title: Lake Tutira: historic water quality, monitoring recommendations and management options

authors: Abell, Jonathan Michael

abstract: Lake Tutira is located 30 km north of Napier and is an important recreational resource for the Hawke's Bay region. The lake has an area of 1.74 km², mean depth of 21 m and maximum depth of 42 m. It has a recent history of poor water quality, and over 2011 and 2012 there were severe blooms of blue-green algae (cyanobacteria), which detracted from the ecological and aesthetic value of the lake, and impacted on its suitability for recreational use.
We analysed the recently-available (2009-2012) monitoring data for Lake Tutira, which included periods of regular (c. monthly) water quality monitoring measurements, as well as data from an automated high-frequency monitoring buoy. Poor water quality in Lake Tutira is not a recent problem and TLI values in the 1960s and 1970s were higher than those for the analysis period. High-frequency buoy data demonstrated that high-intensity rainfall events produced rapid increases in water level and increased turbidity. Increases in chlorophyll fluorescence a few days after major rainfall events indicate that rainfall events may also stimulate increases in phytoplankton biomass in the lake via increased nutrient inputs associated with stormflows.
Grass carp were introduced into Lake Tutira in 2008 to control the invasive weed Hydrilla which had been present in the lake for some decades. There has been a rapid reduction in Hydrilla beds in the lake following the grass carp introduction. We recommend that the impact of grass carp on Lake Tutira be evaluated from an ecosystem perspective, given some marked changes in other components of the lake ecosystem since the introduction.
We evaluated the suitability of Lake Tutira for application of an ecological model to assist with consideration of management options to improve lake water quality. Lake Tutira is a suitable candidate lake for both one-dimensional (1-D; vertically resolved) and three-dimensional (3-D) ecological model applications to represent the vertical variations and whole-lake water column variations, respectively. A comprehensive ecological model of Lake Tutira could be used to simulate the outcomes of various lake restoration strategies, thus acting as a decision support tool for proposed lake management actions. The likely performance of a model application and hence its value for informing management decisions could be improved considerably with substantial additional data collection (e.g. inflow water quality), as well as continuation of the current lake monitoring. A number of potential management options were considered for Lake Tutira and we recommend that these options be considered further with the 1-D and/or 3-D models in order to fully assess their feasibility, effectiveness and value for money.

text: Lake Tutira: historic water quality, monitoring recommendations and management options Lake Tutira is located 30 km north of Napier and is an important recreational resource for the Hawke's Bay region. The lake has an area of 1.74 km², mean depth of 21 m and maximum depth of 42 m. It has a recent history of poor water quality, and over 2011 and 2012 there were severe blooms of blue-green algae (cyanobacteria), which detracted from the ecological and aesthetic value of the lake, and impacted on its suitability for recreational use.
We analysed the recently-available (2009-2012) monitoring data for Lake Tutira, which included periods of regular (c. monthly) water quality monitoring measurements, as well as data from an automated high-frequency monitoring buoy. Poor water quality in Lake Tutira is not a recent problem and TLI values in the 1960s and 1970s were higher than those for the analysis period. High-frequency buoy data demonstrated that high-intensity rainfall events produced rapid increases in water level and increased turbidity. Increases in chlorophyll fluorescence a few days after major rainfall events indicate that rainfall events may also stimulate increases in phytoplankton biomass in the lake via increased nutrient inputs associated with stormflows.
Grass carp were introduced into Lake Tutira in 2008 to control the invasive weed Hydrilla which had been present in the lake for some decades. There has been a rapid reduction in Hydrilla beds in the lake following the grass carp introduction. We recommend that the impact of grass carp on Lake Tutira be evaluated from an ecosystem perspective, given some marked changes in other components of the lake ecosystem since the introduction.
We evaluated the suitability of Lake Tutira for application of an ecological model to assist with consideration of management options to improve lake water quality. Lake Tutira is a suitable candidate lake for both one-dimensional (1-D; vertically resolved) and three-dimensional (3-D) ecological model applications to represent the vertical variations and whole-lake water column variations, respectively. A comprehensive ecological model of Lake Tutira could be used to simulate the outcomes of various lake restoration strategies, thus acting as a decision support tool for proposed lake management actions. The likely performance of a model application and hence its value for informing management decisions could be improved considerably with substantial additional data collection (e.g. inflow water quality), as well as continuation of the current lake monitoring. A number of potential management options were considered for Lake Tutira and we recommend that these options be considered further with the 1-D and/or 3-D models in order to fully assess their feasibility, effectiveness and value for money.

year: 2013

title: Negative political communication on social media and the gender gap: A study of men's and women's reactions to presidential candidate attacks on facebook in 2012 and 2016

authors: Phillips, Justin B.

subjects: Social Sciences

abstract: Do men and women respond differently to negative political communication? Only a limited collection of studies into the effects of negative campaigns have investigated this research question, and the conflicting results produced from such studies have prevented the development of a widely accepted answer. As campaigns transition to new media environments, further problems arise, as any potential gender gap may be magnified on the new political communication battlefield of social media. The present article contributes to this sparsely investigated area through an empirical study of men's and women's reactions on Facebook to US presidential candidate attacks during two general election campaigns (2012 and 2016) and two primaries (2016 Democratic and Republican). Across nearly 400 million reactions and 40 million unique users, women demonstrate lower receptivity to candidate attacks than men. Two potential explanatory factors for the gap are examined, but neither fully captures the magnitude of the differences observed. Conceptualizing the gender gap composition in terms of differential receptivity most accurately explains these findings and potentially resolves the competing explanations for the gap within the existing literature.

text: Negative political communication on social media and the gender gap: A study of men's and women's reactions to presidential candidate attacks on facebook in 2012 and 2016 Do men and women respond differently to negative political communication? Only a limited collection of studies into the effects of negative campaigns have investigated this research question, and the conflicting results produced from such studies have prevented the development of a widely accepted answer. As campaigns transition to new media environments, further problems arise, as any potential gender gap may be magnified on the new political communication battlefield of social media. The present article contributes to this sparsely investigated area through an empirical study of men's and women's reactions on Facebook to US presidential candidate attacks during two general election campaigns (2012 and 2016) and two primaries (2016 Democratic and Republican). Across nearly 400 million reactions and 40 million unique users, women demonstrate lower receptivity to candidate attacks than men. Two potential explanatory factors for the gap are examined, but neither fully captures the magnitude of the differences observed. Conceptualizing the gender gap composition in terms of differential receptivity most accurately explains these findings and potentially resolves the competing explanations for the gap within the existing literature.

year: 2021-09-01

title: Intersecting knowledge worlds: Describing the cultural interfaces within a socioscientific issue

authors: Wagner, Brent

subjects: cultural interface

abstract: Increasing numbers of science teachers in Aotearoa New Zealand are exploring ways to incorporate indigenous mātauranga Māori (Māori knowledge and ways of knowing) into their science programmes. This article presents findings from a study that examined how senior biology students in two English-medium secondary schools incorporated mātauranga Māori alongside biological science knowledge in their discussions about the use of 1080 poison to control mammalian predators. From a social constructivist ontology and interpretivist mode of inquiry using qualitative methodology, a triadic epistemic agency conceptual framework was developed inductively and used to analyse students’ written scripts for their national school leaving qualification (NCEA), and transcriptions of individual interviews. The study took place prior to the introduction of equal status to mātauranga Māori within the New Zealand Curriculum. Deductive analysis using the Triadic identified a group of ten students who drew from both knowledge systems, with varying degrees of knowledge integration. In addition to detailed representations of the theoretical space of the locale of the learner, the findings also identified three distinctive cultural interfaces occupied by the students: conflicted, parallel, and, connected. The findings underscore the importance of enabling diverse knowledge systems in biology classes to converge. Specifically, the incorporation of mātauranga Māori alongside biological science knowledge encourages a critical stance towards knowledge claims, supports pluralist knowledge use among culturally and linguistically diverse learners and promotes critical engagement with socioscientific issues (SSI) in senior secondary school biology.

text: Intersecting knowledge worlds: Describing the cultural interfaces within a socioscientific issue Increasing numbers of science teachers in Aotearoa New Zealand are exploring ways to incorporate indigenous mātauranga Māori (Māori knowledge and ways of knowing) into their science programmes. This article presents findings from a study that examined how senior biology students in two English-medium secondary schools incorporated mātauranga Māori alongside biological science knowledge in their discussions about the use of 1080 poison to control mammalian predators. From a social constructivist ontology and interpretivist mode of inquiry using qualitative methodology, a triadic epistemic agency conceptual framework was developed inductively and used to analyse students’ written scripts for their national school leaving qualification (NCEA), and transcriptions of individual interviews. The study took place prior to the introduction of equal status to mātauranga Māori within the New Zealand Curriculum. Deductive analysis using the Triadic identified a group of ten students who drew from both knowledge systems, with varying degrees of knowledge integration. In addition to detailed representations of the theoretical space of the locale of the learner, the findings also identified three distinctive cultural interfaces occupied by the students: conflicted, parallel, and, connected. The findings underscore the importance of enabling diverse knowledge systems in biology classes to converge. Specifically, the incorporation of mātauranga Māori alongside biological science knowledge encourages a critical stance towards knowledge claims, supports pluralist knowledge use among culturally and linguistically diverse learners and promotes critical engagement with socioscientific issues (SSI) in senior secondary school biology.

year: 2026