, 2008). Six modified Hagge corers ( Fleeger et al., 1988) of 30 cm length and 3.57 cm internal diameter (10 cm2 cross sectional area) were collected by SCUBA at each site. Samples were kept on ice immediately after collection and transferred
to the freezer on return to the laboratory, within 5 h. Cores were defrosted, and the top 5 cm was removed for examination of the Foraminifera (most living Foraminifera are found in this surface layer (Murray, 1991)), and the analysis of environmental factors. A subsample of the layer was homogenised and used for the determination of nitrogen and trace metal content. selleck kinase inhibitor Sediments from the top 5 cm were first preserved in 70% ethanol and stained with Rose Bengal (24 h). Foraminifera were separated from the sediments by floatation using see more carbon tetrachloride (Murray, 1991) and 300 specimens (where possible) were mounted onto a slide for identification and determination of species diversity under a microscope at x 80 magnification. Specimens were separated
into live (stained) and dead individuals, and all were identified to species or morpho-species, where possible. Some Fissurina, Oolina and Lagena were identified only to genus, whilst bolivinids were identified as elongated or perforated. Species richness and diversity (Shannon Index; Magurran, 2004) were determined for each core. All foraminifera in the sediments were counted and abundance data were expressed as numbers/g sediment. After
the removal of the 300 Foraminifera, the sediment was dried (60 °C, 24 h), and sieved through meshes of 500 μm, 250 μm, 125 μm and 63 μm diameter in order to determine the granular size structure. The weight of sediment retained on each mesh was determined and the data were expressed as proportions. Mean sediment grain size (phi units) was calculated using GRADISTAT software ( Blott, 2010). While it could be argued that the removal of the Foraminifera from Calpain the samples might have impacted the size structure of the sediments, this would largely relate to the tests of dead specimens, which made up a maximum of 30% of the total individuals examined at each core. The nitrogen content (% N) of sediments was determined per site and not per core. Approximately 5 g of freshly defrosted sediment (i.e. before staining and extraction of Foraminifera and granulometry) from each core per site was dried (60 °C, 24 h), pooled and homogenised. A subsample was subsequently combusted in the presence of oxygen in order to determine the wt (%) of total nitrogen using a Eurovector EA CHN Analyser. Detection limits for the Analyzer were 0.1 wt (%). Calibration was performed using certified Eurovector standards, accepting a margin of error of 0.02%.