scholarly journals Simulated mining-related sedimentation impacts on the deep-sea macrofauna of the Chatham Rise, New Zealand

2021 ◽  
Author(s):  
Campbell Murray
Keyword(s):  
Community Structure ◽  
New Zealand ◽  
Deep Sea ◽  
Benthic Communities ◽  
Sampling Period ◽  
Mining Area ◽  
Warning Sign ◽  
Disturbed Areas ◽  
One Year ◽  
The Impact

<p>With the possibility of deep-sea mining of marine mineral resources occurring in the near future, it is necessary to understand the potential impacts that mining may have on benthic communities. Previous simulated mining experiments have observed direct impacts of deep-sea mining (e.g., faunal mortality); however, indirect impacts of sedimentation were not understood. In New Zealand, there has been interest in mining the seabed of the Chatham Rise, but mining consents have been refused, partly due to the uncertainties of sedimentation impacts on benthic communities. A disturbance experiment conducted in 2019 on the Rise used a modified agricultural plough designed to create a sediment cloud that could result from mining. This disturbance was used to assess the resilience of benthic communities to sedimentation in a proposed future mining area. Macrofaunal and sediment samples were collected with a multicorer before, immediately after and one year after disturbance to assess the impact on the community and its ability to recover. Samplingevents took place in disturbed (physically run over by the plough and subjected to sedimentation) and undisturbed areas (subjected to sedimentation only) at each sampling period. Macrofaunal abundance significantly decreased in disturbed areas after disturbancebut not in undisturbed areas. However, community structure changed in both areas after disturbance; in disturbed areas this was mostly driven by changes in numerically dominant fauna, but in undisturbed areas by the more sensitive fauna which may provide an early warning sign for further changes under increased sedimentation. One year after disturbance, community structure had recovered in both areas. Abundance-based community structure correlated most strongly with C:N molar ratios in the sediment which increased after disturbance. Ecosystem function was measured by sediment community oxygen consumption (SCOC) which increased similarly in both disturbed and undisturbed areas after disturbance; SCOC may be a more sensitive measure than community structure in assessing sedimentation impacts. No correlations were found between SCOC and macrofaunal abundance, biomass, diversity or bacterial abundance. The results of this research are useful for managing the impacts of industries where sedimentation is an issue, such as for bottom trawl fisheries and deep-sea mining. The results highlight the importance of leaving unmined patches of seabed adjacent to or within mined areas, to aid the recovery of macrofaunal communities subjected to mining disturbance.</p>

scholarly journals Simulated mining-related sedimentation impacts on the deep-sea macrofauna of the Chatham Rise, New Zealand

2021 ◽  
Author(s):  
Campbell Murray
Keyword(s):  
Community Structure ◽  
New Zealand ◽  
Deep Sea ◽  
Benthic Communities ◽  
Sampling Period ◽  
Mining Area ◽  
Warning Sign ◽  
Disturbed Areas ◽  
One Year ◽  
The Impact

<p>With the possibility of deep-sea mining of marine mineral resources occurring in the near future, it is necessary to understand the potential impacts that mining may have on benthic communities. Previous simulated mining experiments have observed direct impacts of deep-sea mining (e.g., faunal mortality); however, indirect impacts of sedimentation were not understood. In New Zealand, there has been interest in mining the seabed of the Chatham Rise, but mining consents have been refused, partly due to the uncertainties of sedimentation impacts on benthic communities. A disturbance experiment conducted in 2019 on the Rise used a modified agricultural plough designed to create a sediment cloud that could result from mining. This disturbance was used to assess the resilience of benthic communities to sedimentation in a proposed future mining area. Macrofaunal and sediment samples were collected with a multicorer before, immediately after and one year after disturbance to assess the impact on the community and its ability to recover. Samplingevents took place in disturbed (physically run over by the plough and subjected to sedimentation) and undisturbed areas (subjected to sedimentation only) at each sampling period. Macrofaunal abundance significantly decreased in disturbed areas after disturbancebut not in undisturbed areas. However, community structure changed in both areas after disturbance; in disturbed areas this was mostly driven by changes in numerically dominant fauna, but in undisturbed areas by the more sensitive fauna which may provide an early warning sign for further changes under increased sedimentation. One year after disturbance, community structure had recovered in both areas. Abundance-based community structure correlated most strongly with C:N molar ratios in the sediment which increased after disturbance. Ecosystem function was measured by sediment community oxygen consumption (SCOC) which increased similarly in both disturbed and undisturbed areas after disturbance; SCOC may be a more sensitive measure than community structure in assessing sedimentation impacts. No correlations were found between SCOC and macrofaunal abundance, biomass, diversity or bacterial abundance. The results of this research are useful for managing the impacts of industries where sedimentation is an issue, such as for bottom trawl fisheries and deep-sea mining. The results highlight the importance of leaving unmined patches of seabed adjacent to or within mined areas, to aid the recovery of macrofaunal communities subjected to mining disturbance.</p>

scholarly journals Differences in meiofauna communities with sediment depth are greater than habitat effects on the New Zealand continental margin: implications for vulnerability to anthropogenic disturbance

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2154 ◽  
Author(s):  
Norliana Rosli ◽  
Daniel Leduc ◽  
Ashley A. Rowden ◽  
Malcolm R. Clark ◽  
P. Keith Probert ◽  
...  
Keyword(s):  
Community Structure ◽  
New Zealand ◽  
Deep Sea ◽  
Anthropogenic Activities ◽  
Benthic Communities ◽  
Regional Scale ◽  
Sediment Surface ◽  
Small Scale ◽  
Sediment Layer ◽  
Meiofaunal Community

Studies of deep-sea benthic communities have largely focused on particular (macro) habitats in isolation, with few studies considering multiple habitats simultaneously in a comparable manner. Compared to mega-epifauna and macrofauna, much less is known about habitat-related variation in meiofaunal community attributes (abundance, diversity and community structure). Here, we investigated meiofaunal community attributes in slope, canyon, seamount, and seep habitats in two regions on the continental slope of New Zealand (Hikurangi Margin and Bay of Plenty) at four water depths (700, 1,000, 1,200 and 1,500 m). We found that patterns were not the same for each community attribute. Significant differences in abundance were consistent across regions, habitats, water and sediment depths, while diversity and community structure only differed between sediment depths. Abundance was higher in canyon and seep habitats compared with other habitats, while between sediment layer, abundance and diversity were higher at the sediment surface. Our findings suggest that meiofaunal community attributes are affected by environmental factors that operate on micro- (cm) to meso- (0.1–10 km), and regional scales (> 100 km). We also found a weak, but significant, correlation between trawling intensity and surface sediment diversity. Overall, our results indicate that variability in meiofaunal communities was greater at small scale than at habitat or regional scale. These findings provide new insights into the factors controlling meiofauna in these deep-sea habitats and their potential vulnerability to anthropogenic activities.

scholarly journals The impact of maternal genetic merit and country of origin on ewe reproductive performance, lambing performance and ewe survival

2021 ◽  
Author(s):  
N Fetherstone ◽  
N McHugh ◽  
T M Boland ◽  
F M McGovern
Keyword(s):  
New Zealand ◽  
Birth Weight ◽  
Litter Size ◽  
Country Of Origin ◽  
Reproductive Traits ◽  
Gestation Length ◽  
Genetic Merit ◽  
Genetic Groups ◽  
One Year ◽  
The Impact

Abstract The objective of this study was to investigate the impact of the ewe’s maternal genetic merit and country of origin (New Zealand or Ireland) on ewe reproductive, lambing and productivity traits. The study was performed over a four year period (2016 to 2019) and consisted of three genetic groups: high maternal genetic merit New Zealand (NZ), high maternal genetic merit Irish (High Irish) and low maternal genetic merit Irish (Low Irish) ewes. Each group contained 30 Suffolk and 30 Texel ewes, selected based on the respective national maternal genetic indexes; i.e. either the New Zealand Maternal Worth (New Zealand group) or the €uro-star Replacement index (Irish groups). The impact of maternal genetic merit on reproductive traits such as litter size; lambing traits such as gestation length, birth weight, lambing difficulty, mothering ability, and productivity traits such as the number of lambs born and weaned were analyzed using linear mixed models. For binary traits, the impact of maternal genetic merit on reproductive traits such as conception to first AI service; lambing traits such as dystocia, perinatal lamb mortality and productivity traits such as ewe survival were analyzed using logistic regression. New Zealand ewes outperformed Low Irish ewes for conception to first AI (P&lt;0.05) and litter size (P=0.05). Irish ewes were more likely to suffer from dystocia (6.84 (High Irish) and 8.25 (Low Irish) times) compared to NZ ewes (P&lt;0.001); birth weight and perinatal mortality did not differ between groups (P&gt;0.05). Lambs born from NZ ewes were 4.67 (95% CI: 1.89 to 11.55; P&lt;0.001) and 6.54 (95% CI: 2.56 to 16.71; P&lt;0.001) times more likely to stand up and suckle unassisted relative to lambs born from High or Low Irish ewes, respectively. New Zealand and High Irish ewes had a greater number of lambs born and weaned throughout the duration of the study compared to their Low Irish counterparts (P&lt;0.001). New Zealand ewes tended to be more likely to survive from one year to the next compared to Low Irish ewes (P=0.07). Irish ewes of high maternal genetic merit outperformed their Low counterparts in total number of lambs born and weaned per ewe, but performance did not differ across other traits investigated. This highlights the importance of continuous development of the Irish maternal sheep index to ensure favourable improvements in reproductive, lambing and productivity traits at farm level. Overall, results demonstrate the suitability of NZ genetics in an Irish production system.

Dissipation rates of some selected pesticides from the soil of tea agroecosystem in Assam, India

2016 ◽  
Author(s):  
Yumnam Devashree ◽  
B. K. Dutta ◽  
S. B. Paul ◽  
Sudip Choudhury
Keyword(s):  
High Performance ◽  
Negative Impact ◽  
Degradation Kinetics ◽  
Cost Benefit ◽  
Sampling Period ◽  
Application Rate ◽  
Tea Plantations ◽  
Tea Plants ◽  
One Year ◽  
The Impact

An experiment was carried out in Rosekandy Tea Estate, Barak Valley, Assam to investigate the persistence of some selected pesticides (i.e Endosulfan, Fipronil, Paraquat and 2,4-D) on the soil. These pesticides were applied in the soil as per the application rate, where one year old tea plants were growing and the residue were analysed for a period of 50 days. Their degradation kinetics in soil was also studied and described. Soil samples were collected with the help of soil corer. The samples were brought to the laboratory, air dried in room temperature and extracted for analysis with high performance liquid chromatography (HPLC). Among the pesticides 2,4-D was highly persistent with half life of 57.75 days followed by Endosulfan which lost 42.64% of its initial concentration by the last sampling period (i.e 50 days) after the spraying. Fipronil and paraquat lost 65% and 70.32% of initial residue in soil making them the least persistent amongst these pesticides in the studied soil. Considering the impact of pesticide residues on human health, the less persistent pesticides may be used in tea plantations to minimize the potential negative impact of pesticides in the environment. The cost benefit ratios of the use of the pesticides should be also worked out.

scholarly journals Impacts of bottom trawling on benthic trophic status and meiofauna in a deep-sea sedimentary environment (Gulf of Castellammare, southwestern Mediterranean Sea)

2020 ◽  
Author(s):  
Antonio Pusceddu ◽  
Sarah Paradis ◽  
Davide Moccia ◽  
Pere Puig ◽  
Pere Masque ◽  
...  
Keyword(s):  
Community Composition ◽  
Deep Sea ◽  
Biochemical Composition ◽  
Benthic Communities ◽  
Sedimentary Environment ◽  
Sediment Cores ◽  
Organic Detritus ◽  
Bottom Trawling ◽  
Sedimentary Environments ◽  
The Impact

&lt;p&gt;The impacts of bottom trawling on the structure of benthic communities can be relatively non-selective, hitting biodiversity as a whole. This holds true also in the deep sea, where the impacts of trawling can be more severe and long-lasting than in shallow-waters, due to the reduced capacity for recovery and greater vulnerability of deep-sea organisms. For years, our knowledge of the impact of trawling on deep-water ecosystems has remained limited and has focused mainly on fish stocks and hard bottom systems. More recently, a number of studies have addressed the impacts of bottom trawling in the deep-sea sedimentary environments, and very few of them have focused on the impacts on meiofauna, though it is a key faunal component of deep-sea ecosystems.&lt;/p&gt;&lt;p&gt;We investigated the impact of bottom trawling on the quantity, biochemical composition and nutritional value of sedimentary organic matter and meiofauna along the Sicilian Margin (Gulf of Castellammare, southwestern Mediterranean) at ca. 550 m depth, during the summer of 2016. Amount, biochemical composition and freshness of sedimentary OM, as well as the abundance and community composition of meiofauna were determined in sediment cores taken at both trawled and untrawled grounds. The continuous erosive processes in the trawled site have led, generally, to the depletion of OM contents (20-60% lower than those in the untrawled site), as well as to statistically significant differences from the untrawled site in its biochemical composition. Nevertheless, the upper 2 cm of the trawled site consisted of recently accumulated sediments, enriched in phytopigments, and bulk OM contents similar to those in the untrawled one, interpreted as a very recent input of fresh OM from the upper water column. The abundance of meiofauna in trawled grounds was significantly higher than that in untrawled ones, whereas no differences were observed between trawled and untrawled grounds deeper in the sediment. Differences in the meiofaunal community composition among sediment layers in each site were larger than those among sites.&lt;/p&gt;&lt;p&gt;As previously reported, deep bottom trawling in the Gulf of Castellammare erodes large volumes of sediment, exposing old compacted sediment that is depleted in OM. This erosive action generally prevents the accumulation of fresh sediment. However, the episodic short-lived deposition of fresh organic detritus between hauls can lead to a temporary accumulation of fresh and bioavailable OM which, in turn, can induce a positive response in meiofauna abundance.&lt;/p&gt;&lt;p&gt;These results pinpoint the need of considering the impacts of bottom trawling on the benthic communities of deep-sea sedimentary environments at temporal scales shorter than previously done.&lt;/p&gt;

scholarly journals Subtidal littering: Indirect effects on soft substratum macrofauna?

2008 ◽  
Vol 9 (2) ◽  
pp. 35 ◽  
Author(s):  
I. AKOUMIANAKI ◽  
P. KONTOLEFAS ◽  
S. KATSANEVAKIS ◽  
A. NICOLAIDOU ◽  
G. VERRIOPOULOS
Keyword(s):  
Community Structure ◽  
Sediment Surface ◽  
Long Run ◽  
Significant Difference ◽  
Before And After ◽  
Soft Substratum ◽  
One Year ◽  
The Impact ◽  
Control Surfaces ◽  
Macrofauna Community

Changes in macrofauna community structure, abundance and species richness were examined both before and one year after the deployment of plastic and glass bottles at littered (litter density: 16 items / 100 m2) and non-littered (control) surfaces at three unimpacted coastal areas of the western Saronikos Gulf (Greece). In parallel, LOI% at the adjacent sediments and changes in the composition of feeding types of the megaepifauna that colonized the litter were examined across treatments. Significant changes in macrofauna community structure were demonstrated between before and after littering. At only one of the sites was there detected a significant difference in macrofauna community structure between control and littered plots after littering. This difference was linked with a significant increase in the abundance of opportunistic polychaete species and LOI% levels in the sediment surface due to the entrapment of macrophytal debris within the littered surface. The study did not show a consistent direct response of macroinfauna community to litter and the associated megafauna. Unlike the megafauna attracted by litter items, soft-substratum macrofauna is less responsive to the addition of novel hard substrates in adjacent sediments. Alternatively, it could be that the impact of littering with small items triggers a macrofauna response detectable in the long-run.

scholarly journals Sediment impacts on sponges and a deep-sea coral in New Zealand

2021 ◽  
Author(s):  
◽  
Valeria Mobilia
Keyword(s):  
New Zealand ◽  
Suspended Sediment ◽  
Deep Sea ◽  
Anthropogenic Disturbance ◽  
Habitat Structure ◽  
Anthropogenic Activities ◽  
Benthic Communities ◽  
Bottom Contact ◽  
Suspended Sediment Concentrations ◽  
Offshore Activities

<p><b>Increased levels of suspended sediment in the water column are important factors contributing to the degradation of marine ecosystems worldwide. In coastal waters, temporal variation in suspended sediment concentrations (SSCs) occurs naturally due to seasonal and oceanographic processes. However, there is evidence that anthropogenic activities are increasing sediment concentrations. The volume of sediment moving from land-based sources into coastal ecosystems and human activities in the ocean disturbing the seafloor, such as dredging and bottom-contact fisheries, have been increasing over the last century. In addition, offshore activities, particularly bottom-contact fishing and potential deep-sea mining, can create sediment plumes in the deep-sea that may extend over long distances. Elevated suspended sediment concentrations have detrimental effects on benthic communities, particularly for suspension feeders like sponges and corals.</b></p> <p>The aim of this thesis was to investigate the effects of increased SSCs that might arise from heavy anthropogenic disturbance on common shallow water and deep-sea sponges and a deep-sea coral in New Zealand, as these groups contribute to habitat structure in some benthic environments, including the deep sea.</p>

scholarly journals Depth and location influence prokaryotic and eukaryotic microbial community structure in New Zealand fjords

2019 ◽  
Author(s):  
Sven P. Tobias-Hünefeldt ◽  
Stephen R. Wing ◽  
Nadjejda Espinel-Velasco ◽  
Federico Baltar ◽  
Sergio E. Morales
Keyword(s):  
Community Structure ◽  
New Zealand ◽  
Microbial Communities ◽  
National Park ◽  
Amplicon Sequencing ◽  
Forested Catchments ◽  
Environmental Forcing ◽  
Low Salinity ◽  
The Impact ◽  
Depth View

SummarySystems with strong horizontal and vertical gradients, such as fjords, are useful models for studying environmental forcing. Here we examine microbial (prokaryotic and eukaryotic) community changes associated with the surface low salinity layer (LSL) and underlying seawater in multiple fjords in Fiordland National Park (New Zealand). High rainfall (1200-8000 mm annually) and linked runoff from native forested catchments results in surface LSLs with high tannin concentrations within each fjord. These gradients are expected to drive changes in microbial communities. We used amplicon sequencing (16S and 18S) to assess the impact of these gradients on microbial communities and identified depth linked changes in diversity and community structure. With increasing depth we observed significant increases in Proteobacteria (15%) and SAR (37%), decreases in Opisthokonta (35%), and transiently increased Bacteroidetes (3% increase from 0 to 40 m, decreasing by 8% at 200 m). Community structure differences were observed along a transect from inner to outer regions, specifically 25% mean relative abundance decreases in Opisthokonta and Bacteroidetes, and increases in SAR (25%) and Proteobacteria (>5%) at the surface, indicating changes based on distance from the ocean. This provides the first in-depth view into the ecological drivers of microbial communities within New Zealand fjords.

scholarly journals Meiofauna in a Potential Deep-Sea Mining Area—Influence of Temporal and Spatial Variability on Small-Scale Abundance Models

Diversity ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 3
Author(s):  
Katja Uhlenkott ◽  
Annemiek Vink ◽  
Thomas Kuhn ◽  
Benjamin Gillard ◽  
Pedro Martínez Arbizu
Keyword(s):  
Deep Sea ◽  
Benthic Communities ◽  
Mining Operation ◽  
Mining Area ◽  
Environmental Drivers ◽  
Small Scale ◽  
Taxon Richness ◽  
Distribution Models ◽  
Polymetallic Nodule ◽  
Meiofauna Abundance

In large areas of the Clarion Clipperton Fracture Zone (northeast Pacific), exploration of deep-sea polymetallic nodules as a potential source of high-technology metals is ongoing. Deep-sea mining may have a severe impact on the benthic communities. Here, we investigated meiofauna communities in the abyss at the scale of a prospective mining operation area. Random forest regressions were computed to spatially predict continuous layers of environmental variables as well as the distribution of meiofauna abundance across the area. Significant models could be computed for 26 sediment and polymetallic nodule parameters. Meiofauna abundance, taxon richness and diversity were also modelled, as well as abundance of the taxon Nematoda. Spatial correlation is high if the predictions of meiofauna are either based on bathymetry and backscatter or include sediment and nodule variables; Pearson’s correlation coefficient varies between 0.42 and 0.91. Comparison of differences in meiofauna abundance between different years shows that spatial patterns do change, with an elevated abundance of meiofauna in the eastern part of the study area in 2013. On the spatial scale of a potential mining operation, distribution models prove to be a useful tool to gain insight into both temporal variability and the influence of potential environmental drivers on meiofauna distribution.

scholarly journals Review and syntheses: Impacts of turbidity flows on deep-sea benthic communities

2021 ◽  
Vol 18 (5) ◽  
pp. 1893-1908
Author(s):  
Katharine T. Bigham ◽  
Ashley A. Rowden ◽  
Daniel Leduc ◽  
David A. Bowden
Keyword(s):  
New Zealand ◽  
Deep Sea ◽  
Benthic Community ◽  
Large Scale ◽  
Benthic Communities ◽  
Clear Cut ◽  
Local Diversity ◽  
Physical Chemical ◽  
Pulse Type ◽  
Diversity Studies

Abstract. Turbidity flows – underwater avalanches – are large-scale physical disturbances that are believed to have profound and lasting impacts on benthic communities in the deep sea, with hypothesized effects on both productivity and diversity. In this review we summarize the physical characteristics of turbidity flows and the mechanisms by which they influence deep-sea benthic communities, both as an immediate pulse-type disturbance and through longer-term press-type impacts. Further, we use data from turbidity flows that occurred hundreds to thousands of years ago as well as three more recent events to assess published hypotheses that turbidity flows affect productivity and diversity. We find, unlike previous reviews, that evidence for changes in productivity in the studies was ambiguous at best, whereas the influence on regional and local diversity was more clear-cut: as had previously been hypothesized, turbidity flows decrease local diversity but create mosaics of habitat patches that contribute to increased regional diversity. Studies of more recent turbidity flows provide greater insights into their impacts in the deep sea, but without pre-disturbance data, the factors that drive patterns in benthic community productivity and diversity, be they physical, chemical, or a combination thereof, still cannot be identified. We propose criteria for data that would be necessary for testing these hypotheses and suggest that studies of Kaikōura Canyon, New Zealand, where an earthquake-triggered turbidity flow occurred in 2016, will provide insights into the impacts of turbidity flows on deep-sea benthic communities as well as the impacts of other large-scale disturbances such as deep-sea mining.

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