Nutrient sampling in the coastal waters of south eastern Tasmania

• Other Authors: Beard, Jason, Mr (pointOfContact), Crawford, Christine, Dr (pointOfContact), Eriksen, Ruth, Dr (pointOfContact), IMAS Data Manager (pointOfContact), Institute for Marine and Antarctic Studies (IMAS), University of Tasmania (UTAS) (hasAssociationWith), Swadling, Kerrie, Dr (hasPrincipalInvestigator)
• Format: Dataset
• Language: unknown
• Published: University of Tasmania, Australia
• Subjects: biota; EARTH SCIENCE | BIOSPHERE | ECOSYSTEMS | AQUATIC ECOSYSTEMS | PLANKTON | PHYTOPLANKTON; EARTH SCIENCE | AGRICULTURE | AGRICULTURAL AQUATIC SCIENCES | AQUACULTURE; EARTH SCIENCE | TERRESTRIAL HYDROSPHERE | WATER QUALITY/WATER CHEMISTRY; EARTH SCIENCE | OCEANS | OCEAN CIRCULATION | OCEAN CURRENTS; EARTH SCIENCE | BIOLOGICAL CLASSIFICATION | PROTISTS | FLAGELLATES | DINOFLAGELLATES; Storm Bay; Marine and Estuarine Ecology (incl. Marine Ichthyology); BIOLOGICAL SCIENCES; ECOLOGY; Biological Oceanography; EARTH SCIENCES; OCEANOGRAPHY; Temperate Reef; research vessel; Sampling depth; DEPTH; SILICATE; PHOSPHATE; NITRATE_NITRITE; AMMONIUM; NITRITE; Concentration of silicate {SiO4} per unit volume of the water body; Concentration of phosphate {PO4} per unit volume of the water body; Concentration of nitrate and nitrite {NO3 and NO2} per unit volume of the water body; Concentration of ammonium {NH4} per unit volume of the water body; Concentration of nitrite {NO2} per unit volume of the water body; Southern Ocean
• Online Access: https://researchdata.edu.au/nutrient-sampling-coastal-eastern-tasmania/1730358

Maintenance and Update Frequency: notPlanned Statement: Water samples were collected, using a 6 L or 8 L Niskin bottle, from 0.5 – 1 m below the surface, at 10 m depth, and within 5 m of the seabed. At site 3 an intermediate sample from 50 m was also collected. Subsamples were taken at each depth for macronutrients (unfiltered), and were frozen and stored in the dark until processing at the CSIRO Marine and Atmospheric Laboratories, Hobart. The biologically relevant nutrients, dissolved nitrate+nitrite, phosphate, ammonia and silicate concentrations (μM) were measured by CSIRO Hydrochemistry laboratory using standard colorimetric methodology adapted for flow injection analysis on a 5-channel Lachat Quick Chem 8000 series Automated Ion Analyser. Method detection limits were 0.02 μM P, 0.05 μM N, 0.05 μM Si, and 0.05 μM ammonia. Credit Fisheries Research and Development Corporation (FRDC) Biologically relevant macronutrients, nitrate + nitrite, silicate, phosphate and ammonia, were measured at all sites throughout the study. Nitrate + nitrite values (NOx) at the surface showed clear seasonal trends, peaking over winter and drawing down to near zero in summer and autumn. Phosphate concentrations also reached a peak in winter, which was associated with Southern Ocean influence. Median ammonium concentrations at all sites were generally <0.5 μM, with no clear peaks in any season or month. Overall, the lowest values were measured in August and other months showed reasonable spread around the median. Median silicate concentrations were consistently highest at sites 1 and 9, followed by site 5. Water from the River Derwent flows through site 1, then tracks east towards site 9 then site 5. Seasonally, silicate was generally highest in winter when the River Derwent outflow is also greatest.