Data_Sheet_1_In situ Pumping Rate of 20 Marine Demosponges Is a Function of Osculum Area.docx

Sponges play a key role in the transfer of energy and nutrients into many benthic ecosystems, and the volume of water they process is an important regulator of these fluxes. Theoretical scaling relationships between sponge volume, osculum cross-sectional area, and pumping rates were recently proposed and confirmed for small sponge specimens in the lab. To examine how these relationships apply to field populations we measured, in situ, the pumping rate (PR) of 20 species representative of different morphologies and host types (high- and low-microbial-abundance, HMA and LMA) from temperate and tropical regions. The total oscula area (∑OSA) increased allometrically with sponge volume (V) exhibiting similar exponents (∑OSA=aVb, b ranging 0.6–0.7) for all species, except for tropical HMAs (b = 0.99). Osculum flow rate (OFR) also increased allometrically with OSA and oscula of the same size pumped at the same rate irrespective of sponge volume. As a result, and in contrast to former reports, the PR of most of the sponges increased allometrically (PR=a∑OSAb) with scaling exponent b≈0.75, whereas PR of tropical HMAs increased isometrically. Osculum jet speed declined with the increase in the OSA for most species. The number of oscula and their OSA were the best predictors of the PR in sponges, explaining 75–94% of the in situ variation in PR throughout the natural range of sponge size. The pumping rate of a sponge population can be estimated by measuring the osculum density and cross-sectional area distribution once the relationships between the OSA and OFR are established for each species.

海绵在能量和营养物质向众多海底生态系统的传输中扮演着至关重要的角色，它们处理的水量是调节这些物质流动的重要因子。近期，研究者们提出了海绵体积、出水口横截面积和抽水速率之间的理论比例关系，并在实验室中对小型海绵样本进行了验证。为了探究这些关系在野外种群中的应用，我们对来自温带和热带地区的20种不同形态和宿主类型（高微生物丰度与低微生物丰度，分别称为HMA和LMA）的海绵进行了现场抽水速率（PR）的测量。总出水口面积（∑OSA）与海绵体积（V）呈现出异速生长关系，所有物种均表现出类似的指数（∑OSA=aVb，b值在0.6至0.7之间），但热带HMA除外（b=0.99）。出水口流速（OFR）也呈现出与出水口横截面积（OSA）的异速生长关系，相同大小出水口的抽水速率不受海绵体积影响。因此，与以往的研究结果相反，大多数海绵的抽水速率（PR）呈现出异速生长关系（PR=a∑OSAb，b值约为0.75），而热带HMA的抽水速率则呈现出等速生长。对于大多数物种，出水口喷射速度随着出水口横截面积的增大而降低。出水口数量及其横截面积是预测海绵抽水速率的最佳指标，解释了海绵自然尺寸范围内抽水速率75%至94%的现场变异。一旦确定了每种物种的OSA与OFR之间的关系，就可以通过测量出水口密度和横截面积分布来估算海绵种群的抽水速率。