title: Littoral sediment budget and beach morphodynamics, Pukehina Beach to Matata, Bay of Plenty

authors: Phizacklea, David Jonathan Dominic

subjects: coast changes

abstract: The Pukehina-Matata coastal sector is one of the least studied parts of the Bay of Plenty coastline. Currently this section of coast is in a stable, tending towards erosive, condition, with historical erosion of 0-0.2 m/year.
Sediment mineralogy reflects the high input of quartzo-feldspathic material into the beach-dune-nearshore system. For the Otamarakau-Matata sector much of the sediment is provided from fluvial sources, predominantly the Waitahanui, Pikowai, and Herepuru streams, although the total stream input in this area is only 3,000 to 7,000 m³ per year. The sources of beach sand from Town Point to Otamarakau includes some erosion of catchment material, supplemented by littoral drift, erosion of submarine rock outcrops in the Town Point-Otamarakau region, and possible onshore reworking of pre-Holocene sediments.
The greywacke gravels present within the littoral system, especially between Rodgers Road and Pukehina, are relict deposits, which are presently active within the beach-dune-nearshore system due to the small volume transfers of sandy sediments. Their original source, is suggested as from marine erosion of Castlecliffian sediments, such as exposed in the coastal cliffs at Matata.
Net littoral drift is suggested as bi-directional from a centre-point near Otamarakau, to both the north-east along Pukehina Spit, and to the south-west towards Matata. Some counter-drift occurs between the Tarawera River mouth and Matata, and along the tip of Pukehina Spit, with nourishment of this area by the Waihi estuary.
Nearshore sedimentary-morphodynamic units show that the nearshore and inner-shelf at Town Point, and from southern Pukehina Beach to Otamarakau, is characterised by the presence of numerous rock outcrops, which are responsible for the coarse sands and relatively higher carbonate abundances in this area.
Sediment volumes within the beach-nearshore system, and alongshore transfers between sectors of the coast are small, with annual net littoral drift estimated as 15,000 m³ at Matata. Diabathic processes are considered to dominate, with the limit of significant onshore-offshore sediment transport no more than 12 m, and a parabathic limit of less than 6 m.
The net change in sediment volume for the entire beach system within the Pukehina-Matata coastal sector between 1989 and 1993, produced a calculated deficit of sediment of 90,570 m³. In comparison a longer-term change, between 1978 and 1993, showed a sediment surplus of 218, 560 m³. Over the Pukehina-Matata coastal sector these volume changes are reasonably small and their variability reflects both the dynamic nature, and the delicate state of equilibrium, of the beach-dune-nearshore system. The derived littoral sediment budget shows that in order to balance the inputs and outputs within the system approximately 27,400 m³ of annual onshore
sediment transport must occur. Current sand extraction at Otamarakau has resulted in a decline in the beach sediment volumes between Otamarakau and Pikowai, with this sector in a sediment deficit. Although natural processes mask the true impacts, the increased sand extraction rate of 36,000 m³ per year is liable to further deplete the beach-dunenearshore system. However, in the short-term these effects are unlikely to be immediately noticeable.

text: Littoral sediment budget and beach morphodynamics, Pukehina Beach to Matata, Bay of Plenty The Pukehina-Matata coastal sector is one of the least studied parts of the Bay of Plenty coastline. Currently this section of coast is in a stable, tending towards erosive, condition, with historical erosion of 0-0.2 m/year.
Sediment mineralogy reflects the high input of quartzo-feldspathic material into the beach-dune-nearshore system. For the Otamarakau-Matata sector much of the sediment is provided from fluvial sources, predominantly the Waitahanui, Pikowai, and Herepuru streams, although the total stream input in this area is only 3,000 to 7,000 m³ per year. The sources of beach sand from Town Point to Otamarakau includes some erosion of catchment material, supplemented by littoral drift, erosion of submarine rock outcrops in the Town Point-Otamarakau region, and possible onshore reworking of pre-Holocene sediments.
The greywacke gravels present within the littoral system, especially between Rodgers Road and Pukehina, are relict deposits, which are presently active within the beach-dune-nearshore system due to the small volume transfers of sandy sediments. Their original source, is suggested as from marine erosion of Castlecliffian sediments, such as exposed in the coastal cliffs at Matata.
Net littoral drift is suggested as bi-directional from a centre-point near Otamarakau, to both the north-east along Pukehina Spit, and to the south-west towards Matata. Some counter-drift occurs between the Tarawera River mouth and Matata, and along the tip of Pukehina Spit, with nourishment of this area by the Waihi estuary.
Nearshore sedimentary-morphodynamic units show that the nearshore and inner-shelf at Town Point, and from southern Pukehina Beach to Otamarakau, is characterised by the presence of numerous rock outcrops, which are responsible for the coarse sands and relatively higher carbonate abundances in this area.
Sediment volumes within the beach-nearshore system, and alongshore transfers between sectors of the coast are small, with annual net littoral drift estimated as 15,000 m³ at Matata. Diabathic processes are considered to dominate, with the limit of significant onshore-offshore sediment transport no more than 12 m, and a parabathic limit of less than 6 m.
The net change in sediment volume for the entire beach system within the Pukehina-Matata coastal sector between 1989 and 1993, produced a calculated deficit of sediment of 90,570 m³. In comparison a longer-term change, between 1978 and 1993, showed a sediment surplus of 218, 560 m³. Over the Pukehina-Matata coastal sector these volume changes are reasonably small and their variability reflects both the dynamic nature, and the delicate state of equilibrium, of the beach-dune-nearshore system. The derived littoral sediment budget shows that in order to balance the inputs and outputs within the system approximately 27,400 m³ of annual onshore
sediment transport must occur. Current sand extraction at Otamarakau has resulted in a decline in the beach sediment volumes between Otamarakau and Pikowai, with this sector in a sediment deficit. Although natural processes mask the true impacts, the increased sand extraction rate of 36,000 m³ per year is liable to further deplete the beach-dunenearshore system. However, in the short-term these effects are unlikely to be immediately noticeable.

year: 1993

title: Exploring rumen microbe-derived fibre-degrading activities for improving feed digestibility

authors: Moon, Christina D.

subjects: Digestibility

abstract: Ruminal fibre degradation is mediated by a complex community of rumen microbes, and its efficiency is crucial for optimal dairy productivity. Enzymes produced by rumen microbes are primarily responsible for degrading the complex structural polysaccharides that comprise fibre in the plant cell walls of feed materials. Because rumen microbes have evolved with their ruminant hosts over millions of years to perform this task, their enzymes are hypothesised to be optimally suited for activity at the temperature, pH range, and anaerobic environment of the rumen. However, fibre-rich diets are not fully digested, which represents a loss in potential animal productivity. Thus, there is opportunity to improve fibre utilisation through treating feeds with rumen microbe-derived fibrolytic enzymes and associated activities that enhance fibre degradation. This research aims to gain a better understanding of the key rumen microbes involved in fibre degradation and the mechanisms they employ to degrade fibre, by applying cultivation-based and culture-independent genomics approaches to rumen microbial communities of New Zealand dairy cattle. Using this knowledge, we aim to identify new opportunities for improving fibre degradation to enhance dairy productivity.
Rumen content samples were taken over the course of a year from a Waikato dairy production herd. Over 1,000 rumen bacterial cultures were obtained from the plant-adherent fraction of the rumen contents. Among these cultures, two, 59 and 103 potentially new families, genera and species of rumen bacteria were identified, respectively. Many of the novel strains are being genome sequenced within the Hungate 1000 rumen microbial reference genome programme, which is providing deeper insights into the range of mechanisms used by the individual strains for fibre degradation. This information has been used to guide the selection of rumen bacterial strains with considerable potential as fibrolytic enzyme producers in vitro, with the intent of developing the strains so that their enzymes may be used as feed pre-treatments for use on farm. Culture-independent metagenomic approaches were also used to explore the activities involved in fibre degradation from the rumen microbial communities. Functional screening has revealed a range of novel enzymes and a novel fibre disrupting activity. Enrichment for the cell-secreted proteins from the community revealed evidence of a diverse range of cellulosomes, which are cell-surface associated multi-enzyme complexes that efficiently degrade plant cell wall polysaccharides. Biochemical and structural characterisation of these proteins has been conducted.
In conclusion, cultivation and culture-independent genomic approaches have been applied to New Zealand bovine rumen microbial communities, and have provided considerable new insights into ruminal fibre degradation processes. Novel activities and bacterial species that display desirable activities on fibrous substrates in vitro are now being explored for their potential to improve ruminal fibre degradation, to allow the development of new technologies that will enhance dairy productivity.

text: Exploring rumen microbe-derived fibre-degrading activities for improving feed digestibility Ruminal fibre degradation is mediated by a complex community of rumen microbes, and its efficiency is crucial for optimal dairy productivity. Enzymes produced by rumen microbes are primarily responsible for degrading the complex structural polysaccharides that comprise fibre in the plant cell walls of feed materials. Because rumen microbes have evolved with their ruminant hosts over millions of years to perform this task, their enzymes are hypothesised to be optimally suited for activity at the temperature, pH range, and anaerobic environment of the rumen. However, fibre-rich diets are not fully digested, which represents a loss in potential animal productivity. Thus, there is opportunity to improve fibre utilisation through treating feeds with rumen microbe-derived fibrolytic enzymes and associated activities that enhance fibre degradation. This research aims to gain a better understanding of the key rumen microbes involved in fibre degradation and the mechanisms they employ to degrade fibre, by applying cultivation-based and culture-independent genomics approaches to rumen microbial communities of New Zealand dairy cattle. Using this knowledge, we aim to identify new opportunities for improving fibre degradation to enhance dairy productivity.
Rumen content samples were taken over the course of a year from a Waikato dairy production herd. Over 1,000 rumen bacterial cultures were obtained from the plant-adherent fraction of the rumen contents. Among these cultures, two, 59 and 103 potentially new families, genera and species of rumen bacteria were identified, respectively. Many of the novel strains are being genome sequenced within the Hungate 1000 rumen microbial reference genome programme, which is providing deeper insights into the range of mechanisms used by the individual strains for fibre degradation. This information has been used to guide the selection of rumen bacterial strains with considerable potential as fibrolytic enzyme producers in vitro, with the intent of developing the strains so that their enzymes may be used as feed pre-treatments for use on farm. Culture-independent metagenomic approaches were also used to explore the activities involved in fibre degradation from the rumen microbial communities. Functional screening has revealed a range of novel enzymes and a novel fibre disrupting activity. Enrichment for the cell-secreted proteins from the community revealed evidence of a diverse range of cellulosomes, which are cell-surface associated multi-enzyme complexes that efficiently degrade plant cell wall polysaccharides. Biochemical and structural characterisation of these proteins has been conducted.
In conclusion, cultivation and culture-independent genomic approaches have been applied to New Zealand bovine rumen microbial communities, and have provided considerable new insights into ruminal fibre degradation processes. Novel activities and bacterial species that display desirable activities on fibrous substrates in vitro are now being explored for their potential to improve ruminal fibre degradation, to allow the development of new technologies that will enhance dairy productivity.

year: 2014

title: Indigenous psychologies, fourth world peoples and the international literature: Finding ourselves in online abstracting and indexing databases

authors: Nikora, Linda Waimarie

subjects: indigenous psychologies

abstract: The presence and visibility of indigenous people and experience in the field of indigenous psychologies is vital to articulating existence, life, self-determination and future making. This article highlights examples of indigenous Psychology being both absent and present at the same time in OAD (online academic databases).

text: Indigenous psychologies, fourth world peoples and the international literature: Finding ourselves in online abstracting and indexing databases The presence and visibility of indigenous people and experience in the field of indigenous psychologies is vital to articulating existence, life, self-determination and future making. This article highlights examples of indigenous Psychology being both absent and present at the same time in OAD (online academic databases).

year: 2016