Rhodoliths are free‐living, coralline algae that create heterogeneous structure over sedimentary habitats. These fragile ecosystems are threatened by anthropogenic disturbances that reduce their size and three‐dimensional structural complexity. We investigated how physical disturbance from boat moorings affects photosynthetic performance in the rhodolith Lithothamnion australe. Photosynthetic parameters were measured for intact rhodoliths and crushed rhodolith fragments of two sizes (ca. 1 and 2 cm diameter), while chlorophyll fluorescence was measured at the surface of rhodoliths of these two sizes, between the interior branches of the larger rhodoliths, and at the surface of 52 various sized (0.4–3.5 cm diameter) rhodoliths. Gross productivity and net productivity were 15% and 36% higher, respectively, in the smaller L. australe, while respiration was 10% higher in the larger individuals. Thallus crushing reduced gross productivity by 20% and 41%, and net productivity by 9% and 14% in the smaller and larger rhodoliths, respectively. It also reduced respiration by 33% and 60% in the smaller and larger rhodoliths, respectively. Fluorescence parameters were all greater at the surface of the larger L. australe than the smaller individuals, and greater at the surface than in the interior parts of the larger individuals. Across a range of rhodolith sizes, surface fluorescence parameters were at their maxima in 1.54 to 2.32 cm diameter individuals. These results show that L. australe’s complex structure creates heterogeneity in photosynthesis and respiration between their surface and interior parts and among rhodolith sizes. This information can help predict how rhodoliths may respond to disturbance and environmental stressors.

中文翻译：

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光合性能的变化，相对于Thalus Microhabitat异质性在澳石碎石（Rhodophyta，Corallinales）Rhodoliths

红景天是自由生活的珊瑚藻，在沉积栖息地上形成异质结构。这些脆弱的生态系统受到人为干扰的威胁，从而减少了生态系统的规模和三维结构的复杂性。我们调查了来自船系泊的物理干扰如何影响在杜鹃石碎石石南极的光合性能。测量了两种尺寸（直径分别为1和2厘米）的完整杜鹃花和压碎的杜鹃花碎片的光合参数，而在这两种尺寸的杜鹃花的表面，较大的杜鹃花的内部分支之间以及在52种不同大小（直径0.4-3.5厘米）的菱锰矿的表面。在较小的L. australe中，总生产率和净生产率分别提高了15％和36％，而较大的个体的呼吸高10％。在较小的和较大的菱锰矿中，hall粉碎会分别使总生产率降低20％和41％，使净生产率降低9％和14％。在较小和较大的菱锰矿中，它也分别使呼吸减少了33％和60％。在较大的L. australe的表面上，荧光参数都比较小的个体大，而在表面上则大于较大的个体内部。在各种菱锰矿尺寸的范围内，直径1.54至2.32 cm的个体的表面荧光参数均达到最大值。这些结果表明L. australe其复杂的结构在其表面与内部部分以及菱形石大小之间的光合作用和呼吸作用中产生异质性。这些信息可以帮助预测菱纹石如何响应干扰和环境压力。