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九条河流的红树林开展潜在净初级生产力（potential net primary production，PN）估算：分别为贾丁河（1个样点）、埃斯皮河（3个样点）、哈默溪（1个样点）、奥利弗河（2个样点）、帕斯科河（1个样点）、内斯比特河（1个样点）、洛基河（3个样点）、安南河（2个样点）与安妮河（3个样点）。
另于澳大利亚西北部设置2个样点（德比码头与亨特河），并在巴布亚新几内亚的普拉里河三角洲布设6个样点开展采样工作。
所选样点覆盖从河口至上游潮汐界的多种生境，均具备发育良好的林冠，且通常拥有至少50米×50米的连片红树林区域。
针对奥利弗河、克劳迪河、诺曼比河、洛克哈特河、麦克弗尔河与恩迪沃河开展了土壤采样。
在每个样点，研究人员通过随机穿行林内的方式，以1米为间隔采集了逾100组光衰减数据，同时在林冠上方开展读数采集。基于上述测量结果可计算得到林冠平均叶绿素含量，进而转化为生产力估算值。
在开展土壤采样的样点中，各采集1根深度达50厘米的土壤柱样；以10厘米为间隔分取5份子样本，用于现场氧化还原电位测定，以及后续的营养盐分析（可提取态磷酸盐与可提取态铵）。采集土壤柱样后留下的孔中积水，并使用便携式电导仪测定土壤水盐度。
本研究的启动目标如下：(1) 探究不同地理尺度下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，以助力解析多种土壤特性与PN之间的关联关系。