Port Phillip Bay Nutrient Patterns During High and Low Runoff

Monthly nutrient and chlorophyll a distributions were measured across Port Phillip Bay for two years as part of the Port Phillip Bay Environmental Study. The Australian Ocean Data Network provides data from two contrasting periods: high runoff in September 1993 and low runoff in January 1995. Surveys covering approximately 2000 km² were completed in 3 days using a continuous profiling technique aboard a ship.

Use Cases

• Analyze ammonium, nitrate, nitrite, phosphate, and silicate concentration variations between high and low runoff periods.
• Map spatial nutrient variability at a 200-meter resolution using continuous profiling data collected every 10 seconds.
• Distinguish nutrient sources by examining ammonium/salinity and silicate/salinity relationships between the Yarra/Maribyrnong and Werribee River systems.
• Investigate correlations between chlorophyll a concentrations (1-6 mg L⁻¹) and freshwater nutrient inputs during different runoff conditions.
• Model the impact of the Werribee River as a significant nutrient source during high precipitation events, challenging prior studies.

Strengths

• Continuous profiling provided nutrient measurements resolved over spatial scales of about 200 meters.
• Surveys covered the entire Port Phillip Bay, an area of approximately 2000 km².
• Data captures contrasting environmental conditions during defined high-runoff (Sep 1993) and low-runoff (Jan 1995) periods.

Limitations

• Dataset is limited to two specific monthly snapshots, not a continuous two-year time series.
• Primary data formats are HTML and PDF, which may require extraction for computational analysis.
• Sample size in terms of discrete data points or rows is not specified.

Provenance

Source

Australian Ocean Data Network, collected as part of the Port Phillip Bay Environmental Study.

Collection Method

Nutrients measured via flow-segmented colorimetric analysis on filtered seawater pumped continuously aboard a ship; hydrographic and chlorophyll a data collected simultaneously.

Time Range

September 1993 and January 1995.

Freshness

Data is historical, covering 1993-1995, but the record was last updated in the system in April 2026.

Geography

Northern Port Phillip Bay, Victoria, Australia, with surveys covering the whole bay.