Guiding ecological principles for marine spatial planning

The declining health of marine ecosystems around the world is evidence that current piecemeal governance is inadequate to successfully support healthy coastal and ocean ecosystems and sustain human uses of the ocean. One proposed solution to this problem is ecosystem-based marine spatial planning (MSP), which is a process that informs the spatial distribution of activities in the ocean so that existing and emerging uses can be maintained, use conflicts reduced, and ecosystem health and services protected and sustained for future generations. Because a key goal of ecosystem-based MSP is to maintain the delivery of ecosystem services that humans want and need, it must be based on ecological principles that articulate the scientifically recognized attributes of healthy, functioning ecosystems. These principles should be incorporated into a decision-making framework with clearly defined targets for these ecological attributes. This paper identifies ecological principles for MSP based on a synthesis of previously suggested and/or operationalized principles, along with recommendations generated by a group of twenty ecologists and marine scientists with diverse backgrounds and perspectives on MSP. The proposed four main ecological principles to guide MSP—maintaining or restoring: native species diversity, habitat diversity and heterogeneity, key species, and connectivity—and two additional guidelines, the need to account for context and uncertainty, must be explicitly taken into account in the planning process. When applied in concert with social, economic, and governance principles, these ecological principles can inform the designation and siting of ocean uses and the management of activities in the ocean to maintain or restore healthy ecosystems, allow delivery of marine ecosystem services, and ensure sustainable economic and social benefits.     

Estimating impacts of warming temperatures on California's electricity system

Despite a clear need, little research has been carried out at the regional-level to quantify potential climate-related impacts to electricity production and delivery systems. This paper introduces a bottom-up study of climate change impacts on California's energy infrastructure, including high temperature effects on power plant capacity, transmission lines, substation capacity, and peak electricity demand. End-of-century impacts were projected using the A2 and B1 Intergovernmental Panel on Climate Change emission scenarios. The study quantifies the effect of high ambient temperatures on electricity generation, the capacity of substations and transmission lines, and the demand for peak power for a set of climate scenarios. Based on these scenarios, atmospheric warming and associated peak demand increases would necessitate up to 38% of additional peak generation capacity and up to 31% additional transmission capacity, assuming current infrastructure. These findings, although based on a limited number of scenarios, suggest that additional funding could be put to good use by supporting R&D into next generation cooling equipment technologies, diversifying the power generation mix without compromising the system's operational flexibility, and designing effective demand side management programs.     

Magnetic Surveying for Buried Metallic Objects

Field tests were conducted to determine representative total-intensity magnetic anomalies due to the presence of underground storage tanks and 55-gallon steel drums. Three different drums were suspended from a non-magnetic tripod and the underlying field surveyed with each drum in an upright and a flipped plus rotated orientation. At drum-to-sensor separations of 11 feet, the anomalies had peak values of around 50 gammas and half-widths about equal to the drum-to-sensor separation. Remanent and induced magnetizations were comparable; crushing one of the drums significantly reduced both. A profile over a single underground storage tank had a 1000-gamma anomaly, which was similar to the modeled anomaly due to an infinitely long cylinder horizontally magnetized perpendicular to its axis. A profile over two adjacent tanks had a smooth 350-gamma single-peak anomaly even though models of two tanks produced dual-peaked anomalies. Demagnetization could explain why crushing a drum reduced its induced magnetization and why two adjacent tanks produced a single-peak anomaly.
A 40-acre abandoned landfill was surveyed on a 50- by 100-foot rectangular grid and along several detailed profiles. The observed field had broad positive and negative anomalies that were similar to modeled anomalies due to thickness variations in a layer of uniformly magnetized material. It was not comparable to the anomalies due to induced magnetization in multiple, randomly located, randomly sized, independent spheres, suggesting that demagnetization may have limited the effective susceptibility of the landfill material. A different 6-acre site survey conducted on a 10- by 10-foot grid was analyzed to determine the maximum station spacing and line separation that could have been used. Essentially, all of the anomalies at this site would have been resolved by a survey conducted on a 20- by 20-foot grid and the larger anomalies would have been detected by a 50- by 50-foot grid.     

AreSpartina marshes a replaceable resource? A functional approach to evaluation of marsh creation efforts

Marsh creation has come into increasing use as a measure to mitigate loss of valuable wetlands. However, few programs have addressed the functional ecological equivalence of man-made marshes and their natural counterparts. This study addresses structural and functional interactions in a man-made and two natural marshes. This was done by integrating substrate characteristics and marsh utilization by organisms of two trophic levels. Sediment properties, infaunal community composition, andFundulus heteroclitus marsh utilization were compared for a man-madeSpartina salt marsh (between ages 1 to 3 yr) in Dills Creek, North Carolina, and adjacent natural marshes to the east and west. East natural marsh and planted marsh sediment grain-size distributions were more similar to each other than to the west natural marsh due to shared drainage systems, but sediment organic content of the planted marsh was much lower than in either natural marsh. This difference was reflected in macrofaunal composition. Natural marsh sediments were inhabited primarily by subsurface, deposit-feeding oligochaetes whereas planted marsh sediments were dominated by the tube-building, surface-deposit feeding polychaetesStreblospio benedicti andManayunkia aestuarina. Infaunal differences were mirrored inFundulus diets. Natural marsh diets contained more detritus and insects, because oligochaetes, though abundant, were relatively inaccessible. Polychaetes and algae were major constituents of the planted marshFundulus diet. Though naturalmarsh fish may acquire a potentially less nutritive, detritus-based diet relative to the higher animal protein diet of the planted marsh fish,Fundulus abundances were markedly lower in the planted marsh than in the natural marshes, indicating fewer fish were being supported. LowerSpartina stem densities in the planted marsh may have provided inadequate protection from predation or insufficient spawning sites for the fundulids. After three years, the planted marsh remained functionally distinct from the adjacent natural marshes. Mitigation success at Dills Creek could have been improved by increasing tidal flushing, thereby enhancing, access to marine organisms and by mulching withSpartina wrack to increase sediment organic-matter content and porosity. Results from this study indicate that salt marshes should not be treated as a replaceable resource in the short term. The extreme spatial and temporal variability inherent to salt marshes make it virtually impossible to exactly replace a marsh by planting one on another site.     

Modal identification of self-adjoint distributed-parameter systems

A new method is introduced for the identification of modal quantities of self-adjoint distributed-parameter systems. The method uses the temporal and spatial orthogonality properties of distributed-parameter systems to form a pseudo-Rayleigh quotient. The stationary values of the pseudo-Rayleigh quotient can be determined by the solution of an eigenvalue problem, where the eigenvalues and eigenfunctions provide the frequencies and natural modes of the distributed-parameter system. By way of formulation, the method is insensitive to zero mean measurement noise and is applicable to continuous as well as discrete systems. Numerical examples are presented in which the modal quantities of a simply-supported beam and a discrete model of a membrane are identified. The results are compared with another modal identification technique, namely, the Ibrahim time domain method.     

The “North American shale composite”: Its compilation,major and trace element characteristics

The compilation and major element composition of the “North American shale composite” (NASC) are reported for the first time, along with redeterminations for the REE and selected other elements by modern, high precision analytical methods. The NASC is not strictly of North American origin; 5 of the constituent samples are from Africa and Antarctica, and 15 are from unspecified locations. The major element composition of the NASC compares quite closely with other average shale compositions. New analyses of the NASC document that significant portions of the REE and some other trace elements are contained in minor phases (zircon and possibly other minerals) and that their uneven distribution in the NASC powder appears to have resulted in heterogeneity among analyzed aliquants. The results of this study show that the REE distributions of detrital sediments can be dependent to some extent on their minor mineral assemblages and the sedimentological factors that control these assemblages. Consequently, caution should be exercised in the interpretation of the REE distributions of sediment samples as they may be variable and biased relative to average REE distribution of the crustal rocks supplying detritus. These effects appear to be largely averaged out in sediment composites, with the result that their REE distributions are more likely to be representative of their provenances.     

Micro Computers Applied to Ground Water Monitoring and Testing

Micro computers have been demonstrated to be a most valuable, cost-effective means of long- and short-term data acquisition for ground water investigations and installations. A system can readily be assembled for the cost of labor saved in the field, or for the same cost as other conventional instruments, which perform only a fraction of the functions of the computer system
Documented in this article are systems which have been developed and used for simultaneous monitoring of several wells during aquifer tests, and systems installed for long-term monitoring of piezometric surface fluctuations. Both systems can be contained in a small suitcase or insulated cooler. Specific features of the systems include multiple channel capacity, one-month maintenance period, variable computer controlled reading intervals, magnetic tape data storage, data reduction and analysis capabilities while maintaining monitoring, graphic display of time and measurements, hard copy capability and barometric pressure change corrections.
Other applications are examined for the complete control of pumping tests, including pumping rate; in situ permeability tests; monitoring changes; and even strain. The pressure transducer system may also be applied for river gauging and current measurement.     

High-Pressure crystal chemistry of spinel (MgAl2O4) and magnetite (Fe3O4): Comparisons with silicate spinels

High-pressure crystal structures and compressibilities have been determined by x-ray methods for MgAl₂O₄ spinel and its isomorph magnetite, Fe₃O₄. The measured bulk moduli, K, of spinel and magnetite (assuming K′=4) are 1.94±0.06 and 1.86±0.05 Mbar, respectively, in accord with previous ultrasonic determinations. The oxygen u parameter, the only variable atomic position coordinate in the spinel structure (Fd3m, Z=8), decreases with pressure in MgAl₂O₄, thus indicating that the magnesium tetrahedron is more compressible than the aluminum octahedron. In magnetite the u parameter is unchanged, and both tetrahedron and octahedron display the 1.9 Mbar bulk modulus characteristic of the entire crystal. This behavior contrasts with that of nickel silicate spinel (γ-Ni₂SiO₄), in which the u parameter increases with pressure because the silicon tetrahedron is relatively incompressible compared to the nickel octahedron.     

Seasonal distributions of suspended particulate material and dissolved nutrients in a coastal plain estuary

The temporal and spatial distributions of salinity, dissolved oxygen, suspended particulate material (SPM), and dissolved nutrients were determined during 1983 in the Choptank River, an estuarine tributary of Chesapeake Bay. During winter and spring freshets, the middle estuary was strongly stratified with changes in salinity of up to 5‰ occurring over 1 m depth intervals. Periodically, the lower estuary was stratified due to the intrusion of higher salinity water from the main channel of Chesapeake Bay. During summer this intrusion caused minimum oxygen and maximum NH₄ ⁺ concentrations at the mouth of the Choptank River estuary. Highest concentrations of SPM, particulate carbon (PC), particulate nitrogen (PN), total nitrogen (TN), total phosphorous (TP) and dissolved inorganic nitrogen (DIN) occurred in the upper estuary during the early spring freshet. In contrast, minimum soluble reactive phosphate (SRP) concentrations were highest in the upper estuary in summer when freshwater discharge was low. In spring, PC:PN ratios were >13, indicating a strong influence by allochthonous plant detritus on PC and PN concentrations. However, high concentrations of PC and PN in fall coincided with maximum chlorophyll a concentrations and PC:PN ratios were <8, indicating in situ productivity controlled PC and PN levels. During late spring and summer, DIN concentrations decreased from >100 to <10 μg-at l^?1, resulting mainly from the nonconservative behavior of NO₃ ^?, which dominated the DIN pool. Atomic ratios of both the inorganic and total forms of N and P exceeded 100 in spring, but by summer, ratios decreased to <5 and <15, respectively. The seasonal and spatial changes in both absolute concentrations and ratios of N and P reflect the strong influence of allochthonous inputs on nutrient distributions in spring, followed by the effects of internal processes in summer and fall.