title: Family-supportive organization perceptions, multiple dimensions of work–family conflict, and employee satisfaction: A test of model across five samples

authors: Lapierre, Laurent M.

subjects: work–family conflict

abstract: Using samples of managers drawn from five Western countries, we tested a theoretical model linking employees’ perceptions of their work environment’s family-supportiveness to six different dimensions of work–family conflict (WFC), and to their job satisfaction, family satisfaction, and life satisfaction. Our results are consistent with a causal process whereby employees working in an environment viewed as more family-supportive experience lower levels of WFC. Reduced WFC then translates into greater job and family satisfaction, followed by greater overall life satisfaction. These findings were generalizable across the five samples.

text: Family-supportive organization perceptions, multiple dimensions of work–family conflict, and employee satisfaction: A test of model across five samples Using samples of managers drawn from five Western countries, we tested a theoretical model linking employees’ perceptions of their work environment’s family-supportiveness to six different dimensions of work–family conflict (WFC), and to their job satisfaction, family satisfaction, and life satisfaction. Our results are consistent with a causal process whereby employees working in an environment viewed as more family-supportive experience lower levels of WFC. Reduced WFC then translates into greater job and family satisfaction, followed by greater overall life satisfaction. These findings were generalizable across the five samples.

year: 2008

title: The effects of terrestrial sediment inputs on ecosystem functions in seagrass meadows and unvegetated sediments

authors: Flowers, Georgina

subjects: seagrass

abstract: Ecological functions in estuarine seagrass and unvegetated soft sediment habitats underpin many valuable ecosystem services. However, changing land-use and climate are accelerating inputs of fine terrestrial sediments, threatening these habitats. The prolonged suspension of fine sediments can reduce seafloor light availability and long-term accumulations increase sediment mud content (particles < 63 µm), both of which could have significant consequences on ecosystem functioning. Understanding how ecosystem functioning may respond to environmental change is vital to estuary management. In this thesis, I investigated the short- and long-term effects of elevated terrestrial sediment inputs on benthic primary production and nutrient cycling in intertidal seagrass meadows (Zostera muelleri) and microphytobenthos-dominated unvegetated habitats. 
To investigate the effects of reduced seafloor light availability and prolonged submergence periods resulting from global heating induced sea-level rise, I conducted a two-year seasonal in situ assessment of photosynthesis-irradiance relationships during submerged and emerged conditions in an adjacent seagrass meadow and unvegetated sandflat. Submerged gross primary production (GPP) in both habitats and emerged GPP in the seagrass habitat were strongly controlled by light availability. Higher rates of light-saturated GPP were found during submerged periods compared to emerged periods in both habitats, but this difference was most pronounced in the unvegetated habitat. If the water-column remains clear, sea-level rise could therefore increase daily GPP in soft sediment habitats. However, declines in submerged GPP with increased water-column turbidity will be exacerbated with sea-level rise. 
Across a natural mud content gradient, I measured primary production in seagrass and unvegetated habitats to address the long-term implications of elevated sediment inputs. In sediments with ≤ 35 % mud content, net primary production (NPP) and GPP was independent of mud content in both habitats. However, extending the mud gradient in unvegetated habitats to 49 % (seagrass habitats restricted to ≤ 35 % mud content) resulted in NPP and GPP declining with increasing mud content. These results highlight that loss of seagrass meadows resulting in expansion of unvegetated habitats could lead to reductions in intertidal production; seen most acutely in areas with high mud content (≥ 39 %).
I also investigated the spatial and temporal variability in nutrient cycling in seagrass and unvegetated habitats to examine how environmental gradients affected sediment nutrient fluxes and denitrification rates. Ammonium effluxes were lower in the seagrass compared to the unvegetated habitats and were lower in both habitats during light compared to dark conditions. Denitrification rates were similar in both habitats but were found to decrease with increasing mud content. Overall, denitrification efficiency was highest in the seagrass habitat. These results indicate that future seagrass decline and/or increased mud content in soft sediment habitats will reduce resilience to eutrophication. 
This thesis demonstrates that future seagrass decline and elevated terrestrial sediment inputs are likely to have serious implications on the high rates of primary production and nutrient cycling of intertidal seagrass meadows and unvegetated habitats. Furthermore, it highlights the value of measuring ecosystem functions in different soft sediment habitat types across multiple spatial and temporal scales to inform future management against anthropogenic stressors.

text: The effects of terrestrial sediment inputs on ecosystem functions in seagrass meadows and unvegetated sediments Ecological functions in estuarine seagrass and unvegetated soft sediment habitats underpin many valuable ecosystem services. However, changing land-use and climate are accelerating inputs of fine terrestrial sediments, threatening these habitats. The prolonged suspension of fine sediments can reduce seafloor light availability and long-term accumulations increase sediment mud content (particles < 63 µm), both of which could have significant consequences on ecosystem functioning. Understanding how ecosystem functioning may respond to environmental change is vital to estuary management. In this thesis, I investigated the short- and long-term effects of elevated terrestrial sediment inputs on benthic primary production and nutrient cycling in intertidal seagrass meadows (Zostera muelleri) and microphytobenthos-dominated unvegetated habitats. 
To investigate the effects of reduced seafloor light availability and prolonged submergence periods resulting from global heating induced sea-level rise, I conducted a two-year seasonal in situ assessment of photosynthesis-irradiance relationships during submerged and emerged conditions in an adjacent seagrass meadow and unvegetated sandflat. Submerged gross primary production (GPP) in both habitats and emerged GPP in the seagrass habitat were strongly controlled by light availability. Higher rates of light-saturated GPP were found during submerged periods compared to emerged periods in both habitats, but this difference was most pronounced in the unvegetated habitat. If the water-column remains clear, sea-level rise could therefore increase daily GPP in soft sediment habitats. However, declines in submerged GPP with increased water-column turbidity will be exacerbated with sea-level rise. 
Across a natural mud content gradient, I measured primary production in seagrass and unvegetated habitats to address the long-term implications of elevated sediment inputs. In sediments with ≤ 35 % mud content, net primary production (NPP) and GPP was independent of mud content in both habitats. However, extending the mud gradient in unvegetated habitats to 49 % (seagrass habitats restricted to ≤ 35 % mud content) resulted in NPP and GPP declining with increasing mud content. These results highlight that loss of seagrass meadows resulting in expansion of unvegetated habitats could lead to reductions in intertidal production; seen most acutely in areas with high mud content (≥ 39 %).
I also investigated the spatial and temporal variability in nutrient cycling in seagrass and unvegetated habitats to examine how environmental gradients affected sediment nutrient fluxes and denitrification rates. Ammonium effluxes were lower in the seagrass compared to the unvegetated habitats and were lower in both habitats during light compared to dark conditions. Denitrification rates were similar in both habitats but were found to decrease with increasing mud content. Overall, denitrification efficiency was highest in the seagrass habitat. These results indicate that future seagrass decline and/or increased mud content in soft sediment habitats will reduce resilience to eutrophication. 
This thesis demonstrates that future seagrass decline and elevated terrestrial sediment inputs are likely to have serious implications on the high rates of primary production and nutrient cycling of intertidal seagrass meadows and unvegetated habitats. Furthermore, it highlights the value of measuring ecosystem functions in different soft sediment habitat types across multiple spatial and temporal scales to inform future management against anthropogenic stressors.

year: 2024-04-15

title: The Effects of Contaminated Rena Sediments on Juvenile Paua (Haliotis iris)

authors: McSweeney, Caleb S.

subjects: contamiant

abstract: The grounding of the MV Rena on Otaiti resulted in the release of heavy fuel oil and container debris contaminants into the surrounding environments including the rocky shores of the adjacent Mōtītī Island. This is the habitat where significant populations of benthic paua reside. Paua (Haliotis iris) are a staple and consistent food source for Mōtītī Island. Being an offshore island with no amenities, Mōtītī Island residents are reliant on the ocean as a pataka kai (food cupboard) and are therefore acutely aware of environmental influences to the harvest of kaimoana.
This thesis aimed to address concerns relating to the effects of contaminated boundary layer water emanating from contaminated ‘Rena’ sediment on juvenile paua. Research was focused in two areas: 1) the sublethal behavioural effects of contaminated Rena sediment to Paua and 2) the accumulation of trace metals in the edible tissue and viscera mass. The experiments were carried out with the use of a close circuit aquaria in a laboratory environment, followed by a field experiment.
In all experiments, paua in control treatments were healthy by comparison to paua exposed to treatments with Rena contaminated sediments and copper as judged by survivorship and behaviour. The most likely cause of of behavioural aberrations and mortality observed was deemed to be copper as demonstrated by Diffusive Gradient in thin film (DGT) and ambient water analyses in both experiments. Copper that is bioavailable can increase quickly in the edible tissue and viscera mass as was identified as the visceral mass of Rena and copper exposed paua had a higher mean concentration of this and other trace metals.
On Otaiti, the effects to paua from the Rena ship wreck and lost container contents, know to include a medly of metals and other contaminants, is not likely to be limited to copper alone. Results demosntrate the relevance of examining the effects of water borne contaminated plumes emanating from complex mixtures of contaminants. This is rarely done in ecotoxicological studies which tend to focus on individual contaminant compounds.

text: The Effects of Contaminated Rena Sediments on Juvenile Paua (Haliotis iris) The grounding of the MV Rena on Otaiti resulted in the release of heavy fuel oil and container debris contaminants into the surrounding environments including the rocky shores of the adjacent Mōtītī Island. This is the habitat where significant populations of benthic paua reside. Paua (Haliotis iris) are a staple and consistent food source for Mōtītī Island. Being an offshore island with no amenities, Mōtītī Island residents are reliant on the ocean as a pataka kai (food cupboard) and are therefore acutely aware of environmental influences to the harvest of kaimoana.
This thesis aimed to address concerns relating to the effects of contaminated boundary layer water emanating from contaminated ‘Rena’ sediment on juvenile paua. Research was focused in two areas: 1) the sublethal behavioural effects of contaminated Rena sediment to Paua and 2) the accumulation of trace metals in the edible tissue and viscera mass. The experiments were carried out with the use of a close circuit aquaria in a laboratory environment, followed by a field experiment.
In all experiments, paua in control treatments were healthy by comparison to paua exposed to treatments with Rena contaminated sediments and copper as judged by survivorship and behaviour. The most likely cause of of behavioural aberrations and mortality observed was deemed to be copper as demonstrated by Diffusive Gradient in thin film (DGT) and ambient water analyses in both experiments. Copper that is bioavailable can increase quickly in the edible tissue and viscera mass as was identified as the visceral mass of Rena and copper exposed paua had a higher mean concentration of this and other trace metals.
On Otaiti, the effects to paua from the Rena ship wreck and lost container contents, know to include a medly of metals and other contaminants, is not likely to be limited to copper alone. Results demosntrate the relevance of examining the effects of water borne contaminated plumes emanating from complex mixtures of contaminants. This is rarely done in ecotoxicological studies which tend to focus on individual contaminant compounds.

year: 2015