Terminology and units in optical oceanography

Abstract

This document presents fundamental terms describing the transfer of radiative energy and relevant optical properties of natural waters. These are primarily based upon the terminology of the “Système International d'Unités (SI)”; and the “International Commission on Illumination (CIE).’’ Quantities and Symbols as proposed in the present terminology follow and extend the terminology that was recommended by the Committee on Radiant Energy in the Sea (of the International Association of Physical Oceanography, IAPO), as published by Jerlov (1968, Optical Oceanography Elsevier Oceanography Series, Vol. 5; 1976, Marine Optics Elsevier Oceanography Series, Vol. 14).     

Deep-sea Fe-Mn Crusts from the Northeast Atlantic Ocean: Composition and Resource Considerations

Eighteen deep-sea ferromanganese crusts (Fe-Mn crusts) from 10 seamounts in the northeast Atlantic were studied. Samples were recovered from water depths of ～1,200 to ～4,600 m from seamounts near Madeira, the Canary and Azores islands, and one sample from the western Mediterranean Sea.

The mineralogical and chemical compositions of the samples indicate that the crusts are typical continental margin, hydrogenetic Fe-Mn crusts. The Fe-Mn crusts exhibit a Co + Cu + Ni maximum of 0.96 wt%. Platinum-group element contents analyzed for five samples showed Pt contents from 153 to 512 ppb.

The resource potential of Fe-Mn crusts within and adjacent to the Portuguese Exclusive Economic Zone (EEZ) is evaluated to be comparable to that of crusts in the central Pacific, indicating that these Atlantic deposits may be an important future resource.     

Population dynamics of cryptogenic calcarean sponges (Porifera,Calcarea) in Southeastern Brazil

The calcarean sponge Paraleucilla magna is classified as being an invasive species on the Mediterranean Sea, where it causes economic damages to mollusc farms. On the Brazilian coast, this species is considered to be cryptogenic, and information on its ecology is scarce. The same is true for Sycettusa hastifera, another calcarean sponge with a worldwide distribution. Data on the ecology of these species could help in elucidating their potential to become a threat if they are found to be exotic species in Brazil. In the present work, we studied habitat selection, growth and mortality of early juveniles of P. magna and habitat selection of S. hastifera in a Marine Reserve from Southeastern Brazil, where these species are abundant in the benthic community. Granite plates were used for habitat selection analysis, varying in substrate inclination (vertical and horizontal) and exposure to light and hydrodynamism (exposed and sheltered). To analyse the growth and mortality rates, sponges were mapped and then measured once a week for 10 weeks. If a monitored sponge was not found in the following week, it was considered to be dead. Our results showed that, although P. magna and S. hastifera are capable of inhabiting substrates exposed to different environmental conditions, they showed habitat preferences. Growth of the juveniles of P. magna seemed not to have damaged any neighbouring invertebrates. The mortality of juveniles of this species was higher during the first 2 weeks of life but its causes could not be elucidated.     

Geochemical model of a magmatic–hydrothermal system at the Lastarria volcano, northern Chile

Lastarria volcano (25°10′ S, 68°31′ W; 5,697 m above sea level), located in the Central Andes Volcanic Zone (northern Chile), is characterized by four distinct fumarolic fields with outlet temperatures ranging between 80°C and 408°C as measured between May 2006–March 2008 and April–June 2009. Fumarolic gasses contain significant concentrations of high temperature gas compounds (i.e., SO₂, HCl, HF, H₂, and CO), and isotopic ratios (³He/⁴He, δ¹³C–CO₂, δ¹⁸O–H₂O, and δD–H₂O) diagnostic of magmatic gas sources. Gas equilibria systematics, in both the H₂O-H₂-CO₂-CO-CH₄ and alkane–alkene C₃ system, suggest that Lastarria fumarolic gasses emanate from a superheated vapor that is later cooled and condensed at relatively shallow depths. This two-stage process inhibits the formation of a continuous aquifer (e.g., horizontal liquid layer) at relatively shallow depth. Recent developments in the magmatic gas system may have enhanced the transfer and release of heat causing shallow aquifer vaporization. The consequent pressure increase and aquifer vaporization likely triggered the inflation events beginning in 2003 at the Lastarria volcano.     

Performance of masonry enclosure walls: lessons learned from recent earthquakes

This paper discusses the issue of performance requirements and construction criteria for masonry enclosure and infill walls.Vertical building enclosures in European countries are very often constituted by non-load-bearing masonry walls, using horizontally perforated clay bricks.These walls are generally supported and confined by a reinforced concrete frame structure of columns and beams/slabs.Since these walls are commonly considered to be nonstructural elements and their influence on the structural response is ignored,their consideration in the design of structures as well as their connection to the adjacent structural elements is frequently negligent or insufficiently detailed.As a consequence,nonstructural elements,as for wall enclosures,are relatively sensitive to drift and acceleration demands when buildings are subjected to seismic actions. Many international standards and technical documents stress the need for design acceptability criteria for nonstructural elements,however they do not specifically indicate how to prevent collapse and severe cracking,and how to enhance the overall stability in the case of moderate to high seismic loading.Furthermore,a review of appropriate measures to improve enclosure wall performance and both in-plane and out-of-plane integrity under seismic actions is addressed.     

A Comprehensive Method for Fractionating Soil Organic Matter Not Protected and Protected from Decomposition by Physical and Chemical Mechanisms

The objective of this work was to describe a method for isolating meaningful and measurable soil organic matter (SOM) pools that differ in the mechanisms by which they are protected from decomposition. The proposed method is appropriate for soil C stabilization and sequestration studies. Unlike previous fractionation schemes, this procedure allows free SOM located between aggregates (unprotected C pool) and SOM occluded within both macroaggregates and microaggregates (C weakly and strongly protected by physical mechanisms, respectively) to be recovered separately, freed from the soil mineral matrix and the mineral‐associated SOM pool (C pool protected by chemical mechanisms) and thus well suited to advanced chemical characterization by ¹³C‐NMR. Briefly, free SOM is isolated by an initial density separation. Stable macroaggregates are broken up into stable microaggregates and intra‐macroaggregate SOM, which is then separated by density. Finally, intra‐microaggregate SOM is isolated from mineral‐associated SOM by a third density separation after ultrasonic disruption. The SOM dissolved during the fractionation procedure is also recovered. Results obtained on soil samples with contrasting textures suggested that clay content induces a decrease of the proportion of free organic C and an increase of mineral‐associated organic C content. Free SOM is characterized by a marked presence of undecayed organic material and biologically labile substances, such as carbohydrates and proteins. In contrast, SOM occluded within aggregates, especially within microaggregates, represents a more decomposed fraction, relatively enriched in unsubstituted‐aliphatic material, most probably lipid biopolymers.     

Sediments Quality Assessment of Jacarepaguá Lagoon: The Venue of the 2011 Rock in Rio

In order to aid in the efforts of the 2016 Olympic Games, the organizers of 2011 Rock in Rio decided to build a permanent venue next to the Olympic Park. The area is problematic from the geotechnical point of view since it presents soils with low shear strength, low permeability, and high plasticity, so major soil improvement works were carried out. Bored soil–cement columns were placed to increase soil shear strength and reduce compressibility. A meter thick fill composed of gneiss residual soil was placed and trenches were digged to drain rainwater. However, earlier studies conducted on Jacarepaguá Lagoon have detected the presence of heavy metals in these sediments. In this study, an environmental survey on the Jacarepaguá Lagoon sediments took place in order to choose a place where its sediments could be dredged to be later used in the drainage facilities. The results indicated areas where the threshold level 1 (low probability of adverse effects) issued by the general procedures for sediments quality assessments for dredging purposes, Resolution no 344 of the Brazilian Federal Government, was surpassed. Levels above the limits established for cadmium (Cd), lead (Pb), copper (Cu), nickel (Ni), and zinc (Zn) were detected. Based on this consideration the State Environmental Agency issued a permit allowing the organizers of 2011 Rock in Rio to dredge an area close to City of Rock in order to obtain coarse sediments for the drainage facilities. In addition, it was found that those sediments were ideal for this application since their hydraulic conductivity is on the order of 10^?2 cm/s.     

Process-based 2DH morphodynamic modeling of tidal inlets: A comparison with empirical classifications and theories

The economical and ecological importance of tidal inlets has fostered the development of empirical tools for inlet management during the last century. This study aims at confronting these empirical theories with results obtained with a process-based numerical model, MORSYS2D. This 2DH morphodynamic modeling system is applied to an idealized tidal inlet/lagoon system with different combinations of significant wave height, tidal range and tidal prism. The numerical model predictions are compared to the empirical models of Hayes, Bruun, O'Brien and FitzGerald and to morphologies observed at natural tidal inlets. The results present good accordance with observations as well as with some key behaviors predicted with the empirical theories. The predicted morphologies satisfy the relation of O'Brien between the tidal prism and the cross-sectional area, the model reproduces the conceptual model of sand by-passing by ebb-tidal delta breaching of FitzGerald and the classifications of Hayes and Bruun are generally respected. However, some inconsistencies between model results and Hayes classification highlight the limitations of applying this classification, which only considers the yearly-averaged significant wave height and tidal range, to a single tidal inlet case.     

Coral communities and reefs from Guerrero,Southern Mexican Pacific

Corals in the Eastern Pacific extend south from the Gulf of California to Ecuador and oceanic Chile, and west from Colombia to Clipperton Atoll. Nevertheless, large stretches of the Mexican Pacific remain fundamentally unstudied. Therefore, to assess the current conditions of coral communities, a coastal fringe ～300 km long (17°40′ N, 101°39′ W to 16°46′ N, 99°49′ W) was surveyed within the Southern Mexican Pacific, between 2005 and 2009. Fifteen stony coral species were identified at 13 coral communities and six Pocillopora‐dominated fringing reefs, with Pocillopora verrucosa and Pocillopora damicornis the primary contributing taxa. Reef development was identified in embayments or behind rocks or islands that offered shelter from northern and northwestern winds. Observations of Pocillopora effusus, Pocillopora inflata, Porites lobata, Pavona clavus, and Pavona varians expanded the species known geographic ranges by several degrees of latitude, suggesting reef building fauna comprised a mixture of widespread and relatively rare Eastern Pacific corals. Results indicated greater live coral cover in the Ixtapa‐Zihuatanejo area (15–73%) than in the Acapulco localities, which had high algal dominance; the reefs in the latter region exhibited high erosion. Regional differences are likely the result of long‐standing anthropogenic pressures around Acapulco since 1950, when it became an important tourist destination. This paper is the first detailed report of ecologically stressed corals and coral reefs from the state of Guerrero on the Mexican Southern Pacific coast.