Nutrient partitioning and storage, nutrient use efficiency and below-ground decomposition of organic matter in mangroves along the arid coast of the Pilbara Region, Western Australia

The data were used to examine 3 different aspects of nutrient dynamics of mangrove forests in the arid coastal zone of north Western Australia: Below-ground decomposition; nutrient partitioning and storage; and nutrient use efficiency.Samples were collected during October to November 1993 and September 1994 from mangrove forests near Dampier, at Port Hedland, in the Bay of Rest (Exmouth Gulf) and at Mangrove Bay (Cape Range National Park). Forest characteristics recorded were: intertidal zone (low, mid and high); type (Rhizophora apiculata or Avicennia marina);Estimates of above-ground biomass were based on calculations of stems/ha and diameter at breast height (DBH). Net primary production was estimated using light interception methods and measurements of light absorption were used to estimate leaf area index. Below-ground biomass estimates (metric tons dry weight/ha) were made for living and dead roots. Net primary production was estimated using mol C/ha/day.Bulk sediment and nutrient sampling: samples were taken for grain size and water content; temperature, redox potential and pH were measured; samples for solid-phase nutrients and porewater were obtained. Samples were analysed for ammonium, nitrite, nitrate, silicate, phosphate, DON and DOP. Separate samples were taken for sulphate and methane, TOC, TC and TN values .Flux measurements of CO2 production were estimated using a core incubation method. Net rates of Mn and Fe were estimated using a different core incubation method, and rates of sulphate reduction were measured using a core injection technique. Gas (O2, CO2, methane) and solute (silicate, phosphate, DOP, DON, ammonium, nitrite, nitrate) fluxes were also measured.Sediment respiration to forest net primary production (TCOx/NPP ratios) was calculated. Individual trees were cut and divided into component parts and analyses carried out on each component.Nutrient use efficiency was estimated on the basis of productivity per nutrient uptake or loss using litter fall rates and rates of leaf CO2 exchange. To examine differences between 3 Rhizophora stylosa and 3 Avicennia marina forests in different coastal settings of arid Western Australia. Above and below ground nutrients, trace elements concentrations were estimated and the efficiency of the use of nutrients related to primary productivity were estimated.To determine the impact of intertidal position, tidal range, and coastal geomorphology on differences and similarities in biogeochemical processes and forests of A. marina and R. stylosa.To collect data, to compare arid zone mangroves with the more studied mangrove forests of the northeast Australian humid tropics, three to four permanent study plots were established to carry out long term observational and experimental studies in the region.Permanent study plots were established to carry out long-term observational and experimental studies in the region and to collect data to compare arid zone mangroves with the more studied, mangrove forests of the northeast Australian humid tropics. Experiments were set up to measure leaf fall and degradation within these forests. Soil characteristics, including particle size, dissolved and particulate nutrients, salinity and heavy metal content, and microbial parameters such as bacterial sulfite reduction, were determined at each site.One component of this project was to test the hypothesis that regional mangrove forest structure and growth, mangrove-based food chains and soil biogeochemistry are strongly regulated by aridity. Research was designed to provide scientific information necessary to assess current and potential impacts of human activities on mangroves, including recovery from oil spills, heavy metal stress, changes in soil salinities from salt pond construction and sea level rise. Surveys were also carried out to establish sites for estimating potential impacts of sea level rise on regional mangrove communities.Replicate plots were established in mangrove forests near Dampier, at Port Hedland, in the Bay of Rest (Exmouth Gulf) and Mangrove Bay (Cape Range National Park). These sites encompass most of the important geomorphological settings in which mangrove forests occur in the Pilbara region.At each of the above locations, three to four permanent plots were established in canopy forests of Avicennia marina and Rhizophora stylosa, the dominant mangrove tree species in the region. All trees in each plot were tagged and measured to initiate long-term measurements of trunk growth, net biomass production and tree survival. Where seedlings occurred in the understorey, they were tagged to follow their growth and survival.

本数据集用于探究澳大利亚西北部干旱沿海区域红树林的3种核心营养动态特征：地下分解过程、营养元素分配与储存，以及营养利用效率。样本采集于1993年10-11月及1994年9月，采集地点包括丹皮尔（Dampier）附近、黑德兰港（Port Hedland）、雷斯特湾（埃克斯茅斯湾，Exmouth Gulf）以及曼格罗夫湾（开普山脉国家公园，Cape Range National Park）内的红树林。记录的红树林群落特征包括：潮间带位置（低、中、高潮区）、群落类型（柱果木榄Rhizophora apiculata或白骨壤Avicennia marina）。地上生物量估算基于单位公顷茎秆数量与胸径（diameter at breast height, DBH）的测算结果；净初级生产力通过光拦截法估算，同时通过光吸收测量值推算叶面积指数（Leaf Area Index, LAI）。地下生物量（以干重吨/公顷为单位）针对活根与死根分别进行估算；净初级生产力以mol C/ha/day为单位进行测算。沉积物与营养元素批量采样：采集样本用于分析粒度与含水率；测定温度、氧化还原电位与pH值；采集固相营养元素与孔隙水样本。样本分析指标包括铵态氮、亚硝态氮、硝态氮、硅酸盐、磷酸盐、溶解有机氮（Dissolved Organic Nitrogen, DON）与溶解有机磷（Dissolved Organic Phosphorus, DOP）。另行采集样本用于分析硫酸盐、甲烷、总有机碳（Total Organic Carbon, TOC）、总碳（Total Carbon, TC）与总氮（Total Nitrogen, TN）含量。二氧化碳产生通量通过柱状培养法进行估算；锰（Mn）与铁（Fe）的净速率采用另一套柱状培养法测算；硫酸盐还原速率则通过柱状注入技术测定。同时测定气体（氧气O₂、二氧化碳CO₂、甲烷）与溶质（硅酸盐、磷酸盐、溶解有机磷DOP、溶解有机氮DON、铵态氮、亚硝态氮、硝态氮）通量。计算沉积物呼吸与群落净初级生产力的比值（TCOₓ/NPP）。将单株红树林伐倒并分解为不同组分，对各组分分别开展分析。营养利用效率通过单位营养元素吸收或流失对应的生产力水平进行估算，测算过程结合了凋落物流失速率与叶片二氧化碳交换速率。本研究旨在探究澳大利亚西北部干旱区域不同沿海生境下的3片柱形红树（Rhizophora stylosa）林与3片白骨壤（Avicennia marina）林之间的差异；估算地上与地下营养元素、微量元素浓度，并测算与初级生产力相关的营养利用效率；明确潮间带位置、潮差与沿海地貌对白骨壤（A. marina）与柱形红树（R. stylosa）林的生物地球化学过程及其异同的影响。为收集数据并对比干旱区红树林与研究更为充分的澳大利亚东北部湿润热带红树林，研究团队在该区域设立3-4个永久性研究样地，以开展长期观测与实验研究。研究团队同时设立永久性研究样地以开展该区域的长期观测与实验研究，并收集数据用于对比干旱区红树林与澳大利亚东北部湿润热带的成熟红树林。在各样地内开展实验以测定森林内的叶片凋落与降解过程；测定各站点的土壤特征，包括粒度、溶解态与颗粒态营养元素、盐度与重金属含量，以及微生物参数（如细菌亚硫酸盐还原活性）。本项目的研究内容之一为验证以下假说：区域红树林群落结构与生长、以红树林为基础的食物链以及土壤生物地球化学过程均受干旱程度的显著调控。本研究旨在提供必要的科学信息，以评估人类活动对红树林的当前与潜在影响，包括油污泄漏后的恢复、重金属胁迫、盐田建设导致的土壤盐度变化以及海平面上升的影响。同时开展调查以选定研究站点，用于评估海平面上升对区域红树林群落的潜在影响。在丹皮尔附近、黑德兰港、雷斯特湾（埃克斯茅斯湾）以及曼格罗夫湾（开普山脉国家公园）的红树林内设立重复样地；这些站点涵盖了皮尔巴拉（Pilbara）区域内红树林分布的绝大多数重要地貌生境类型。在上述各站点，针对该区域优势红树林树种白骨壤与柱形红树的冠层林分别设立3-4个永久性样地。对每个样地内的所有成树进行标记与测量，以启动树干生长、净生物量生产与树木存活率的长期监测；若林下存在幼苗，则对幼苗进行标记以追踪其生长与存活情况。