High-resolution grid of H/V spectral ratios and spatial variability on microtremors at Port of Spain,Trinidad

We performed dense single mobile microtremor measurements at 1181 sites throughout the city of Port of Spain, Trinidad. The results yielded fundamental periods of the soil of 1.2–1.7 s in the coastal areas, 0.3–1.2 s in the downtown area, and 0.0–0.3 s in the surrounding areas of the city. We employed the variogram plot to retrieve the spatial variability of fundamental periods. The results suggest that the variability of the period yields about 0.010 s² at short distances of 100 m and it can be modeled as a Gaussian distribution which is directionally dependent. Finally, we propose an elastic design response spectra for different zones in the city in accordance with the observed periods of vibration and compatible with the International Building Code (IBC) provisions.     

Pseudo-nitzschia spp. (Bacillariophyceae) and dissolved organic matter (DOM) dynamics in the Ebro Delta (Alfacs Bay, NW Mediterranean Sea)

Samples were collected during one annual cycle (April 2007–March 2008) at Alfacs Bay (NW Mediterranean Sea) central station in order to assess the influence of organic nutrients in the growth of the microalgae assemblage, with special reference to Pseudo-nitzschia spp. This potentially toxic diatom forms natural and recurrent blooms in the study area. To assess further the relationship between Pseudo-nitzschia spp. and nutrients an enrichment experiment with high molecular weight dissolved organic matter (HMWDOM) was performed with field samples obtained during a Pseudo-nitzschia spp. bloom. HMWDOM was extracted from water collected at Alfacs Bay. Five bioassays were prepared: N + P (seawater with addition of nitrate and phosphate), DOM (addition of HMWDOM), (−N + P) + DOM (nitrogen deficient, with addition of phosphate and HMWDOM), (N + P) + DOM (addition of nitrate, phosphate and HMWDOM), seawater control (without added nutrients), and B + DOM (control of bacteria, without microalgae). The experiment was run in batch mode over 4 days. Results from the field study revealed that the concentrations of organic nutrients mostly surpassed the inorganic pool. Pseudo-nitzschia spp. was the most frequent and abundant taxa of the microalgae community. The micro-planktonic assemblage was arranged according to a seasonal factor (ANOSIM and cluster analysis). DON, nitrate and silicate were the most important abiotic parameters contributing to the dissimilarities between seasons (SIMPER analysis) and thereby potentially influencing the seasonal distribution of microalgae in the representative station. In the experimental investigation, Pseudo-nitzschia cells increased by the end of the experiment in the DOM bioassay but no respective increase was observed for chlorophyll a. This could point to an acquisition of nutrients through the DOM fraction that would conjointly reduce the need of chlorophyll a. The data obtained suggest that organic nutrients may exert an important role in the development of microalgae, including Pseudo-nitzschia spp., in the selected location.     

Contaminant exposures at the 4H shell mounds in the Santa Barbara Channel

Remobilization, bioavailability, and potential toxicity of chemical contaminants were evaluated at the 4H shell mounds – the site of abandoned offshore oil and gas production platforms in the Santa Barbara Channel region of the Southern California Bight. Evaluations used a weight-of-evidence approach based on results from bulk phase chemical analyses and laboratory toxicity testing of shell mound cores, in situ field bioassays using caged mussels, and surficial sediment chemistry. Shell mound cores contained elevated concentrations of metals associated with drilling wastes (e.g., Ba, Cr, Pb, and Zn), as well as monocyclic and polycyclic aromatic hydrocarbons (PAHs). The highest concentrations along with pockets of free oil were associated with the middle “cuttings” stratum. Sediments composited from all core strata caused significant acute toxicity and bioaccumulation of Ba and PAHs in test organisms during laboratory exposures. In contrast, caged mussels placed at each of the shell mounds for a period of 57–58 days had greater than 90% survival, and there were no significant differences in survival of mussels placed at the shell mounds and corresponding reference sites. While all mussel samples exhibited increases in shell length, whole animal weight, and tissue lipid content, in some cases growth metrics for the shell mound mussels were significantly higher than those for the reference sites. Concentrations of metals, PAHs, and polychlorinated biphenyls (PCBs) in tissues of the shell mound mussels were not significantly different from those at reference sites. The presence of labile aromatic hydrocarbons in shell mound cores and absence of significant contaminant accumulation of tissues of caged mussels indicated that chemical contaminants are not being remobilized from the 4H shell mounds. Surficial bottom sediments near the shell mounds contained elevated Ba concentrations that probably were associated with drilling wastes. However, concentrations did not exhibit clear spatial gradients with distance from the shell mounds. Despite a number of storm events during the mussel exposures, maximum currents were 34 cm s⁻¹ and unlikely to erode materials from the shell mounds. Thus, Ba distributions in bottom sediments probably were due to episodic disturbance such as platform removal or trawling rather than ongoing erosion and dispersion of shell mound solids by near-bottom currents. These results suggest that, in the absence of physical disturbances, contaminants are expected to remain sequestered in the shell mounds.     

A way forward on adaptation to climate change in Colombian agriculture: perspectives towards 2050

Policy measures regarding adaptation to climate change include efforts to adjust socio-economic and ecologic systems. Colombia has undertaken various measures in terms of climate change mitigation and adaptation since becoming a party of the Kyoto protocol in 2001 and a party of the United Nations Framework Convention on Climate Change (UNFCCC) in 1995. The first national communication to the UNFCCC stated how Colombian agriculture will be severely impacted under different emission scenarios and time frames. The analyses in this document further support that climate change will severely threaten the socioeconomics of Colombian agriculture. We first query national data sources to characterize the agricultural sector. We then use 17 Global Circulation Model (GCM) outputs to quantify how Colombian agricultural production may be affected by climate change, and show the expected changes to years 2040–2069 (“2050”) under the A2 scenario of the Intergovernmental Panel on Climate Change Special Report on Emissions Scenarios (SRES-A2) and the overall trends in both precipitation and temperature to 2100. We then evaluate expected changes within different regions and measure the proportion of area affected within each crop’s distributional range. By 2050, climatic change in Colombia will likely impact 3.5 million people, 14?% of national GDP corresponding to agriculture, employment of 21?% of the population, agro-industries, supply chains, and food and nutritional security. If no adaptation measures are taken, 80?% of crops would be impacted in more than 60?% of their current areas of cultivation, with particularly severe impacts in high value perennial and exportable crops. Impacts also include soil degradation and organic matter losses in the Andes hillsides; likely flooding in the Caribbean and Pacific coasts; niche losses for coffee, fruit, cocoa, and bananas; changes in prevalence of pests and diseases; and increases in the vulnerabilities of non-technically developed smallholders. There is, however, still time to change the current levels of vulnerability if a multidisciplinary focus (i.e., agronomic, economic, and social) in vulnerable sectors is undertaken. Each sub-sector and the Government need to invest in: (1) data collection, (2) detailed, regionally-based impact assessments, (3) research and development, and (4) extension and technology transfer. Support to vulnerable smallholders should be given by the state in the form of agricultural insurance systems contextualized under the phenomenon of climate change. A national coordination scheme led by (but not restricted to) the Ministry of Agriculture and Rural Development (MADR) with the contributions of national and international institutions is needed to address agricultural adaptation.     

DDT in endangered Galapagos sea lions (Zalophus wollebaeki)

We characterize for the first time the presence of DDT and its metabolites in tropical Galapagos sea lions (Zalophus wolleabeki). ∑DDT concentrations in Galapagos sea lion pups sampled in 2005 and 2008 ranged from 16 to 3070 μg/kg lipid. Concentrations of ∑DDT in pups in 2008 averaged 525 μg/kg lipid and were 1.9 times higher than that (281 μg/kg lipid) detected in pups in 2005. These concentrations are lower than those reported in many pinnipeds elsewhere, comparable to those in Hawaiian monk seals, and higher than those in southern elephant seals. The health risk characterization showed that 1% of the male pups exceeded the p,p′-DDE toxic effect concentration associated with anti-androgenic effects reported in rats. The findings provide preliminary guidance on the relationship between DDT use and ecological impacts, serving as a reference point against which possible future impact of tropical DDT use can be assessed.     

Harmful algal blooms (HABs), dissolved organic matter (DOM), and planktonic microbial community dynamics at a near-shore and a harbour station influenced by upwelling (SW Iberian Peninsula)

The surface microalgal community, including harmful species, dissolved organic matter (DOM), and bacterial and viral populations were studied during an annual cycle (November 2007–October 2008) in a Near-shore (NS) and a Harbour (H) station located in an upwelling area (Sagres, SW Iberian Peninsula). The higher water residence time, water stability and shallowness of harbours in comparison with open waters likely contributed to the differences found between stations regarding chemical variables, statistical correlations and harmful algal proliferations. Also, several differences were noticed from a previous assessment (Loureiro et al., 2005) including higher SST, lower nitrate and chlorophyll a concentrations, along with a shift in the microplankton community structure from diatom to nanoflagellate predominance. These variations feasibly reflect the response of this dynamic system to regional environmental modifications contributing to the understanding of common patterns in environmental change trends. The division of the sampling period into (1) non-upwelling (Non-Uw), (2) “spin-up” of upwelling (SU-Uw), and (3) “spin-down” and relaxation-downwelling (SD-Rel) stages allowed the identification of natural groupings of microplankton samples by Multi Dimensional Scaling (MDS) analysis. Dissolved organic nitrogen (DON) and viruses were the most significant abiotic and biotic variables, respectively, contributing to the dissimilarities between these stages (SIMPER analysis) and, therefore, potentially affecting the microplankton community structure. Harmful algal species and a stable viral community appeared to be favoured by SD-Rel conditions. Data seem to indicate that both Gymnodinium catenatum and Heterosigma akashiwo, the most abundant potentially harmful species, have been imported into the sampling area. Also, the H location, together with potential retention sites developing around the Cabo de São Vicente upwelling centre, may contribute to the local accumulation of harmful species. The associations found between harmful algal species and bacterioplankton and virioplankton call for detailed studies in order to evaluate species-specific interactions.     

Assessing progress in MRV capacity development: experience with a scorecard approach

This article reports experiences gathered in 12 developing countries in Latin America and Africa with capacity development for national GHG inventory systems. The national systems and their ability to deliver on measurement, reporting and verification (MRV) requirements is assessed using a scorecard that covers the transparency, accuracy, completeness, consistency, and comparability of the GHG inventory as well as its institutional set-up and management aspects. The analysis shows that a quantitative assessment of GHG inventory systems with a scorecard is feasible and useful, and could commonly be used for tracking progress in MRV capacity development.

Policy relevance

A large number of capacity development initiatives are underway to advance national GHG inventory systems in developing countries, particularly in the land-use sector. These aim to promote the reliable MRV of GHG emissions and removals, which is expected to underpin developing countries’ contributions to global mitigation efforts, including through results-based payments. Although MRV is a cornerstone of climate change policy and despite widespread capacity gaps, there is little conclusive evidence about the effectiveness of such capacity development. This article relates the positive experience from one initiative, the Capacity Development for REDD+ project, which employed a novel, scorecard-based approach to results monitoring. Considerable progress is observed and provides reassurance regarding the soundness of development agencies’ significant investments in MRV. Disaggregating scores by countries and by underlying criteria also provides insights to prioritize further investments.     

Multi-method assessment of connectivity between surface water and shallow groundwater: the case of Limarí River basin,north-central Chile

A study that tests the applicability and consistency of independent but complementary approaches in the assessment of interactions between surface water and shallow groundwater within a water-stressed basin is described. The mostly agricultural Limarí basin in arid north-central Chile was chosen as a suitable case study. The analyses involved: (1) a connectivity index method, (2) hydrochemistry, and (3) water isotopic geochemistry. Chemical and isotopic data were obtained from two sampling campaigns conducted in April (fall) and December (summer) of 2011 in 22 sampling locations, which included surface water and groundwater. The results obtained by each of the methodologies were mutually consistent and indicate high connectivity conditions. Additionally, the relative contribution by different sources was assessed through end-member mixing analysis, and for reaches of the river that showed gaining conditions, the contribution of groundwater inflow to stream discharge was estimated. It is suggested that this multi-method approach is useful for the characterization of surface-water–groundwater interactions, since it at least represents a suitable starting point for obtaining basic information on these relationships. Thus, it may become the base for further studies in arid and semi-arid basins facing water management challenges.     

Finding a Way: Modeling Landscape Prerequisites for Roman and Early‐Medieval Routes in the Netherlands

This study focuses on reconstructing landscape prerequisites for Roman and early‐medieval routes in the Netherlands. We applied spatial modeling to modern and paleogeographical landscape data in order to determine geographical obstacles for possible translocation in ca. A.D. 100 and 800 via land and water. Network‐friction values were calculated to produce a spatial model of possible movement corridors and to enable the integration of archaeological data. Results show that in geographically dynamic lowland regions such as the current Netherlands, landscape units such as water, peat, and levees must have had a high impact on route orientation. The lower parts of the western Netherlands were almost inaccessible by land, implying that its inhabitants largely must have depended on rivers and streams for transportation. In Dutch coastal and river areas, the landscape changed drastically between A.D. 100 and 800, the largest changes occurring along the coast.