Blooms of green macroalgae (Ulva spp.) occur frequently in the hypereutrophic Yatsu tidal flat of eastern Japan. In this study, to elucidate the effects of such blooms on nutrients and sulfide dynamics, we measured Ulva nutrients uptakes and stocks, and sulfide release during Ulva blooms decay. NH₄⁺ uptake was greater than NO₃^– uptake when NH₄⁺ was sufficient, whereas NO₃^– uptake increased in the absence of NH₄⁺. NH₄⁺ concentration was generally higher than that of NO₃^– in seawater; thus, Ulva spp. would prefer NH₄⁺ as N substrate. The mean N and P amounts in Ulva blooms were 2,320 kg-N and 116 kg-P, respectively. Sudden, rapid blooms collapse appears to release extremely high amounts of nutrients, especially NH₄⁺. Thus, Ulva blooms affect NH₄⁺ behavior and consequently affect N cycling in the Yatsu tidal flat. High sulfide concentrations were detected under anoxic Ulva mats following peaks in biomass. Incubation experiments revealed that sulfide was derived not only from SO₄^2– in seawater but also from the S contained in Ulva spp. Subsequently, sulfide might be microbiologically oxidized to elemental sulfur thereafter. Moreover, sulfide was not detected without Ulva spp.. Therefore, Ulva blooms also influence S cycling in Yatsu tidal flat.

在日本东部的富营养化的Yatsu潮滩中，绿色大型藻类（Ulva spp。）经常开花。在这项研究中，为阐明此类开花对养分和硫化物动力学的影响，我们测量了Ulva养分的吸收和储量，以及Ulva开花衰变期间的硫化物释放。NH ₄ ⁺的摄取比NO了较大的₃ ^-摄取当NH ₄ ⁺是足够的，而NO ₃ ^-在不存在NH的摄取增加₄ ⁺。NH ₄ ⁺浓度一般比NO的更高₃ ^-海水中; 从而，乌尔瓦种 将更喜欢NH ₄ ⁺作为N底物。Ulva盛开的平均N和P量分别为2,320 kg-N和116 kg-P。突然的快速开花崩溃似乎释放出大量的养分，尤其是NH ₄ ⁺。因此，Ulva绽放会影响NH ₄ ^+的行为，并因此影响八叠滩中的N循环。在生物量达到峰值后，在缺氧的Ulva垫下检测到高硫化物浓度。孵化实验表明，硫化物不仅源自海水中的SO ₄ ^2–，而且源自Ulva中所含的S。spp。随后，硫化物可能随后被微生物氧化成元素硫。此外，没有Ulva物种就没有检测到硫化物。因此，Ulva盛开也影响了Yatsu潮滩的S循环。