Mangrove forest productivity in northern Australia and Papua New Guinea

Estimates of potential net primary production were made in the mangroves forests of nine Cape York rivers: Jardine River (1 site); Escape River (3 sites); Harmer Creek (1 site); Olive River (2 sites), Pascoe River (1 site); Nesbit River (1 site); Rocky River (3 sites); Annan River (2 sites) and Annie River (3 sites). Two sites in northwestern Australia (Derby Wharf and Hunter River) and six sites in the delta of the Purari River, Papua New Guinea were also sampled. The sites chosen covered a range of environments from river mouth to upstream tidal limits, had a well developed canopy and usually had an area of at least 50x50m of continuous forest. Soil sampling was carried out at the Olive River, Claudie River, Normanby River, Lockhart River, McIvor River and Endeavour River.At each site, usually >100 light attenuation readings were made at 1m intervals on random walks through the forest. Readings were also taken above the canopy. These measurements enabled the calculation of an average canopy chlorophyll content, which was then converted to a productivity estimate.At sites where soil was sampled, a single core was taken to a depth of 50cm. Five subsamples were taken at 10cm intervals for redox potential measurements in the field and later nutrient analysis (extractable phosphate and extractable ammonium). The water which filled the holes after core extractions was sampled and soil water salinity measured with a portable conductivity meter.
This research was initiated to:(1) examine the variation in estimates of potential net primary production (PN) for mangroves, over a wide geographical range.(2) carry out a regional soil sampling survey, which would facilitate examination of the relationship between a range of soil characteristics and PN.

本研究针对约克角半岛（Cape York）九条河流的红树林开展了潜在净初级生产力（potential net primary production，PN）估算：分别为贾丁河（Jardine River）（1个样点）、埃斯卡佩河（Escape River）（3个样点）、哈默溪（Harmer Creek）（1个样点）、奥利弗河（Olive River）（2个样点）、帕斯科河（Pascoe River）（1个样点）、内斯比特河（Nesbit River）（1个样点）、罗基河（Rocky River）（3个样点）、安南河（Annan River）（2个样点）以及安妮河（Annie River）（3个样点）。此外，我们还对澳大利亚西北部的两个样点（德比码头（Derby Wharf）与亨特河（Hunter River））以及巴布亚新几内亚普拉里河（Purari River）三角洲的六个样点进行了采样。所选样点覆盖了从河口至上游潮汐上限的多样生境，均具备发育良好的林冠，且通常拥有至少50m×50m的连续林地区域。
土壤采样工作在奥利弗河、克劳迪河（Claudie River）、诺曼比河（Normanby River）、洛克哈特河（Lockhart River）、麦基弗河（McIvor River）与恩迪沃弗河（Endeavour River）开展。在每个样点，研究团队通常会在林内随机步道上以1米为间隔采集超过100组光照衰减读数，并同步获取林冠上方的光照数据。通过上述测量可计算得到平均林冠叶绿素含量，进而将其转化为生产力估算值。
在开展土壤采样的样点中，我们采集单根深度达50cm的土芯，以10cm间隔获取5个子样本，分别用于现场测定氧化还原电位，以及后续的养分分析（可提取态磷酸盐与可提取态铵）。采集土芯后残留孔洞中的积水也被采样，并使用便携式电导仪测定土壤水盐度。
本研究旨在达成两大目标：(1) 探究地理分布跨度广阔的红树林潜在净初级生产力估算值的变异特征；(2) 开展区域性土壤采样调查，以助力分析一系列土壤特性与潜在净初级生产力之间的关联关系。