The role of current velocity in structuring eelgrass (Zostera marina L.) meadows

Measurements of velocity profiles, bathymetry, and surface sediment characteristics across eelgrass (Zostera marina L.) meadows yielded information on community development processes and functional attributes of this ecosystem. Height/length ratios of the meadows were positively correlated with tidal current velocity. Low, medium, and high current regimes were separated by surface current velocities of approximately 50 and 90 cm s^?1. Z. marina can tolerate approximately 120–150 cm/sec current velocities in the areas studied. Per cent silt-clay and organic matter content of the surface sediments are negatively associated with shear velocity, suggesting that meadows in high current areas are sources while meadows in low current areas are sinks of autochthonous detritus. Current velocity maintains seagrass meadows at different equilibrium levels (relative climaxes). We theorize these different equilibrium levels provide unequal habitat utilization potentials for the associated faunal community.     

MgSO4 ION association in seawater

Examination of the consequences of the stoichiometric association constant $\text{K}{}^1{}_{\mathrm{<mtext>a</mtext>}}\text{= 41.7}$ for MgSO₄ in seawater as advocated by Johnson and Pytkowicz (1979) leads to a thermodynamic association constant K_a = 212.6, a value 32% greater than K_A = 160 derived from conductance data. Use of K_a = 160 leads to a $\text{K}{}^1{}_{\mathrm{<mtext>a</mtext>}}$ in essential agreement with the value of 10.2 reported by Kester and Pytkowicz (1969).     

STRUCTURAL ADJUSTMENTS IN THE SOUTHERN MANUFACTURING SECTOR

The diversity of manufacturing in the United States South has shown a substantial increase during the post-World War II period. The basis for this changing industrial structure is found in the expansion of food processing and apparel industries but particularly since 1967 in a variety of higher-pay and higher-technology industries. The traditional textile states remain the least diversified and the slowest to change.     

Hα coronagraph observations of a flare spray,March 1, 1969

An H solar prominence with the characteristics of a spray was ejected in association with a bright limb flare. Knots of material were observed to a distance of more than one solar radius above the west limb of the Sun. The optical event was followed by 80 MHz emission from a type IV source which was observed moving out through several solar radii.Coronagraph observations have been used to determine the trajectories and velocities of the knots in directions perpendicular to the line of sight. After some early deceleration velocities increase to 300–500 km/sec and slowly decline with variations depending on the initial direction of outflow. We suggest that the magnetic field over the spot group is deformed by the energy of the mass motions of material fragments, some of which then continue to move outward from the Sun.     

Monochromatic observations of a coronal loop

An isophotal map of a small coronal loop, obtained from a coronagraph observation through a solid Fabry-Perot interferometer, is used to estimate the variation of emission per unit volume and the pressure gradient at the top and sides of the loop. The magnitude of the magnetic field necessary to maintain the estimated pressure gradients is found to be ¦H ²¦ = 30 G².     

A late Lake Minong transgression in the Lake Superior basin as documented by sediments from Fenton Lake, Ontario

The evolution of the early Great Lakes was driven by changing ice sheet geometry, meltwater influx, variable climate, and isostatic rebound. Unfortunately none of these factors are fully understood. Sediment cores from Fenton Lake and other sites in the Lake Superior basin have been used to document constantly falling water levels in glacial Lake Minong between 9,000 and 10,600 cal (8.1–9.5 ka) BP. Over three meters of previously unrecovered sediment from Fenton Lake detail a more complex lake level history than formerly realized, and consists of an early regression, transgression, and final regression. The initial regression is documented by a transition from gray, clayey silt to black sapropelic silt. The transgression is recorded by an abrupt return to gray sand and silt, and dates between 9,000 and 9,500 cal (8.1–8.6 ka) BP. The transgression could be the result of increased discharge from Lake Agassiz overflow or the Laurentide Ice Sheet, and hydraulic damming at the Lake Minong outlet. Alternatively ice advance in northern Ontario may have blocked an unrecognized low level northern outlet to glacial Lake Ojibway, which switched Lake Minong overflow back to the Lake Huron basin and raised lake levels. Multiple sites in the Lake Huron and Michigan basins suggest increased meltwater discharges occurred around the time of the transgression in Lake Minong, suggesting a possible linkage. The final regression in Fenton Lake is documented by a return to black sapropelic silt, which coincides with varve cessation in the Superior basin when Lake Agassiz overflow and glacial meltwater was diverted to glacial Lake Ojibway in northern Ontario.     

North polar frontal clouds and dust storms on Mars during spring and summer

The complete archive of Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) Mars Daily Global Maps (MDGM) are used to study north polar clouds and dust storms that exhibit frontal structures during the spring and summer (L_s 0-180°). Results show that frontal events generally follow the edge of the polar cap during spring and mid/late summer with a gap in the distribution in early summer. The exact duration and timing of the gap vary from year to year. Ten to twenty percent of spring and summer time frontal events exhibit complex morphologies. Distinct temperature signatures are associated with features observed in images in many but not all cases. The general travel paths of the frontal events are eastward around the polar cap. Westward paths exist only at the edge of the polar cap in late spring/early summer. Occasionally, the paths curve toward or away from the polar cap in certain longitude sectors.     

Can We Determine Electric Fields and Poynting Fluxes from Vector Magnetograms and Doppler Measurements?

The availability of vector-magnetogram sequences with sufficient accuracy and cadence to estimate the temporal derivative of the magnetic field allows us to use Faraday’s law to find an approximate solution for the electric field in the photosphere, using a Poloidal–Toroidal Decomposition (PTD) of the magnetic field and its partial time derivative. Without additional information, however, the electric field found from this technique is under-determined – Faraday’s law provides no information about the electric field that can be derived from the gradient of a scalar potential. Here, we show how additional information in the form of line-of-sight Doppler-flow measurements, and motions transverse to the line-of-sight determined with ad-hoc methods such as local correlation tracking, can be combined with the PTD solutions to provide much more accurate solutions for the solar electric field, and therefore the Poynting flux of electromagnetic energy in the solar photosphere. Reliable, accurate maps of the Poynting flux are essential for quantitative studies of the buildup of magnetic energy before flares and coronal mass ejections.     

Collaborative Governance and Conflict Management: Lessons Learned and Good Practices from a Case Study in the Amazon Basin

Abstract

Given the linkages between natural resources and social conflicts, evidence increasingly shows that successful natural resource management requires conflict mitigation and prevention. However, there may be a gap in practice between knowing what processes and tools need to be used to manage conservation conflicts and how to actually implement them. We present learning from a practice-based case study of conflict management in the Amarakaeri Communal Reserve in the Peruvian Amazon that aimed to develop natural resource governance institutions and build stakeholder capacity, including of indigenous groups, to navigate existing conflict resolution mechanisms. Through applying good practices in conservation conflict management and collaborative governance, we generated important lessons on the practical considerations involved in collaborative conservation. These lessons, while specific to our case, could be applied to a variety of protected areas facing complex social-ecological systems dynamics and wicked problems.