[en] The ecological degradation of Santa Marta's Big Marsh and their next areas it has motivated the realization of diagnosis studies and design by several state and private entities. One of the recommended efforts for international advisory it was to develop an ecological model that allowed the handling of the water body and the economic test of alternative of solution to those ecological problems. The first part of a model of this type is in turn a model that simulates the movement of the water inside the marsh, that is to say, a hydrodynamic model. The realization of this was taken charge to the civil engineering department, on the part of Colciencias. This article contains a general explanation of the hydrodynamic pattern that this being developed by a professors group. The ecological causes are described and antecedent, the parts that conform the complex of the Santa Marta big Marsh The marsh modeling is made and it is explained in qualitative form the model type Hydrodynamic used

[en] Highlights: • Agrochemicals from horticulture contaminate adjacent streams on the Argentine Pampas. • Pesticide concentrations in sediments were lower downstream from a riparian wetland. • Sediment toxicity to Hyalella curvispina decreased downstream from the wetland. • Pesticide-sensitive Hyalella curvispina was dominant downstream from the wetland. • Riparian marshes should be preserved and restored to attenuate stream contamination. Horticulture has greatly increased in Argentina in recent decades mainly due to increasing greenhouse utilization and agrochemical consumption, thus representing a threat to adjacent water bodies. Riparian wetlands, however, could attenuate agrochemical contamination. The present work therefore compared insecticide concentrations in bottom sediments in addition to sediment toxicity to the amphipod Hyalella curvispina and investigated the macroinvertebrate composition upstream and downstream from a natural wetland in a small stream draining a basin undergoing intense horticultural production. The wetland surface was covered by macrophytes, mainly Thypha sp., and the insecticide concentrations measured downstream from the wetland were significantly lower, at roughly 19% of the upstream values. The growth rates of H. curvispina were significantly higher when exposed to the sediments downstream from the wetland, while the macroinvertebrate-assemblage composition was significantly different upstream and downstream: the snail Pomacea canaliculata was the dominant species upstream while the amphipod H. curvispina was dominant downstream. Pomacea canaliculata is often the dominant species in the regional streams draining agriculture and horticultural basins. Hyalella curvispina is sensitive to pesticide toxicity and is often dominant in streams draining extensive livestock basins and within a biosphere reserve. We conclude that riparian wetlands effectively attenuate horticulture contamination in pampean streams and should therefore be preserved and restored.

[en] A series of experimental trials are in progress to investigate the effectiveness and consequences of oil spill cleanup methods for areas of mud flats and salt marsh. Trials have shown that wheeled and tracked vehicles have limited utility. Field measurements of the load bearing capacity of the mud can show where such vehicles may be used. Lightweight hover craft provide a useful means of transport. Shallow-draft boats can have a useful transport role: whether such craft can be used depends on the local topography and tidal regime. The trials showed that practical problems associated with implementing low-pressure flushing operations (lack of water for flushing, recovery of the flushed oil) can be overcome - although the environmental effects have yet to be assessed. The use of straw matting as a sorbent material was also demonstrated. The objective of the first two phases of the project, reported here, was to select workable methods with a view to subsequently employing them in larger-scale trials. The environmental consequences of using the selected methods will be examined in the later trials

[en] An examination of tissue metal levels in Sudbury-area muskrat (Ondatra zibethica) revealed that animals collected in the vicinity of the local ore-smelters contained elevated burdens of Cd and Ni in their liver and kidneys. Respective tissue concentrations averaged 2-fold and 3- to 6-fold higher than background values and are believed to reflect accumulations resulting from food chain contamination in regional marshes, including that reportedly characterizing Typha latifolia stands--their primary food source--and adherent sediments which may be consumed inadvertently while feeding. No evidence of site-influence or enhanced tissue metal levels was seen for Cu, Pb or Zn. While Cd : Ni accumulations were positively correlated in both the liver (r=0.78) and the kidneys (r=0.65), between-tissue comparisons indicated that hepatic : renal burdens were significantly correlated (r=0.75) only in the case of Ni. With the exception of 30-35% lower hepatic Zn levels in females relative to males within the Sudbury population, tissue metal levels did not vary according to sex or age class at either site. Our findings substantiate the potential of muskrat to serve as useful bioindicators/monitors of metal pollution in semi-aquatic environments. - Muskrats appear to be useful bioindicators of metal pollution in semi-aquatic environments

[en] Wetlands are commonly limited in available nitrogen. But marshes in the Sanjiang Plain, Northeastern China suffer large amounts of exogenous nitrogen from agriculture fertilization after wetland reclamation. This paper focuses on the ecological effects of a short-term increase of nitrogen input on collembolan communities. Our results show a significant decrease in collembolan abundance and Shannon diversity index, and the abundance of euedaphic and hemiedaphic collembolans decreased faster than epedaphic collembolans. These results indicate that euedaphic or hemiedaphic fauna suffer more biodiversity loss caused by nitrogen deposition than epedaphic fauna and call for more researches on trait-based approaches under environmental stress in the future. - Highlights: • Nitrogen inputs significantly decreased Collembola density and diversity. • Collembola are species-specific sensitive to nitrogen inputs. • Euedaphic and hemiedaphic Collembola suffer larger damages than epedaphic species to nitrogen input. - Expect the traditional density or diversity index, current trait-based approaches can supplement our knowledge about environmental stress on belowground ecosystems.

[en] Highlights: • Landscape modification reduces net primary production (NPP) supporting other species. • Wetlands are being lost faster than forests but the associated loss of NPP is unknown. • We show that 77% loss of habitats from a large wetland ecosystem reduced NPP by 94%. • Success at meeting habitat restoration targets could recover 12% of lost NPP. • Estimated losses of ecosystem functions from habitat loss can guide restoration plans. Humans are changing the Earth's surface at an accelerating pace, with significant consequences for ecosystems and their biodiversity. Landscape transformation has far-reaching implications including reduced net primary production (NPP) available to support ecosystems, reduced energy supplies to consumers, and disruption of ecosystem services such as carbon storage. Anthropogenic activities have reduced global NPP available to terrestrial ecosystems by nearly 25%, but the loss of NPP from wetland ecosystems is unknown. We used a simple approach to estimate aquatic NPP from measured habitat areas and habitat-specific areal productivity in the largest wetland complex on the USA west coast, comparing historical and modern landscapes and a scenario of wetland restoration. Results show that a 77% loss of wetland habitats (primarily marshes) has reduced ecosystem NPP by 94%, C (energy) flow to herbivores by 89%, and detritus production by 94%. Our results also show that attainment of habitat restoration goals could recover 12% of lost NPP and measurably increase carbon flow to consumers, including at-risk species and their food resources. This case study illustrates how a simple approach for quantifying the loss of NPP from measured habitat losses can guide wetland conservation plans by establishing historical baselines, projecting functional outcomes of different restoration scenarios, and establishing performance metrics to gauge success.

[en] The effects of crude oil and oil spill dispersants on saltmarsh vegetation were examined to determine whether near shore use of dispersants is an appropriate management response to oil spills. At a Nova Scotia saltmarsh, the effects of treatments of oil, dispersant, or both on three distinct marsh vegetation types were tested. Treatments were applied in July 1986 and vegetation and soil characteristics were measured in late summer 1986, 1987, 1988 (vegetation only), and 1990. Results from the 1988 and 1990 sampling periods are presented. Overall, post-treatment effects of oil ranged from relatively small but persistently negative at the creek edge and high marsh to negative but short-lived in the mid-marsh. Dispersant effects ranged from slightly positive in the creek edge to acutely negative but ephemeral in the mid- and high-marsh. Oil + dispersant effects ranged from slightly positive in the creek edge to slightly negative in the mid- and high-marsh. Applying management recommendations from an experimental study to an actual spill situation is complicated by differences in scale. Many of the mechanisms by which recovery occurs might conceivably operate more quickly in small treatment plots surrounded by undamaged vegetation than in marshes suffering substantial disruption of vegetation over large areas. Whether spilled oil should be chemically dispersed before it enters a saltmarsh is still open to question. The study suggests that any benefits of dispersal in terms of more rapid vegetational recovery would be relatively small, if they exist at all. 11 refs., 6 figs., 2 tabs

[en] A break in Rainbow Pipeline's main line occurred in February 1993 north of Slave Lake, resulting in 2,500 cubic metres of light crude being spilled onto peat moss covered tundra. Oil recovery from this natural sorbent was almost impossible. After 21 days, only 650 cubic metres of free standing oil had been recovered. The boggy muskeg was causing problems and would cause even more when it began to thaw. With the weather window closing rapidly, the crew resorted to in situ burning. The oil soaked debris was piled in containment areas and burned in the air curtain incinerator owned by the Canadian Association of Petroleum Producers. When the burn was completed only some ashes remained with very negligible oil residue. 2 figs

[en] Using published data on the responses of individual species to ozone, 54 EUNIS (European Nature Information System) level 4 communities with six or more ozone-sensitive species (%OS) and c. 20% or more species tested for ozone sensitivity, were identified as potentially ozone-sensitive. The largest number of these communities (23) was associated with Grasslands, with Heathland, scrub and tundra, and Mires, bogs and fens having the next highest representation at 11 and 8 level 4 communities each respectively. Within the grasslands classification, E4 (Alpine and sub-alpine grasslands), E5 (Woodland fringes and clearings) and E1 (Dry grasslands) were the most sensitive with 68.1, 51.6 and 48.6%OS respectively. It is feasible to map the land-cover for these and other communities at level 2, but it may not be currently possible to map the land-cover for all communities identified to be ozone-sensitive at levels 3 and 4. - Grassland communities such as alpine and sub-alpine grasslands have the highest potential sensitivity ozone, based on the responses of their component species

[en] Highlights: • Data on lateral dynamics and volumetric changes occurring in lagoon marshes. • Human interventions caused modifications in the configuration of marshes. • Sea-level rise will lead to major changes in marsh stability in the next ~100 years. • Under high sea-level rise regime land cover trajectories show marsh state shifts. It is rational to assume that salt marshes in regions where sediment loads are high should remain stable or prograde when facing a range of sea-level scenarios, whereas those in sediment-poor systems may erode or drown. Despite extensive theoretical and laboratory studies, additional marsh ‘persistence’ indicators under human pressures and accelerated sea-level rise rates are still needed. This study investigates the recent lateral and volumetric changes occurring in the lagoon marshes of the Ria Formosa lagoon (south Portugal), under human pressures and sea-level rise. Our analysis assesses the past (1947–2014) geomorphological evolution of marshes based on aerial imagery analysis and estimates its potential future adjustment to sea-level rise (~100 years) based on SLAMM (landscape-based model) simulated land cover changes. We highlight the influence of both stressors on marsh ecosystems and examine how their interactions can contribute to understanding sea-level rise impacts and ecological resilience of lagoon marshes. Salt marshes in the Ria Formosa have slowly expanded over the last 70 years (~0.2 mm/yr), with local erosion in front of tidal inlets and along the main navigable channels, associated with inlet migration and dredging activities. Past evolution shows that the ecosystem was able to maintain its functions and cope with sea-level rise. However, future marsh trajectories under a high sea-level rise rate suggest unbalanced vertical marsh accretion and progressive migration of the tidal flat (and water bodies) towards the salt marsh area. The model results show evidence of non-linearity in marsh response to high sea-level rise rates, which could indicate the presence of a system tipping-point and potential positive (disturbance-reinforcing) feedbacks within the system, with significant implications to marsh resilience.