Distribution of rotifers in North Island, New Zealand, and their potential use as bioindicators of lake trophic state

Rotifera IX ◽  
2001 ◽  
pp. 155-164 ◽  
Author(s):  
I. C. Duggan ◽  
J. D. Green ◽  
R. J. Shiel
Keyword(s):  
New Zealand ◽  
Trophic State ◽  
Lake Trophic State ◽  
Potential Use

Sediment and nutrient accumulation rates in sediments of twelve New Zealand lakes: influence of lake morphology, catchment characteristics and trophic state

2008 ◽  
Vol 59 (12) ◽  
pp. 1067 ◽  
Author(s):  
Dennis Trolle ◽  
David P. Hamilton ◽  
Chris Hendy ◽  
Conrad Pilditch
Keyword(s):  
New Zealand ◽  
Water Column ◽  
Catchment Area ◽  
Trophic State ◽  
Temporal Changes ◽  
Nutrient Concentrations ◽  
Sedimentation Rates ◽  
Catchment Characteristics ◽  
Lake Morphology ◽  
Lake Trophic State

Intact sediment cores were collected from the deepest basins of 12 lakes in the Rotorua District, New Zealand, to test for effects of morphological features, catchment characteristics and lake trophic state on net sedimentation rates and sediment nutrient concentrations. Multiple linear regression was used to show that 68% of the variation in net sedimentation rates across the lakes could be explained by lake trophic state and catchment area. Comparison of 2006 data with results from a survey in 1995 showed that surficial sediment (0–2 cm) total phosphorus concentrations (TP) have increased in three of the 12 lakes, at rates ranging from 27.5 to 114.4 mg P kg–1 dry wt y–1. Total nitrogen (TN) concentrations in surficial sediments have increased in nine of the 12 lakes at rates ranging from 51.8 to 869.2 mg N kg–1 dry wt y–1. Temporal changes in sediment TP and TN concentrations were not significantly linearly related (P = 0.12–0.88) to catchment area or different water column indices considered to reflect lake trophic state, including annual mean water column concentrations of TP, TN or chlorophyll a. It is concluded that between-lake variations in sediment TP and TN concentrations are influenced by a range of complex interacting factors, such as sediment redox conditions (and periodic anoxia in the hypolimnion of some lakes) as well as variations in sediment mineral composition (which influences retention and release of various sediment phosphorus and nitrogen species). Subsequently, these factors cause sediment TP and TN concentrations across the 12 lakes to respond differently to temporal changes in water column TP and TN concentrations.

Direct Determination of Apatite in Lake Sediments

1980 ◽  
Vol 37 (4) ◽  
pp. 640-646 ◽  
Author(s):  
R. P. Reid ◽  
C. H. Pharo ◽  
W. C. Barnes
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Lake Sediments ◽  
Trophic State ◽  
Inorganic Phosphorus ◽  
Source Rocks ◽  
Emission Spectrometry ◽  
Phosphorus Load ◽  
Lake Trophic State ◽  
Scanning Electron

Apatite is a common accessory mineral in the source rocks for the glacial debris supplying sediments to many Canadian lakes. A method has been developed which uses scanning electron microscopy and energy dispersive X-ray emission spectrometry for direct identification of apatite. This method has been used to examine the apatite content of various size fractions in Kamloops Lake sediments. Apatite concentrations obtained by this direct examination correlate well (r > 0.999) with apatite concentrations determined by chemical analyses and indicate that, in addition to comprising as much as 70% of the total phosphorus load, apatite may comprise as much as one-third of the "dissolved" (< 0.45 μm) inorganic phosphorus load. Consequently the use of classical (e.g. Vollenweider 1968; Vollenweider and Dillon 1974) methods of estimating lake trophic state from inorganic phosphorus concentrations in lake water must be done with care, recognizing that the bulk of inorganic phosphorus in lakes deriving sediment from glaciated igneous or metamorphic terrains may be in the form of apatite.Key words: apatite, lake, trophic state, phosphorus load, scanning electron microscopy

Maori and Alcohol: A Reconsidered History

2000 ◽  
Vol 34 (1) ◽  
pp. 129-134 ◽  
Author(s):  
Peter C. Mancall ◽  
Paul Robertson ◽  
Terry Huriwai
Keyword(s):  
Nineteenth Century ◽  
New Zealand ◽  
Historical Record ◽  
Historical Records ◽  
European Contact ◽  
History Of ◽  
Alcohol Related Harm ◽  
Potential Use ◽  
Related Harm ◽  
Different Parts

Objective: To document aspects of the history of alcohol use among Maori, with a particular focus on the period from 1840 to 1872 and to identify potential use of this knowledge in the development of strategies for the prevention and treatment of alcohol-related harm among Maori in contemporary New Zealand. Method: A survey of the surviving documentation about alcohol in nineteenth-century New Zealand; materials were predominantly drawn from the writings of pakeha (non-Maori) missionaries, officials and travellers, as well as available statistical records. Results: Analysis of early written historical records suggests significant variation in the response of Maori to the introduction of alcohol in different parts of New Zealand during the period following European contact. Conclusions: One stereotype that has arisen suggests Maori have been incapable of and/or unable to manage the production and use of alcohol. On the other hand, another commonly held belief has been that Maori supported abstinence or ‘resisted alcohol’ because they recognised its ‘ruinous nature’ and because it was contrary to traditional custom and practices. Historical information indicates that the Maori response to the introduction of alcohol was in fact diverse and for much of the nineteenth century alcohol was non-problematic for many Maori. This reinterpretation of the historical record can potentially empower contemporary Maori to take greater responsibility for the use of alcohol. It also challenges the negativity of the stereotypes generated by historical misinformation.

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