Effects of Taxonomy, Sediment, and Water Column on C:N:P Stoichiometry of Submerged Macrophytes in Yangtze Floodplain Shallow Lakes, China
Total Page：16
File Type：pdf, Size：1020Kb
Environ Sci Pollut Res (2016) 23:22577–22585 DOI 10.1007/s11356-016-7435-1 RESEARCH ARTICLE Effects of taxonomy, sediment, and water column on C:N:P stoichiometry of submerged macrophytes in Yangtze floodplain shallow lakes, China Haojie Su1,2 & Yao Wu 1,2 & Ping Xie1 & Jun Chen1 & Te Cao 1 & Wulai Xia 1,2 Received: 4 April 2016 /Accepted: 8 August 2016 /Published online: 24 August 2016 # Springer-Verlag Berlin Heidelberg 2016 Abstract Carbon (C), nitrogen (N) and phosphorus (P) are Introduction the three most important essential elements limiting growth of primary producers. Submerged macrophytes generally absorb Carbon (C):nitrogen (N):phosphorous (P) stoichiometry pro- nutrients from sediments by root uptake. However, the C:N:P vides a very powerful way to enhance our understanding of stoichiometric signatures of plant tissue are affected by many primary production, nutrient cycling, and population dynam- additional factors such as taxonomy, nutrient availability, and ics in freshwater and terrestrial ecosystems (Andersen et al. light availability. We first revealed the relative importance of 2004;ElserandUrabe1999; Evans-White and Lamberti taxonomy, sediment, and water column on plant C:N:P stoi- 2006; Sterner and Hessen 2003). C, N and P are three essential chiometry using variance partitioning based on partial redun- elements of organisms and have strong interactions in bio- dancy analyses. Results showed that taxonomy was the most chemical functioning (Agren 2008). Many ecological process- important factor in determining C:N:P stoichiometry, then the es such as photosynthesis (Elser et al. 2000; Reich et al. 1997), water column and finally the sediment. In this study, a signif- litter decomposition (Güsewell and Gessner 2009), predator– icant positive relationship was found between community C prey relationships (Ngai and Jefferies 2004; Tibbets and concentration and macrophyte community biomass, indicat- Molles 2005), community composition, and species diversity ing that the local low C availability in macrophytes probably (Bedford et al. 2008;Gusewelletal.2005) are related to C, N was the main reason why submerged macrophytes declined in and P contents or C:N:P mass ratios. In freshwater ecosys- Yangtze floodplain shallow lakes. Based on our study, it is tems, for instance, N:P ratio can influence the productivity suggested that submerged macrophytes in Yangtze floodplain and species composition of plant communities (Hall et al. shallow lakes are primarily limited by low light levels rather 2005; Harpole et al. 2011; Willby et al. 2001). than nutrient availability. C:N:P stoichiometry of submerged vegetation could be in- fluenced by sediment and water column nutrient availability because submerged macrophytes rely on the surrounding sed- Keywords Submerged macrophyte . Sediment . Water iment and water to satisfy their N and P requirements (Cao column . C:N:P stoichiometry . Eutrophication et al. 2011; Madsen and Cedergreen 2002). Previous studies have addressed the relative importance of roots and leaves in Responsible editor: Thomas Hein nutrient uptake of rooted submerged macrophytes (Carignan and Kalff 1980; Rattray et al. 1991; Robach et al. 1995). * Ping Xie Given that the concentrations of nutrients in sediments are [email protected] usually higher than that of in water column, it is generally accepted that sediments are the major source of N and P for submerged macrophytes (Barko and Smart 1981; Best and 1 Donghu Experimental Station of Lake Ecosystems, State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Mantai 1978; Bristow and Whitcombe 1971;Carignanand Hydrobiology, The Chinese Academy of Sciences, 7# Donghu South Kalff 1980; Smith and Adams 1986). Road, Wuhan 430072, China The C:N:P stoichiometric signatures in plant tissue, 2 University of Chinese Academy of Sciences, Beijing 100049, China however, depend not only on nutrient supply but also on 22578 Environ Sci Pollut Res (2016) 23:22577–22585 the light availability in water column. Light availability in stoichiometry may have important implications for the eco- water column can affect physiology, morphology, biomass logical functioning of lake ecosystems. Additionally, since allocation, community structure, or distribution of sub- submerged macrophytes are different in taxonomy, growth mersed macrophytes, causing great variation in the C, N, forms, and C/N/P metabolic strategies, their stoichiometric and P concentrations and C:N:P stoichiometry in plant signatures are species-specific (Yuan et al. 2016). Thus, which (Cao et al. 2011;ChambersandKalff1987; Cronin and one of the three factors (taxonomy, sediment, and water col- Lodge 2003;Xingetal.2013). For instance, to alleviate umn) is having the greatest influence on C:N:P stoichiometry low light availability in deep waters, Potamogeton of macrophytes is still unclear. In this paper, we aim to (i) maackianus and Potamogeton malaianus tend to enhance explore how sediment and water column affect C, N, and P light harvesting by allocating more biomass to the stem, stoichiometry of submerged macrophytes and (ii) reveal the increasing shoot height and specific leaf area, whereas relative importance of taxonomy, sediment, and water column Vallisneria natans tend to allocate more biomass to the on the C:N:P stoichiometry of submerged macrophytes. leaf than to the rosette (Fu et al. 2012). Furthermore, the C:N:P stoichiometry in plant tissue is not always directly correlated with sediment or water column N and P avail- Materials and methods ability (Güsewell and Koerselman 2002). Indeed, plants will accumulate nutrients in excess of their cellular re- Study sites and field sampling quirements when their growth is not limited by N and P availability (Cao et al. 2011;DemarsandEdwards2007). Fourteen lakes along the mid-lower Yangtze River were in- In recent years, eutrophication induced by human activities vestigated from June to August 2014 (Fig. 1). The longitudes has changed water and sediment physicochemical conditions of the studied lakes range from 112.2° E to 120.4° E and extensively. Consequently, these changes have altered nutrient latitudes range from 29.7° N to 33.8° N. All the studied lakes and light availability, leading to variations of nutrient uptake are large shallow floodplain lakes (water depth ranged from by plants. Thus, current anthropogenic changes in N:P 1.1 to 4.1 m) with different nutrient levels (Table 1). Fig. 1 Location of sampled lakes along the middle and lower Yangtze River, China Environ Sci Pollut Res (2016) 23:22577 Table 1 Geographic and trophic parameters of the 14 lakes along the mid-lower Yangtze River − − − − − − − Lake Latitude Longitude Area (km2)S-N(mgg1) S-C (mg g 1)S-WC(%)S-P(mgg1)WD(m)SD(m)TN(mgL1)TP(mgL1)Chla (μgL 1) K (m 1) Taihu Lake 31.19 120.41 2537.2 1.12 6.1 38.6 0.41 2.1 1.2 0.69 0.02 13.7 1.87 Gaoyou Lake 32.84 119.33 639.2 1.09 11.1 48.9 0.62 1.9 0.7 0.71 0.04 23.6 3.71 Luoma Lake 33.75 118.22 290.9 1.35 18.4 37.2 0.61 2.1 0.9 0.73 0.04 39.9 2.20 Longgan Lake 29.96 116.03 280.5 3.46 28.8 62.1 0.75 2.8 0.6 1.08 0.04 50.6 2.63 Chihu Lake 29.79 115.69 62.8 3.48 45.8 69.0 0.58 4.1 1.6 0.49 0.01 10.9 1.18 Huayuan Lake 33.02 117.85 47.7 1.26 23.8 37.0 0.65 1.7 0.6 0.70 0.04 31.9 3.11 Wuchang Lake 30.24 116.67 100.5 1.32 7.1 40.3 0.55 3.1 1.7 0.58 0.01 6.0 1.74 Yezhu Lake 30.89 114.08 25.9 1.50 9.1 47.7 0.51 1.5 0.4 1.20 0.13 87.9 4.35 – Wuhu Lake 30.81 114.50 27.5 2.87 20.6 50.0 0.63 1.7 1.0 1.05 0.04 10.2 1.61 22585 Futou Lake 29.96 114.20 141.2 2.55 27.9 55.0 0.88 2.0 0.8 1.17 0.05 14.2 2.53 Liangzi Lake 30.25 114.55 351.8 2.25 17.6 48.9 0.37 2.0 0.7 0.66 0.04 21.9 2.04 Honghu Lake 29.83 113.36 340.1 2.79 29.9 56.8 0.69 1.5 0.9 0.74 0.06 27.4 2.63 Chonghu Lake 29.92 112.27 16.9 3.10 37.3 63.5 0.70 1.1 1.1 0.64 0.05 7.6 3.80 Xiliang Lake 29.98 114.10 98.1 2.83 33.8 60.7 0.56 1.9 1.9 0.34 0.02 3.9 1.26 S-N sediment nitrogen, S-C sediment carbon, S-WC sediment water content, S-P sediment phosphorus, WD water depth, SD Secchi depth, TN total nitrogen in water column, TP total phosphorus in water column, Chl a chlorophyll a, K light attenuation coefficient Su et al. handled scythe-type sampler (0.2 m by random sampling (three replicates) at each site with a long- cluding morphological feature andgrowth metabolism forms (Ni andmental have stress, various these adaptive macrophyte strategies, species in- take different the 14 lakesDistribution was shown of in the Table collected submerged macrophytes at umn was calculated based on the equation: collected from the topfrom 0 0.5 m below thebags water with surface. Surface waterproof sediments labels. were Corresponding waterof was the taken six plantweighed species for were wet collected and biomass,macrophytes put respectively.