Seasonal variation in dissolved organic and inorganic materials in Coral Creek, Hinchinbrook Island, north Queensland

The concentration of dissolved organic and inorganic material was measured in water samples collected near the mouth of Coral Creek, Hinchinbrook Island between December 1982 and July 1984. Sampling was conducted for 16 tidal cycles at 1 to 2 monthly intervals during this period. For each 12 hour tidal cycle, water was sampled at various depths or locations across the channel each half hour. In July 1984, sampling was carried out over 2 consecutive tidal cycles. Water samples were immediately filtered and frozen and analysed within 1 to 2 weeks of collection.Dissolved organic carbon (DOC) analyses were carried out using a thin-film UV oxidation method. Analyses of inorganic nutrients (ammonium, nitrate, nitrite and phosphate) were carried out using an autoanalyser. Dissolved organic nitrogen (DON) and dissolved organic phosphorus (DOP) analyses were carried by first digesting samples for 12 hours in a photodigestion apparatus and then analysing the samples for nitrate and nitrite, or phosphate. The concentrations of these nutrients found in samples analysed for inorganic nutrients only, were then subtracted to derive concentrations of organic N and P.A Microdata weather station was erected above the mangrove canopy, near the channel edge, close to the sampling station, for the duration of the study. Rainfall, humidity, solar radiation, air temperature, mud temperature (30cm below the mud surface), wind speed and wind direction were measured at 30 minute intervals. This research was initiated to:1. determine whether mangroves act as a source of carbon, nitrogen and phosphorus for adjacent coastal waters and benthic habitats or function as a sink for carbon and nutrients.2. determine if there are seasonal variations in flux rates and directions3. determine whether seasonal variations could be related to climatic factors

1982年12月至1984年7月期间，在欣钦布鲁克岛珊瑚溪入海口附近采集的水样中，对溶解态有机与无机物质的浓度进行了测定。本研究期间以1~2个月为采样间隔，累计覆盖16个潮汐周期。在每个12小时潮汐周期内，每半小时对河道内不同深度及位置的水体开展采样；1984年7月的采样则连续覆盖2个潮汐周期。采集的水样即刻完成过滤与冷冻保存，并于采样后1~2周内开展分析。
溶解有机碳（Dissolved Organic Carbon, DOC）采用薄膜紫外氧化法进行分析。无机营养盐（包括铵盐、硝酸盐、亚硝酸盐与磷酸盐）采用自动分析仪进行分析。溶解有机氮（Dissolved Organic Nitrogen, DON）与溶解有机磷（Dissolved Organic Phosphorus, DOP）的分析流程如下：先将样品置于光解装置中消解12小时，随后分别测定硝酸盐、亚硝酸盐或磷酸盐的浓度；再扣除仅通过无机营养盐分析方法测得的对应营养盐浓度，以此得到有机氮与有机磷的实际浓度。
本研究全程在采样点附近河道边缘的红树林冠层上方架设了一台Microdata气象站，该气象站以30分钟为间隔记录降雨量、相对湿度、太阳辐射、空气温度、泥温（泥面下30cm处）、风速与风向。
本研究旨在达成以下三项目标：1. 明确红树林对于邻近近岸水体与底栖生境而言，是碳、氮、磷的源，还是碳与营养盐的汇；2. 探明通量速率与方向是否存在季节变化；3. 厘清季节变化是否与气候因素相关。