropical coastal regions, as well as in the global carbon cycle. The grain size characteristic and sedimentary rate of two mangrove swamps were studied. The grain size and proportion of storm deposit were determined, and the factors that influenced storm sediment inputting flux were analyzed. The variation of mangrove swamp accretion rate in response to climate change was also studied. The main conclusions are as follows. 1) The inputted sediments were silt and clay in normal weather condition during tidal process, while the sand component in mangrove swamp sediment was likely inputted by storms. In mangrove swamp sediment, the proportion of storm deposit was 56% for mangrove swamp of the Nanliujiang River estuary and 73% for Daguansha mangrove swamp. 2) The sedimentation rate of mangrove swamp was positive related to typhoon landfall frequency rather than rain fall. 3) The storm energy was higher in Daguansha mangrove swamp than in the Nanliujiang River estuary, likely attributing to its open coastline shape with narrow width in tidal zone and mangrove belt, which may deduce more storm deposit inputted and higher sedimentary rate.
Key words: mangrove swamp; typhoon; sedimentary rate; grain size
Fig. 1 The locations of two mangrove swamps and the sampling sites图1 红树林湿地的位置及取样点 |
Fig. 2 Grain size parameters and spectra of sediments in mangrove图2 红树林沉积物粒度特征 |
Tab. 1 Contents of grain size groups in mangrove sediment表1 红树林沉积物中各粒级组分含量(柱状样各深度均值) |
柱状样 | <63μm 组分含量/% | >63μm 组分含量/% | >250μm 组分含量/% |
---|---|---|---|
NL1 | 79.8 | 20.2 | 4.7 |
DGS3 | 27.1 | 72.9 | 52.6 |
Tab. 2 The raw data and calibration of 210Pbex in two cores表2 沉积柱210Pbex比活度测定及校正信息表 |
深度/cm | 泥质组分 含量/% | NL1 | 深度/cm | 泥质组分 含量/% | DGS3 | ||||
---|---|---|---|---|---|---|---|---|---|
校正前 210Pbex比活度/(Bq·kg-1) | 校正后 210Pbex比活度/(Bq·kg-1) | 测量误差(±2δ) | 校正前 210Pbex比活度/(Bq·kg-1) | 校正后 210Pbex比活度/(Bq·kg-1) | 测量误差(±2δ) | ||||
0~2 | 75.99 | 227 | 216 | 20 | 0~2 | 23.5 | 102 | 123 | 14 |
2~4 | 71.83 | 247 | 223 | 21 | 2~4 | 25.2 | 103 | 117 | 13 |
4~6 | 67.46 | 148 | 125 | 15 | 8~10 | 22.7 | 48 | 61 | 6 |
6~8 | 85.31 | 165 | 177 | 17 | 10~12 | 35.58 | 103 | 82 | 9 |
8~10 | 79.77 | 170 | 170 | 16 | 14~16 | 24.22 | 54 | 64 | 6 |
10~12 | 87.09 | 203 | 222 | 21 | 18~20 | 25.71 | 69 | 76 | 8 |
12~14 | 83.18 | 253 | 264 | 22 | 22~24 | 41.58 | 104 | 71 | 6 |
14~16 | 87.41 | 237 | 260 | 23 | 26~28 | 27.67 | 64 | 65 | 6 |
16~18 | 70.92 | 248 | 221 | 21 | 30~32 | 35.05 | 74 | 60 | 5 |
18~20 | 87.28 | 148 | 162 | 15 | 34~36 | 44.66 | 112 | 71 | 6 |
20~22 | 84.38 | 218 | 230 | 21 | 38~40 | 21.5 | 45 | 60 | 7 |
22~24 | 74.1 | 183 | 170 | 16 | 42~44 | 20.7 | 42 | 57 | 6 |
24~26 | 85.29 | 119 | 127 | 15 | 46~48 | 26.82 | 41 | 44 | 4 |
26~28 | 85.01 | 125 | 133 | 15 | 50~52 | 33.3 | 40 | 34 | 4 |
28~30 | 79.39 | 170 | 169 | 16 | 58~60 | 19.77 | 29 | 42 | 3 |
30~32 | 71.81 | 201 | 181 | 16 | 66~68 | 27.05 | 27 | 29 | 3 |
32~34 | 84.26 | 69 | 73 | 9 | |||||
34~36 | 71.56 | 126 | 113 | 11 | |||||
36~38 | 78.35 | 171 | 168 | 17 | |||||
38~40 | 78.36 | 120 | 118 | 13 | |||||
40~42 | 86.72 | 61 | 66 | 11 | |||||
42~44 | 67.61 | 58 | 49 | 9 | |||||
44~46 | 79.36 | 90 | 90 | 10 | |||||
46~48 | 84.69 | 98 | 104 | 12 | |||||
48~50 | 86.67 | 54 | 59 | 9 |
Fig. 3 Depth profiles of 210Pbex in two sediment cores图3 柱状样沉积物210Pbex比活度深度剖面 |
Fig. 4 Variation of accretion rate with depth in sediment cores图4 沉积速率随深度变化情况 |
Tab. 3 Summary of accretion rate characteristic of sediment cores表3 沉积柱沉积速率特征 |
柱状样 | 沉积速率突变深度/cm | 突变深度以上平均沉积速率/(cm·a-1) | 突变深度以下平均沉积速率/(cm·a-1) | 总平均沉积速率/(cm·a-1) |
---|---|---|---|---|
NL1 | 10 | 1.63 | 0.88 | 1.03 |
DS3 | 16 | 2.23 | 1.55 | 1.76 |
Fig. 5 Variation of accretion rate (a), rain fall (b) and typhoon landfall frequency (c) since 1980图5 1980年以来柱状样NL1的沉积速率(a)、北海市年降雨量变化情况(b)及影响广西的台风频率(c) |
The authors have declared that no competing interests exist.
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