Rising air and stream-water temperatures in Chesapeake Bay region, USA

Abstract

Monthly mean air temperature (AT) at 85 sites and instantaneous stream-water temperature (WT) at 129 sites for 1960-2010 are examined for the mid-Atlantic region, USA. Temperature anomalies for two periods, 1961-1985 and 1985-2010, relative to the climate normal period of 1971-2000, indicate that the latter period was statistically significantly warmer than the former for both mean AT and WT. Statistically significant temporal trends across the region of 0.023°C per year for AT and 0.028°C per year for WT are detected using simple linear regression. Sensitivity analyses show that the irregularly sampled WT data are appropriate for trend analyses, resulting in conservative estimates of trend magnitude. Relations between 190 landscape factors and significant trends in AT-WT relations are examined using principal components analysis. Measures of major dams and deciduous forest are correlated with WT increasing slower than AT, whereas agriculture in the absence of major dams is correlated with WT increasing faster than AT. Increasing WT trends are detected despite increasing trends in streamflow in the northern part of the study area. Continued warming of contributing streams to Chesapeake Bay likely will result in shifts in distributions of aquatic biota and contribute to worsened eutrophic conditions in the bay and its estuaries.

Changes in river water temperature between 1980 and 2012 in Yongan watershed, eastern China: Magnitude, drivers and models

“…2) reported for rivers in the U.S.A. (0.009-0.077°C yr À1 , Kaushal et al, 2010;Isaak et al, 2012;Null et al, 2013a,b;Rice and Jastram, 2015), Europe (0.006-0.18°C yr À1 , Moatar and Gailhard, 2006;Albek and Albek, 2009;Pekárová et al, 2011;Žganec, 2012;Jurgelė naitė et al, 2012;Markovic et al, 2013;Lepori et al, 2014;Orr et al, 2015), and Australia (0.014-0.017°C yr À1 , Webb and Nobilis, 2007). Although no relevant reports are currently available for rivers in China, the rapid economic development and urbanization in China, especially in eastern China over the past several decades, are expected to enhance rising river water temperature rates in conjunction with the interactive effects of climate change for many rivers.…”

“…To detect the trends in air temperature, river water temperature and discharge over the 1980-2012 period, a linear regression analysis was adopted to establish the relationship between each of variables and year number over the study period (Kaushal et al, 2010;Chen et al, 2014;Rice and Jastram, 2015). When regression equations were statistically significant (p < 0.05), the change in rate or percentage was determined by the regression slope.…”

“…Water temperature is an important river physical property with a crucial impact on aquatic ecosystem health, as most river biogeochemical processes are functions of temperature (Webb and Nobilis, 2007;Webb et al, 2008;Kaushal et al, 2010;evan Vliet et al, 2012;Xin and Kinouchi, 2013;Luce et al, 2014;Rice and Jastram, 2015). Higher water temperature can impair the habitat of a wide range of aquatic organisms from invertebrates to salmonids (Langan et al, 2001;Caissie, 2006;Isaak et al, 2012;Markovic et al, 2013;Null et al, 2013a,b), as well as degrade water quality such as decreased oxygen-holding capacity, increased oxygen consumption, and enhanced formation of potentially toxic NH 3 (Webb and Nobilis, 2007;Pekárová et al, 2011;El-Jabi et al, 2014).…”

“…Higher water temperature can impair the habitat of a wide range of aquatic organisms from invertebrates to salmonids (Langan et al, 2001;Caissie, 2006;Isaak et al, 2012;Markovic et al, 2013;Null et al, 2013a,b), as well as degrade water quality such as decreased oxygen-holding capacity, increased oxygen consumption, and enhanced formation of potentially toxic NH 3 (Webb and Nobilis, 2007;Pekárová et al, 2011;El-Jabi et al, 2014). Furthermore, increasing riverine heat flux has a great potential to aggravate eutrophication (including harmful algal blooms) and hypoxia in downstream lakes, estuaries and coastal waters (Liu et al, 2005;Ozaki et al, 2008;Ye et al, 2011;Rice and Jastram, 2015), as well as to impair their biological communities (Seekell and Pace, 2011).…”

Twenty-first century climate change and submerged aquatic vegetation in a temperate estuary: the case of Chesapeake Bay

“…Freshwater plants are common in the lower salinity regions of the Chesapeake and these areas also have experienced significant warming (Seekell and Pace 2011;Ding and Elmore 2015;Rice and Jastram 2015). The physiological impacts are numerous.…”