title: The dynamics of ¹³C in several New Zealand lakes

authors: McCabe, Bruce

abstract: The main objectives of this study were to;
(i) Determine how the 𝜹¹³C of autochthonous production in fresh water lakes varies with productivity and trophic state.
(ii) Determine if such variations can be used for the investigation of lake palaeoenvironment.
(iii) Quantify the effect of anthropogenic activity on the productivity of Hamilton Basin lakes.
The viability of this project was assessed by monitoring the dissolved inorganic carbon chemistry of an eutrophic pond during a period of high insolation and algal productivity. These observations revealed that during the day, the Pc0₂ in the euphotic zone was reduced to levels low enough to affect. photosynthetic carbon isotopic fractionation, and hence plankton 𝜹¹³C values. The enrichment of ¹³C in the dissolved inorganic carbon (DIC) pool during periods of high
photosynthetic productivity also affects plankton 𝜹¹³C values. Analysis of diurnal changes in 𝜹¹³C and DIC concentration using the Rayleigh equation suggested that photosynthetic fractionation factors changed in response to changes in ambient P𝒸ₒ₂  levels.
The effect of lake trophic state on phytoplankton photosynthetic carbon isotopic fractionation was further investigated using closed system batch cultures of zooplankton-free natural algal populations collected from lakes of differing trophic state. The results indicated
that;
(i) There are considerable differences between algal communities, photosynthetic production and apparent CO₂  compensation points for cultures of algae from lakes of differing trophic state.
(ii) Plankton from a eutrophic lake were able to photosynthesise down to a low and had a variable photosynthetic carbon isotopic fractionation factor, (ep), which varied as a function of the P𝒸ₒ₂ .
(iii) Plankton from a mesotrophic lake were unable to reduce the Pc0₂   below 300ppm and exhibited a constant ∈p .
(iv) Carbon dioxide availability could be limiting plankton photosynthesis in productive eutrophic lakes, and may result in HCO₃⁻ use.
Phytoplankton 𝜹¹³C values and photosynthetic fractionation factors have the potential to be used to detect changes in plankton productivity and substrate use.
A study was made of the isotopic chemistry of the DIC and particulate organic matter, (POM), in six Hamilton Basin lakes with trophic states ranging from hypertrophic to oligotrophic-mesotrophic and dystrophic. From this study, it was concluded that;
(i) The isotopic chemistry of the DIC is a function of:
- catchment composition
- the relative amounts and 𝜹¹³C of inorganic carbon supplied from the atmosphere and biogenic sources.
- the mixing regime of the lake.
(ii) 𝜹¹³Cₚₒₘ varies seasonally in concert with changes in algal biomass.
(iii) Because variations in 𝜹¹³Cₚₒₘ result primarily from changes in the photosynthetic fractionation factor, ∆¹³C₍ₚₒₘ₋𝒸ₒ₂₍ₐq₎₎they can be used to detect changes in the productivity of lakes.
(i v) 𝜹¹³Cₚₒₘ values could not be used to rank lakes in order of increasing productivity because of the effect of systematic differences in the 𝜹¹³C 𝒸ₒ₂₍ₐq₎of different lakes.
(v) POM produced in the euphotic zone is incorporated in the sediment with only a small (-1%) change in its 𝜹¹³C, thus enabling sediment 𝜹¹³C values to be used to source organic carbon in the sediment and to investigate lake palaeoproductivity.
Large systematic variations were observed in sediment 𝜹¹³C values during the development of lakes. By assuming that the 𝜹¹³C 𝒸ₒ₂₍ₐq₎ had remained constant during lake development, an attempt was made to determine the palaeoenvironment of these lakes from sediment 𝜹¹³C values. It was concluded that the productivity of these lakes had undergone considerable changes during their development in response to climatically and anthropologically induced changes in the catchment vegetation. Low forest cover results in high or increased lake productivity, whilst dense forest cover led to low or reduced lake productivity. Lakes formed in the late glacial times had a high productivity, (low forest cover and high nutrient loading), which reduced as the forest cover developed. Peat development also affected some of the lakes.
An attempt was made to assess the effect of anthropogenic activity in the Hamilton Basin on the metabolism of the lakes from changes in the recent sediment 𝜹¹³C values and a comparison of present day 𝜹¹³Cₚₒₘ values with recent sediment 𝜹¹³C values. The results indicate that;
(i) Anthropogenic activity had a marked affect on lake metabolism, resulting in increased terrigenous inputs and/or increased productivity. This was particularly evident in Lake Hakanoa, where deforestation of the area by early Polynesian settlers resulted in a large increase in lake productivity.
(ii) Several of the lakes have very recently undergone a marked increase in their productivity, a result of European activity in the area. 
Thus, plankton productivity has a systematic affect on the 𝜹¹³C of the POM incorporated in lake sediments, which has the potential to be used in the investigation of lake palaeoproductivity, and in assessing the effect of anthropogenic activity on lake productivity.

text: The dynamics of ¹³C in several New Zealand lakes The main objectives of this study were to;
(i) Determine how the 𝜹¹³C of autochthonous production in fresh water lakes varies with productivity and trophic state.
(ii) Determine if such variations can be used for the investigation of lake palaeoenvironment.
(iii) Quantify the effect of anthropogenic activity on the productivity of Hamilton Basin lakes.
The viability of this project was assessed by monitoring the dissolved inorganic carbon chemistry of an eutrophic pond during a period of high insolation and algal productivity. These observations revealed that during the day, the Pc0₂ in the euphotic zone was reduced to levels low enough to affect. photosynthetic carbon isotopic fractionation, and hence plankton 𝜹¹³C values. The enrichment of ¹³C in the dissolved inorganic carbon (DIC) pool during periods of high
photosynthetic productivity also affects plankton 𝜹¹³C values. Analysis of diurnal changes in 𝜹¹³C and DIC concentration using the Rayleigh equation suggested that photosynthetic fractionation factors changed in response to changes in ambient P𝒸ₒ₂  levels.
The effect of lake trophic state on phytoplankton photosynthetic carbon isotopic fractionation was further investigated using closed system batch cultures of zooplankton-free natural algal populations collected from lakes of differing trophic state. The results indicated
that;
(i) There are considerable differences between algal communities, photosynthetic production and apparent CO₂  compensation points for cultures of algae from lakes of differing trophic state.
(ii) Plankton from a eutrophic lake were able to photosynthesise down to a low and had a variable photosynthetic carbon isotopic fractionation factor, (ep), which varied as a function of the P𝒸ₒ₂ .
(iii) Plankton from a mesotrophic lake were unable to reduce the Pc0₂   below 300ppm and exhibited a constant ∈p .
(iv) Carbon dioxide availability could be limiting plankton photosynthesis in productive eutrophic lakes, and may result in HCO₃⁻ use.
Phytoplankton 𝜹¹³C values and photosynthetic fractionation factors have the potential to be used to detect changes in plankton productivity and substrate use.
A study was made of the isotopic chemistry of the DIC and particulate organic matter, (POM), in six Hamilton Basin lakes with trophic states ranging from hypertrophic to oligotrophic-mesotrophic and dystrophic. From this study, it was concluded that;
(i) The isotopic chemistry of the DIC is a function of:
- catchment composition
- the relative amounts and 𝜹¹³C of inorganic carbon supplied from the atmosphere and biogenic sources.
- the mixing regime of the lake.
(ii) 𝜹¹³Cₚₒₘ varies seasonally in concert with changes in algal biomass.
(iii) Because variations in 𝜹¹³Cₚₒₘ result primarily from changes in the photosynthetic fractionation factor, ∆¹³C₍ₚₒₘ₋𝒸ₒ₂₍ₐq₎₎they can be used to detect changes in the productivity of lakes.
(i v) 𝜹¹³Cₚₒₘ values could not be used to rank lakes in order of increasing productivity because of the effect of systematic differences in the 𝜹¹³C 𝒸ₒ₂₍ₐq₎of different lakes.
(v) POM produced in the euphotic zone is incorporated in the sediment with only a small (-1%) change in its 𝜹¹³C, thus enabling sediment 𝜹¹³C values to be used to source organic carbon in the sediment and to investigate lake palaeoproductivity.
Large systematic variations were observed in sediment 𝜹¹³C values during the development of lakes. By assuming that the 𝜹¹³C 𝒸ₒ₂₍ₐq₎ had remained constant during lake development, an attempt was made to determine the palaeoenvironment of these lakes from sediment 𝜹¹³C values. It was concluded that the productivity of these lakes had undergone considerable changes during their development in response to climatically and anthropologically induced changes in the catchment vegetation. Low forest cover results in high or increased lake productivity, whilst dense forest cover led to low or reduced lake productivity. Lakes formed in the late glacial times had a high productivity, (low forest cover and high nutrient loading), which reduced as the forest cover developed. Peat development also affected some of the lakes.
An attempt was made to assess the effect of anthropogenic activity in the Hamilton Basin on the metabolism of the lakes from changes in the recent sediment 𝜹¹³C values and a comparison of present day 𝜹¹³Cₚₒₘ values with recent sediment 𝜹¹³C values. The results indicate that;
(i) Anthropogenic activity had a marked affect on lake metabolism, resulting in increased terrigenous inputs and/or increased productivity. This was particularly evident in Lake Hakanoa, where deforestation of the area by early Polynesian settlers resulted in a large increase in lake productivity.
(ii) Several of the lakes have very recently undergone a marked increase in their productivity, a result of European activity in the area. 
Thus, plankton productivity has a systematic affect on the 𝜹¹³C of the POM incorporated in lake sediments, which has the potential to be used in the investigation of lake palaeoproductivity, and in assessing the effect of anthropogenic activity on lake productivity.

year: 1985

title: An unusual growth form of Cladonia furcata: The trampling-resistant primary thallus colonizing a paved pathway

authors: Lange, Otto L.

abstract: Lichens are well known to be susceptible to damage by trampling. Fruticose species, with their
highly branched structure, are particularly sensitive and Bayfield et al. (1981)
described substantial damage to Cladonia uncialis, C. arbuscula, C. rangiferina,
and C. impexa on paths in lichen-rich heath communities in north-east
Scotland. Less visible communities, biotic soil crusts in arid and semi-arid
areas with their cover of crustose lichens, are also easily disturbed by walking,
car driving, or grazing and recovery can take decades.
We report here an interesting situation where a lichen (Cladonia furcata) is apparently being
maintained and even spread in a habitat because trampling prevents it from
completing its monocarpic life cycle.

text: An unusual growth form of Cladonia furcata: The trampling-resistant primary thallus colonizing a paved pathway Lichens are well known to be susceptible to damage by trampling. Fruticose species, with their
highly branched structure, are particularly sensitive and Bayfield et al. (1981)
described substantial damage to Cladonia uncialis, C. arbuscula, C. rangiferina,
and C. impexa on paths in lichen-rich heath communities in north-east
Scotland. Less visible communities, biotic soil crusts in arid and semi-arid
areas with their cover of crustose lichens, are also easily disturbed by walking,
car driving, or grazing and recovery can take decades.
We report here an interesting situation where a lichen (Cladonia furcata) is apparently being
maintained and even spread in a habitat because trampling prevents it from
completing its monocarpic life cycle.

year: 1998

title: Reha Aperahama: a Ngati Rahiri rangatira

authors: Hart, Philip

abstract: Reha Aperahama had an illustrious whakapapa and was affiliated to several hapu. His father was notable as one of the most loyal rangatira (from the Crown’s perspective) in Hauraki, and Reha followed his lead, probably in part because of the financial rewards he received from selling land to settlers. He tried to maximize his income from this source, spending several years pleading for permission to sell his Te Kawana block (near Te Aroha). After opposing Ngati Haua ambitions to acquire the Aroha block, by 1878 he was willing to encourage road building. 
Reha was regularly before the courts because of his inability or reluctance to pay his debts, occasionally perjuring himself to avoid liability. In his later years he had little money. Despite occasionally being drunk and even violent, he was an important figure in Maori society, with a leadership role in his hapu and in the Mormon church. He was also notable for his marital complications.

text: Reha Aperahama: a Ngati Rahiri rangatira Reha Aperahama had an illustrious whakapapa and was affiliated to several hapu. His father was notable as one of the most loyal rangatira (from the Crown’s perspective) in Hauraki, and Reha followed his lead, probably in part because of the financial rewards he received from selling land to settlers. He tried to maximize his income from this source, spending several years pleading for permission to sell his Te Kawana block (near Te Aroha). After opposing Ngati Haua ambitions to acquire the Aroha block, by 1878 he was willing to encourage road building. 
Reha was regularly before the courts because of his inability or reluctance to pay his debts, occasionally perjuring himself to avoid liability. In his later years he had little money. Despite occasionally being drunk and even violent, he was an important figure in Maori society, with a leadership role in his hapu and in the Mormon church. He was also notable for his marital complications.

year: 2016