The characteristics of the summer precipitation diurnal cycle over South Asia and East Asia during 2001–13 are investigated based on the high spatiotemporal resolution estimates of the CPC(Climate Prediction Center) ...The characteristics of the summer precipitation diurnal cycle over South Asia and East Asia during 2001–13 are investigated based on the high spatiotemporal resolution estimates of the CPC(Climate Prediction Center) Morphing(CMORPH) technique. The results show that summer precipitation over South Asia and East Asia possesses a remarkable diurnal cycle, with obvious regional differences. Over the coastal areas, plateau, and high mountains, summer precipitation peaks in the late afternoon; while over low altitude areas, such as valleys, basins, and inshore seas, it peaks during midnight to early morning. In addition to these general features consistent with previous studies, the high resolution CMORPH technique can depict finer regional details, such as the less coherent phase pattern over a few regions. Besides, through comparative analysis of the diurnal cycle strength and precipitation fields, the authors find that for humid areas the summer precipitation diurnal cycle is especially significant over Southeast China, the Sichuan Basin, Hainan Province, Taiwan Province, the Philippines, and Indonesia. And it is relatively weak over the south of Northeast China, central East China, Yunnan Province, the central Indian Peninsula, and most oceanic areas. Comparisons between two satellite datasets—those of the CMORPH and Tropical Rainfall Measuring Mission(TRMM) 3B42 products—are also presented. For summer precipitation and the main diurnal cycle features, the results from both products agree over most regions, except a few areas, e.g., the Tibetan Plateau.展开更多
This study investigated the second indirect climatic effect of anthropogenic aerosols,including sulfate,organic carbon(OC) ,and black carbon(BC) ,over East Asia.The seasonal variation of the climatic response to the s...This study investigated the second indirect climatic effect of anthropogenic aerosols,including sulfate,organic carbon(OC) ,and black carbon(BC) ,over East Asia.The seasonal variation of the climatic response to the second indirect effect was also characterized.The simulation period for this study was 2006.Due to a decrease in autoconversion rate from cloud water to rain as a result of aerosols,the cloud liquid water path(LWP) ,and radiative flux(RF) at the top of the atmosphere(TOA) changed dramatically,increasing by 14.3 g m-2 and decreasing by-4.1 W m-2 in terms of domain and annual average.Both LWP and RF changed most in autumn. There were strong decreases in ground temperature in Southwest China,the middle reaches of the Yangtze River in spring and autumn,while maximum cooling of up to-1.5 K occurred in the Chongqing district.The regional and annual mean change in ground temperature reached-0.2 K over eastern China.In all seasons except summer,precipitation generally decreased in most areas north of the Yangtze River,whereas precipitation changed little in South China.Precipitation changed most in summer,with alternating bands of increasing(~40 mm) and decreasing(~40 mm) precipitation appearing in eastern China.Precipitation decreased by 1.5-40 mm over large areas of Northeast China and the Huabei Plain.The domain and annual mean change in precipitation was approximately-0.3 mm over eastern China.The maximum reduction in precipitation occurred in summer,with mean absolute and relative changes of-1.2 mm and-3.8%over eastern China.This study revealed considerable climate responses to the second indirect effect of aerosols over specific regions of China.展开更多
Results of the definition of South China Sea summer monsoon onset date and East Asian summermonsoon index in recent years are summarized in this paper. And more questions to be resolved are introducedlater.
The relationship between variations in the East Asian trough(EAT)intensity and spring extreme precipitation over Southwest China(SWC)during 1961-2020 is investigated.The results indicate that there is an interdecadal ...The relationship between variations in the East Asian trough(EAT)intensity and spring extreme precipitation over Southwest China(SWC)during 1961-2020 is investigated.The results indicate that there is an interdecadal increase in the relationship between the EAT and spring extreme precipitation over eastern SWC around the late1980 s.During the latter period,the weak(strong)EAT corresponds to a strong and large-scale anomalous anticyclone(cyclone)over the East Asia-Northwest Pacific region.The EAT-related anomalous southerlies(northerlies)dominate eastern SWC,leading to significant upward(downward)motion and moisture convergence(divergence)over the region,providing favorable(unfavorable)dynamic and moisture conditions for extreme precipitation over eastern SWC.In contrast,during the former period,the EAT-related circulation anomalies are weak and cover a relatively smaller region,which cannot significantly affect the moisture and dynamic conditions over eastern SWC;therefore,the response in extreme precipitation over eastern SWC to EAT is weak over the period.The interdecadal change in the relationship between eastern SWC spring extreme precipitation and the EAT could be related to the interdecadal change in the EAT variability.The large(small)variability of the EAT is associated with significant(insignificant)changes in spring extreme precipitation over eastern SWC during the latter(former)period.展开更多
The PRD (Pearl River Delta) was subjected to two transgressions respectively in the latest Pleistocene and Holocene. Position of coastal line of the latest Pleistocene transgression in some localities, especially at...The PRD (Pearl River Delta) was subjected to two transgressions respectively in the latest Pleistocene and Holocene. Position of coastal line of the latest Pleistocene transgression in some localities, especially at the center part of PRD is still uncertain. Thus quaternary sandy sediments in the central PRD are dated by OSL Optically Stimulated Luminescence) for determining the ancient coastal line. Samples are from Xiaohushan Hill at the center of PRD, where quaternary sediments deposited on a wave-cut platlbrm consist of two kinds of sediments: marine muddy-silt on the top and alluvial fine-sand in the lower part. The former is dated at 5.0-5.5 ka, which defines the time of Holocene transgression in the PRD. The alluvial fine-sand in the part is dated at 22-26 ka. For the alluvial fine-sand rests directly on a wave-cut platform, thus this wave-cut platform should have been existed before deposit of alluvial sand, i.e., formed during an earlier marine transgression that may have culminated in the sea level high at about 40 ka. The optically stimulated luminescence results are consistent with geological observations and compatible with TL (thermoluminescence) and ^14C ages from the same layers at other localities of the PRD.展开更多
A coupled meteorology and aerosol/chemistry model WRF-Chem (Weather Research and Forecast model coupled with Chemistry) was used to conduct a pair of simulations with present-day (PD) and preindustrial (P1) emis...A coupled meteorology and aerosol/chemistry model WRF-Chem (Weather Research and Forecast model coupled with Chemistry) was used to conduct a pair of simulations with present-day (PD) and preindustrial (P1) emissions over East Asia to examine the aerosol indirect effect on clouds. As a result of an increase in aerosols in January, the cloud droplet number increased by 650 cm-3 over the ocean and East China, 400 cm-3 over Central and Southwest China, and less than 200 cm-3 over North China. The cloud liquid water path (LWP) increased by 40-60 g m-2 over the ocean and Southeast China and 30 g m-2 over Central China; the LWP in- creased less than 5 g m-2 or decreased by 5 g m2 over North China. The effective radius (Re) decreased by more than 4 pm over Southwest, Central, and Southeast China and 2 pm over North China. In July, variations in cloud properties were more uniform; the cloud droplet number increased by approximately 250400 cm-3, the LWP increased by approximately 30-50 g m 2, and Re decreased by approximately 3 μm over most regions of China. In response to cloud property changes from PI to PD, shortwave (SW) cloud radiative m-2 over the ocean and 10 forcing strengthened by 30 W W m-2 over Southeast China, and it weakened slightly by approximately 2-10 W m-2 over Central and Southwest China in January. In July, SW cloud radiative forcing strengthened by 15 W m-2 over Southeast and North China and weakened by l0 W m-2 over Central China. The different responses of SW cloud radiative forcing in different regions was related to cloud feedbacks and natural variability.展开更多
Based on daily precipitation and monthly temperature data in southern China, the winter extreme precipitation changes in southern China have been investigated by using the Mann-Kendall test and the return values of Ge...Based on daily precipitation and monthly temperature data in southern China, the winter extreme precipitation changes in southern China have been investigated by using the Mann-Kendall test and the return values of Generalized Pareto Distribution. The results show that a winter climate catastrophe in southern China occurred around i99I, and the intensity of winter extreme precipitation was strengthened after climate wanning. The anomalous circulation characteristics before and after the climate wanning was further analyzed by using the U.S. National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis data. It is found that the tropical winter monsoon over East Asia is negatively correlated with the precipitation in southeastern China. After climate warming the meridionality of the circulations in middle and high latitudes increases, which is favorable for the southward movement of the cold air from the north. In addition, the increase of the temperature over southern China may lead to the decrease of the differential heating between the continent and the ocean. Consequently, the tropical winter monsoon over East Asia is weakened, which is favorable for the transport of the warm and humid air to southeastem China and the formation of the anomalous convergence of the moisture flux, resulting in large precipitation over southeastern China. As a result, the interaction between the anomalous circulations in the middle and high latitudes and lower latitudes after the climate warming plays a major role in the increase of the winter precipitation intensity over southeastem China.展开更多
The purposes of this research were: (1) to create a training package to prepare secondary school students in northeastern of Thailand toward ASEAN (Association of Southeast Asian Nations) Community; (2) to comp...The purposes of this research were: (1) to create a training package to prepare secondary school students in northeastern of Thailand toward ASEAN (Association of Southeast Asian Nations) Community; (2) to compare the knowledge of secondary school students toward ASEAN before and after use training package; and (3) the expectations of the students in the northeast of their own preparation for the ASEAN community. Experimental research was used in this research. The subject was including 2,000 students who were randomly divided into groups of seven provinces. The statistics used in data analysis were percentage, average, standard deviation, and T-test. The research results showed that: (1) a training package to prepare secondary school students in northeastern of Thailand toward ASEAN Community, the effectiveness index (E.I.) was .57, according to the established criteria; (2) a comparison of pretest and post-test results found the use of cognitive training may vary, statistically significant at the .05 level; (3) an expectation of the secondary school students in the preparation of role into ASEAN Community found that the students who participated in a concept reflect that the knowledge and attitudes to prepare themselves for the ASEAN community.展开更多
The distinct influences of eastern Pacific (EP) and central Pacific (CP) La Nina on rainfall anomalies over Southeast Asia and Australia in boreal autumn (September to November) are explored in this study. Compo...The distinct influences of eastern Pacific (EP) and central Pacific (CP) La Nina on rainfall anomalies over Southeast Asia and Australia in boreal autumn (September to November) are explored in this study. Composite results reveal that CP La Nina gives rise to significant and severe flooding over Southeast Asia and Australia, whereas EP La Nina fails to exert any evident impacts on rainfall over this region. This difference can be attributed to the distinct features of cooling sea surface temperature anomalies (SSTAs) between EP and CP La Nina. With a more westward location and stronger intensity of the negative SSTAs during CP La Nina autumn, the highest and lowest SLP anomalies are substantially enhanced and shift westwards too, further causing intense easterly winds over the western Pacific and westerly anomalies over the Indian Ocean driven by this SLP gradient. Subsequently, robust low-level convergence and high-level divergence is observed over the Maritime Continent and Australia, resulting in significant above-normal rainfall anomalies in those regions. In contrast, weak and eastern Pacific-confined cooling SSTAs during EP La Nina produce correspondingly weak low-level convergence over the Maritime Continent conditions that make it hard for significant rainfall anomalies to arise.展开更多
Archaea play an important role in global carbon and nitrogen cycles. Archaeal lipids, such as isoprenoid glycerol diakyl glycerol tetraethers(i GDGTs), are important biomarkers tracing change in archaeal community str...Archaea play an important role in global carbon and nitrogen cycles. Archaeal lipids, such as isoprenoid glycerol diakyl glycerol tetraethers(i GDGTs), are important biomarkers tracing change in archaeal community structure and biogeochemical processes in the natural environments. In this research, the spatial distributions of archaeal lipids in the surface sediments of the Jiulong River(JR) and the Jiulong River estuary(JRE) were examined. GDGT-0(containing zero cyclopentyl ring) and crenarchaeol were the most abundant i GDGTs in the JR and JRE. From the rivers to the estuary, the total i GDGTs, GDGT-0, crenarchaeol and archaeol concentrations showed significant spatial variation; in particular, GDGT-0 and archaeol in the river may be predominantly derived in situ from methanogens, whereas crenarchaeol in the estuary mainly derived in situ from Thaumarchaeota. We inferred that archaeal community was dominated by methanogens in the Jiulong River and by Thaumarchaeota in the Jiulong River estuary, which are consistent with change in archaeal community structure observed in other estuarine environments.展开更多
基金supported by the National Basic Research Program of China(Grant No.2013CB430201)the China Meteorological Administration Special Fund for Scientific Research in the Public Interest(Grant No.GYHY201206008)
文摘The characteristics of the summer precipitation diurnal cycle over South Asia and East Asia during 2001–13 are investigated based on the high spatiotemporal resolution estimates of the CPC(Climate Prediction Center) Morphing(CMORPH) technique. The results show that summer precipitation over South Asia and East Asia possesses a remarkable diurnal cycle, with obvious regional differences. Over the coastal areas, plateau, and high mountains, summer precipitation peaks in the late afternoon; while over low altitude areas, such as valleys, basins, and inshore seas, it peaks during midnight to early morning. In addition to these general features consistent with previous studies, the high resolution CMORPH technique can depict finer regional details, such as the less coherent phase pattern over a few regions. Besides, through comparative analysis of the diurnal cycle strength and precipitation fields, the authors find that for humid areas the summer precipitation diurnal cycle is especially significant over Southeast China, the Sichuan Basin, Hainan Province, Taiwan Province, the Philippines, and Indonesia. And it is relatively weak over the south of Northeast China, central East China, Yunnan Province, the central Indian Peninsula, and most oceanic areas. Comparisons between two satellite datasets—those of the CMORPH and Tropical Rainfall Measuring Mission(TRMM) 3B42 products—are also presented. For summer precipitation and the main diurnal cycle features, the results from both products agree over most regions, except a few areas, e.g., the Tibetan Plateau.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No. KZCX2-YW-Q11-03)the"Strategic Priority Research Program"of the Chinese Academy of Sciences(Grant No.XDA05100502)+1 种基金the R&D Special Fund for Public Welfare Industry(Meteorology) (Grant No.GYHY200906020)100 Talents Program of the Chinese Academy of Sciences
文摘This study investigated the second indirect climatic effect of anthropogenic aerosols,including sulfate,organic carbon(OC) ,and black carbon(BC) ,over East Asia.The seasonal variation of the climatic response to the second indirect effect was also characterized.The simulation period for this study was 2006.Due to a decrease in autoconversion rate from cloud water to rain as a result of aerosols,the cloud liquid water path(LWP) ,and radiative flux(RF) at the top of the atmosphere(TOA) changed dramatically,increasing by 14.3 g m-2 and decreasing by-4.1 W m-2 in terms of domain and annual average.Both LWP and RF changed most in autumn. There were strong decreases in ground temperature in Southwest China,the middle reaches of the Yangtze River in spring and autumn,while maximum cooling of up to-1.5 K occurred in the Chongqing district.The regional and annual mean change in ground temperature reached-0.2 K over eastern China.In all seasons except summer,precipitation generally decreased in most areas north of the Yangtze River,whereas precipitation changed little in South China.Precipitation changed most in summer,with alternating bands of increasing(~40 mm) and decreasing(~40 mm) precipitation appearing in eastern China.Precipitation decreased by 1.5-40 mm over large areas of Northeast China and the Huabei Plain.The domain and annual mean change in precipitation was approximately-0.3 mm over eastern China.The maximum reduction in precipitation occurred in summer,with mean absolute and relative changes of-1.2 mm and-3.8%over eastern China.This study revealed considerable climate responses to the second indirect effect of aerosols over specific regions of China.
基金Natural Science Foundation of China (grant No.40233027)Natural Science Foundation ofChina (Project 90211010)"Research on the monitoring and service of South China Sea monsoons", ResearchFund for Tropical Marine Meteorology
文摘Results of the definition of South China Sea summer monsoon onset date and East Asian summermonsoon index in recent years are summarized in this paper. And more questions to be resolved are introducedlater.
基金jointly supported by the National Natural Science Foundation of China[grant number 41825010]the Strategic Priority Research Program of the Chinese Academy of Sciences[grant number XDA23090102]。
文摘The relationship between variations in the East Asian trough(EAT)intensity and spring extreme precipitation over Southwest China(SWC)during 1961-2020 is investigated.The results indicate that there is an interdecadal increase in the relationship between the EAT and spring extreme precipitation over eastern SWC around the late1980 s.During the latter period,the weak(strong)EAT corresponds to a strong and large-scale anomalous anticyclone(cyclone)over the East Asia-Northwest Pacific region.The EAT-related anomalous southerlies(northerlies)dominate eastern SWC,leading to significant upward(downward)motion and moisture convergence(divergence)over the region,providing favorable(unfavorable)dynamic and moisture conditions for extreme precipitation over eastern SWC.In contrast,during the former period,the EAT-related circulation anomalies are weak and cover a relatively smaller region,which cannot significantly affect the moisture and dynamic conditions over eastern SWC;therefore,the response in extreme precipitation over eastern SWC to EAT is weak over the period.The interdecadal change in the relationship between eastern SWC spring extreme precipitation and the EAT could be related to the interdecadal change in the EAT variability.The large(small)variability of the EAT is associated with significant(insignificant)changes in spring extreme precipitation over eastern SWC during the latter(former)period.
文摘The PRD (Pearl River Delta) was subjected to two transgressions respectively in the latest Pleistocene and Holocene. Position of coastal line of the latest Pleistocene transgression in some localities, especially at the center part of PRD is still uncertain. Thus quaternary sandy sediments in the central PRD are dated by OSL Optically Stimulated Luminescence) for determining the ancient coastal line. Samples are from Xiaohushan Hill at the center of PRD, where quaternary sediments deposited on a wave-cut platlbrm consist of two kinds of sediments: marine muddy-silt on the top and alluvial fine-sand in the lower part. The former is dated at 5.0-5.5 ka, which defines the time of Holocene transgression in the PRD. The alluvial fine-sand in the part is dated at 22-26 ka. For the alluvial fine-sand rests directly on a wave-cut platform, thus this wave-cut platform should have been existed before deposit of alluvial sand, i.e., formed during an earlier marine transgression that may have culminated in the sea level high at about 40 ka. The optically stimulated luminescence results are consistent with geological observations and compatible with TL (thermoluminescence) and ^14C ages from the same layers at other localities of the PRD.
基金supported by the Knowledge Innovation Program of the Chinese Academy of Sciences (KZCX2-YW-Q11-04)the "Strategic Priority Research Program" of the Chinese Academy of Sciences (XDA05100502)
文摘A coupled meteorology and aerosol/chemistry model WRF-Chem (Weather Research and Forecast model coupled with Chemistry) was used to conduct a pair of simulations with present-day (PD) and preindustrial (P1) emissions over East Asia to examine the aerosol indirect effect on clouds. As a result of an increase in aerosols in January, the cloud droplet number increased by 650 cm-3 over the ocean and East China, 400 cm-3 over Central and Southwest China, and less than 200 cm-3 over North China. The cloud liquid water path (LWP) increased by 40-60 g m-2 over the ocean and Southeast China and 30 g m-2 over Central China; the LWP in- creased less than 5 g m-2 or decreased by 5 g m2 over North China. The effective radius (Re) decreased by more than 4 pm over Southwest, Central, and Southeast China and 2 pm over North China. In July, variations in cloud properties were more uniform; the cloud droplet number increased by approximately 250400 cm-3, the LWP increased by approximately 30-50 g m 2, and Re decreased by approximately 3 μm over most regions of China. In response to cloud property changes from PI to PD, shortwave (SW) cloud radiative m-2 over the ocean and 10 forcing strengthened by 30 W W m-2 over Southeast China, and it weakened slightly by approximately 2-10 W m-2 over Central and Southwest China in January. In July, SW cloud radiative forcing strengthened by 15 W m-2 over Southeast and North China and weakened by l0 W m-2 over Central China. The different responses of SW cloud radiative forcing in different regions was related to cloud feedbacks and natural variability.
基金National Key Technology Support Program (2009BAC51B03)Scientific Research Foundation for the Returned Overseas Chinese Scholars, Ministry of Education (2007)
文摘Based on daily precipitation and monthly temperature data in southern China, the winter extreme precipitation changes in southern China have been investigated by using the Mann-Kendall test and the return values of Generalized Pareto Distribution. The results show that a winter climate catastrophe in southern China occurred around i99I, and the intensity of winter extreme precipitation was strengthened after climate wanning. The anomalous circulation characteristics before and after the climate wanning was further analyzed by using the U.S. National Centers for Environmental Prediction/National Center for Atmospheric Research reanalysis data. It is found that the tropical winter monsoon over East Asia is negatively correlated with the precipitation in southeastern China. After climate warming the meridionality of the circulations in middle and high latitudes increases, which is favorable for the southward movement of the cold air from the north. In addition, the increase of the temperature over southern China may lead to the decrease of the differential heating between the continent and the ocean. Consequently, the tropical winter monsoon over East Asia is weakened, which is favorable for the transport of the warm and humid air to southeastem China and the formation of the anomalous convergence of the moisture flux, resulting in large precipitation over southeastern China. As a result, the interaction between the anomalous circulations in the middle and high latitudes and lower latitudes after the climate warming plays a major role in the increase of the winter precipitation intensity over southeastem China.
文摘The purposes of this research were: (1) to create a training package to prepare secondary school students in northeastern of Thailand toward ASEAN (Association of Southeast Asian Nations) Community; (2) to compare the knowledge of secondary school students toward ASEAN before and after use training package; and (3) the expectations of the students in the northeast of their own preparation for the ASEAN community. Experimental research was used in this research. The subject was including 2,000 students who were randomly divided into groups of seven provinces. The statistics used in data analysis were percentage, average, standard deviation, and T-test. The research results showed that: (1) a training package to prepare secondary school students in northeastern of Thailand toward ASEAN Community, the effectiveness index (E.I.) was .57, according to the established criteria; (2) a comparison of pretest and post-test results found the use of cognitive training may vary, statistically significant at the .05 level; (3) an expectation of the secondary school students in the preparation of role into ASEAN Community found that the students who participated in a concept reflect that the knowledge and attitudes to prepare themselves for the ASEAN community.
基金supported by the National Natural Science Foundation of China[grant number 41230527][grant number41675091][grant number 41461164005]
文摘The distinct influences of eastern Pacific (EP) and central Pacific (CP) La Nina on rainfall anomalies over Southeast Asia and Australia in boreal autumn (September to November) are explored in this study. Composite results reveal that CP La Nina gives rise to significant and severe flooding over Southeast Asia and Australia, whereas EP La Nina fails to exert any evident impacts on rainfall over this region. This difference can be attributed to the distinct features of cooling sea surface temperature anomalies (SSTAs) between EP and CP La Nina. With a more westward location and stronger intensity of the negative SSTAs during CP La Nina autumn, the highest and lowest SLP anomalies are substantially enhanced and shift westwards too, further causing intense easterly winds over the western Pacific and westerly anomalies over the Indian Ocean driven by this SLP gradient. Subsequently, robust low-level convergence and high-level divergence is observed over the Maritime Continent and Australia, resulting in significant above-normal rainfall anomalies in those regions. In contrast, weak and eastern Pacific-confined cooling SSTAs during EP La Nina produce correspondingly weak low-level convergence over the Maritime Continent conditions that make it hard for significant rainfall anomalies to arise.
基金supported by the National Key Basic Research Program of China (Grant No. 2013CB955703)the South China Sea-Deep Program of the National Natural Science Foundation of China (Grant Nos. 91028005 & 91428308)+3 种基金the National Natural Science Foundation of China (Grant Nos. 41276125 & 31470539)the "National Thousand Talents Program" at the State Key Laboratory of Marine Geology of Tongji Universitythe Expenses for Chinese University Basic Researchinterdisciplinary Programs (Grant No. 1350219165)the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. IUEQN201307)
文摘Archaea play an important role in global carbon and nitrogen cycles. Archaeal lipids, such as isoprenoid glycerol diakyl glycerol tetraethers(i GDGTs), are important biomarkers tracing change in archaeal community structure and biogeochemical processes in the natural environments. In this research, the spatial distributions of archaeal lipids in the surface sediments of the Jiulong River(JR) and the Jiulong River estuary(JRE) were examined. GDGT-0(containing zero cyclopentyl ring) and crenarchaeol were the most abundant i GDGTs in the JR and JRE. From the rivers to the estuary, the total i GDGTs, GDGT-0, crenarchaeol and archaeol concentrations showed significant spatial variation; in particular, GDGT-0 and archaeol in the river may be predominantly derived in situ from methanogens, whereas crenarchaeol in the estuary mainly derived in situ from Thaumarchaeota. We inferred that archaeal community was dominated by methanogens in the Jiulong River and by Thaumarchaeota in the Jiulong River estuary, which are consistent with change in archaeal community structure observed in other estuarine environments.