Sediment microbial enzyme activity as an indicator of nutrient limitation in Great Lakes coastal wetlands

Abstract

1. We compared the extracellular enzyme activity (EEA) of sediment microbial assemblages with sediment and water chemistry, gradients in agricultural nutrient loading (derived from principal component analyses), atmospheric deposition and hydrological turnover time in coastal wetlands of the Laurentian Great Lakes. 2. There were distinct increases in nutrient concentrations in the water and in atmospheric N deposition along the gradient from Lake Superior to Lake Ontario, but few differences between lakes in sediment carbon (C), nitrogen (N) or phosphorus (P). Wetland water and sediment chemistry were correlated with the agricultural stress gradient, hydrological turnover time and atmospheric deposition. 3. The N : P ratio of wetland waters and sediments indicated that these coastal wetlands were N-limited. Nutrient stoichiometry was correlated with the agricultural stress gradient, hydrological turnover time and atmospheric deposition. 4. Extracellular enzyme activity was correlated with wetland sediment and water chemistry and stoichiometry, atmospheric N deposition, the agricultural stress gradient and the hydrological turnover time. The ratios of glycosidases to peptidases and phosphatases yielded estimates of nutrient limitation that agreed with those based solely on nutrient chemistry. 5. This study, the first to link microbial enzyme activities to regional-scale anthropogenic stressors, suggests that quantities and ratios of microbial enzymes are directly related to the concentrations and ratios of limiting nutrients, and may be sensitive indicators of nutrient dynamics in wetland ecosystems, but further work is needed to elucidate these relationships.

The phosphorus release pathways and their mechanisms driven by organic carbon and nitrogen in sediments of eutrophic shallow lakes

“…All of these facts can be explained by the proportional imbalance of the input of different type of nutrient, which acts as a functional stimulation to acquire the lacking nutrient. The growth of different organism need specific nutrient ratio, such as 108C:16N:1P for algae (Falkowski, 2010), 60C:7N:1P for bacteria (Cleveland and Liptzin, 2007;Hill et al, 2006). Departures from these ratios suggest that an organism's metabolism and growth will be limited by the element presented in limiting concentrations (Sinsabaugh et al, 2009;Hall et al, 2011).…”

“…The degradation of organic matter mainly relies on microbial communities and extracellular enzymes (enzymes outside microbial cell membranes) produced by them (Sinsabaugh and Foreman, 2001;Sinsabaugh et al, 2009). Thus far, the studies on extracellular enzymes activities (EEA) have been mainly associated with organic matter degradation by microbes (Teske et al, 2011;Alvarez and Guerrero, 2000;Hiroki et al, 2007) and nutrient limitation (Hill et al, 2012;Hill et al, 2010). Furthermore, EEA was also used to reflect the different trophic status of shallow lakes (Caruso et al, 2005;Kalwasinska and Brzezinska, 2013;Ziervogel et al, 2014) and estimate degradation rates (Jackson et al, 1995;Alvarez and Guerrero, 2000;Sciessere et al, 2011) and turnover times (Misic and Harriague, 2009) of organic matter.…”

Indicadores de salud y calidad de suelos en cuencas hídricas en Bogotá

“…La introducción de de materiales orgánicos derivados de residuos urbanos trae consigo aumento en los contenidos de carbono y así como aumento en las actividades fosfatasa y deshidrogenasa (Gianfreda et al, 2005;Singh y Agrawal, 2008) actividades que también responden a gradientes por el mismo tipo de contaminación, en humedales (Hill et al, 2006). Por otra parte, la canalización de los ríos trae con sigo modificaciones en la disponibilidad de agua para los suelos aledaños y en la química de los suelos, así como modificaciones en la estructura de las comunidades vegetales, mostrando (Kang y Stanley, 2005) que dichos cambios llevaron a un incremento significativo en las actividades deshidrogenasa, ń-glucosidasa y fosfatasa, también la modificación en el régimen hídrico tienen influencia en la composición vegetal y en la dinámica de la materia orgánica.…”

Variation in microbial function through soil depth profiles in the Kushiro Wetland, northeastern Hokkaido, Japan

“…7a, b). Exogenous phosphatases are central to the regeneration of inorganic phosphorus, particularly in P-limited aquatic ecosystems (Prenger and Reddy 2004;Hill et al 2006Hill et al , 2010. An increase in AP activity in response to declining or limiting inorganic phosphorus has been demonstrated in numerous aquatic environments (Kang and Freeman 1999;Wright and Reddy 2001;Hill et al 2006), and it is likely that the soil in the Kushiro Wetland is also P limited.…”