scholarly journals The Effect of Suspended Sediment Loads on the Growth, Oxygen Consumption and Mucus Production of Pāua (Haliotis iris)

2021 ◽  
Author(s):  
◽  
Taputukura Raea

<p>Land based-effects, including sedimentation are threatening estuarine and coastal systems globally. Ecological systems are faced with significant pressures from human activities including toxic pollution, eutrophication, habitat fragmentation and sedimentation. In recent years sediment inputs into marine systems have been greatly accelerated through land-based activities such as urban-land use, agriculture, coastal developments, large scale land clearances and farming. Effects of sedimentation on marine organisms include suffocation, reduced foraging efficiency and clogging of the gills of filter feeders.  In New Zealand, sedimentation is the most important land-based stressor on the coastal marine environment. The pāua (Haliotis iris), is an important macroalgal grazer and is one of New Zealand’s top 10 seafood exports. However, little is known about the effects suspended sediments have on H. iris. The aim of this thesis is to experimentally test the effects of suspended sediment on the growth, oxygen consumption and mucus production for H. iris, using sediment concentrations that would naturally occur within Wellington Harbour, New Zealand.  Suspended sediment had no significant effect on H. iris growth or oxygen consumption. However, exposure to suspended sediments significantly reduced mucus production in H. iris. There were also trends in the data to suggest that respiration in smaller H. iris was reduced by suspended sediments.  Limited studies have explored the effect of suspended sediments on gastropods, even though sedimentation is one of the most significant land based stressors on the marine environment, not only in New Zealand, but also worldwide. This study has led to a better understanding of the potential implications suspended sediment may incur for not only H. iris, but also Haliotis species in general.</p>

2021 ◽  
Author(s):  
◽  
Taputukura Raea

<p>Land based-effects, including sedimentation are threatening estuarine and coastal systems globally. Ecological systems are faced with significant pressures from human activities including toxic pollution, eutrophication, habitat fragmentation and sedimentation. In recent years sediment inputs into marine systems have been greatly accelerated through land-based activities such as urban-land use, agriculture, coastal developments, large scale land clearances and farming. Effects of sedimentation on marine organisms include suffocation, reduced foraging efficiency and clogging of the gills of filter feeders.  In New Zealand, sedimentation is the most important land-based stressor on the coastal marine environment. The pāua (Haliotis iris), is an important macroalgal grazer and is one of New Zealand’s top 10 seafood exports. However, little is known about the effects suspended sediments have on H. iris. The aim of this thesis is to experimentally test the effects of suspended sediment on the growth, oxygen consumption and mucus production for H. iris, using sediment concentrations that would naturally occur within Wellington Harbour, New Zealand.  Suspended sediment had no significant effect on H. iris growth or oxygen consumption. However, exposure to suspended sediments significantly reduced mucus production in H. iris. There were also trends in the data to suggest that respiration in smaller H. iris was reduced by suspended sediments.  Limited studies have explored the effect of suspended sediments on gastropods, even though sedimentation is one of the most significant land based stressors on the marine environment, not only in New Zealand, but also worldwide. This study has led to a better understanding of the potential implications suspended sediment may incur for not only H. iris, but also Haliotis species in general.</p>


2020 ◽  
Vol 13 (3) ◽  
pp. 1248 ◽  
Author(s):  
Solange Cavalcanti de Melo ◽  
José Coelho de Araújo Filho ◽  
Renata Maria Caminha Mendes de Oliveira Carvalho

RESUMOO conhecimento da análise quantitativa das concentrações de sedimentos em suspensão transportados pelo rio São Francisco bem como sua relação com as vazões é de muita importância, pois pode auxiliar na identificação dos efeitos da intervenção humana e ou ocasionados pelas condições naturais da região. As regiões a jusante dos barramentos no rio São Francisco apresentam como principal consequência a regularização das vazões e a diminuição das concentrações de sedimentos. O objetivo da pesquisa foi determinar as curvas-chave de sedimentos em suspensão (CCS) nas estações fluviométricas instaladas no Baixo São Francisco (BSF) após a barragem de Xingó. Para o estabelecimento dessas curvas foram utilizados dados de vazão e concentração de sedimentos em suspensão, obtidos do sistema Hidroweb no site da Agência Nacional da Água (ANA) no período de 1999 a 2018. Foram obtidas CCS para todo o trecho do BSF as quais apresentaram bons coeficientes de determinação. Na análise dos dados também foi possível perceber que nos últimos anos, desde 2013 houve redução gradativa das vazões disponibilizadas na barragem de Xingó. Consequentemente, houve também a redução gradativa das cargas de sedimentos em suspensão geradas nas estações de Piranhas, Traipu e Propriá, ou seja, os menores valores já registrados no BSF correspondendo as menores séries históricas tanto de vazão como de sedimentos em suspensão.  Keys curves of sediment discharges in suspension in the Lower São Francisco A B S T R A C TThe knowledge of the quantitative analysis of suspended sediment concentrations carried by the São Francisco River as well as its relation with the flows is of great importance, since it can help in the identification of the effects of human intervention and/or caused by the natural conditions of the region. In the downstream regions of the São Francisco riverbanks, the main consequence was the regularization of flow rates and the reduction of sediment concentrations. The objective of the research was to determine the key curves of suspended sediments (CCS) at the fluviometric stations installed in the lower São Francisco river after Xingó dam. For the evaluation, flow data and suspended sediment concentration were used. These data were obtained from the Hidroweb system on the website of the National Water Agency (ANA) from 1999 to 2018. CCS were plotted for all stretches and presented good coefficients of determination (R2). Based on the analysis of the data it was also possible to notice that in recent years, since 2013 there has been a gradual reduction of the flows available in the Xingó dam. Consequently, there was also a gradual reduction of suspended sediment loads generated at the Piranhas, Traipu and Propriá stations, that is, the lowest values already recorded in lower São Francisco, corresponding to the lower historical series of both discharge and suspended sediments.Keywords: dam, flow, sediments 


2017 ◽  
Vol 284 (1866) ◽  
pp. 20171279 ◽  
Author(s):  
Sybille Hess ◽  
Leteisha J. Prescott ◽  
Andrew S. Hoey ◽  
Shannon A. McMahon ◽  
Amelia S. Wenger ◽  
...  

Reduced water quality, in particular increases in suspended sediments, has been linked to declines in fish abundance on coral reefs. Changes in gill structure induced by suspended sediments have been hypothesized to impair gill function and may provide a mechanistic basis for the observed declines; yet, evidence for this is lacking. We exposed juveniles of three reef fish species ( Amphiprion melanopus , Amphiprion percula and Acanthochromis polyacanthus ) to suspended sediments (0–180 mg l −1 ) for 7 days and examined changes in gill structure and metabolic performance (i.e. oxygen consumption). Exposure to suspended sediments led to shorter gill lamellae in A. melanopus and A. polyacanthus and reduced oxygen diffusion distances in all three species. While A. melanopus exhibited impaired oxygen uptake after suspended sediment exposure, i.e. decreased maximum and increased resting oxygen consumption rates resulting in decreased aerobic scope, the oxygen consumption rates of the other two species remained unaffected. These findings imply that species sensitive to changes in gill structure such as A. melanopus may decline in abundance as reefs become more turbid, whereas species that are able to maintain metabolic performance despite suspended sediment exposure, such as A. polyacanthus or A. percula , may be able to persist or gain a competitive advantage.


2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Catherine M. Febria ◽  
Maggie Bayfield ◽  
Kathryn E. Collins ◽  
Hayley S. Devlin ◽  
Brandon C. Goeller ◽  
...  

In Aotearoa New Zealand, agricultural land-use intensification and decline in freshwater ecosystem integrity pose complex challenges for science and society. Despite riparian management programmes across the country, there is frustration over a lack in widespread uptake, upfront financial costs, possible loss in income, obstructive legislation and delays in ecological recovery. Thus, social, economic and institutional barriers exist when implementing and assessing agricultural freshwater restoration. Partnerships are essential to overcome such barriers by identifying and promoting co-benefits that result in amplifying individual efforts among stakeholder groups into coordinated, large-scale change. Here, we describe how initial progress by a sole farming family at the Silverstream in the Canterbury region, South Island, New Zealand, was used as a catalyst for change by the Canterbury Waterway Rehabilitation Experiment, a university-led restoration research project. Partners included farmers, researchers, government, industry, treaty partners (Indigenous rights-holders) and practitioners. Local capacity and capability was strengthened with practitioner groups, schools and the wider community. With partnerships in place, co-benefits included lowered costs involved with large-scale actions (e.g., earth moving), reduced pressure on individual farmers to undertake large-scale change (e.g., increased participation and engagement), while also legitimising the social contracts for farmers, scientists, government and industry to engage in farming and freshwater management. We describe contributions and benefits generated from the project and describe iterative actions that together built trust, leveraged and aligned opportunities. These actions were scaled from a single farm to multiple catchments nationally.


1995 ◽  
Vol 31 (5-6) ◽  
pp. 231-234 ◽  
Author(s):  
Gillian D. Lewis

To assess the F-specific bacteriophage as an indicator of pathogenic viruses, a comparative study has been made of the occurrence of F-phage and human enteroviruses in sewage wastes and the marine environment. Although F-phage seemed in several respects to match pathogen behaviour, its low abundance in bathing beach water, uncertainty as to its source and other detection irregularities make its use as an indicator problematical.


2004 ◽  
Vol 31 (3) ◽  
pp. 319 ◽  
Author(s):  
Jane Catherine Kitson

Sooty shearwaters (tītī, muttonbird, Puffinus griseus) are highly abundant migratory seabirds, which return to breeding colonies in New Zealand. The Rakiura Māori annual chick harvest on islands adjacent to Rakiura (Stewart Island), is one of the last large-scale customary uses of native wildlife in New Zealand. This study aimed to establish whether the rate at which muttonbirders can extract chicks from their breeding burrows indicates population trends of sooty shearwaters. Harvest rates increased slightly with increasing chick densities on Putauhinu Island. Birders' harvest rates vary in their sensitivities to changing chick density. Therefore a monitoring panel requires careful screening to ensure that harvest rates of the birders selected are sensitive to chick density, and represents a cross-section of different islands. Though harvest rates can provide only a general index of population change, it can provide an inexpensive and feasible way to measure population trends. Detecting trends is the first step to assessing the long-term sustainability of the harvest.


Author(s):  
Carla Houkamau ◽  
Petar Milojev ◽  
Lara Greaves ◽  
Kiri Dell ◽  
Chris G Sibley ◽  
...  

AbstractLongitudinal studies into the relationship between affect (positive or negative feelings) towards one’s own ethnic group and wellbeing are rare, particularly for Indigenous peoples. In this paper, we test the longitudinal effects of in-group warmth (a measure of ethnic identity affect) and ethnic identity centrality on three wellbeing measures for New Zealand Māori: life satisfaction (LS), self-esteem (SE), and personal wellbeing (PW). Longitudinal panel data collected from Māori (N = 3803) aged 18 or over throughout seven annual assessments (2009–2015) in the New Zealand Attitudes and Values Study were analyzed using latent trajectory models with structured residuals to examine cross-lagged within-person effects. Higher in-group warmth towards Māori predicted increases in all three wellbeing measures, even more strongly than ethnic identity centrality. Bi-directionally, PW and SE predicted increased in-group warmth, and SE predicted ethnic identification. Further, in sample-level (between-person) trends, LS and PW rose, but ethnic identity centrality interestingly declined over time. This is the first large-scale longitudinal study showing a strong relationship between positive affect towards one’s Indigenous ethnic group and wellbeing. Efforts at cultural recovery and restoration have been a deliberate protective response to colonization, but among Māori, enculturation and access to traditional cultural knowledge varies widely. The data reported here underline the role of ethnic identity affect as an important dimension of wellbeing and call for continued research into the role of this dimension of ethnic identity for Indigenous peoples.


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