• Journal of Ecology and Environment
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• 제42권4호
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• pp.155-162
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• 2018

Background: In ecosystem carbon cycle studies, distinguishing between $CO_2$ emitted by roots and by microbes remains very difficult because it is mixed before being released into the atmosphere. Currently, no method for quantifying root and microbial respiration is effective. Therefore, this study investigated the relationship between soil respiration and underground root biomass at varying distances from the tree and tested possibilities for measuring root and microbial respiration. Methods: Soil respiration was measured by the closed chamber method, in which acrylic collars were placed at regular intervals from the tree base. Measurements were made irregularly during one season, including high temperatures in summer and low temperatures in autumn; the soil's temperature and moisture content were also collected. After measurements, roots of each plot were collected, and their dry matter biomass measured to analyze relationships between root biomass and soil respiration. Results: Apart from root biomass, which affects soil's temperature and moisture, no other factors affecting soil respiration showed significant differences between measuring points. At each point, soil respiration showed clear seasonal variations and high exponential correlation with increasing soil temperatures. The root biomass decreased exponentially with increasing distance from the tree. The rate of soil respiration was also highly correlated exponentially with root biomass. Based on these results, the average rate of root respiration in the soil was estimated to be 34.4% (26.6~43.1%). Conclusions: In this study, attempts were made to differentiate the root respiration rate by analyzing the distribution of root biomass and resulting changes in soil respiration. As distance from the tree increased, root biomass and soil respiration values were shown to strongly decrease exponentially. Root biomass increased logarithmically with increases in soil respiration. In addition, soil respiration and underground root biomass were logarithmically related; the calculated root-breathing rate was around 44%. This study method is applicable for determining root and microbial respiration in forest ecosystem carbon cycle research. However, more data should be collected on the distribution of root biomass and the correlated soil respiration.

• The Korean Journal of Ecology
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• 제26권5호
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• pp.289-296
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• 2003

The ecological process-based approach provides a detailed assessment of belowground compartment as one of the major compartment of carbon balance. Carbon net balance (NEP: net ecosystem production) in forest ecosystems by ecological process-based approach is determined by the balance between net primary production (NPP) of vegetation and heterotrophic respiration (HR) of soil (NEP=NPP-HR). Respiration due to soil heterotrophs is the difference between total soil respiration (SR) and root respiration (RR) (HR=SR-RR, NEP=NPP-(SR-RR)). If NEP is positive, it is a sink of carbon. This study assessed the forest carbon balance by ecological process-based approach included belowground compartment intensively. The case study in the Takayama Station, cool-temperate deciduous broad-leaved forest was reported. From the result, NEP was estimated approximately 1.2 t C $ha^{-1} yr^{-1}$ in 1996. Therefore, the study area as a whole was estimated to act as a sink of carbon. According to flux tower result, the net uptake rate of carbon was 1.1 t C $ha^{-1} yr^{-1}$.

• 한국지반환경공학회 논문집
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• 제22권3호
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• pp.15-29
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• 2021

본 연구는 낙동강 하구역에 대한 생태계 변동을 예측할 수 있는 생태계 모델을 구축하고 이 모델을 이용하여 총일차생산량과 호흡량을 산정하고자 하였다. 생태계 모델을 AQUATOX 모델을 사용하여 구축하였고 측정된 자료를 이용하여 모델의 검량과 검증을 하였다. 모델의 검량은 낙동강 하구역에서 측정된 클로로필-a 자료를 사용하였고, DO, TN, TP 자료를 이용하여 모델 검증을 수행하였다. 총일차생산량과 호흡량은 계절에 따라 큰 차이를 보이는 것이 일반적이나 낙동강 하구역의 총일차생산량과 호흡량은 하굿둑 방류수의 양에 크게 영향을 받았다. 방류수의 양이 증가할 때는 하구역에 서식하는 식물성 플랑크톤의 유실로 인해 광합성을 할 수 없어 총일차생산량은 0에 수렴하였고, 반면 방류수에 포함된 유기물질의 유입으로 인해 호흡량이 급격히 증가하였다. 유입수량의 증가는 유입수에 포함된 유기물질의 유입을 의미하며, 이 유기물질은 산화작용에 의해 분해되면서 용존산소를 감소시켰다. 다른 나라의 하구역과 비교 시 낙동강 하구역은 총일차생산량이 가장 적은 것으로 나타났고 호흡량이 총일차생산량보다 크기 때문에 유기물의 산화작용에 의해 용존산소를 고갈시키는 상태인 것으로 확인되었다.

• Journal of Ecology and Environment
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• 제38권3호
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• pp.281-291
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• 2015

To clarify the effects of forest fire on the carbon budget of a forest ecosystem, this study compared the seasonal variation of soil respiration, net primary production and net ecosystem production (NEP) over the year in unburned and burned Pinus densiflora forest areas. The annual net carbon storage (i.e., NPP) was $5.75t\;C\;ha^{-1}$ in the unburned site and $2.14t\;C\;ha^{-1}$ in the burned site in 2012. The temperature sensitivity of soil respiration (i.e., $Q_{10}$ value) was higher in the unburned site than in the burned site. The annual soil respiration rate was estimated by the exponential regression equation with the soil temperatures continuously measured at the soil depth of 10 cm. The estimated annual soil respiration and heterotrophic respiration (HR) rates were 8.66 and $4.50t\;C\;ha^{-1}yr^{-1}$ in the unburned site and 4.08 and $2.12t\;C\;ha^{-1}yr^{-1}$ in the burned site, respectively. The estimated annual NEP in the unburned and burned forest areas was found to be 1.25 and $0.02t\;C\;ha^{-1}yr^{-1}$, respectively. Our results indicate that the differences of carbon budget and cycling between both study sites are considerably correlated with the losses of living plant biomass, insufficient nutrients and low organic materials in the forest soil due to severe damages caused by the forest fire. The burned Pinus densiflora forest area requires at least 50 years to attain the natural conditions of the forest ecosystem prior to the forest fire.

• 한국환경과학회지
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• 제19권2호
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• pp.217-227
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• 2010

This paper was studied $CO_2$ respiration rate with physicochemical properties of soils at wetland, paddy field and forest in Nongju-ri, Haeryong-myeon, Suncheon city, Jeollanam-do. Soil temperature and $CO_2$ respiration rate were measured at the field, and soil pH, moisture and soil organic carbon were analyzed in laboratory. Field monitoring was conducted at 6 points (W3, W7, W13, W17, W23, W27) for wetland, 3 points (P1, P2, P3) for paddy field and 3 points (F1, F2, F3) for forest in 10 January 2009. $CO_2$ concentrations in chamber were measured 352~382 ppm for wetland, 364~382 ppm for paddy field and 379~390 ppm for forest, and the average values were 370 ppm, 370 ppm and 385 ppm, respectively. $CO_2$ respiration rates of soils were measured $-73{\sim}44\;mg/m^2/hr$ for wetland, $-74{\sim}24\;mg/m^2/hr$ for paddy field and $-55{\sim}106\;mg/m^2/hr$ for forest, and the average values were $-8\;mg/m^2/hr$, $-25\;mg/m^2/hr$ and $38\;mg/m^2/hr$. $CO_2$ was uptake from air to soil in wetland and paddy field, but it was emission from soil to air in forest. $CO_2$ respiration rate function in uptake condition increased exponential and linear as soil temperature and soil organic carbon. But, it in emission condition decreased linear as soil temperature and soil organic carbon. $CO_2$ respiration rate function in wetland decreased linear as soil moisture, but its in paddy and forest increased linear as soil moisture. $CO_2$ respiration rate function in all sites increased linear as soil pH, and increasing rate at forest was highest.

• ALGAE
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• 제35권3호
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• pp.237-252
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• 2020

Temperate rocky reefs dominated by the giant kelp, Macrocystis pyrifera, support diverse assemblages of benthic macroalgae that provide a suite of ecosystem services, including high rates of primary production in aquatic ecosystems. These forests and the benthic macroalgae that inhabit them are facing both short-term losses and long-term declines throughout much of their range in the eastern Pacific Ocean. Here, we quantified patterns of benthic macroalgal biomass and irradiance on rocky reefs that had intact kelp forests and nearby reefs where the benthic macroalgae had been lost due to deforestation at three sites along the California, USA and Baja California, MEX coasts during the springs and summers of 2017 and 2018. We then modeled how the loss of macroalgae from these reefs impacted net benthic productivity using species-specific, mass-dependent rates of photosynthesis and respiration that we measured in the laboratory. Our results show that the macroalgal assemblages at these sites were dominated by a few species of stipitate kelps and fleshy red algae whose relative abundances were spatially and temporally variable, and which exhibited variable rates of photosynthesis and respiration. Together, our model estimates that the dominant macroalgae on these reefs contribute 15 to 4,300 mg C m^-2 d^-1 to net benthic primary production, and that this is driven primarily by a few dominant taxa that have large biomasses and high rates of photosynthesis and / or respiration. Consequently, we propose that the loss of these macroalgae results in the loss of an important contribution to primary production and overall ecosystem function.

• 한국습지학회지
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• 제16권3호
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• pp.315-325
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• 2014

월악산국립공원에 발달되어 있는 신갈나무림에서 2012년 5월부터 2013년 4월까지 유기탄소 분포와 순환을 통한 생태계 서비스 가치를 파악하였다. 지상부와 지하부 생물량에 분포되어 있는 유기탄소량은 각각 81.94 및 20.53 ton C/ha 이었으며, 낙엽층과 토양의 유기탄소량은 각각 6.49 ton C $ha^{-1}$, 141.23 ton C $ha^{-1}$ $50cm-depth^{-1}$로 조사되였다. 조사지 신갈나무림의 전체 유기탄소량은 250.19 ton C $ha^{-1}$이었으며, 이중 41.0%가 식물체에 분포하였다. 신갈나무림의 전체 유기탄소량을 원화로 환산하면 약 527만원 $ha^{-1}$의 가치를 갖는 것으로 추정되었다. 조사기간 동안 토양호흡을 통하여 방출되는 탄소량은 7.31 ton C $ha^{-1}yr^{-1}$으로 이중 미생물호흡과 뿌리호흡을 통해 방출되는 탄소량은 각각 3.58, 3.73 ton C $ha^{-1}yr^{-1}$이었다. 유기탄소 순 생산량과 미생물호흡량의 차이로 추정했을 때 본 신갈나무림에서 연간 대기로부터 흡수하는 순 유기탄소는 1.61 ton C $ha^{-1}yr^{-1}$로서, 이를 원화로 환산하면 약 33,000원 $ha^{-1}$의 가치를 갖는 것으로 추정되었다.

• 환경생물
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• 제33권3호
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• pp.345-351
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• 2015

본 연구는 IPCC (2006)의 농업분야 온실가스 배출권 측정의 새로운 지침에 의거하여 과수와 토양, 대기 간의 탄소수지 산정 방법론을 제시하고자 전남 나주시의 배 재배농가를 대상으로 토양 호흡량과 초본류, 그리고 과수의 생태계 순생산량을 측정하였다. 토양 호흡량 및 초본류 생태계 순생산량은 Closed Dynamic Chamber (CDC) 방법으로 측정하였고, 배 과수의 생태계 순생산량은 EddyPro 5.2.1 프로그램을 이용하여 공분산법으로 측정하였다. 배 과수원의 토양 호흡량으로 연간 $429.1mgCO_2m^{-2}h^{-1}$이 배출되었으며, 토양온도민감도 ($Q_{10}$)는 2.3으로 나타났다. 초본류의 경우 측정기간 동안 호흡이 광합성보다 우세하게 나타났다. 2015년 6월 20일부터 24일까지 초본류의 광합성 또는 호흡을 통해 흡수 및 배출된 $CO_2$의 총합은 $156.1mgCO_2m^{-2}h^{-1}$으로 상대적으로 호흡이 더 많았던 것으로 나타났다. 배 과수의 광합성 또는 호흡에 의한 $CO_2$ 총합은 $-680.1mgCO_2m^{-2}h^{-1}$로 광합성에 의해 $CO_2$가 흡수되었다. 배 과원 단위의 토양 호흡량과 초본류 및 배 과수의 광합성 및 호흡량의 총합은 $-0.04tonCO_2ha^{-1}$로 $CO_2$의 흡수원이었다. 결론적으로 배 과원에서의 다양한 접근방법을 통한 향후 다년생 목본 작물 재배지에서의 탄소수지 산정 방법론 제시에 꼭 필요하다고 판단된다.

• 한국물환경학회지
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• 제34권6호
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• pp.579-590
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• 2018

The lakes' metabolism bears important information for the assessment of the carbon budget due to the accumulation or loss of carbon in the lake as well as the dynamics of the food webs through primary production. A lake-scale metabolism is evaluated by Gross Primary Production (GPP), Ecosystem Respiration (R), and Net Ecosystem Production (NEP), which is the difference between the first two values. Methods for estimating GPP and R are based on the levels carbon and oxygen. Estimation of carbon is expensive because of the use of radioactive materials which requires a high degree of proficiency. The purpose of this study was to estimate Lake Daecheong ecosystem metabolism using high frequency water temperature data and DO measurement sensor, widely utilized in the field of water quality monitoring, and to evaluate the possibility of using the application method. High frequency data was collected at intervals of 10 minutes from September to December 2017 by installing a thermistor chain and a DO sensor in downstream of Daechung Dam. The data was then used to estimate GPP, R and NEP using the R public program LakeMetabolizer, and other metabolism models (mle, ols, kalman, bookkeep). Calculations of gas exchange coefficient methods (cole, crusius, heiskanen, macIntyre, read, soloviev, vachon) were compared. According to the result, Lake Daecheong has some deviation based on the application method, but it was generally estimated that the NEP value is negative and acts as a source of atmospheric carbon in a heterotrophic system. Although the high frequency sensor data used in this study had negative and positive GPP and R values during the physical mixing process, they can be used to monitor real-time metabolic changes in the ecosystem if these problems are solved.

• Journal of Ecology and Environment
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• 제41권11호
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• pp.302-309
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• 2017

Background: Large-scale land-use change is being caused by various socioeconomic problems. Land-use change is necessarily accompanied by changes in the regional carbon balance in terrestrial ecosystems and affects climate change. Therefore, it is crucial to understand the correlation between environmental factors altered by land-use change and the carbon balance. To address this issue, we studied the characteristics of soil carbon flux and soil moisture content related to rainfall events in mountain pastures converted from deciduous forest in Korea. Results: The average soil moisture contents (SMC) during the study period were 23.1% in the soil respiration (SR) plot and 25.2% in the heterotrophic respiration (HR) plot. The average SMC was increased to 2.1 and 1.1% in the SR and HR plots after rainfall events, respectively. In addition, saturated water content was 29.36% in this grassland. The soil water content was saturated under the consistent rainfall of more than $5mm\;h^{-1}$ rather than short-term heavy rainfall event. The average SR was increased to 28.4% after a rainfall event, but the average HR was decreased to 70. 1%. The correlation between soil carbon flux rates and rainfall was lower than other environmental factors. The correlation between SMC and soil carbon flux rates was low. However, HR exhibited a tendency to be decreased when SMC was 24.5%. In addition, the correlation between soil temperature and respiration rate was significant. Conclusions: In a mountain pasture ecosystem, rainfall induced the important change of soil moisture content related to respiration in soil. SR and HR were very sensitive to change of SMC in soil surface layer about 0-10-cm depth. SR was increased by elevation of SMC due to a rainfall event, and the result was assumed from maintaining moderate soil moisture content for respiration in microorganism and plant root. However, HR was decreased in long-time saturated condition of soil moisture content. Root has obviously contributed to high respiration in heavy rainfall, but it was affected to quick depression in respiration under low rainfall. The difference of SMC due to rainfall event was causative of a highly fluctuated soil respiration rate in the same soil temperature condition. Therefore, rainfall factor or SMC are to be considered in predicting the soil carbon flux of grassland ecosystems for future climate change.