1. Studies in the Northern Hemisphere have shown that mussels play important roles as benthic‐pelagic couplers in freshwater systems, transferring filtered material, nutrients, and energy from the water column to sediments, through biodeposition and excretion. However, we know little of the functional roles of species of the Southern Hemisphere Hyriidae, the second most diverse family of the Unionoida.
2. The aims of this study were to determine the biodeposition and excretion rates of nutrients and organic matter of the hyriid Alathyria jacksoni in an unregulated Australian river and test experimentally if the physical structure and biodeposition of A. jacksoni influenced sediment nutrients, organic matter, periphyton concentrations and meiofauna densities.
3. In a lowland Australian river in late summer over 4 weeks, we measured biodeposition and excretion rates of A. jacksoni, and conducted a mesocosm experiment, during which we compared the effects of live mussels, dead mussel shells (shams), and controls without mussels on nutrients, organic matter, and meiofauna invertebrate densities in the sediment.
4. Mean (± SE) mass of biodeposition was 70.85 ± 3.20 mg mussel⁻¹ hr⁻¹ and the relative rates of inorganic and organic biodeposition were 60.9 ± 3.1 and 9.9 ± 0.8 mg mussel⁻¹ hr⁻¹, respectively. Organic matter was significantly greater in the sediment of the mesocosms with live mussels than in that of the control mesocosms. There was also a trend of greater mean sediment chlorophyll‐a and total nitrogen concentrations in mussel treatments than in the controls. No significant difference was detected in sediment total phosphorous between mussel and control enclosures.
5. The valves of live mussels had significantly higher amounts of organic material and chlorophyll‐a concentrations than the valves of sham mussels. There was a consistent trend of higher meiofauna densities collected in the benthos of the mussel enclosures than the control enclosures for total density and densities of Rotifera, Copepoda, Cladocera, Diptera, Oligocheata, Nematoda, and Ostracoda; this trend was near significant for total density; and significant for densities of Ostracoda, Rotifera, Cladocera, and Nematoda.
6. Using our biodeposition and excretion rate estimates, and estimates of population size of A. jacksoni in the Lower Ovens River, we estimated that in a typical 1‐km reach in a month over summer, A. jacksoni would be biodepositing approximately 4.8 kg/day of organic matter (dry mass), 137 g N/day and 19 g P/day, and excreting 21 g N/day and 3.7 g P/day.
7. Our findings are similar to those for Northern Hemisphere families of the Unionoida and serve to highlight the roles mussels play in processing of organic matter and cycling of nutrients in freshwater ecosystems.

中文翻译：

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鬣蜥贻贝（Unionoida）在温带的澳大利亚河中提高底栖有机质和鱼类的密度

1. 北半球的研究表明，贻贝在淡水系统中作为底栖上层耦合体发挥着重要作用，通过生物沉积和排泄将贻贝的滤过物质，营养物质和能量从水柱转移到沉积物中。但是，我们对南半球鬣蜥科（Unionoida的第二大多样性科）的功能作用知之甚少。
2. 这项研究的目的是确定未受管制的澳大利亚河流中的水草Alathyria jacksoni的养分和有机物的生物沉积和排泄速率，并通过实验测试A. jacksoni的物理结构和生物沉积是否影响了沉积物养分，有机质，浮游植物的浓度。和meiofauna密度。
3. 在夏季夏末4周多的澳大利亚低地河流中，我们测量了A. jacksoni的生物沉积和排泄率，并进行了介观试验，在此期间，我们比较了活贻贝，死贻贝壳（假）和无贻贝的对照组的影响沉积物中养分，有机质和藻类无脊椎动物密度的变化。
4. 生物沉积的平均（± SE）质量为70.85±3.20 mg贻贝^-1  hr ^-1，无机和有机生物沉积的相对速率分别为60.9±3.1和9.9±0.8 mg贻贝^-1  hr ^-1。与贻贝相比，活贻贝的中层沉积物中的有机物明显多。与贻贝处理相比，贻贝处理中的平均沉积物叶绿素a和总氮浓度也有增加的趋势。贻贝和对照围栏之间的总磷沉积物未检测到显着差异。
5. 活贻贝的瓣膜中的有机物质和叶绿素a的含量明显高于假贻贝的瓣膜。轮虫，Co足类，克拉多菌纲，双翅类，低纲纲，线虫和Ostracoda的总密度和密度，在贻贝围栏的底栖动物中收集到的中型动物的密度一直高于对照围栏。这种趋势对于总密度几乎是显着的；并对于骨纲，轮虫，克拉多菌和线虫的密度具有重要意义。
6. 使用我们的生物沉积和排泄率估算，以及人口规模的估计A. jacksoni在较低的烘炉河，我们估计，在一个典型的1公里范围一个月了夏天，A. jacksoni将biodepositing约4.8 kg /天每天137 g N /天和19 g P /天的有机物（干重），以及21 g N /天和3.7 g P /天的排泄物。
7. 我们的发现与北半球Unionina家族的发现相似，并有助于突出贻贝在淡水生态系统中有机物的加工和养分循环中的作用。