Bacterial metabolism in small temperate streams under contemporary and future climates

Sand‐Jensen, Kaj; Pedersen, Niels Lagergaard; Søndergaard, Morten

doi:10.1111/j.1365-2427.2007.01852.x

Cited by 83 publications

(70 citation statements)

References 43 publications

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“…Respiration was correlated with temperature (and chl a) as expected based on other studies (Hall & Cotner, 2007;Apple et al, 2006;Sand-Jensen et al, 2007;Lee et al, 2009). Even though reservoir sites had higher temperatures than river sites, BR rates did not differ among sites.…”

Section: Experimental Microcosmssupporting

confidence: 61%

Bacterial community composition and function along a river to reservoir transition

Moitra

Leff

2014

Hydrobiologia

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Bacteria in reservoir systems are controlled by a variety of factors. In this study, a lacustrine system with high primary production fed by a river with lower algal biomass was used to examine the relationship between bacterial community composition (BCC) and function under varying environmental conditions. Bacterial abundance, respiration, production, and growth efficiency were measured in the Cuyahoga River and Lake Rockwell reservoir in Ohio (USA). BCC was determined via terminal restriction length polymorphisms of 16S rRNA genes. Also, in laboratory experiments, bacterial communities were exposed to algal exudates and leaf leachates. Concurrently with physicochemical differences between lacustrine and riverine sites, there were differences in BCC that seemed unrelated to environmental conditions and DOC sources (color: chlorophyll a ratio). Functional attributes varied among dates but not sites, except for bacterial heterotrophic productivity. Overall, the source of DOC differed between the river and reservoir as did BCC. In contrast, bacterial functions, with the exception of productivity, were similar between the river and reservoir sites. Environmental variables (e.g., temperature, nutrient, and chlorophyll a) were correlated with differences in bacterial function. Differences in BCC did not coincide with functional differences in the field or controlled laboratory conditions suggesting that structure and function were uncoupled.

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Section: Experimental Microcosmssupporting

confidence: 61%

Bacterial community composition and function along a river to reservoir transition

Moitra

Leff

2014

Hydrobiologia

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“…Nevertheless, several studies have been carried out in both natural pelagic and sedimentary marine and freshwater environments. Reported Q 10 values typically vary between 1.8 and 3.3 (e.g., Thamdrup et al 1998;Lomas et al 2002;Sand-Jensen et al 2007), but values as high as 5 to 9 (Lefevre et al 1994;Shiah and Ducklow 1994;Pomeroy and Wiebe 2001) and as low as 1.2 (Smith 1973) have also been published. Assuming a constant flux of organic matter, the , 2.0uC increase in bottom-water temperatures would result in a , 11% to 27% increase in respiration rate for 1.8 , Q 10 , 3.3.…”

Section: Discussionmentioning

confidence: 99%

“…The relative abundance of certain species, such as Bulimina marginata, Elphidium excavatum, Nonionellina labradorica, Lagena sp., and Glandulina sp., decreases sharply and some of the taxa disappear towards the sediment-water interface. The reason for changes in foraminifer abundances cannot be assessed unequivocally since the tolerance limits of these species to the physical and chemical properties of water masses are poorly known (Sen Gupta and Machain-Castillo 1993;Gooday et al 2009). Nevertheless, the general decrease in species diversity probably reflects an additional stress, which could have been caused by the lowering of DO concentrations.…”

Section: Discussionmentioning

confidence: 99%

Recent changes in bottom water oxygenation and temperature in the Gulf of St. Lawrence: Micropaleontological and geochemical evidence

Genovesi

Vernal

Thibodeau

et al. 2011

Limnology & Oceanography

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Micropaleontological and geochemical analyses of a sediment core collected in the Laurentian Trough of the Gulf of St. Lawrence were carried out to reconstruct temporal variations in pelagic productivity and benthic environmental conditions. Dinoflagellate cyst assemblages reveal relatively stable pelagic productivity over the last two centuries. Similarly, geochemical (organic C, C org : N) and isotopic (d 13 C org , d 15 N) data reveal that organic matter fluxes to the seafloor have been relatively constant over the same period. In contrast, significant changes are recorded in the benthic foraminifer assemblages. A sediment surface peak in the abundance of Cassidulina laevigata and Brizalina subaenariensis is consistent with the recent record of oxygen depletion in the bottom water. A decrease in the relative abundance of Nonionellina labradorica, concomitant with a relatively higher occurrence of Oridorsalis umbonatus in the upper part of the core, reflects a significant warming of the bottom water. Changes in bottom-water properties are further constrained by a negative trend of the d 18 O in Bulimina exilis carbonate shells over the last century, corresponding to a warming of about 2uC. These results strongly suggest that the recent oxygen depletion in the bottom waters of the Gulf of St. Lawrence is due to changes in water masses that have led to increased bottom-water temperatures and, to some extent, a resultant increase in organic matter respiration rates.Eutrophication is often identified as the main cause of bottom-water hypoxia (, 2 mg L 21 or 62.5 mmol L 21 ) in coastal environments (Cloern 2001). In the Lower St. Lawrence Estuary (LSLE), direct measurements have documented a progressive depletion of dissolved oxygen (DO) in bottom waters (. 250 m), from , 125 to 60 mmol L 21 over the last 80 yr (Gilbert et al. 2005). These observations are consistent with results of micropaleontological and geochemical analyses of sediment cores that show clear evidence of bottom-water oxygen depletion since the 1960s (Thibodeau et al. 2006). Whereas one half to two thirds of the oxygen depletion has been ascribed to a change in ocean circulation in the northwest Atlantic and, thus, variations in the water properties (DO, temperature, salinity) of the bottom waters that enter the Gulf and St. Lawrence through Cabot Strait (Gilbert et al. 2005), the remainder has been speculatively associated with increased organic carbon (C org ) fluxes to the seafloor, possibly due to anthropogenic eutrophication (Thibodeau et al. 2006). Thibodeau et al. (2006) and Gilbert et al. (2007) have shown that increases in sales of agricultural fertilizers, especially nitrogen fertilizers, in the St. Lawrence River drainage basin are concurrent with the depletion of bottom-water oxygen concentrations in the LSLE. Finally, an increase in bottom-water temperatures (Gilbert et al. 2005), leading to increased respiration rates, could also explain the recent decrease of DO concentrations.To determine if eutrophication and the trend ...

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“…Modeling will require intensive studies of EFS hydrology at multiple locations, especially to address important but unknown issues such as groundwater relations, winter precipitation, delineation of hydrological catchments, and evaporation-transpiration relations. Research needs to be increased to better our understanding of the relationships among EFS hydrology and ecology and shortterm weather factors (Sand-Jensen et al 2007), which will improve our projections for the potential impacts of long-term climate change. An increased research focus on EFS and climate change could result in new conservation priorities and strategies to mediate potential impending impacts.…”

Section: Potential Impacts Of Global Climate Change On the Hydrology mentioning

confidence: 99%

Potential impacts of global climate change on the hydrology and ecology of ephemeral freshwater systems of the forests of the northeastern United States

2009

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Global, national, and regional assessments of the potential effects of Global Climate Change (GCC) have been recently released, but not one of these assessments has specifically addressed the critical issue of the potential impacts of GCC on ephemeral freshwater systems (EFS). I suggest that this is a major oversight as EFS occur in various forms across the globe. In the northeastern United States, these systems, whether ephemeral ("vernal") pools or ephemeral or intermittent headwater streams are abundant and provide unique habitats critical to the maintenance of forest biodiversity. Since the hydrology of these waterbodies is strongly affected by weather patterns (in the short-term) or climate (long-term), they are especially sensitive to climate change. In this essay, I review the literature on relationships between climate and hydrology of EFS and on relationships between hydrology and ecology of these systems. I then conclude with my assessment of potential impacts of GCC on the hydrology of EFS and implications for their ecology. The focus of this essay will be on EFS of the forests of the northeastern United States, but will include literature from other regions as they relate to the general relationships between GCC and EFS.

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Bacterial metabolism in small temperate streams under contemporary and future climates

Cited by 83 publications

References 43 publications

Bacterial community composition and function along a river to reservoir transition

Bacterial community composition and function along a river to reservoir transition

Recent changes in bottom water oxygenation and temperature in the Gulf of St. Lawrence: Micropaleontological and geochemical evidence

Potential impacts of global climate change on the hydrology and ecology of ephemeral freshwater systems of the forests of the northeastern United States

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