Coastal ecosystems are prone to multiple anthropogenic and natural stressors including eutrophication, acidification, and invasive species. While the growth of some macroalgae can be promoted by excessive nutrient loading and/or elevated pCO₂, responses differ among species and ecosystems. Native to the western Pacific Ocean, the filamentous, turf-forming rhodophyte, Dasysiphonia japonica, appeared in estuaries of the northeastern Atlantic Ocean during the 1980s and the northwestern Atlantic Ocean during the late 2000s. Here, we report on the southernmost expansion of the D. japonica in North America and the effects of elevated nutrients and elevated pCO₂ on the growth of D. japonica over an annual cycle in Long Island, New York, USA. Growth limitation of the macroalga varied seasonally. During winter and spring, when water temperatures were < 15 °C, growth was significantly enhanced by elevated pCO₂ (p < 0.05). During summer and fall, when the water temperature was 15–24 °C, growth was significantly higher under elevated nutrient treatments (p < 0.05). When temperatures reached 28 °C, the macroalga grew poorly and was unaffected by nutrients or pCO₂. The δ¹³C content of regional populations of D. japonica was −30‰, indicating the macroalga is an obligate CO₂-user. This result, coupled with significantly increased growth under elevated pCO₂ when temperatures were < 15 °C, indicates this macroalga is carbon-limited during colder months, when in situ pCO₂ was significantly lower in Long Island estuaries compared to warmer months when estuaries are enriched in metabolically derived CO₂. The δ¹⁵N content of this macroalga (9‰) indicated it utilized wastewater-derived N and its N limitation during warmer months coincided with lower concentrations of dissolved inorganic N in the water column. Given the stimulatory effect of nutrients on this macroalga and that eutrophication can promote seasonally elevated pCO₂, this study suggests that eutrophic estuaries subject to peak annual temperatures < 28 °C may be particularly vulnerable to future invasions of D. japonica as ocean acidification intensifies. Conversely, nutrient reductions would serve as a management approach that would make coastal regions more resilient to invasions by this macroalga.

沿海生态系统容易遭受多种人为和自然压力，包括富营养化，酸化和入侵物种。尽管过量的养分负荷和/或升高的p CO ₂可以促进某些大型藻类的生长，但物种和生态系统的响应却有所不同。原产于西太平洋的丝状，草皮形成的红藻，Dasysiphonia japonica，出现在1980年代的东北大西洋和2000年代后期的西北大西洋的河口。在这里，我们报道了北美D. japonica的最南端扩张，以及养分含量升高和p CO ₂含量升高对褐飞虱生长的影响。D. japonica在美国纽约长岛的年度循环中。大型藻类的生长限制随季节变化。在冬季和春季，当水温<15°C时，p CO ₂升高会显着促进生长（p  <0.05）。在夏季和秋季，当水温为15–24°C时，在提高营养水平的情况下，其生长显着提高（p  <0.05）。当温度达到28°C时，大型藻类生长不良，不受养分或p CO _2的影响。的δ ¹³的区域群的C含量D. 粳稻为-30‰，指示所述大藻是一种专性的CO ₂-用户。该结果加上温度低于15°C时p CO ₂升高下的生长显着增加，表明该大型藻类在较冷的月份受碳限制，而长岛河口的原位p CO ₂明显低于较温暖的月份。河口富含代谢产生的CO ₂。的δ ¹⁵这个大藻（9‰）的N含量表示，它利用废水来源在温暖的月份N和其N限制正好与在水柱下的浓度溶解无机氮。考虑到养分对这种大型藻类的刺激作用，并且富营养化可以促进季节性p CO升高_{如图2所示}，这项研究表明，随着海洋酸化的加剧，年峰值温度<28°C的富营养化河口可能特别容易受到未来D. japonica入侵的影响。相反，减少养分将作为一种管理方法，使沿海地区对这种大型藻类的入侵更具抵抗力。