title: Dewfall as a water source frequently activates the endolithic cyanobacterial communities in the granites of Taylor Valley, Antarctica

authors: Büdel, Burkhard

subjects: Antarctica

abstract: Endolithic photosynthetic microorganisms like cyanobacteria and algae are well known from savannas and deserts of the world, the high Arctic, and also Antarctic habitats like the Dry Valleys in the Ross Dependency. These endolithic microbial communities are thought to be at the limits of life with reported ages in the order of thousands of years. Here we report on an extensive chasmoendolithic cyanobacterial community inside granite rocks of Mt. Falconer in the lower Taylor Valley, Dry Valleys. On average, the cyanobacterial community was 4.49 ± 0.95 mm below the rock surface, where it formed a blue-green layer. The community was composed mainly of the cyanobacterium Chroococcidiopsis sp., with occasional Cyanothece cf. aeruginosa (Nägeli) Komárek and Nostoc sp. Mean biomass was 168 ± 44 g carbon • m⁻², and the mean chl a content was 24.3 ± 34.2 mg • m⁻². In situ chl fluorescence measurements—a relative measure of photosynthetic activity—showed that they were active over long periods each day and also showed activity the next day in the absence of any moisture. Radiocarbon dating gave a relatively young age (175–280 years) for the community. Calculations from microclimate data demonstrated that formation of dew or rime was possible and could frequently activate the cyanobacteria and may explain the younger age of microbial communities at Mt. Falconer compared to older and less active endolithic microorganisms reported earlier from Linnaeus Terrace, a higher altitude region that experiences colder, drier conditions.

text: Dewfall as a water source frequently activates the endolithic cyanobacterial communities in the granites of Taylor Valley, Antarctica Endolithic photosynthetic microorganisms like cyanobacteria and algae are well known from savannas and deserts of the world, the high Arctic, and also Antarctic habitats like the Dry Valleys in the Ross Dependency. These endolithic microbial communities are thought to be at the limits of life with reported ages in the order of thousands of years. Here we report on an extensive chasmoendolithic cyanobacterial community inside granite rocks of Mt. Falconer in the lower Taylor Valley, Dry Valleys. On average, the cyanobacterial community was 4.49 ± 0.95 mm below the rock surface, where it formed a blue-green layer. The community was composed mainly of the cyanobacterium Chroococcidiopsis sp., with occasional Cyanothece cf. aeruginosa (Nägeli) Komárek and Nostoc sp. Mean biomass was 168 ± 44 g carbon • m⁻², and the mean chl a content was 24.3 ± 34.2 mg • m⁻². In situ chl fluorescence measurements—a relative measure of photosynthetic activity—showed that they were active over long periods each day and also showed activity the next day in the absence of any moisture. Radiocarbon dating gave a relatively young age (175–280 years) for the community. Calculations from microclimate data demonstrated that formation of dew or rime was possible and could frequently activate the cyanobacteria and may explain the younger age of microbial communities at Mt. Falconer compared to older and less active endolithic microorganisms reported earlier from Linnaeus Terrace, a higher altitude region that experiences colder, drier conditions.

year: 2008

title: The phenology of an enclosed pasture area with specific reference to the soil-vegetation interface

authors: Rosenberg, David Ronald

abstract: Over a seven year period (1966-1972) a systematic survey was made of an enclosed pasture area on the campus of the University of Waikato, Hamilton, New Zealand. Areas of similar soil type and floral composition were used for comparison at Newstead and Tamahere. Comparisons are made with shorter-term studies at Newstead and in other countries.

None of the three sites had fertiliser applied during the survey period. Apart from sampling procedures, no vegetation was removed from Hillcrest, but Newstead and Tamahere were subjected to systematic mowing.

Seasonal and long-term fluctuations of populations were determined for all major faunal groups, together with seasonal and successional development of the flora.

Relationships between meteorological factors, faunal and floral composition have been subjected to computer analysis. Some correlations are suggested. The emphasis in the survey has been upon the fluctuations and relationships of groups rather than the precise responses of individual species to environmental variations.

Feeding experiments with fauna in the laboratory have helped to add to the knowledge of the trophic position of some New Zealand species.

The results of the survey show the effects of floral competition where Holcus lanatus, Bromus unioloides and Ranunculus sardous replace rosette and soft annual plants. The rate and sequence of succession are shown.

An adaptation of the Berlese extractor was developed to give indications of the vertical distribution of fauna.

Long term change in faunal composition are not clearly indicated. Changes which do occur are mostly at the soil surface, reflecting the state of vegetation and litter.

As a result of the extended survey, it would seem that one of the most important influences in the ecology of light loam agricultural pastures is the quality of the soil/vegetation interface. When a litter layer is retained throughout the year, faunal numbers fluctuate less rapidly and to a lesser extent than in exposed short vegetation pastures. Basically, litter acts as an ecological buffer, dampens down extremes of microclimate change, and provides a greater number of niches for soil microfauna. Where vegetation removal does not occur, small low-growing plants and seedlings are suppressed. The smothering effects of the stems and leaves from taller plants maintain the dominance of perennial species.

text: The phenology of an enclosed pasture area with specific reference to the soil-vegetation interface Over a seven year period (1966-1972) a systematic survey was made of an enclosed pasture area on the campus of the University of Waikato, Hamilton, New Zealand. Areas of similar soil type and floral composition were used for comparison at Newstead and Tamahere. Comparisons are made with shorter-term studies at Newstead and in other countries.

None of the three sites had fertiliser applied during the survey period. Apart from sampling procedures, no vegetation was removed from Hillcrest, but Newstead and Tamahere were subjected to systematic mowing.

Seasonal and long-term fluctuations of populations were determined for all major faunal groups, together with seasonal and successional development of the flora.

Relationships between meteorological factors, faunal and floral composition have been subjected to computer analysis. Some correlations are suggested. The emphasis in the survey has been upon the fluctuations and relationships of groups rather than the precise responses of individual species to environmental variations.

Feeding experiments with fauna in the laboratory have helped to add to the knowledge of the trophic position of some New Zealand species.

The results of the survey show the effects of floral competition where Holcus lanatus, Bromus unioloides and Ranunculus sardous replace rosette and soft annual plants. The rate and sequence of succession are shown.

An adaptation of the Berlese extractor was developed to give indications of the vertical distribution of fauna.

Long term change in faunal composition are not clearly indicated. Changes which do occur are mostly at the soil surface, reflecting the state of vegetation and litter.

As a result of the extended survey, it would seem that one of the most important influences in the ecology of light loam agricultural pastures is the quality of the soil/vegetation interface. When a litter layer is retained throughout the year, faunal numbers fluctuate less rapidly and to a lesser extent than in exposed short vegetation pastures. Basically, litter acts as an ecological buffer, dampens down extremes of microclimate change, and provides a greater number of niches for soil microfauna. Where vegetation removal does not occur, small low-growing plants and seedlings are suppressed. The smothering effects of the stems and leaves from taller plants maintain the dominance of perennial species.

year: 1974

title: Green or grey pandemic recovery? Revealing the blue–green infrastructure influences in Aotearoa-New Zealand’s “Shovel Ready” Covid-19 response

authors: Hanna, Christina Jane

abstract: This paper analyses Aotearoa-New Zealand’s “shovel-ready fund” to assess if, and how, blue–green infrastructure systems were present in bids from its largest city regions. Findings indicate a greater prevalence in areas with existing spatial plans, and while there was some consideration of climate resilience, there was no real acknowledgement of the pandemic or human health. More positively, there was some evidence of unique indigenous influences that have potential to develop more inclusive and holistic blue–green infrastructure initiatives. The overall response, however, demonstrates a disjointed approach to blue–green infrastructure-related projects, and a missed opportunity for a more transformative response to the climate crisis and human health emergencies.

text: Green or grey pandemic recovery? Revealing the blue–green infrastructure influences in Aotearoa-New Zealand’s “Shovel Ready” Covid-19 response This paper analyses Aotearoa-New Zealand’s “shovel-ready fund” to assess if, and how, blue–green infrastructure systems were present in bids from its largest city regions. Findings indicate a greater prevalence in areas with existing spatial plans, and while there was some consideration of climate resilience, there was no real acknowledgement of the pandemic or human health. More positively, there was some evidence of unique indigenous influences that have potential to develop more inclusive and holistic blue–green infrastructure initiatives. The overall response, however, demonstrates a disjointed approach to blue–green infrastructure-related projects, and a missed opportunity for a more transformative response to the climate crisis and human health emergencies.

year: 2022