{"title":"地貌复杂性影响着源流粗颗粒有机质的运移和储存","authors":"Caleb B. Fogel, Katherine B. Lininger","doi":"10.3389/frwa.2023.1227167","DOIUrl":null,"url":null,"abstract":"Coarse particulate organic matter (CPOM; organic matter 1–100 mm in diameter, excluding small wood) stored in streams provides an important energy source for aquatic ecosystems, and CPOM transport provides downstream energy subsidies and is a pathway for watershed carbon export. However, we lack understanding of the magnitude of and processes influencing CPOM storage and transport in headwater streams. We assessed how geomorphic complexity and hydrologic regime influence CPOM transport and storage in the Colorado Front Range, USA. We compared CPOM transport during snowmelt in a stream reach with high retentive feature (e.g., wood, cobbles, and other features) frequency to a reach with low retentive feature frequency, assessing how within-a-reach geomorphic context influences CPOM transport. We also compared CPOM transport in reaches with differing valley geometry (two confined reaches versus a wide, multi-thread river bead) to assess the influence of geomorphic variations occurring over larger spatial extents. Additionally, we compared CPOM storage in accumulations in reaches ( n = 14) with flowing water or dry conditions in late summer and investigated how small pieces of organic matter [e.g., woody CPOM and small wood (>1 min length and 0.05–1 min diameter or 0.5–1 min length and >0.1 min diameter)] influence CPOM storage. We found that within-a-reach retentive feature frequency did not influence CPOM transport. However, valley geometry influenced CPOM transport, with a higher CPOM transport rate (median: 1.53 g min −1 ) downstream of a confined stream reach and a lower CPOM transport rate (median: 0.13 g min −1 ) downstream of a low gradient, multi-thread river bead. Additionally, we found that particulate organic carbon (POC) export (0.063 Mg C) in the form of CPOM was substantially lower than dissolved organic carbon (DOC) export (12.3 Mg C) in one of these headwater streams during the 2022 water year. Dry reaches stored a higher volume of CPOM (mean = 29.18 m 3 ha −1 ) compared to reaches with flowing water (15.75 m 3 ha −1 ), and woody CPOM pieces trapped 37% of CPOM accumulations. Our results demonstrate that the influence of geomorphic context on CPOM transport depends on the scale and type of geomorphic complexity, POC may be lower than DOC export in some headwater streams, and small woody organic material is important for trapping CPOM small streams.","PeriodicalId":33801,"journal":{"name":"Frontiers in Water","volume":"18 1","pages":"0"},"PeriodicalIF":2.6000,"publicationDate":"2023-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Geomorphic complexity influences coarse particulate organic matter transport and storage in headwater streams\",\"authors\":\"Caleb B. Fogel, Katherine B. 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We also compared CPOM transport in reaches with differing valley geometry (two confined reaches versus a wide, multi-thread river bead) to assess the influence of geomorphic variations occurring over larger spatial extents. Additionally, we compared CPOM storage in accumulations in reaches ( n = 14) with flowing water or dry conditions in late summer and investigated how small pieces of organic matter [e.g., woody CPOM and small wood (>1 min length and 0.05–1 min diameter or 0.5–1 min length and >0.1 min diameter)] influence CPOM storage. We found that within-a-reach retentive feature frequency did not influence CPOM transport. However, valley geometry influenced CPOM transport, with a higher CPOM transport rate (median: 1.53 g min −1 ) downstream of a confined stream reach and a lower CPOM transport rate (median: 0.13 g min −1 ) downstream of a low gradient, multi-thread river bead. Additionally, we found that particulate organic carbon (POC) export (0.063 Mg C) in the form of CPOM was substantially lower than dissolved organic carbon (DOC) export (12.3 Mg C) in one of these headwater streams during the 2022 water year. Dry reaches stored a higher volume of CPOM (mean = 29.18 m 3 ha −1 ) compared to reaches with flowing water (15.75 m 3 ha −1 ), and woody CPOM pieces trapped 37% of CPOM accumulations. Our results demonstrate that the influence of geomorphic context on CPOM transport depends on the scale and type of geomorphic complexity, POC may be lower than DOC export in some headwater streams, and small woody organic material is important for trapping CPOM small streams.\",\"PeriodicalId\":33801,\"journal\":{\"name\":\"Frontiers in Water\",\"volume\":\"18 1\",\"pages\":\"0\"},\"PeriodicalIF\":2.6000,\"publicationDate\":\"2023-09-15\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Frontiers in Water\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.3389/frwa.2023.1227167\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"WATER RESOURCES\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Frontiers in Water","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.3389/frwa.2023.1227167","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"WATER RESOURCES","Score":null,"Total":0}
引用次数: 0
摘要
粗颗粒有机物(CPOM;河流中储存的1 ~ 100 mm直径的有机物(不包括小木材)为水生生态系统提供了重要的能量来源,CPOM运输为下游提供了能量补贴,是流域碳输出的途径。然而,我们对水源中CPOM储运的影响程度和过程缺乏了解。我们评估了地貌复杂性和水文制度如何影响美国科罗拉多前山脉的cpm运输和储存。我们比较了具有高保留特征(例如,木材,鹅卵石和其他特征)频率的河流河段与具有低保留特征频率的河段在融雪期间的CPOM运输,评估河段内地貌环境如何影响CPOM运输。我们还比较了不同山谷几何形状河段(两个受限河段与一个宽阔的多线程河段)的CPOM输送,以评估在更大空间范围内发生的地貌变化的影响。此外,我们将河段(n = 14)的累积CPOM储量与夏末的流动水或干燥条件进行了比较,并研究了小块有机质[例如木质CPOM和小块木材(长度为1分钟,直径为0.05-1分钟或长度为0.5-1分钟,直径为0.1分钟)]如何影响CPOM储量。我们发现在可及范围内保留特征频率不影响CPOM传输。然而,山谷几何形状影响了CPOM的输送,在受限河段下游,CPOM输送速率较高(中值:1.53 g min - 1),而在低坡度、多线程河段下游,CPOM输送速率较低(中值:0.13 g min - 1)。此外,我们发现,在2022水年期间,其中一条源流中以CPOM形式输出的颗粒有机碳(POC) (0.063 Mg C)显著低于溶解有机碳(DOC)输出(12.3 Mg C)。与有流水的河段(15.75 m 3 ha - 1)相比,干河段储存了更高的CPOM体积(平均为29.18 m 3 ha - 1),而木质CPOM片捕获了37%的CPOM积累量。研究结果表明,地貌环境对CPOM运移的影响取决于地貌复杂性的尺度和类型,部分源流的POC可能低于DOC输出,小木本有机物对CPOM小源流的捕获很重要。
Geomorphic complexity influences coarse particulate organic matter transport and storage in headwater streams
Coarse particulate organic matter (CPOM; organic matter 1–100 mm in diameter, excluding small wood) stored in streams provides an important energy source for aquatic ecosystems, and CPOM transport provides downstream energy subsidies and is a pathway for watershed carbon export. However, we lack understanding of the magnitude of and processes influencing CPOM storage and transport in headwater streams. We assessed how geomorphic complexity and hydrologic regime influence CPOM transport and storage in the Colorado Front Range, USA. We compared CPOM transport during snowmelt in a stream reach with high retentive feature (e.g., wood, cobbles, and other features) frequency to a reach with low retentive feature frequency, assessing how within-a-reach geomorphic context influences CPOM transport. We also compared CPOM transport in reaches with differing valley geometry (two confined reaches versus a wide, multi-thread river bead) to assess the influence of geomorphic variations occurring over larger spatial extents. Additionally, we compared CPOM storage in accumulations in reaches ( n = 14) with flowing water or dry conditions in late summer and investigated how small pieces of organic matter [e.g., woody CPOM and small wood (>1 min length and 0.05–1 min diameter or 0.5–1 min length and >0.1 min diameter)] influence CPOM storage. We found that within-a-reach retentive feature frequency did not influence CPOM transport. However, valley geometry influenced CPOM transport, with a higher CPOM transport rate (median: 1.53 g min −1 ) downstream of a confined stream reach and a lower CPOM transport rate (median: 0.13 g min −1 ) downstream of a low gradient, multi-thread river bead. Additionally, we found that particulate organic carbon (POC) export (0.063 Mg C) in the form of CPOM was substantially lower than dissolved organic carbon (DOC) export (12.3 Mg C) in one of these headwater streams during the 2022 water year. Dry reaches stored a higher volume of CPOM (mean = 29.18 m 3 ha −1 ) compared to reaches with flowing water (15.75 m 3 ha −1 ), and woody CPOM pieces trapped 37% of CPOM accumulations. Our results demonstrate that the influence of geomorphic context on CPOM transport depends on the scale and type of geomorphic complexity, POC may be lower than DOC export in some headwater streams, and small woody organic material is important for trapping CPOM small streams.