title: Historical anthropogenic heavy metal input to the south-eastern North Sea

authors: Boxberg, Florian

abstract: The Helgoland Mud Area (HMA) in the German Bight, covering an area of approximately 500 km2, is one of a few depocentres for finer sediments in the North Sea. Radiocarbon and 210Pb analyses revealed continuous sedimentation over the last several centuries. Zinc (Zn) and lead (Pb) contents in the sediments show a distinct increase towards the youngest most sediments with the thickness of the heavy metal enriched sediments ranging from 15 to 103 cm. Stratigraphic data indicate that the onset of heavy metal enrichment is diachronous progressing north-westward over the depocentre, paralleled by a decrease in the thickness of the enriched layer. Beginning already during medieval times, the enhanced input of Zn and Pb seemingly is related to silver and zinc mining in the Harz Mountains and the Erzgebirge, well-known mining areas since the Bronze Age. Both regions are directly connected to the HMA by the Elbe and Weser rivers. Zn and Pb enrichment began in the south-eastern HMA and progressed subsequently with an average of 10 m per year north-westward, most likely triggered by variations in river discharge and by the hydrodynamic setting. Quantitative assessments of the Zn and Pb content in the sediments suggest that since the onset of enhanced Zn and Pb deposition, the anthropic Zn and Pb input in the HMA amounts to ~ 12,000 t and ~ 4000 t, respectively.

text: Historical anthropogenic heavy metal input to the south-eastern North Sea The Helgoland Mud Area (HMA) in the German Bight, covering an area of approximately 500 km2, is one of a few depocentres for finer sediments in the North Sea. Radiocarbon and 210Pb analyses revealed continuous sedimentation over the last several centuries. Zinc (Zn) and lead (Pb) contents in the sediments show a distinct increase towards the youngest most sediments with the thickness of the heavy metal enriched sediments ranging from 15 to 103 cm. Stratigraphic data indicate that the onset of heavy metal enrichment is diachronous progressing north-westward over the depocentre, paralleled by a decrease in the thickness of the enriched layer. Beginning already during medieval times, the enhanced input of Zn and Pb seemingly is related to silver and zinc mining in the Harz Mountains and the Erzgebirge, well-known mining areas since the Bronze Age. Both regions are directly connected to the HMA by the Elbe and Weser rivers. Zn and Pb enrichment began in the south-eastern HMA and progressed subsequently with an average of 10 m per year north-westward, most likely triggered by variations in river discharge and by the hydrodynamic setting. Quantitative assessments of the Zn and Pb content in the sediments suggest that since the onset of enhanced Zn and Pb deposition, the anthropic Zn and Pb input in the HMA amounts to ~ 12,000 t and ~ 4000 t, respectively.

year: 2019

title: Population Genetics and Photobiont Selectivity in Antarctic Lichens

authors: Burgess-Jones, Tracey

subjects: Lichen

abstract: This thesis examines population genetic structure and migration indices of an Antarctic endemic lichen Buellia frigida as well as algal selectivity of the lichens Buellia frigida, Umbilicaria aprina and Umbilicaria decussata in the Ross Sea Region of Antarctica. My aim was to determine where current populations may have originated (i.e. ancient or recent introductions to Antarctica) and if the level of algal selectivity potentially affects colonisation. 
Chapter 2 reviews historical climate change in Antarctica, particularly in the Ross Sea Region, and introduces the basic characteristics of lichens. It also outlines how molecular analyses of lichen can aid in determining the genetic structure of populations and add to the growing data set which highlights sites in the Ross Sea Region (e.g. Dry Valleys) as glacial refugia. 
To examine population differentiation between populations in this region it was necessary to develop polymorphic markers capable of delineating individuals.  Chapter 3 focuses on the development of five microsatellite markers for this purpose. The initial data for these microsatellites suggested they were suitable for individual genotyping and characterization of B. frigida population structure being mycobiont specific with a high degree of polymorphism. A method of decreasing inhibiting factors present in lichen cells is also provided.
In Chapter 4 regional genetic differentiation was revealed by an analysis using microsatellite markers developed in Chapter 3 over 11 populations in five regions of the Ross Sea Region. The identification of three populations with high allelic richness and sites of high dispersal indicated three regions as putative refugia (Terra Nova Bay, Dry Valleys and Beardmore Glacier). Terra Nova Bay has not previously been highlighted putatively as refugia. Limited mixing between adjacent geographical areas (such as the Dry Valleys and Ross Island) was identified, with migration likely to be influenced by wind currents.
The photobionts of the lichens Buellia frigida, Umbilicaria aprina and Umbilicaria decussata were examined using ITS rDNA sequence analysis in chapter 5. This identified that over a latitudinal gradient of roughly 10˚, there was a single haplotype present in the majority (>95%) of samples. This haplotype was nearly identical to haplotypes from as far afield as Svalbard showing a consistency in photobiont selection over a very wide geographical range and may be micro-climate specific. Other haplotypes present were specific to single geographical areas, and mutation may play the major role in this. 
Collectively, these findings suggest that despite potentially high dispersal of propagules, populations of lichen species in the Ross Dependency show differentiation among locations and are potentially limited in their dispersal to different habitats. This may be the result of high selectivity for the photobiont. I conclude that lichen populations in the Ross Sea Region have originated from ancient, refugial populations rather than being populated via recent dispersal from northern continents. Dispersal within this region is likely to be restricted by ice-covered areas and relichenisation is potentially limited to particular photobiont strains which are suited to the micro-climatic conditions found in this region. In order to minimise the consequences of anthropological disturbance, we recommend the continued protection of areas (e.g. Dry Valleys) housing high lichen and photobiont diversity.

text: Population Genetics and Photobiont Selectivity in Antarctic Lichens This thesis examines population genetic structure and migration indices of an Antarctic endemic lichen Buellia frigida as well as algal selectivity of the lichens Buellia frigida, Umbilicaria aprina and Umbilicaria decussata in the Ross Sea Region of Antarctica. My aim was to determine where current populations may have originated (i.e. ancient or recent introductions to Antarctica) and if the level of algal selectivity potentially affects colonisation. 
Chapter 2 reviews historical climate change in Antarctica, particularly in the Ross Sea Region, and introduces the basic characteristics of lichens. It also outlines how molecular analyses of lichen can aid in determining the genetic structure of populations and add to the growing data set which highlights sites in the Ross Sea Region (e.g. Dry Valleys) as glacial refugia. 
To examine population differentiation between populations in this region it was necessary to develop polymorphic markers capable of delineating individuals.  Chapter 3 focuses on the development of five microsatellite markers for this purpose. The initial data for these microsatellites suggested they were suitable for individual genotyping and characterization of B. frigida population structure being mycobiont specific with a high degree of polymorphism. A method of decreasing inhibiting factors present in lichen cells is also provided.
In Chapter 4 regional genetic differentiation was revealed by an analysis using microsatellite markers developed in Chapter 3 over 11 populations in five regions of the Ross Sea Region. The identification of three populations with high allelic richness and sites of high dispersal indicated three regions as putative refugia (Terra Nova Bay, Dry Valleys and Beardmore Glacier). Terra Nova Bay has not previously been highlighted putatively as refugia. Limited mixing between adjacent geographical areas (such as the Dry Valleys and Ross Island) was identified, with migration likely to be influenced by wind currents.
The photobionts of the lichens Buellia frigida, Umbilicaria aprina and Umbilicaria decussata were examined using ITS rDNA sequence analysis in chapter 5. This identified that over a latitudinal gradient of roughly 10˚, there was a single haplotype present in the majority (>95%) of samples. This haplotype was nearly identical to haplotypes from as far afield as Svalbard showing a consistency in photobiont selection over a very wide geographical range and may be micro-climate specific. Other haplotypes present were specific to single geographical areas, and mutation may play the major role in this. 
Collectively, these findings suggest that despite potentially high dispersal of propagules, populations of lichen species in the Ross Dependency show differentiation among locations and are potentially limited in their dispersal to different habitats. This may be the result of high selectivity for the photobiont. I conclude that lichen populations in the Ross Sea Region have originated from ancient, refugial populations rather than being populated via recent dispersal from northern continents. Dispersal within this region is likely to be restricted by ice-covered areas and relichenisation is potentially limited to particular photobiont strains which are suited to the micro-climatic conditions found in this region. In order to minimise the consequences of anthropological disturbance, we recommend the continued protection of areas (e.g. Dry Valleys) housing high lichen and photobiont diversity.

year: 2013

title: Māori social identities in New Zealand and Hawai'i

authors: Nikora, Linda Waimarie

subjects: Maori

abstract: This research is comprised of two narrative interview studies of Māori in two different settings, New Zealand (n=20) and Hawai'i (n=30).  The data was gathered over the 1994-1996 period.  The two settings have some commonalities and differences.  In both settings Māori are required to make decisions about the continuity of their ethnic Māori identities and hereditary cultural identities of iwi, hapu and whanau, and the part that they wish these identities to play in their daily lives.  The focus of this research was about how Māori create meaning in their lives and maintain their social identities across and within those contexts they move through. 

The findings of this research suggest that Māori in New Zealand continue to value and gain meaning and satisfaction from their cultural collectivities and the social identities derived from them.  However, the results tend to suggest that there are changes in the ways that individuals conceptualise these identities and concomitantly, how they see of themselves.
For New Zealand participants, conceptions of hapu and iwi appear to be converging with an increasing focus on the physicality of marae, its environment and symbolism, and the social events and relationships negotiated in that space.  New Zealand participants saw some hapu and iwi maintenance activities as more legitimate than others.  More value was placed on returning to hapu and iwi homelands however irregular these returns were.  In contrast, conceptions of hapu and iwi held by participants in Hawai'i seemed less intense.  There were few opportunities to engage with other hapu or iwi members.  Being Māori had greater meaning and was understood, probed and valued by others in the culturally plural context of Hawai'i.  For New Zealand participants, being Māori was enacted in the context of being a discriminated, negatively constructed minority.  All were aware of the defining effect that the presence of a dominant majority could have and countered these effects by engaging in social justice and in-group solidarity activities.

The changing identity conceptions held by members of Māori social groups will have implications for a sense of community and social cohesion, for tribal asset management, service delivery and crown settlement processes.  If Māori are redefining and renegotiating their social identities to achieve greater meaning and satisfaction then these changes are important to respond to and recognise.

text: Māori social identities in New Zealand and Hawai'i This research is comprised of two narrative interview studies of Māori in two different settings, New Zealand (n=20) and Hawai'i (n=30).  The data was gathered over the 1994-1996 period.  The two settings have some commonalities and differences.  In both settings Māori are required to make decisions about the continuity of their ethnic Māori identities and hereditary cultural identities of iwi, hapu and whanau, and the part that they wish these identities to play in their daily lives.  The focus of this research was about how Māori create meaning in their lives and maintain their social identities across and within those contexts they move through. 

The findings of this research suggest that Māori in New Zealand continue to value and gain meaning and satisfaction from their cultural collectivities and the social identities derived from them.  However, the results tend to suggest that there are changes in the ways that individuals conceptualise these identities and concomitantly, how they see of themselves.
For New Zealand participants, conceptions of hapu and iwi appear to be converging with an increasing focus on the physicality of marae, its environment and symbolism, and the social events and relationships negotiated in that space.  New Zealand participants saw some hapu and iwi maintenance activities as more legitimate than others.  More value was placed on returning to hapu and iwi homelands however irregular these returns were.  In contrast, conceptions of hapu and iwi held by participants in Hawai'i seemed less intense.  There were few opportunities to engage with other hapu or iwi members.  Being Māori had greater meaning and was understood, probed and valued by others in the culturally plural context of Hawai'i.  For New Zealand participants, being Māori was enacted in the context of being a discriminated, negatively constructed minority.  All were aware of the defining effect that the presence of a dominant majority could have and countered these effects by engaging in social justice and in-group solidarity activities.

The changing identity conceptions held by members of Māori social groups will have implications for a sense of community and social cohesion, for tribal asset management, service delivery and crown settlement processes.  If Māori are redefining and renegotiating their social identities to achieve greater meaning and satisfaction then these changes are important to respond to and recognise.

year: 2007