Insects associated to ephemeral pools in Huentelauquén (29ºS Coquimbo Region, Chile)

In northern central Chile, ephemeral pools constitute shallow isolated water bodies with a favourable habitat for fauna adapted to seasonal changes. Based on the limited knowledge about the fauna—particularly insects—associated to these ecosystems, the objective of this study was to characterize the richness, composition, structure and similarity of the insect communities associated with ephemeral pools in Huentelauquén (29º S, Coquimbo Region, Chile). By using pitfall traps, 10,762 individuals were captured, represented by 7 orders, 27 families, and 51 species. Coleoptera and Hymenoptera were the best represented orders, with Neuroptera, Orthoptera and Plecoptera being poorly represented groups. The non-parametric estimators evaluated showed wealth values above those observed for all the studied pools, and their accumulation curves suggest the existence of an incomplete species inventory in the studied community. Additionally, the hierarchical and ordering analysis showed groupings of pools located in the northwest and southeast of Huentelauquén. Preliminarily we found a negative correlation between the area of the pools and the richness (species) and abundance of insects. Additional studies (on other arthropod groups and other seasons of the year) could provide a better understanding of the local processes of extinction and colonization of the species inhabiting these fragile coastal environments.

A framework to evaluate and elucidate the driving mechanisms of coastal sea surface <i>p</i>CO₂ seasonality using an ocean general circulation model (MOM6-COBALT)

The temporal variability of the sea surface partial pressure of CO2 (pCO2) and the underlying processes driving this variability are poorly understood in the coastal ocean. In this study, we tailor an existing method that quantifies the effects of thermal changes, biological activity, ocean circulation and freshwater fluxes to examine seasonal pCO2 changes in highly variable coastal environments. We first use the Modular Ocean Model version 6 (MOM6) and biogeochemical module Carbon Ocean Biogeochemistry And Lower Trophics version 2 (COBALTv2) at a half-degree resolution to simulate coastal CO2 dynamics and evaluate them against pCO2 from the Surface Ocean CO2 Atlas database (SOCAT) and from the continuous coastal pCO2 product generated from SOCAT by a two-step neuronal network interpolation method (coastal Self-Organizing Map Feed-Forward neural Network SOM-FFN, Laruelle et al., 2017). The MOM6-COBALT model reproduces the observed spatiotemporal variability not only in pCO2 but also in sea surface temperature, salinity and nutrients in most coastal environments, except in a few specific regions such as marginal seas. Based on this evaluation, we identify coastal regions of “high” and “medium” agreement between model and coastal SOM-FFN where the drivers of coastal pCO2 seasonal changes can be examined with reasonable confidence. Second, we apply our decomposition method in three contrasted coastal regions: an eastern (US East Coast) and a western (the Californian Current) boundary current and a polar coastal region (the Norwegian Basin). Results show that differences in pCO2 seasonality in the three regions are controlled by the balance between ocean circulation and biological and thermal changes. Circulation controls the pCO2 seasonality in the Californian Current; biological activity controls pCO2 in the Norwegian Basin; and the interplay between biological processes and thermal and circulation changes is key on the US East Coast. The refined approach presented here allows the attribution of pCO2 changes with small residual biases in the coastal ocean, allowing for future work on the mechanisms controlling coastal air–sea CO2 exchanges and how they are likely to be affected by future changes in sea surface temperature, hydrodynamics and biological dynamics.

Untargeted Metabolomics Reveals a Complex Impact on Different Metabolic Pathways in Scallop Mimachlamys varia (Linnaeus, 1758) after Short-Term Exposure to Copper at Environmental Dose

Ports are a good example of how coastal environments, gathering a set of diverse ecosystems, are subjected to pollution factors coming from human activities both on land and at sea. Among them, trace element as copper represents a major factor. Abundant in port ecosystem, copper is transported by runoff water and results from diverse port features (corrosion of structures, fuel, anti-fouling products, etc.). The variegated scallop Mimachlamys varia is common in the Atlantic port areas and is likely to be directly influenced by copper pollution, due to its sessile and filtering lifestyle. Thus, the aim of the present study is to investigate the disruption of the variegated scallop metabolism, under a short exposure (48 h) to a copper concentration frequently encountered in the waters of the largest marina in Europe (82 μg/L). For this, we chose a non-targeted metabolomic approach using ultra-high performance liquid chromatography coupled to high resolution mass spectrometry (UHPLC-HRMS), offering a high level of sensitivity and allowing the study without a priori of the entire metabolome. We described 28 metabolites clearly modulated by copper. They reflected the action of copper on several biological functions such as osmoregulation, oxidative stress, reproduction and energy metabolism.

Evaluating the functional role of betacyanin in salinity tolerance of Horokaka (Disphyma australe)

<p>Yield loss in agriculture due saline soils is a growing problem in arid and semi-arid regions as traditional crop species are inherently sensitive to salinity in the root zone. In the face of diminishing fresh water resources it is necessary to explore the traits which allow naturally salt tolerant species to exploit high saline environments. In the hope of transferring these traits via genetic modification to traditional crop species, or utilising these species as niche crops in their own right. While a majority of plants appear green, red pigmented plants are commonly associated with marginal environments. In these leaves anthocyanins or less commonly betalains are responsible for leaf reddening. The betalains are small class of tyrosine derived chromo alkaloids found in the core Caryophyllales and in some Basidiomycetes. There are two structural groups: the red/violet betacyanins and the yellow/orange betaxanthins. Due to this distribution pattern, betalain pigments are thought to function in salinity stress tolerance. However, minimal research has been conducted to support this salinity tolerance hypothesis due to a lack of an appropriate model species. Horokaka (Disphyma australe) exhibits colour dimorphism among populations, green and red morphs grow contiguously in coastal environments where the frequency of red morphs positively correlates with increased substrate salinity. Betacyanins have previously been implicated in serving a photo protective for D. australe. In dimorphic populations D. australe along the south Wellington coastline, the red morph has been shown to be more tolerant to the combination of high light and salinity, as measured by higher CO2 assimilation rates, reduced inhibition of PSII and enhanced water use efficiency relative to the green morph. In these studies, betacyanin production in the red morphs was shown to depend on duel exposure to both salinity and high light, however the green morph was unable to produce betacyanin under the same conditions (Jain & Gould, 2015). This easy manipulation of leaf colour by salinity and high light offers a system to study whether betacyanin pigments aid salinity tolerance. I aimed further investigate the photo protective hypothesis of betalain using D. australe, and how this may influence distribution patterns by focusing on three areas: the capacity for new root growth along a salinity gradient, germination capacity under saline conditions, and ion content in the roots at low, moderate and high NaCl concentrations. Shoots with no roots and a minimum of two mature leaf pairs were cut from green and red morphs of D.asutrale growing in the greenhouse facilities at Victoria University of Wellington. The shoots were grown hydroponically in 10% Hoaglands solution supplemented or not with (50, 100, or 150 mM) NaCl. To test the light screening capacity of leaf betacyanin a red filter was secured of half the green shoots, the cuttings were grown for 5 weeks under a controlled 16h light/ 8h dark photoperiod. Final weights of the shoot and roots, along with tissue water content of the shoots and roots were obtained to establish the relative capacity for new root growth when subjected to increasing salinity. Seeds were germinated in vitro in the presence of increasing NaCl concentrations (0, 100, 200, 300, and 400 mM NaCl), and subject to recovery tests after stress. The germination percentages and velocity were determined to establish te relative tolerance and competitiveness of the two D. australe morphs. Salt treatments were also applied to plants with an established root system, by 14-day treatment with increasing NaCl concentrations (0, 200, 400, 800 mM). The tissue water content of the shoots and ion contents (Na+ and K+) in the roots were determined in the control and the stressed plants of the two colour morphs. The different germination behaviour of the two morphs and capacity for root development appears to contribute to their distribution along a salinity gradient. Despite some differences under the control treatment, the concentrations of the two ions (Na+ and K+) were similar in the two morphs, not explaining differences in salinity tolerance, except for the increase of K+ in the roots of the green morph in the absence of NaCl. This specific response may be relevant for distribution patterns in D. australe. The ecological implications of these findings, which can contribute to vegetation distribution of D. australe in coastal environments, and the relevance of betacyanin accumulation in salinity tolerance for halophytes, and potential application for improved crop vigour are discussed.</p>

Evaluating the functional role of betacyanin in salinity tolerance of Horokaka (Disphyma australe)

<p>Yield loss in agriculture due saline soils is a growing problem in arid and semi-arid regions as traditional crop species are inherently sensitive to salinity in the root zone. In the face of diminishing fresh water resources it is necessary to explore the traits which allow naturally salt tolerant species to exploit high saline environments. In the hope of transferring these traits via genetic modification to traditional crop species, or utilising these species as niche crops in their own right. While a majority of plants appear green, red pigmented plants are commonly associated with marginal environments. In these leaves anthocyanins or less commonly betalains are responsible for leaf reddening. The betalains are small class of tyrosine derived chromo alkaloids found in the core Caryophyllales and in some Basidiomycetes. There are two structural groups: the red/violet betacyanins and the yellow/orange betaxanthins. Due to this distribution pattern, betalain pigments are thought to function in salinity stress tolerance. However, minimal research has been conducted to support this salinity tolerance hypothesis due to a lack of an appropriate model species. Horokaka (Disphyma australe) exhibits colour dimorphism among populations, green and red morphs grow contiguously in coastal environments where the frequency of red morphs positively correlates with increased substrate salinity. Betacyanins have previously been implicated in serving a photo protective for D. australe. In dimorphic populations D. australe along the south Wellington coastline, the red morph has been shown to be more tolerant to the combination of high light and salinity, as measured by higher CO2 assimilation rates, reduced inhibition of PSII and enhanced water use efficiency relative to the green morph. In these studies, betacyanin production in the red morphs was shown to depend on duel exposure to both salinity and high light, however the green morph was unable to produce betacyanin under the same conditions (Jain & Gould, 2015). This easy manipulation of leaf colour by salinity and high light offers a system to study whether betacyanin pigments aid salinity tolerance. I aimed further investigate the photo protective hypothesis of betalain using D. australe, and how this may influence distribution patterns by focusing on three areas: the capacity for new root growth along a salinity gradient, germination capacity under saline conditions, and ion content in the roots at low, moderate and high NaCl concentrations. Shoots with no roots and a minimum of two mature leaf pairs were cut from green and red morphs of D.asutrale growing in the greenhouse facilities at Victoria University of Wellington. The shoots were grown hydroponically in 10% Hoaglands solution supplemented or not with (50, 100, or 150 mM) NaCl. To test the light screening capacity of leaf betacyanin a red filter was secured of half the green shoots, the cuttings were grown for 5 weeks under a controlled 16h light/ 8h dark photoperiod. Final weights of the shoot and roots, along with tissue water content of the shoots and roots were obtained to establish the relative capacity for new root growth when subjected to increasing salinity. Seeds were germinated in vitro in the presence of increasing NaCl concentrations (0, 100, 200, 300, and 400 mM NaCl), and subject to recovery tests after stress. The germination percentages and velocity were determined to establish te relative tolerance and competitiveness of the two D. australe morphs. Salt treatments were also applied to plants with an established root system, by 14-day treatment with increasing NaCl concentrations (0, 200, 400, 800 mM). The tissue water content of the shoots and ion contents (Na+ and K+) in the roots were determined in the control and the stressed plants of the two colour morphs. The different germination behaviour of the two morphs and capacity for root development appears to contribute to their distribution along a salinity gradient. Despite some differences under the control treatment, the concentrations of the two ions (Na+ and K+) were similar in the two morphs, not explaining differences in salinity tolerance, except for the increase of K+ in the roots of the green morph in the absence of NaCl. This specific response may be relevant for distribution patterns in D. australe. The ecological implications of these findings, which can contribute to vegetation distribution of D. australe in coastal environments, and the relevance of betacyanin accumulation in salinity tolerance for halophytes, and potential application for improved crop vigour are discussed.</p>

The Unsettled Landscape: The Core to Coastal Fabrics

<p>‘The Unsettled Landscape’ considers an alternative sustainable manner in which communities can settle New Zealand’s coastland. Living at the ocean edge is ingrained in the way many of our urban settlements have formed, and is intricately linked with how we define ourselves. Unfortunately the way these places have manifested in reality has produced ecological barriers to natural cycles paramount to ecosystem health. Sea walls, housing, roads and many other infrastructural typologies resist the natural ‘flux’ of these areas, which results in dysfunctional ecosystems as well as putting residents of these places at risk of numerous threats which occur along these interface sites. Earthquakes, river movement, erosion, sea level rise, flooding and the continual movement of the dunes are just some of the issues coastal settlements face. The conflict forms where the sought after coastal environments are applied to in a permanent manner that is irresponsive of a landscape which functions in a most dynamic way. This thesis looks towards the geomorphological patterns in the coast as an indicator for how a complete shift in infrastructural application might occur responsively. This new fabric distinguishes stable components in this shifting landscape, utilising them as a stable network from which settlement can develop. This network could become the basis of more responsive settlements, stronger communities, and will act as a way to future proof inhabitation of these fragile yet hazardous places. Design research explores the physical as well as intangible aspects of settlement application, and focuses on communities forming the ‘real’ foundation of these temporal environments. Responsive communities arise ‘reactively’ avoiding hazards, and allowing inhabitants to take advantage of what these precious sites offer.</p>

Amphipods as biomonitors of marine coastal environments: a Chatham Island case study

<p>New Zealand’s coastal marine environment has high economic, social and cultural importance. In order to manage, preserve and safely enjoy coastal environments and their resources, a good understanding of their biochemistry is required. Biomonitors provide a mechanism for monitoring changes in an environment especially in measuring metals entering the food chain. Trace metals are non-biodegradable, have the ability to become highly toxic to biota at relatively low concentrations, and bio-magnify up the food chain. Amphipods, a diverse order of crustacea, are widespread, abundant, relatively sedentary and important at the base of the food web. Furthermore, amphipods bioaccumulate pollutants through multiple sources, including seawater, sediment and their diet, and may thus provide a comprehensive insight into the chemistry of an environment. This study investigates the trace metal chemistry of amphipods and associated algae, seawater and sediment, from coastal marine sites around Chatham Island. Samples were obtained from 11 coastal localities with the sampling sites located near potential point pollutants and on distinct basement lithologies, as well as a site identified by Te Aitanga o Ngā Uri o Wharekauri as relatively pristine. Three algal-dwelling amphipods (Aora sp. 1, Apohyale sp. 1, Eusiroides sp. 1) and one sand hopper species (Bellorchestia chathamensis (Hurley, 1956)) were found to be the most abundant and ubiquitous species collected. Sites were prioritised based on the abundances of these amphipod species and samples were analysed for >35 trace elements. Spatial and interspecific variations were observed for all amphipod species investigated. Eusiroides sp. 1 was the most sensitive algal-dwelling amphipod species analysed and consistently had highest concentrations of trace metals at a given site. No size effect was found for most trace element concentrations in two amphipod species. All three algal-dwelling amphipod species and associated seawater samples from Hanson Point South had elevated concentrations for > 19 trace metals, including potentially ecotoxic trace metals such as Ti, V, Cr, Co, Ni, Cu, and Fe. Arsenic was elevated in the algal-dwelling amphipod species at Owenga and Cd at Kaingaroa West and Cape Pattisson. Trace metal concentrations in the algal-dwelling amphipod specimens were broadly reflected in their associated seawater and/or algae. However there were variations in this, with the Hanson Point South amphipods more closely matching seawater than algae concentration patterns, and the algae at Owenga not showing As elevations noted in the amphipods. This suggests amphipods accumulate metals from a variety of sources, both directly from seawater and variably from algae. Sediments appeared to have little influence on the trace metals bioaccumulated in the amphipod specimens. Results from this research demonstrate that species and size effects must be considered to rigorously use amphipods as biomonitors. Amphipods appear to provide a better insight to bio-available trace metal contamination compared to the other sample types analysed here. This thesis aids in the development and application of amphipods as biomonitors in New Zealand coastal waters and provides a baseline for sites located across Chatham Island for >30 trace elements. This baseline may be utilized by future studies to investigate temporal variations in trace metal concentrations on Chatham Island.</p>