Sponges are a crucial component of Caribbean coral reef ecosystem structure and function. In the Caribbean, many sponges show a predictable increase in percent cover or abundance as depth increases from shallow (< 30 m) to mesophotic (30–150 m) depths. Given that sponge abundances are predicted to increase in the Caribbean as coral cover declines, understanding ecological factors that control their distribution is critical. Here we assess if sponge cover increases as depth increases into the mesophotic zone for three common Caribbean reef sponges, Xestospongia muta, Agelas tubulata, and Plakortis angulospiculatus, and use stable isotope analyses to determine whether shifts in trophic resource utilization along a shallow to mesophotic gradient occurred. Ecological surveys show that all target sponges significantly increase in percent cover as depth increases. Using bulk stable isotope analysis, we show that as depth increases there are increases in the δ¹³C and δ¹⁵N values, reflecting that all sponges consumed more heterotrophic picoplankton, with low C:N ratios in the mesophotic zone. However, compound‐specific isotope analysis of amino acids (CSIA‐AA) shows that there are species‐specific increases in δ¹³C_AA and δ¹⁵N_AA values. Xestospongia muta and P. angulospiculatus showed a reduced reliance on photoautotrophic resources as depth increased, while A. tubulata appears to rely on heterotrophy at all depths. The δ¹³C_AA and δ¹⁵N_AA values of these sponges also reflect species‐specific patterns of host utilization of both POM and dissolved organic matter (DOM), its subsequent re‐synthesis, and translocation, by their microbiomes.

中文翻译：

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中生区加勒比海海绵的营养生态学

海绵是加勒比珊瑚礁生态系统结构和功能的重要组成部分。在加勒比海，随着深度从浅（<30 m）到中生（30–150 m）深度增加，许多海绵显示出可预测的覆盖率或丰度百分比增加。考虑到随着珊瑚覆盖率的下降，预计加勒比海海绵的丰度将增加，因此了解控制其分布的生态因素至关重要。在这里，我们评估了三种常见的加勒比礁海绵Xestospongia muta，Agelas tubulata和Plakortis angulospiculatus，随着海绵覆盖深度的增加，海绵覆盖度是否会增加。，并使用稳定同位素分析来确定营养资源利用率是否沿从浅到中生的梯度发生变化。生态调查显示，随着深度的增加，所有目标海绵的覆盖百分比均显着增加。使用批量稳定同位素分析，我们表明，作为深度的增加有升高的δ ¹³ C和δ ¹⁵的N个值，反映了所有海绵消耗更多的异养超微型浮游生物，具有低C：N比在mesophotic区。然而，氨基酸（CSIA-AA）表示的特定化合物的同位素分析，有在δ物种特异性增加¹³ Ç _AA和δ ^15个Ñ _AA值。Xestospongia突变和P. angulospiculatus显示随着深度的增加，对光合自养资源的依赖性降低，而A.tubulata似乎在所有深度都依赖异养。的δ ¹³ C ^ _AA和δ ^15个Ñ _AA这些海绵的值也反映了POM的宿主利用率和溶解的有机物质（DOM），其随后的再合成，和易位的物种特异性的图案，可以通过微生物组。