Occurrence and possible causes of a severe cyanobacterial bloom in Lake Cargelligo, New South Wales

1994 ◽  
Vol 45 (5) ◽  
pp. 737 ◽  
Author(s):  
L Bowling

Although smaller cyanobacterial blooms had occurred in Lake Cargelligo in previous summers, a severe bloom of Anabaena circinalis occurred in the lake in November 1990. Cell numbers exceeded 100 000 cells m L -1 , and toxicity tests revealed the bloom to be highly hepatotoxic. This resulted in the first known closure of a town water supply due to cyanobacteria in New South Wales. Blooms of Microcystis aeruginosa, Aphanizomenon issatschenkoi, Oscillatoria rnougeotii and Cylindrospermopsis raciborskii also occurred in the lake at similar very high cell numbers during the summer and autumn of 1990-91. All five species persisted until May 1991, although there was no detectable toxicity from January onwards. Severe flooding in the Lachlan River valley upstream of Lake Cargelligo during the winter of 1990 led to nutrient enrlched inflows to the lake. These elevated nutrient concentrations would have been a major factor contributing to the bloom. However, other physico-chemical factors were also suitable for cyanobacterial growth.


1997 ◽  
Vol 48 (4) ◽  
pp. 353 ◽  
Author(s):  
Michelle T. Casanova ◽  
Annabel Douglas-Hill ◽  
Margaret A. Brock ◽  
Monika Muschal ◽  
Michael Bales

The physical, chemical and biological characteristics of 65 farm ponds in the Northern Tablelands and Central Western Slopes regions of New South Wales, Australia, were similar to those recorded for Australian ponds in other studies. The strongest single relationship between physico-chemical characteristics and biological characteristics was for high abundance of phytoplankton, low abundance of macrophytes, high turbidity, and high nutrient concentrations in ponds on granitic soil. Variation among the ponds was such that no other relationship was significant. Five groups of ponds were discerned on the basis of their biological and physico-chemical characteristics. One group could be classed as reasonably ‘pristine’, with high water clarity and high abundance of macrophytes; another group presented highly eutrophic, phytoplankton-dominated conditions. Ponds in these two groups can be described as being in ‘alternative stable states’. A third group had been modified with the intention of improving the appearance or utility of the ponds. The last two groups identified in this analysis had no specific parallels in the literature. Abundance of macrophytes was related to good water quality, and encouragement of increased abundance of submerged plants in farm ponds could result in improved water quality.



Soil Research ◽  
2009 ◽  
Vol 47 (6) ◽  
pp. 555 ◽  
Author(s):  
Michael G. Jones ◽  
R. Willem Vervoort ◽  
Julie Cattle

Understanding the process by which nutrients and solids enter waterways from pastures in the Great Lakes district, New South Wales, Australia, may assist in maintaining water quality to ensure ongoing environmental and economic sustainability of the region. Rainfall simulations, using a 100-year return storm event, were conducted to determine nutrient and suspended solid concentrations in the runoff of 8 pasture sites in 3 of the catchments in the district. On 5 of the 8 sites, considerable concentrations of N or P were mobilised during the simulated rainfall event, but average nutrient concentrations and total loads across all sites were relatively low and similar to other studies of nutrient runoff from pastures. In addition, low runoff coefficients indicated that runoff is probably not the major pathway for nutrient losses from pasture in this area. Overall, rainfall runoff responses at the sites were similar in the 3 catchments. In contrast, the results suggest that, despite generating more runoff, the sites in the Wang Wauk catchment generated less nutrients in runoff than the sites in the Wallamba and Myall catchments. There was no difference in total suspended solids loads for the sites analysed by catchment. Relationships between soil physical and chemical characteristics and total nutrients loads or cumulative runoff were not strong.



1996 ◽  
Vol 47 (4) ◽  
pp. 643 ◽  
Author(s):  
LC Bowling ◽  
PD Baker

The occurrence of a severe cyanobacterial bloom is described. This bloom affected almost 1000 km of the Barwon-Darling River, New South Wales, Australia, in November and December 1991 and was dominated by Anabaena circinalis Rabenhorst. This cyanobacterium was present in concentrations of around half a million cells per millilitre at some localities during its peak in mid November. Moderate to very high toxicity was demonstrated by mouse bioassay at many localities during this time. The bloom was attributed to very low flow conditions and high nutrient concentrations, especially of total phosphorus. However, warm water temperatures, elevated pH, reduced turbidity, and improved water transparency would also have been contributing factors. Very high ammonia concentrations were also observed during the bloom. The bloom declined during December and was eventually flushed from the river by increased flows following heavy catchment rainfall between mid December and early January.



1974 ◽  
Vol 14 (66) ◽  
pp. 112 ◽  
Author(s):  
DW Turner ◽  
B Barkus

At Alstonville, New South Wales, leaf position had a greater effect than season on the nutrient concentrations of N, P, K, Ca, Mn, Cu, and Zn in the laminae of Williams bananas growing on a krasnozem soil and sampled over a 4-year period. However, season was more important for Mg. The effect of stage of plant growth was significant but much smaller than the other influences. When sampling for leaf analysis, leaf position and plant age can be standardised, but a major problem in this investigation was unpredictable, significant changes in nutrient composition from one sampling date to another. If these results are true for other soils. the data do not allow critical levels to be applied.







Soil Research ◽  
2013 ◽  
Vol 51 (8) ◽  
pp. 631 ◽  
Author(s):  
M. C. Davy ◽  
T. B. Koen

The aim of this study was to investigate variations in soil organic carbon (SOC) for two soil types and six common land uses in the New South Wales Murray Catchment and to explore the factors influencing those variations. Samples were collected from 100 sites on duplex soils (Ustalfs) of the Slopes region, and 100 sites on red-brown earths (Xeralfs) of the Plains region. Stocks of SOC (0–30 cm) across the study area ranged between 22.3 and 86.0 t ha–1, with means (± s.e.) of 42.0 ± 1.3 and 37.9 ± 0.8 t ha–1 for the Slopes and Plains regions, respectively. Higher SOC stocks were present in pasture-dominated land uses compared with mixed cropping in the Slopes region, with particularly high stocks found in pastures at positions on a slope of 7–10%. No significant differences in SOC stocks were identified between land-use groups (pastures or cropping) in the Plains region (<500-mm rainfall zone). Significant correlations were found between SOC and a range of climatic, topographical, and soil physico-chemical variables at both the catchment and sub-regional scale. Soil physico-chemical and topographical factors play an important role in explaining SOC variation and should be incorporated into models that aim to predict SOC sequestration across agricultural landscapes.



2007 ◽  
Vol 47 (7) ◽  
pp. 869 ◽  
Author(s):  
D. O. Huett ◽  
I. Vimpany

Leaf nutrient analyses are widely used to determine the nutritional status of macadamia orchards. A commercial database was developed from 2186 observations collected from 186 farms across 56 geographical areas spanning New South Wales and Queensland. The data were collected over 10 years, with 1 to 9 sequential annual observations on each farm. An experimental database was also developed where several of the most popular commercial cultivars growing in the Lismore area of New South Wales and the Bundaberg area of Queensland were sampled at monthly intervals over a 2–3 year period. Two canopy sampling heights were used to confirm the effect of shading (irradiance) on leaf nutrient composition. This latter study confirmed that spring was an appropriate time to sample and that irradiated leaves, usually located in an upper canopy position, should be sampled. The most important change to the recommended leaf nutrient standards was the increase in the leaf nitrogen range from 1.3–1.4% to 1.4–1.7% for all cultivars except 344, where we recommend 1.6–2.0%. The study also confirmed that the adequate concentration range for zinc should be much lower than originally recommended. We recommend concentrations of 6–15 mg/kg. Minor changes were made to most other macro- and micronutrients. We also advise caution when interpreting the analyses of some nutrients because concentrations can change over the spring period. The revised leaf nutrient standards were developed from two large and comprehensive databases and reliably represent adequate leaf nutrient concentrations in productive, well-managed macadamia orchards in Australia. A single leaf analysis will not reliably indicate the nutritional status of a macadamia orchard. Additional information is required on trends in leaf and soil analyses over time as well as fertiliser, yield and management history.



1997 ◽  
Vol 37 (1) ◽  
pp. 119 ◽  
Author(s):  
D. O. Huett ◽  
A. P. George ◽  
J. M. Slack ◽  
S. C. Morris

Summary. A leaf nutrient survey was conducted of the low-chill peach cultivars, Flordaprince (October maturing) and Flordagold (mid November–early December maturing) at 3 commercial sites in both northern New South Wales and southern Queensland. Recently mature leaves from the middle third of a current season’s fruiting lateral (spring flush) were sampled at stone hardening and 2-weeks postharvest and of a non-fruiting lateral at maturity of the summer flush (after summer pruning) during the 1992–93 and 1993–94 seasons. At an additional site in New South Wales (Alstonville), leaf nutrient concentrations were also determined on cv. Flordagem (early November maturing) at 2-week intervals during both seasons. Soil (0–30 cm) chemical determinations were conducted at all sites at 2-weeks postharvest Seasonal trends in leaf nutrient composition were associated with a leaf age–maturity effect. As flush leaves matured during spring, and as mature leaves aged after hardening of the summer flush, nitrogen (N) concentration declined and calcium (Ca) concentration increased. Nitrogen and Ca concentrations increased when young leaves produced from the summer flush were sampled. Time of sampling produced the most consistently significant (P<0.05) main effects on leaf nutrient concentration. The 2-week postharvest period was selected as a convenient time to sample—when leaves were of a consistent age and maturity, and the effect of crop load on tree nutrient reserves was still present. Paclobutrazol, which reduces vegetative growth in stonefruit, was applied to all Queensland sites and, as a consequence, mid lateral leaves contained higher (P<0.05) Ca, magnesium (Mg) and chloride (Cl) and lower (P<0.05) N and phosphorus (P) concentrations than leaves from New South Wales sites. State effects can therefore be interpreted as paclobutrazol effects. Cultivar effects (P<0.05) occurred for many leaf nutrients, however, at the 2-week postharvest sampling, concentrations were sufficiently similar to combine as a narrow adequate concentration range for both cultivars. The diagnostic adequate leaf nutrient concentrations were within the range developed for high-chill peaches (Leece et al. 1971) with the exception of lower Ca, lower Mg for New South Wales (both cultivars), lower iron for Flordaprince (both states), higher P for Flordaprince in New South Wales and higher manganese values for Queensland (both cultivars). Regression analyses were conducted between leaf and fruit nutrient concentrations and soil chemical properties. The only consistent result demonstrated that as the soil Ca : Mg ratio increased, leaf Mg concentration decreased exponentially (P<0.001), indicating that the practice of heavy annual agricultural limestone or gypsum applications in the absence of Mg fertiliser, which had been adopted by several growers in the survey, is associated with lower leaf Mg concentrations.



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