The role of iron as a micro-nutrient to the Antarctic sea-ice zone algal community

Metadata record for data from AAS (ASAC) project 3026.

Public
This project will assess the importance of the trace micro-nutrient element iron to Antarctic sea-ice algal communities during the International Polar Year (2007-2009). We will investigate the biogeochemistry of iron, including a comprehensive examination of its distribution, speciation, cycling and role in fuelling ice-edge phytoplankton blooms. A significant part of this research will concentrate on the the influence of organic exopolysaccharides on iron solubility, complexation and bioavailability, both within the ice and in surrounding snow and surface seawater. This innovative research will improve our understanding of key processes that control the productivity of the climatically-important Antarctic sea-ice zone.

Project objectives:
This project will assess the importance of the trace element iron (Fe) as a micro-nutrient to seasonal sea-ice algal communities in the Australian sector of Antarctica during the International Polar Year (2007-09). We will investigate the biogeochemistry of Fe, including a comprehensive examination of its distribution, speciation, cycling and role in fuelling ice-edge phytoplankton blooms. A significant part of this research will concentrate on the influence of organic exopolysaccharides (EPS) on Fe solubility and complexation (and hence bioavailability), both within the ice and in surrounding surface waters. This innovative research will improve our understanding of key processes that control the productivity of the climatically-important Antarctic sea-ice zone.

Specifically, in this project:
- The biogeochemical behaviour of Fe in sea-ice with regards to EPS complexation, and key physicochemical and biological data will be evaluated.
- The bioavailability of Fe for phytoplankton growth during sea-ice melt will be investigated through laboratory-based experiments designed to mimic spring conditions.
- The distribution of other bioactive trace elements in the Antarctic sea-ice environment will be examined as a means of fingerprinting the source(s) of Fe, as well as indicating their biological requirement.

Taken from the 2008-2009 Progress Report:
Progress against objectives:
In the last twelve months we achieved all the objectives planned for the shore-based sample processing and analysis from the SIPEX voyage (fieldwork September-October 2007). An extensive and unique seasonal and spatial data set was put together including parameters such as ice texture, salinity, temperature, Chlorophyll a, particulate organic carbon (POC), dissolved
organic carbon (DOC), macro-nutrients (silicate, phosphate and nitrate), and exoplysaccharides (EPS, using both alcian blue and PSA methods). Dissolved iron (dFe) and total dissolvable iron (TDFe) were analysed by flow injection - chemiluminescence (FIA-CL) analysis in Hobart. Polycarbonate (PC) filters (Nuclepore 0.2 micron pore size) retaining particulate metals were digested
in a mixture of strong, ultrapure acids (750 micro litre 12N HCl, 250 micro litre 40% HF, 250 micro litre 14N HNO3) on a hotplate at 125 degrees C for 8 h. The procedure was successfully applied to plankton, estuarine and river sediment reference materials to verify the recovery of the digestion treatment. The concentrations of particulate iron (PFe) were determined by high resolution ICP-MS at the Central Science Laboratory at UTAS. This data has been quality-controlled, analysed, interpreted and published (see below).
Due to the fact that logistical support was not possible for 2008/09 (insufficient berths at Casey Station) despite approval of our project, the field component of the project was delayed.

Taken from the 2009-2010 Progress Report:
Progress against objectives:

Monthly Milestones of PhD student Pier van der Merwe:
Successful Antarctic research expedition occurred in Oct-Dec 2009 at Casey Station Antarctica with logistical support from AAS project #3026 (flight on FA02 and berths at Casey station as well as field support of personnel).
OCT-DEC 2009 - Antarctic time series data collection and processing successful. Data analysis scheduled for Jan - Mar. Write up of last paper(s) scheduled for Mar-June. Final completion of thesis due in August.
DEC - Chlorophyll a data analysed
JAN - FIA and CLECSV analyses start simultaneously
FEB - Finish FIA analyses and attend Ocean science meeting in Portland Oregon.
MAR - Finish CLECSV analyses and run POC and PFe digestions and analyses. Scheduled with Thomas Rodemann and Ashley Townsend at the CSL, UTAS.
APR - MAY Data analysis and write up of 3rd paper, and possibly 4th based on field work at Casey station Oct-Dec 2009.

See the child metadata records for more information about the data.

AAS（ASAC）项目3026数据的元数据记录。

公开

本项目将评估国际极地年（2007-2009）期间微量营养元素铁对南极海冰藻类群落的重要性。我们将研究铁的生物地球化学特征，包括全面考察其分布、形态、循环过程及其在驱动冰缘浮游植物水华中的作用。本研究的重要部分将聚焦于有机胞外多糖对冰体内部及周边积雪与表层海水中铁的溶解度、络合作用及生物可利用性的影响。这项创新性研究将提升我们对调控气候关键区域——南极海冰带生产力核心过程的理解。

项目目标：
本项目将评估国际极地年（2007-09）期间微量营养元素铁（Fe）作为营养物质对南极澳大利亚区域季节性海冰藻类群落的重要性。我们将研究铁的生物地球化学特征，包括全面考察其分布、形态、循环过程及其在驱动冰缘浮游植物水华中的作用。本研究的重要部分将聚焦于有机胞外多糖对冰体内部及周边表层水体中铁的溶解度、络合作用及生物可利用性的影响。这项创新性研究将提升我们对调控气候关键区域——南极海冰带生产力核心过程的理解。

具体而言，本项目将：
- 评估海冰中铁（Fe）的生物地球化学行为，重点关注其与有机胞外多糖（EPS）的络合作用及关键理化与生物数据；
- 通过模拟春季条件的实验室实验，研究海冰融化期间铁对浮游植物生长的生物可利用性；
- 考察南极海冰环境中其他生物活性微量元素的分布，以此作为铁源的指纹识别手段，并指示其生物需求。

摘自2008-2009年进度报告：
目标完成情况：
过去12个月，我们完成了SIPEX航次（2007年9-10月实地工作）岸上样品处理与分析的所有计划目标。我们构建了一个广泛且独特的季节与空间数据集，涵盖冰结构、盐度、温度、叶绿素a、颗粒有机碳（POC）、溶解有机碳（DOC）、大量营养盐（硅酸盐、磷酸盐和硝酸盐）以及胞外多糖（EPS，采用阿尔新蓝法和PSA法）等参数。溶解铁（dFe）和总可溶铁（TDFe）在霍巴特通过流动注射-化学发光（FIA-CL）分析法测定。截留颗粒态金属的聚碳酸酯（PC）滤膜（Nuclepore，孔径0.2微米）在125℃加热板上用强超纯酸混合物（750微升12N盐酸、250微升40%氢氟酸、250微升14N硝酸）消解8小时。该流程已成功应用于浮游生物、河口及河流沉积物标准物质，以验证消解处理的回收率。颗粒态铁（PFe）浓度由塔斯马尼亚大学（UTAS）中央科学实验室通过高分辨率电感耦合等离子体质谱（ICP-MS）测定。该数据已完成质量控制、分析、解读并发表（见下文）。尽管项目已获批，但由于2008/09年度无法获得后勤支持（Casey站泊位不足），项目的实地部分被推迟。

摘自2009-2010年进度报告：
目标完成情况：

博士生Pier van der Merwe的月度里程碑：
2009年10-12月，在AAS项目#3026的后勤支持下（乘坐FA02航班、Casey站泊位及实地人员支持），南极Casey站研究考察顺利完成。
2009年10-12月——南极时间序列数据采集与处理完成；数据分析计划于1-3月进行；最后一篇（或多篇）论文撰写计划于3-6月；论文最终完成截止日期为8月。
12月——叶绿素a数据分析完成；
1月——FIA与CLECSV分析同步启动；
2月——完成FIA分析并参加俄勒冈州波特兰海洋科学会议；
3月——完成CLECSV分析，开展POC与PFe消解及分析（与塔斯马尼亚大学中央科学实验室的Thomas Rodemann和Ashley Townsend安排）；
4-5月——数据分析及第三篇论文撰写，可能基于2009年10-12月Casey站实地工作撰写第四篇论文。

有关数据的更多信息，请参见子元数据记录。