Sponges are ubiquitous components of various deep‐sea habitats, including cold water coral reefs, and form deep‐sea sponge grounds. Although the deep sea is generally considered to be a food‐limited environment, these ecosystems are known to be hotspots of biodiversity and carbon cycling. To assess the role of sponges in the carbon cycling of deep‐sea ecosystems, we studied the carbon budgets of six dominant deep‐sea sponges of different phylogenetic origin, with various growth forms and hosting distinct associated microbial communities, in an ex situ aquarium setup. Additionally, we determined biomass metrics—planar surface area, volume, wet weight, dry weight (DW), ash‐free dry weight, and organic carbon (C) content—and conversion factors for all species. Oxygen (O₂) removal rates averaged 3.3 ± 2.8 μmol O₂ g DW_sponge h⁻¹ (mean ± SD), live particulate (bacterio‐ and phytoplankton) organic carbon removal rates averaged 0.30 ± 0.39 μmol C g DW_sponge h⁻¹ and dissolved organic carbon (DOC) removal rates averaged 18.70 ± 25.02 μmol C g DW_sponge h⁻¹. Carbon mass balances were calculated for four species and revealed that the sponges acquired 1.3–6.6 times the amount of carbon needed to sustain their minimal respiratory demands. These results indicate that irrespective of taxonomic class, growth form, and abundance of microbial symbionts, DOC is responsible for over 90% of the total net organic carbon removal of deep‐sea sponges and allows them to sustain themselves in otherwise food‐limited environments on the ocean floor.

中文翻译：

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溶解有机碳（DOC）对于平衡四种主要北大西洋深海海绵的代谢需求至关重要

海绵是各种深海栖息地（包括冷水珊瑚礁）无处不在的组成部分，形成深海海绵地。尽管通常认为深海是一种限制食物的环境，但众所周知，这些生态系统是生物多样性和碳循环的热点。为了评估海绵在深海生态系统碳循环中的作用，我们在异地水族馆设置中研究了六种不同系统发育起源的优势深海海绵的碳预算，这些海绵具有不同的生长形式并拥有不同的相关微生物群落。 。此外，我们确定了所有物种的生物量指标，包括表面积，体积，湿重，干重（DW），无灰干重和有机碳（C）含量。氧气（O ₂）去除率平均为3.3±2.8μ摩尔ø ₂克DW_海绵ħ ^-1（平均值±SD），活微粒（bacterio-和浮游植物）有机碳的去除速率平均为0.30±0.39  μ摩尔C g还DW_海绵ħ ^-1和溶解的有机碳（DOC）的去除速率平均18.70±25.02  μ摩尔C g还DW_海绵ħ ^-1。计算了四个物种的碳质量平衡，结果表明，海绵获得的碳量是维持其最小呼吸需求所需要的碳量的1.3–6.6倍。这些结果表明，不管分类类别，生长形式和微生物共生体的丰度如何，DOC占深海海绵净有机碳去除总量的90％以上，并使其能够在其他食物受限的环境中生存。海底。