Publications by authors named "Patrick Meire"

Tidal marshes are often restored on compact agricultural soil that limits tidally induced groundwater dynamics and soil aeration after restoration. We hypothesized that impaired soil aeration affects biogeochemical cycling and leads to altered porewater nutrient concentrations in restored tidal marshes. We studied soil hydraulic properties, groundwater dynamics and porewater nutrient concentrations (nitrogen, phosphorus and dissolved silica) over the course of one year in a natural and a restored freshwater tidal marsh in the Scheldt estuary, Belgium.

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Intertidal microphytobenthos (MPB) are a major contributor to primary production in estuarine ecosystems. While their biomass is highly variable at multiple spatial and temporal scales, the underlying drivers are as yet little understood. Both in situ sampling and remote-sensing techniques often lack the temporal resolution or coverage to simultaneously capture short-term (intratidal to daily) and longer-term (weekly to annual) biomass changes.

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Article Synopsis
  • * Research in two southwest Greenland fjords from 2016 shows that ocean discharge from marine-terminating glaciers promotes high levels of phytoplankton growth, mainly diatoms, feeding larger zooplankton.
  • * In contrast, land-terminating glaciers create fjords with less phytoplankton productivity, dominated by bacteria and smaller organisms, resulting in significantly lower ecosystem productivity and carbon uptake.
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Increased pressures from human activities may cause cumulative ecological effects on marine ecosystems. Increasingly, the study of ecosystem services is applied in the marine environment to assess the full effects of human activities on the ecosystem and on the benefits it provides. However, in the marine environment, such integrated studies have yet to move from qualitative and score-based to fully quantitative assessments.

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Meltwater runoff from glaciers carries particles, so-called glacial flour that may affect planktonic organisms and the functioning of marine ecosystems. Protist microplankton is at the base of marine food webs and thus plays an important role in sustaining important ecosystem services. To assess the effect of glacial flour on photoautotrophic, heterotrophic and mixotrophic microplankton, the spatial distribution of these trophic groups was studied in four Greenlandic fjords during summer.

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We studied how changing human impacts affected phytoplankton dynamics in the freshwater and brackish tidal reaches of the Zeeschelde estuary (Belgium) between 2002 and 2018. Until the early 2000s, the Zeeschelde was heavily polluted due to high wastewater discharges. By 2008, water quality had improved, resulting in lower nutrient concentrations and higher oxygen levels.

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Much uncertainty exists about the vulnerability of valuable tidal marsh ecosystems to relative sea level rise. Previous assessments of resilience to sea level rise, to which marshes can adjust by sediment accretion and elevation gain, revealed contrasting results, depending on contemporary or Holocene geological data. By analyzing globally distributed contemporary data, we found that marsh sediment accretion increases in parity with sea level rise, seemingly confirming previously claimed marsh resilience.

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In this study we explore the sub-lethal effects of two malaria vector control pesticides, deltamethrin and dichlorodiphenyltrichloroethane (DDT), on Xenopus laevis by incorporating different levels of biological organisation. Pesticide accumulation in frog tissue was measured alongside liver metabolomics and individual swimming behaviour to assess whether changes presented at these different levels, and if such changes could be linked between levels. Results showed evidence of concentration dependent accumulation of DDT and its metabolites, but no measurable accumulation of deltamethrin in adult X.

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The threat to wildlife from chemical exposure exists regardless of the presence of conservation boundaries. An issue exacerbated by the use of environmentally persistent insecticides for vector control and long-range transport of legacy persistent organic pollutants. In this comparative study between two important conservation regions in South Africa, Kruger National Park (KNP) and Ndumo Game Reserve (NGR), we assessed organochlorine pesticide (OCP) accumulation in several anuran species collected from within the conservation regions.

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Transport and transformation of inorganic nutrients are influenced by abiotic-biotic interactions and determine downstream water quality. Macrophytes play an important role in these complex ecological interactions. The role of macrophytes was studied in three reaches of the groundwater-fed, oligotrophic River Fischa with different macrophyte coverage and biomass.

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Although the consideration of socio-economic demands with biodiversity conservation is now high on the environmental policy agenda, it is not yet standard practice in spatial planning. This is argued to be related, among others, to a lack of awareness among stakeholders and practitioners of the underpinning role of ecosystem functioning and biodiversity to support human well-being. Meanwhile, there is mounting critique on the absolute focus of biodiversity conservation on static properties such as species and habitats.

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Anurans from the genus Xenopus have long been used as standard testing organisms and occur naturally in tropical and sub-tropical areas where malaria vector control pesticides are actively used. However, literature on the toxic effects of these pesticides is limited. This review analyses the available data pertaining to both Xenopus and the pesticides used for malaria vector control in order to determine the pesticides that have the greatest potential to influence amphibian health while also identifying gaps in literature that need to be addressed.

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Near-infrared spectroscopy (NIRS) is a high-throughput technology with potential to infer nitrogen (N), phosphorus (P) and carbon (C) content of all vascular plants based on empirical calibrations with chemical analysis, but is currently limited to the sample populations upon which it is based. Here we provide a first step towards a global arctic-alpine NIRS model of foliar N, P and C content. We found calibration models to perform well (R = 0.

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While the importance of grasslands in terrestrial silicon (Si) cycling and fluxes to rivers is established, the influence of large grazers has not been considered. Here, we show that hippopotamuses are key actors in the savannah biogeochemical Si cycle. Through a detailed analysis of Si concentrations and stable isotope compositions in multiple ecosystem compartments of a savannah-river continuum, we constrain the processes influencing the Si flux.

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The representation of the temporal dynamics of ecosystem services (ES) is a crucial research frontier in the field of ES modeling. In fact, most current ES models focus on static ES assessments, that need to be repeated with different inputs per time step to explore potential changes in ES. Here, we present a new approach for the dynamic modeling of multiple ES, based on the Petri Net modeling framework.

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Despite the importance of water purification to society, it is one of the more difficult wetland ecosystem services to quantify. It remains an issue in ecosystem service assessments where rapid estimates are needed, and poor-quality indicators are overused. We attempted to quantify the water purification service of South African palmiet wetlands (valley-bottom peatlands highly threatened by agriculture).

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We provide reflectance spectra for 22 South African palmiet wetland species collected in spring 2015 from three wetlands throughout the Cape Floristic Region. In addition, we provide summarized plant functional trait data, as well as supporting and meta-data. Reflectance spectra were collected with a portable ASD Fieldspec Pro using standard methods.

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Freshwater ecosystems are confronted with the effects of climate change. One of the major changes is an increased concentration of aquatic carbon. Macrophytes are important in the aquatic carbon cycle and play as primary producers a crucial role in carbon storage in aquatic systems.

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Accelerated mass loss from the Greenland ice sheet leads to glacier retreat and an increasing input of glacial meltwater to the fjords and coastal waters around Greenland. These high latitude ecosystems are highly productive and sustain important fisheries, yet it remains uncertain how they will respond to future changes in the Arctic cryosphere. Here we show that marine-terminating glaciers play a crucial role in sustaining high productivity of the fjord ecosystems.

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River systems are highly complex, hierarchical and patchy systems which are greatly influenced by both catchment surroundings and in-stream processes. Natural and anthropogenic land uses and processes affect water quality (WQ) through different pathways and scales. Understanding under which conditions these different river and catchment properties become dominant towards water chemistry remains a challenge.

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The presence of vegetation in stream ecosystems is highly dynamic in both space and time. A digital photography technique is developed to map aquatic vegetation cover at species level, which has a very high spatial and a flexible temporal resolution. A digital single-lens reflex (DSLR) camera mounted on a handheld telescopic pole is used.

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Wetlands fed by rivers can be a sink for elements depending on elemental concentrations, wetland hydrology, geochemistry, vegetation and climate. In the case of the Okavango Delta, northern Botswana, the outflow discharge is a small fraction (2-5%) of the inflow. This has strong potential consequences for the Delta, as it strongly affects element cycling and storage within the Delta.

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The trade in soybean, an important animal feed product, exemplifies the environmental and socio-economic impact of global markets and global agricultural policy. This paper analyses the impact of increasing production of soybean in the exporting countries (deforestation and grassland conversion) as well as in importing regions (decrease in permanent grassland by substitution of grass as feed). Ecosystem services monetary values were used to calculate the environmental and socio-economic impact of observed land use changes.

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Changing fire regimes in response to climate change are likely to have significant effects on terrestrial ecosystems and biogeochemical cycles. While effects of fire on some nutrient cycles have been quite well-studied, little attention has been paid to the silicon cycle. We used an alkaline continuous extraction to examine changes in the quantity and characteristics of alkaline extractable Si (AlkExSi) after applying two burning treatments (no heating, 350°C and 550°C) to three types of organic soil material (from spruce forest, beech forest and a commercial peat).

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