Both temperature and nutrient nitrogen are rising in worldwide aquatic ecosystems. To explore their interactive impacts on algal physiology, we measured the growth, cell components, photosynthesis, and dark respiration of a farmed green alga, Caulerpa lentillifera, under a matrix of temperatures (low, 22 °C; high, 27 °C) and nitrogen concentrations (low, 47 μmol L⁻¹; medium, 188 μmol L⁻¹; high, 750 μmol L⁻¹). The relative growth rate (RGR) was less than 1.0% day⁻¹ at low temperature, which was ~ eightfold higher at high temperature, with no significant effect of nitrogen. Pigment contents of chlorophyll a (Chl a) and carotenoids (Car) and soluble protein content increased with increasing nitrogen levels. High temperature reduced Chl a content under lower nitrogen and enhanced Car contents under higher nitrogen, but had a limited effect on proteins. Photosynthetic parameters, i.e., light-utilized efficiency (α) and maximum photosynthetic rate (P_max), and dark respiration rate (R_d) increased with increasing nitrogen levels at low temperature. High temperature enhanced the α, P_max, and R_d under low nitrogen, but reduced them under high nitrogen. Moreover, high temperature lowered both superoxide dismutase (SOD) and catalase (CAT) contents, indicating the beneficial effects on metabolism of C. lentillifera and thus the growth. In addition, our results indicate that the temperature-caused effects on photosynthesis and respiration of C. lentillifera are reversed by increased nitrogen levels.

温度和营养氮在全球水生生态系统中都在上升。为了探讨它们对藻类生理的互动影响，我们在温度（低，22°C，高，27°C）和低热的条件下，测量了养殖的绿藻（Caulerpa lentillifera）的生长，细胞成分，光合作用和黑暗呼吸。氮浓度（低47μmolL ^-1；中等188μmolL ^-1；高750μmolL ^-1）。低温下的相对生长率（RGR）在第^-1天小于1.0％，在高温下约高八倍，而氮没有显着影响。叶绿素a（Chl a）和类胡萝卜素（Car）和可溶性蛋白质含量随氮水平的增加而增加。高温降低叶绿素一个较低的氮和更高的氮气下增强汽车内容下的内容，但对蛋白质的影响有限。随着低温下氮含量的增加，光合参数，即光利用效率（α）和最大光合速率（P _max）以及暗呼吸速率（R _d）增加。高温增强了α，P _max和R _d在低氮条件下，但在高氮条件下还原它们。此外，高温降低了超氧化物歧化酶（SOD）和过氧化氢酶（CAT）的含量，表明对扁豆梭状芽胞杆菌代谢及其生长具有有益作用。此外，我们的结果表明，温度升高对扁豆梭菌光合作用和呼吸作用的影响可以通过增加氮含量来逆转。