Submerged aquatic vegetation (SAV) enhances assimilation efficiency of nutrients in wetlands, and improves the water quality, but may serve as secondary sources when their litter residues are decomposed. A laboratory incubation was conducted to investigate the biomass decay rate of four common SAV species: Hydrilla (Hydrilla verticillata), Naiad (Najas guadalupensis), Potamogeton (P. illinoensis), and Chara (Chara spp). Plant biomass samples were collected from the stormwater treatment areas in south Florida, USA and incubated in water at 40 °C for 126 days. At the end of incubation, the mixtures were passed through a 1 m sieve, and the plant debris above the screen were rinsed, oven-dried, and weighed. Biomass (dry matter) was measured and the decay rate was calculated, and total concentration of carbon (C), nitrogen (N), phosphorus (P) and other elements (K, Na, Ca, Mg, Al, Fe, and Mn) in the SAV plants were determined. Subsamples (5 mL) of the suspension (representing floc solution) were used for bacteria and fungi colony counting. The relationships between the decay rate and nutrient features or chemical components were analyzed. The results showed that Hydrilla had the highest decay rate (0.007930 d⁻¹), and Chara had the lowest (0.002798 d⁻¹). Concentrations of N, P, C and cations (K, Na, and Mn), and the ratio (K + Na)/(Ca + Al) in the SAVs had positive correlations with the biomass decay rate, whereas concentrations of Ca and Al, and the ratios of C/N and C/P in the plants were negatively correlated with the decay rate. However, the effect of microorganisms in the biomass decay rate of SAVs was not significant. These results suggest that high C concentration and more Ca and Al in the plant tissues can retard SAV biomass decomposition.

淹没的水生植被（SAV）增强了湿地中养分的吸收效率，并改善了水质，但当枯枝落叶的残留物分解时，可作为次要来源。进行了实验室培养，以研究四种常见SAV物种的生物量衰减率：水草（Hydrilla verticillata），奈德（Najas guadalupensis），波塔莫格顿（P. illinoensis）和Chara（Chara spp））。从美国佛罗里达州南部的雨水处理区收集植物生物质样品，并在40°C的水中孵育126天。孵育结束时，将混合物通过1 m的筛子，并将筛子上方的植物残渣冲洗，烘干并称重。测量生物质（干物质）并计算衰减速率，并计算碳（C），氮（N），磷（P）和其他元素（钾，钠，钙，镁，铝，铁和锰）的总浓度）在SAV工厂中确定。悬浮液（代表絮凝溶液）的子样品（5 mL）用于细菌和真菌菌落计数。分析了腐烂率与养分特征或化学成分之间的关​​系。结果表明，Hydrilla具有最高的衰减率（0.007930 d ^-1），而Chara最低（0.002798 d ^-1）。SAV中N，P，C和阳离子（K，Na和Mn）的浓度以及（K + Na）/（Ca + Al）的比值与生物量衰减率成正相关，而Ca和Al的浓度，植物中C / N和C / P之比与衰变率呈负相关。但是，微生物对SAV的生物量衰减率的影响并不显着。这些结果表明植物组织中的高C浓度和更多的Ca和Al可以延迟SAV生物量的分解。