Methods for measuring benthic nutrient flux on the California Margin: Comparing shipboard core incubations to in situ lander results
Methods for measuring benthic nutrient flux on the California Margin: Comparing shipboard core incubations to in situ lander results
复制标题
测量加州边缘海底营养通量的方法：比较船上核心孵化与原位着陆器结果
DOI：
10.4319/lom.2004.2.146
复制
发表时间：
2004
期刊：
影响因子：
--
通讯作者：
F. Spagnoli
中科院分区：
文献类型：
--
作者：
D. Hammond;Kathleen M. Cummins;J. McManus;W. Berelson;Gerald P. Smith;F. Spagnoli
本研究的目的是比较两种技术估计底栖通量的营养盐（硝酸盐，磷酸盐和草酸）和Ge/Si通量比。2001年7月，在加州边缘的9个沿着地点部署了原位通量室，收集并培养了岩心。这两种技术都成功地在8个地点，从100至3300米的深度。通量室部署1至2天，并在船上的冷室中孵育芯稍长时间。在某些情况下，岩心孵育通量温度与原位温度的差异高达5°C，并根据温度对扩散率和草酸吸附的影响对岩心孵育结果进行了调整。研究的网站有一个范围内的营养通量超过一个数量级，基于原位室。温度调整的核心孵化通量显示出类似的，但略小的范围。这两种方法具有相似的精度的基础上重复，与不确定性高通量站的5%至20%的平均值。只有磷酸盐显示出显着的（95%的置信水平）在复制核心的空间变异性，较大的原位通量室的空间变异性较小。这两种技术确实显示出一些系统性差异，这些差异归因于岩心回收产生的几个伪影。从核心的硅酸通量显着低于原位通量在2个站点，总体平均值为80%左右的原位室。这些差异归因于孵化核心中大型底栖动物灌溉减少。硝酸盐吸收的核心孵化在8个站点中的5个显着低于原位吸收，船上率为所有网站平均约66%的原位室率。这种差异主要归因于回收的岩心中的反硝化速率随着温度和压力的变化而降低。磷酸盐通量从核心显着较低，只有一个网站，总体而言，这两种技术的结果是无法区分的。只有一个站点具有显著不同的Ge/Si通量比。
The objective of this study was to compare two techniques for estimating benthic fluxes of nutrients (nitrate, phosphate, and silicic acid) and Ge/Si flux ratios. In situ flux chambers were deployed, and cores were collected and incubated at 9 sites along the California margin in July 2001. Both techniques were successful at 8 sites, at depths from 100 to 3300 m. Flux chambers were deployed for 1 to 2 d, and cores were incubated for slightly longer on board the ship in a cold room. In some cases, core incubation flux temperature varied by up to 5°C from in situ temperature, and core incubation results were adjusted for this factor based on the effects of temperature on diffusivities and the adsorption of silicic acid. Sites studied had a range in nutrient fluxes of more than an order of magnitude, based on in situ chambers. The temperature‐adjusted core incubation fluxes showed a similar, but slightly smaller range. Both methods had similar precision based on replicates, with uncertainties for high flux stations that were 5% to 20% of the mean. Only phosphate showed significant (95% confidence level) spatial variability in replicate cores; the larger in situ flux chambers had less spatial variability. The two techniques did show some systematic differences that are attributed to several artifacts created by core recovery. Silicic acid fluxes from cores were significantly lower than in situ fluxes at 2 sites; overall averages were about 80% of those for in situ chambers. The differences are attributed to reduced macrofaunal irrigation in incubated cores. Nitrate uptake in core incubations at 5 of 8 stations was significantly lower than in situ uptake; shipboard rates for all sites averaged about 66% of in situ chamber rates. This difference is attributed primarily to decreased denitrification rates in recovered cores in response to altered temperature and pressure. Phosphate fluxes from cores were significantly lower at only one site; overall, results for the two techniques were indistinguishable. Only one site had a significantly different Ge/Si flux ratio.