Combining multi-marker metabarcoding and digital holography to describe eukaryotic plankton across the Newfoundland Shelf.

The planktonic diversity throughout the oceans is vital to ecosystem functioning and linked to environmental change. Plankton monitoring tools have advanced considerably with high-throughput in-situ digital cameras and genomic sequencing, opening new challenges for high-frequency observations of community composition, structure, and species discovery. Here, we combine multi-marker metabarcoding based on nuclear 18S (V4) and plastidial 16S (V4-V5) rRNA gene amplicons with a digital in-line holographic microscope to provide a synoptic diversity survey of eukaryotic plankton along the Newfoundland Shelf (Canada) during the winter transition phase of the North Atlantic bloom phenomenon. Metabarcoding revealed a rich eukaryotic diversity unidentifiable in the imaging samples, confirming the presence of ecologically important saprophytic protists which were unclassifiable in matching images, and detecting important groups unobserved or taxonomically unresolved during similar sequencing campaigns in the Northwest Atlantic Ocean. In turn, imaging analysis provided quantitative observations of widely prevalent plankton from every trophic level. Despite contrasting plankton compositions portrayed by each sampling method, both capture broad spatial differences between the northern and southern sectors of the Newfoundland Shelf and suggest complementary estimations of important features in eukaryotic assemblages. Future tasks will involve standardizing digital imaging and metabarcoding for wider use and consistent, comparable ocean observations.

Addressing distribution equity in spatial conservation prioritization for small-scale fisheries.

Spatial conservation prioritization is used worldwide for designing marine protected areas (MPA) that achieve set conservation objectives with minimal impacts to marine users. People involved in small-scale fisheries (SSF) may incur negative and disproportionate impacts from implementing MPAs, yet limited available data often restricts their representation in MPA planning. Using a Philippines case study, we focus here on the systematic design of a MPA network that aims to minimize and distribute costs equitably for SSF whilst achieving representation targets for biodiversity conservation. The objectives of the study are to: (1) document a participatory mapping approach for collecting SSF data for prioritization using the local knowledge of fishers; and (2) examine how the completeness and resolution of SSF data may affect prioritization outputs in terms of biodiversity representation, spatial efficiency, and distribution equity. In the data-poor region, we conducted participatory mapping workshops with fishers in 79 communities to collect data on the spatial distribution patterns of different SSF fisheries and communities, and employed remote sensing techniques to define coastal habitats, which were targeted for inclusion in MPAs. The datasets were integrated within the decision-support tool Marxan with Zones to develop three scenarios. The SSF data incorporated in each scenario varied based on their completeness (considered all fishing methods or only dominant methods) and resolution (fishing methods itemized by community or municipality). All scenarios derived MPA plans that met representation targets with similar area coverage. The outputs, however, varied in terms of distribution equity, measured by the distribution of opportunity costs (loss of fishing grounds) across different fisheries and communities. Scenarios that did not include minority fisheries or variations between communities, led to inequitable costs. These results highlight the need to incorporate detailed data on SSF at appropriate resolutions, and how this can be achieved through participatory approaches.

Evaluating approaches for scaling-up community-based marine-protected areas into socially equitable and ecologically representative networks.

Marine-protected areas (MPAs) are vital to marine conservation, but their coverage and distribution is insufficient to address declines in global biodiversity and fisheries. In response, many countries have committed through the Aichi Target 11 of the Convention on Biological Diversity to conserve 10% of the marine environment through ecologically representative and equitably managed MPAs by 2020. The rush to fulfill this commitment has raised concerns on how increasing MPA coverage will affect other elements of Target 11, including representation and equity. We examined a Philippines case study to assess and compare 3 MPA planning approaches for biodiversity representation and equitable distribution of costs to small-scale fishers. In the opportunistic approach, MPAs were identified and supported by coastal communities. The donor-assisted approach used local knowledge to select MPAs through a national-scale and donor-assisted conservation project. The systematic conservation planning approach identified MPA locations with the spatial prioritization software Marxan with Zones to achieve biodiversity objectives with minimal costs to fishers. We collected spatial data on biodiversity and fisheries features and performed a gap analysis to evaluate MPAs derived from different approaches. We assessed representation based on the proportion of biodiversity features conserved in MPAs and distribution equity by the distribution of opportunity costs (fishing areas lost in MPAs) among fisher stakeholder groups. The opportunistic approach did not ineffectively represent biodiversity and resulted in inequitable costs to fishers. The donor-assisted approach affected fishers disproportionately but provided near-optimal regional representation. Only the systematic approach achieved all representation targets with minimal and equitable costs to fishers. Our results demonstrate the utility of systematic conservation planning to address key elements of Target 11 and highlight opportunities (e.g., integration of local and scientific knowledge can address representation and equity concerns) and pitfalls (e.g., insufficient stakeholder considerations can exacerbate social inequalities) for planning MPAs in similar contexts.

Evaluación de las Estrategias para Ampliar las Áreas Marinas Protegidas Basadas en Comunidades a Redes Equitativa y Ecológicamente Representativas Resumen Las áreas marinas protegidas (AMP) son vitales para la conservación marina, pero su cobertura y distribución es insuficiente para tratar las declinaciones globales en la biodiversidad y en las pesquerías. Como respuesta, muchos países se comprometieron por medio del Objetivo 11 de Aichi de la Convención sobre la Diversidad Biológica a conservar el 10% del ambiente marino por medio de AMP ecológicamente representativas y manejadas equitativamente para el año 2020. La prisa por cumplir con este compromiso ha incrementado la preocupación sobre cómo el incremento de la cobertura de las AMP afectará a otros elementos del Objetivo 11, incluyendo la representación y la equidad. Examinamos un estudio de caso de las Filipinas para evaluar y comparar 3 estrategias de planeación de AMP en cuanto a la representación de la biodiversidad y la distribución equitativa de los costos para las pesquerías a pequeña escala. En la estrategia oportunista, las AMP fueron identificadas y respaldadas por las comunidades costeras. La estrategia asistida por donantes usó el conocimiento local para seleccionar las AMP por medio de un proyecto de conservación a escala local y asistido por donantes. La estrategia de planeación sistemática de la conservación identificó la ubicación de las AMP con el software de priorización espacial Marxan with Zones para lograr los objetivos de biodiversidad con un costo mínimo para los pescadores. Recolectamos datos espaciales de las características de la biodiversidad y de las pesquerías y realizamos un análisis de vacío para evaluar las AMP derivadas de las diferentes estrategias. Evaluamos la representación con base en la proporción de las características de la biodiversidad conservadas en las AMP y en la distribución de la equidad por distribución de los costos de oportunidad (áreas de pesca perdidas en las AMP) entre los grupos de accionistas de las pesquerías. La estrategia oportunista no representó inefectivamente a la biodiversidad y resultó en costos injustos para los pescadores. La estrategia asistida por donantes afectó desproporcionalmente a los pescadores, pero proporcionó una representación regional cercana a la óptima. Sólo la estrategia sistemática logró todos los objetivos de representación con costos mínimos y equitativos para los pescadores. Nuestros resultados demuestran la utilidad de la planeación sistemática de la conservación para tratar los elementos importantes del Objetivo 11 y resalta las oportunidades (p. ej.: la integración del conocimiento científico y local puede lidiar con los temas de representación y equidad) y obstáculos (p. ej.: las consideraciones insuficientes de los actores pueden exacerbar las desigualdades sociales) que tienen la planeación de las AMP en contextos similares.

Remote sensing of aquatic vegetation: theory and applications.

Aquatic vegetation is an important component of wetland and coastal ecosystems, playing a key role in the ecological functions of these environments. Surveys of macrophyte communities are commonly hindered by logistic problems, and remote sensing represents a powerful alternative, allowing comprehensive assessment and monitoring. Also, many vegetation characteristics can be estimated from reflectance measurements, such as species composition, vegetation structure, biomass, and plant physiological parameters. However, proper use of these methods requires an understanding of the physical processes behind the interaction between electromagnetic radiation and vegetation, and remote sensing of aquatic plants have some particular difficulties that have to be properly addressed in order to obtain successful results. The present paper reviews the theoretical background and possible applications of remote sensing techniques to the study of aquatic vegetation.

The source and fate of sediment and mercury in the Tapajós River, Pará, Brazilian Amazon: Ground- and space-based evidence.

We present results of mercury (Hg) in surface waters and soils and an analysis of satellite imagery from the Tapajós River basin, Brazilian Amazon, and the Reserva Garimpeira do Tapajós, the legal gold mining district of the basin. Hg bound to suspended sediment was roughly 600 and 200 times the concentration of dissolved Hg per litre of water, in impacted and pristine areas, respectively. Suspended sediments thus represent the major pathway of river-borne Hg. Median concentrations of Hg in suspended load from both impacted and pristine waters were 134 ppb, and 80% of samples were below 300ppb-in the range of naturally occurring surficial materials in the tropics. Regionally, riverine Hg fluxes were proportional to the concentration of total suspended solids. This shows that the dominant source of Hg is the sediment itself rather than anthropogenic mercury discharge from the small-scale mines. To independently test this conclusion, a mass balance was performed. A conservative calculation of the annual export of mercury (Hg) from the Creporí River (a minimum) was 1.6 tonnes for the year 1998-it could be significantly larger. This amount of Hg is difficult to account for by anthropogenic discharge alone, confirming that enhanced physical erosion caused by sluicing and dredging operations is the dominant source of Hg. We therefore conclude that gold mining operations are primarily responsible for elevated Hg concentrations. The dominant source of contamination is not, however, the loss of Hg in the gold amalgamation process. Rather, the disturbance and mobilization of large quantities of Hg-rich sediment and floodplain soil into the water column during mining operations is the source of contamination. These findings shift the focus of remediation and prevention efforts away from Hg control toward soil and sediment erosion control. The minimization or elimination of Hg losses in the mining process remains important for the health of local peoples and environments, but keeping basin soils and sediments in place would be a much more effective means of minimizing Hg fluxes to the region's rivers. To gain a spatial and historical perspective on the source and extent of emissions, satellite imagery was used. We were able to reconstruct historical mining activity, locate impacted areas, and estimate historical Hg fluxes with the imagery. To do so, the spectral characteristics of satellite images were calibrated to the concentration of suspended sediment in the rivers, which, in turn, is proportional to the Hg concentration. This analysis shows that mining-induced sediment plumes have been a dominant source of sediment to the Tapajós River system for decades. As well, the intensity and location of these emissions has varied through time. For example, sediment discharge from the Creporí River was greater in 1985 than in 1998; and the tributaries on the west bank of the Tapajós were actively being mined in 1985 but had been abandoned in 1998. This type of information should greatly assist in understanding original and ongoing sources of emissions, and in managing prevention and remediation efforts.

Uso de imagens de radar para o cálculo da produção primária de plantas aquáticas nas várzeas da Amazônia / Use of radar imagery for estimating net primary productivity of aquatic vegetation in the Amazon floodplain

A área da planície de inundação da Amazônia é estimada em 300 000km² e sua produtividade primária em 1,17 x 10(14) g C yr-1. Deste total de área e produtividade, estimativas sugerem que 43 por cento e 62 por cento, respectivamente, são atribuídos às plantas aquáticas. Estas estimativas variam de acordo com o pulso de inundação. Por exemplo, durante o período de seca as plantas terrestres (herbáceas) geralmente ocupam áreas que apresentam plantas aquáticas na cheia. A área e a produtividade destes ecossistemas são informações essenciais para a compreensão da dinâmica biogeoquímica da Amazônia. Imagens de satélites (radar) combinadas com amostragem de campo foram utilizadas para estimar a biomassa e mapear a área de cobertura de plantas aquáticas emergentes para calcular a produção primária de plantas aquáticas na várzea do baixo Amazonas. A combinação de bandas C e L forneceu a melhor correlação (r=0,82) e um ponto de saturação de biomassa intermediário (620 gm-2) para estimar biomassa aérea. O método de segmentação e classificação por região foi utilizado para classificar combinações de bandas C e L para cada período de nível de água, e forneceu uma precisão de mapeamento maior que 95 por cento para determinação espacial de áreas cobertas por plantas aquáticas. Combinando a distribuição espacial de plantas aquáticas, o modelo para estimativa de biomassa aérea e a porcentagem de biomassa submersa, estimou-se espacialmente uma produção primária líquida anual de 1.9x10(12) g C yr-1 (±28 por cento) para as plantas aquáticas em uma área de 394km².