All three macroalgal clades (Chlorophyta, Rhodophyta, and Phaeophyceae) contain bloom-forming species. Macroalgal blooms occur worldwide and have negative consequences for coastal habitats and economies. Narragansett Bay (NB), Rhode Island, USA, is a medium sized estuary that is heavily influenced by anthropogenic activities and has been plagued by macroalgal blooms for over a century. Over the past decade, significant investment has upgraded wastewater treatment from secondary treatment to water-quality based limits (i.e. tertiary treatment) in an effort to control coastal eutrophication in this system. The goal of this study was to improve the understanding of multi-year macroalgal bloom dynamics through intensive aerial and ground surveys conducted monthly to bi-monthly during low tides in May–October 2006–2013 in NB. Aerial surveys provided a rapid characterization of macroalgal densities across a large area, while ground surveys provided high resolution measurements of macroalgal identity, percent cover, and biomass.

Macroalgal blooms in NB are dominated by Ulva and Gracilaria spp. regardless of year or month, although all three clades of macroalgae were documented. Chlorophyta cover and nutrient concentrations were highest in the middle and upper bay. Rhodophyta cover was highest in the middle and lower bay, while drifting Phaeophyceae cover was patchy. Macroalgal blooms of >1000 g fresh mass (gfm)/m² (max = 3510 gfm/m²) in the intertidal zone and >3000 gfm/m³ (max = 8555 gfm/m³) in the subtidal zone were observed within a heavily impacted embayment (Greenwich Bay). Macroalgal percent cover (intertidal), biomass (subtidal), and diversity varied significantly between year, month-group, site, and even within sites, with the highest species diversity at sites outside of Greenwich Bay. Total intertidal macroalgal percent cover, as well as subtidal Ulva biomass, were positively correlated with temperature. Dissolved inorganic nitrogen concentrations were correlated with the total biomass of macroalgae and the subtidal biomass of Gracilaria spp. but not the biomass of Ulva spp. Despite seasonal reductions in the nutrient output of wastewater treatment facilities emptying into upper Narragansett Bay in recent years, macroalgal blooms still persist. Continued long-term monitoring of water quality, macroalgal blooms, and ecological indicators is essential to understand the changes in macroalgal bloom dynamics that occur after nutrient reductions from management efforts.

所有三个大型藻类进化枝（绿藻，红藻和藻科）都含有形成花的物种。大型藻类的花开遍布世界各地，并对沿海生境和经济产生负面影响。美国罗得岛州的纳拉甘西特湾（NB）是一个中等规模的河口，受人为活动的影响很大，一个世纪以来一直受到大型藻类繁殖的困扰。在过去的十年中，为了控制该系统中的沿海富营养化，大量投资已将废水处理从二级处理升级到基于水质的限值（即第三级处理）。本研究的目的是通过在2006年5月至2013年10月NB潮退潮期间每月至每两个月进行一次密集的空中和地面调查，以增进对多年巨藻水华动态的了解。

NB中的巨藻水华主要由Ulva和Gracilaria spp所控制。不论年份还是月份，尽管都记录了全部三个藻类进化枝。中部和上部海湾的叶绿体覆盖率和养分浓度最高。红藻盖层在中部和下部海湾最高，而漂移的藻科盖片状。潮间带的大型藻华> 1000 g新鲜质量（gfm）/ m ²（最大= 3510 gfm / m ²），> 3000 gfm / m ³（最大= 8555 gfm / m ^3）潮汐带中的）在一个严重受影响的小岛（格林威治湾）内被观察到。在年，月，月，地点，甚至地点内，大型藻类的覆盖率（潮间带），生物量（潮下带）和多样性差异很大，其中格林威治湾以外的地点物种多样性最高。潮间带总的藻类百分覆盖率以及潮间带Ulva生物量与温度呈正相关。溶解的无机氮浓度与大型藻类的总生物量和龙须藻的潮下生物量相关。但不是Ulva的生物量spp。尽管近年来排入纳拉甘西特湾上游的废水处理设施的养分输出量季节性减少，但大型藻类水华仍持续存在。持续长期监测水质，藻类大量繁殖和生态指标对于了解由于管理而减少养分后藻类大量繁殖动态的变化至关重要。