Search results for " Planetary"
showing 10 items of 5408 documents
Impact of Freshwater Inflow From the Volturno River on Coastal Circulation
2020
The coastal area located in front of the Volturno river's estuary (Gulf of Gaeta, central-eastern Tyrrhenian Sea) has been synoptically sampled during seven surveys, between June 2012 and October 2014. The vertical profiles of temperature and salinity have been acquired on a high resolution nearly-regular grid, in order to describe the spatial and temporal variability of the water masses characteristics. Moreover, to provide a first assessment of the steady circulation at small scale, the three-dimensional velocity field associated to each survey has been obtained through the full momentum equations of the Princeton Ocean Model. The data analysis has shown the entire water column characteri…
Influence of Riverine Input on Norwegian Coastal Systems
2020
Coastal ecosystems are of high ecological and socioeconomic importance and are strongly influenced by processes from land, sea, and human activities. In this study, we present physical, chemical, and biological observations over two consecutive years from three study regions along the Norwegian coast that represent a broad latitudinal gradient in catchment and oceanographic conditions (∼59–69°N): outer Oslofjord/southern Norway, Runde/western Norway, and Malangen/northern Norway. The observations included river monitoring, coastal monitoring, and sensor-equipped ships of opportunity (“FerryBox”). The riverine discharge and transports were an order of magnitude higher, and the spatiotemporal…
Satellite survey of seasonal trophic status and occasional anoxic 'malaigue' crises in the Thau lagoon using MERIS images
2011
International audience; The Thau lagoon, located in southern France, suffers episodically from anoxic crises locally known as 'malaigue'. Such crises mostly occur under warm conditions, low winds leading to a strong eutrophication of the lagoon. The development of a sulphur bacterium sometimes gives locally to the waters a 'milky turquoise' appearance and leads to shellfish mortality. One of the indicators of the eutrophication status of the lagoon can be surveyed by the chlorophyll product provided by remote sensing images such as Medium Resolution Imaging Spectrometer (MERIS). In this paper we compare chl2 (or algal2) estimations provided by MERIS level 2 products and the ground measureme…
Interannual memory effects for spring NDVI in semi-arid South Africa
2008
[1] Almost 20 years of Normalized Difference Vegetative Index (NDVI) and precipitation (PPT) data are analysed to better understand the interannual memory effects on vegetation dynamics observed at regional scales in Southern Africa (SA). The study focuses on a semi-arid region (25°S–31°S; 21°E–26°E) during the austral early summer (September–December). The memory effects are examined using simple statistical approaches (linear correlations and regressions) which require the definition of an early summer vegetation predictand (December NDVI minus September NDVI) and a consistent set of potential predictors (rainfall amount, number of rainy days, rainfall intensity, NDVI and Rain-Use-Efficie…
Global patterns and drivers of alpine plant species richness
2021
B.J.-A. was funded by the Marie Curie Clarín-COFUND program of the Principality of Asturias-EU (ACB17-26) and the Spanish Research Agency (AEI/10.13039/501100011033).
Ticket to spawn: Combining economic and genetic data to evaluate the effect of climate and demographic structure on spawning distribution in Atlantic…
2019
Abstract Climate warming and harvesting affect the dynamics of species across the globe through a multitude of mechanisms, including distribution changes. In fish, migrations to and distribution on spawning grounds are likely influenced by both climate warming and harvesting. The Northeast Arctic (NEA) cod (Gadus morhua) performs seasonal migrations from its feeding grounds in the Barents Sea to spawning grounds along the Norwegian coast. The distribution of cod between the spawning grounds has historically changed at decadal scales, mainly due to variable use of the northern and southern margins of the spawning area. Based on historical landing records, two major hypotheses have been put f…
Partitioning net carbon dioxide fluxes into photosynthesis and respiration using neural networks
2020
Abstract The eddy covariance (EC) technique is used to measure the net ecosystem exchange (NEE) of CO2 between ecosystems and the atmosphere, offering a unique opportunity to study ecosystem responses to climate change. NEE is the difference between the total CO2 release due to all respiration processes (RECO), and the gross carbon uptake by photosynthesis (GPP). These two gross CO2 fluxes are derived from EC measurements by applying partitioning methods that rely on physiologically based functional relationships with a limited number of environmental drivers. However, the partitioning methods applied in the global FLUXNET network of EC observations do not account for the multiple co‐acting…
A global analysis of complexity–biodiversity relationships on marine artificial structures
2020
Aim Topographic complexity is widely accepted as a key driver of biodiversity, but at the patch‐scale, complexity–biodiversity relationships may vary spatially and temporally according to the environmental stressors complexity mitigates, and the species richness and identity of potential colonists. Using a manipulative experiment, we assessed spatial variation in patch‐scale effects of complexity on intertidal biodiversity. Location 27 sites within 14 estuaries/bays distributed globally. Time period 2015–2017. Major taxa studied Functional groups of algae, sessile and mobile invertebrates. Methods Concrete tiles of differing complexity (flat; 2.5‐cm or 5‐cm complex) were affixed at low–high…
The thermal structure, subglacial topography and surface structures of the NE outlet of Eyjabakkajökull, east Iceland
2020
Abstract This study presents the detailed surveys of the NE outlet of Eyjabakkajokull glacier, East Iceland, from the combination of low-frequency ground penetrating radar (GPR), unmanned aerial vehicle (UAV) and GNSS measurements. Data analyses reveal the complex subglacial topography with a prominent, up to 45-m-deep longitudinal trough in the central part of the outlet that serves as the main trunk for the fast ice flow during the glacier surges. During the last decade (2010–2018), the studied part of the glacier has thinned by 4.37 m/yr on average and the ice margin has retreated ~750 m. We detect a boundary between scatter-free zone and zone of intense scattering near the ice margin an…
Forest bioenergy harvesting changes carbon balance and risks biodiversity in boreal forest landscapes
2020
Climate solutions relying on forest bioenergy may be in conflict with carbon sequestration and storage by forests as well as conservation of biodiversity. We quantified effects of forest-residue harvesting for bioenergy on both forest carbon balance and biodiversity in a boreal forest landscape. Through a modeling framework, we simulated forest development in four real watersheds with three scenarios: (i) with and (ii) without forest-residue harvesting and (iii) set aside to study the conservation potential of these landscapes in the future without management. We simulated changes in the forest carbon stocks and in the quality and quantity of deadwood resources for 100 years and combined t…