|
Pumicestone Passage received a "C+" in the 2009
Report Card, a slight improvement in ecosystem health from the previous
year ("C"). Overall, there was little change in the EHI water quality
indicators aggregated for the entire passage from the previous year. In
the northern part of the water body there were small improvements since
2007/2008 from reductions in phytoplankton abundance, increased water
clarity and reduced sewage nitrogen. In contrast, in the southern
waters there was a slight decrease in water quality mainly due to a
small increase in sewage nitrogen levels. However, the overall water
quality as measured by EHI indicators was better in the southern
sections of the passage with TN and water clarity (Secchi depth) fully
compliant with QWQ guidelines (consistent with results from previous
years).
EHI indicators in the southern reaches of
Pumicestone Passage typically vary with ambient wind speed and
direction. The wide and open channels in the southern reaches of the
system are particularly affected by strong south-easterly winds which
often occur in the summer months.
Biannual seagrass depth ranges surveys conducted in 2008-09 show that
seagrass meadows have been stable with the maximum depth range of Zostera
muelleri (species formerly known as Zostera capricorni)reaching to 0.8 m
near Bell's Creek and 0.7 m at Gallagher’s Point in the southern reaches.
Water within the Pumicestone Passage was 82%
compliant with QWQ objectives for sewage nitrogen (δ15N),
little change from 2007/2008. The majority of the non-compliance
occurred in the northern section of the Passage between Egg Island and
Bells Creek which was consistent with elevated water column TN and
dissolved inorganic nitrogen concentrations in the same area.
Abbreviations glossary |
Indicators and methods
|
