Seabed biotope characterisation based on acoustic sensing

The background to this thesis is Australia’s Oceans Policy, which aims to develop an integrated and ecosystem-based approach to planning and management. An important part of this approach is the identification of natural regions in regional marine planning, for example by establishing marine protected areas for biodiversity conservation. These natural regions will need to be identified on a range of scales for different planning and management actions. The scale of the investigation reported in this thesis is applicable to spatial management at 1 km to 10 km scale and monitoring impacts at the 10s of m to 1 km biotope scale. Seabed biotopes represent a combination of seabed physical attributes and related organisms. To map seabed biotopes in deep water, remote sensing using a combination of acoustic, optical and physical sensors is investigated. The hypothesis tested in this thesis is that acoustic bathymetry and backscatter data from a Simrad EM1002 multi-beam sonar (MBS) can be used to infer (act as a surrogate of) seabed biotopes. To establish a link between the acoustic data and seabed biotopes the acoustic metrics are compared to the physical attributes of the seabed in terms of its substrate and geomorphology at the 10s m to 1 km scale using optical and physical sensors. At this scale the relationship between the dominant faunal functional groups and both the physical attributes of the seabed and the acoustic data is also tested. These tests use data collected from 14 regions and 2 biomes to the south of Australia during a voyage in 2000. Based on 62 reference sites of acoustic, video and physical samples, a significant relationship between ecological seabed terrain types and acoustic backscatter and bathymetry was observed.These ecological terrain types of soft-smooth, soft-rough, hard-smooth and hard-rough were chosen as they were the most relevant to the biota in their ability to attach on or burrow into the seabed. A seabed scattering model supported this empirical relationship and the overall shape of backscatter to incidence angle relationship for soft and hard seabed types. The correlation between acoustic data (backscatter mean and standard deviation) and the visual and physical samples was most consistent between soft-smooth and hard-rough terrain types for a large range of incidence angles (16o to 70o). Using phenomenological backscatter features segmented into 10 common incidence angle bins from -70o to 70o the length resolution of the data decreased to 0.55 times depth. The decreased resolution was offset by improved near normal incidence (0o to 30o) seabed type discrimination with cross validation error reducing from 32% to 4%. A significant relationship was also established between the acoustic data and the dominant functional groups of fauna. Faunal functional groups were based on the ecological function, feeding mode and substrate preference, with 8 out of the 10 groups predicted with 70% correctness by the four acoustically derived ecological terrain types. Restricting the terrain classification to simple soft and hard using the acoustic backscatter data improved the prediction of three faunal functional groups to greater than 80%. Combining the acoustic bathymetry and backscatter data an example region, Everard Canyon, was interpreted at a range of spatial scales and the ability to predict the preferred habitat of a stalked crinoid demonstrated.Seabed terrain of soft and hard was predicted from the acoustic backscatter data referenced to a common seabed incidence angle of 40o. This method of analysis was selected due to its combined properties of high spatial resolution, consistent between terrain discrimination at the widest range of incidence angles and consistent data quality checking at varying ranges. Based in part on the research reported in this thesis a mid-depth Simrad EM300 multibeam sonar was purchased for use in Australian waters. A sampling strategy is outlined to map all offshore waters with priority within the 100 m to 1500 m depths

An investigation into active and passive acoustic techniques to study aggregating fish species

Techniques of single- and multi-beam active acoustics and the passive recording of fish vocalisations were employed to evaluate the benefits and limitations of each technique as a method for assessing and monitoring fish aggregations. Five species, Samson fish (Seriola hippos), mulloway (Argyrosomus japonicus), West Australian dhufish (Glaucosoma hebraicum), Bight redfish (Centroberyx gerrardi) and pink snapper (Pagrus auratus) were investigated on the basis of their abundance, ecological importance and differing behaviour. The primary focus was on S. hippos, a large nonvocal schooling fish, and A. japonicus, a large vocal fish, with each species forming aggregations for spawning purposes.Simrad EQ60 single-beam echosounder assessments of mid-water, S. hippos aggregations at seven sites west of Rottnest Island illustrated the relative biomass increase, stabilisation and decrease between the months of October and March each year from October 2004 to March 2007. Surveys highlighted the preferred sites for spawning, spatial extents of each aggregation, as well as a decline in aggregation stability at full moon and end of season periods. Regular Department of Fisheries surveys displayed the relative ease with which single-beam techniques could be deployed, used and data analysed to monitor large, comparatively stable, deep (>50 m) aggregations of large swimbladdered fish. Acquired acoustic data illustrated the limitations of single-beam surveys conducted on a mobile school of fish.RESON 8125 and 7125 multi-beam sonar (MBS) surveys of S. hippos at Rottnest Island locations, some conducted simultaneously with the Simrad EQ60 single-beam, illustrated the improved spatial resolution of midwater targets achievable with MBS systems. The identification of individual S. hippos targets in MBS data facilitated the confirmation of S. hippos undetected by single-beam transects, due to relative sampling volumes. The MBS surveys showed evidence of possible fishing effects on S. hippos aggregations with school structure varying after a two hour period of fishing and video tows. Relative decline in aggregation stability towards the end of the season and possible avoidance behaviour from approaching vessels was observed as successive MBS transects, over a short space of time, recorded school movement around the wreck above which S. hippos aggregations sit.P. auratus spawning in the Cockburn Sound, Fremantle illustrated the limitations of single-beam acoustics to monitor aggregations of mobile fish in shallow water, due to vessel avoidance behaviour. Similar sampling issues were observed in MBS surveys despite the inherent geometric advantages of the wide acoustic swath and increased sample volume. It was anticipated that adjusting the MBS mounting position, such that nadir beams were orientated laterally athwartships (rather then vertically downwards), increased the lateral distance at which the fish could be observed, thus reducing vessel avoidance implications. However, due to time constraints and equipment availability, remounting the MBS was not possible at the time of survey and the effects of MBS orientation could not be verified.Single-beam and passive acoustic surveys of G. hebraicum illustrated the complexity of acoustic investigation of comparatively sedentary, demersal fish which often spawn in small groups. Discrimination of individuals using single-beam techniques was often restricted by the fish proximity to the seafloor and the footprint of the single-beam. Single-beam species identification of small groups of fish is impractical without simultaneous visual confirmation, due to the stochastic nature of fish reflectance. However, single-beam acoustics could provide information on G. hebraicum spawning related essential fish habitat using seafloor classification. While biological assessment of G. hebraicum otoliths, swimbladder and related muscular structure imply a soniferous species, as yet no vocal behaviour of any of the Glaucosomatidae has been reported, despite attempts here to detect vocalisations. Thus the characteristics of this species presented the greatest limitations for study using active or passive acoustic techniques.Passive acoustic techniques were shown to be ideally suited for monitoring the low density, benthic aggregations of A. japonicus in the Swan River. Spawning related vocalisations of A. japonicus were recorded in situ and in aquaria (Mosman Bay, Swan River and TAFE, Fremantle aquaculture centre respectively) each spawning season between October and May for four spawning seasons. A. japonicus calls, produced by the contraction of bi-lateral paired sonic muscles around the posterior two thirds of a heavily damped swimbladder, were classified into three categories relating to differing spawning functions. Category 1 calls (‘Bup’) of 2-4 swimbladder pulses were believed to function to gather males together in temporary broadcasting territories and to announce readiness to spawn. Category 2 calls comprised 11-32 pulses in a single audible tone (‘Baarp’), which could also be broken into two or more parts (‘Ba-Baarp’) with a believed function as a call of attraction, predominantly from males to females. The third Category comprised calls produced in quick succession at increasing call rate to a point of cessation. Series of Category 3 calls (‘Thup’) were recorded only at times associated with spawning, in fewer numbers than other call categories and consisted of between 1 and 4 pulses.Pulse repetition and spectral peak frequencies of Category 3 calls were notably higher than those of Category 1 and 2, both in situ and in aquaria, despite the similar number of pulses. For example, in situ pulse repetition frequencies of up to 114 Hz for Category 3 calls compared with approximately 59 Hz for other categories. It is suggested that the increased pulse repetition frequencies of Category 3 calls require greater, unsustainable levels of energy (corroborated by the decreasing pulse rate as these calls progress) and such calls are therefore reserved for specific, uncommon events, possibly episodes of courtship. Ground truth in aquaria calls exhibited similar call structure to those recorded in situ, however, pulse repetition rates and occurrence were significantly lower (respective pulse repetition frequencies of 41.74 and 58.68 Hz for captive and in situ Category 2 calls).Season-long monitoring of sound production in Mosman Bay determined spawning commencement was correlated with a daytime water temperature threshold at, or above 18.5 °C, occurring between October and November. Generalized Additive Models showed sound pressure levels (SPLs) and, by proxy spawning throughout the season, were correlated with temperature, salinity, sunset and tidal effects with decreasing order of effect. Increases in short-term sound production were observed on a semi-lunar basis, occurring at the new and full moons. Local chorus level maxima were found to occur on a 3.97 day basis (s.d. = 1.8), similar to that found from egg collection in aquaria and previous in situ SPLs in local studies of A. japonicus. Comparisons between Mosman Bay tidal related afternoon/evening activity and nocturnal behaviour of alternative populations in captivity suggest that A. japonicus exhibits adaptive vocal behaviour, and by proxy spawning activities, dependent on environmental variables.Individual A. japonicus were localised during spawning within and close to an array of hydrophones by using vocalisation arrival-time differences, surface reflection and comparative energy level techniques to analyse vocalisations. Several individual A. japonicus were followed for periods ranging from seconds to several minutes as they called repetitively. Monitoring individual movement and separation distances between calling fish confirmed low mobility over long periods, indicative of lekking behaviour. The determination of call source levels employed calls of known range using data from the localisation study. Mean squared pressure source levels and 95 % confidence limits of the three call categories were measured as: 163 (147.7, 178.6), 172 (168.4, 176.0) and 157 (154.0, 160.3) dB re 1μPa for Categories 1, 2 and 3, respectively.During periods of low density calling in the 2006-7 spawning season, techniques of call counting produced absolute abundance estimates for A. japonicus present within the hydrophone detection range of approximately 500 m, observing a maximum of 15 calling individuals. Assuming a 1.3:1 sex ratio this implies a detectable spawning population of 26 fish within approximately 100, 000 m[superscript]2 (range restricted across stream by depth) equivalent to approximately 3, 850 m[superscript]2 per fish (assuming a random distribution of callers and recipients). However, during high density ‘continuous chorus’ calling the maximum number of callers able to be discerned using call counting techniques was exceeded. The application of call counting techniques and call contributions to overall SPLs to estimate biomass during ‘chorus’ calling, where calls merge together, requires further investigation. Recorded chorus levels were not a simple function of animals calling within the receiver proximity, but were strongly influenced by source-receiver range. A preliminary model to estimate minimum numbers of callers within derived range boundaries has been laid out.Recording of A. japonicus vocalisations illustrated the developing capabilities of passive acoustics to monitor soniferous fish species. A suggested set of protocols has been laid out to standardise the reporting of fish calls together with supplementary data relating environmental variables to their subsequent effects on the acoustic characteristics of the call. Standardisation of reporting will facilitate future spatial and temporal comparison of inter- and intra-species sound production.This study has illustrated that the features of each acoustic technique endear them to particular species-specific characteristics. For example, although S. hippos did not vocalise they formed midwater aggregations of large fish (107 cm mean fork length) and were thus amenable to active acoustic monitoring. In contrast, A. japonicus form low density, benthic aggregations and hence are not suited to study by active acoustics, but vocalised profusely rendering them suitable for passive acoustic monitoring. In many cases a combination of techniques both acoustic and non-acoustic is required to monitor the particular species, in order to ground truth the data

Sediment Dispersion at the New Auckland Marine Disposal Ground, Northeast New Zealand

A controversial history of near shore dredged material disposal east of Auckland, New Zealand, starting in the mid-1980s, resulted in the use of a temporary deep water site that did not satisfy the requirements of the London Dumping Convention. In New Zealand, since most maintenance dredged material contains a low level of contamination, it is a common requirement that open-sea disposal sites are retentive, so that impacts can be monitored. In 2007, preliminary investigations for a proposed site located on New Zealand’s northeast shelf were initiated. Indications that the site was suitable prompted Maritime New Zealand (MNZ) to grant a permit for a trial disposal of 5,000 m3 of muddy dredged material on the condition that disposal operations were monitored to assess the potential for dispersion of the material beyond the boundary of the site. The overall aim for this thesis research, based on the questions raised by MNZ, was to determine the potential for dispersion at the AMDG and classify the site based on its dispersive qualities. This aim was approached in three ways: (i) investigation of the hydrodynamic setting, (ii) measurement of the disposal process and the resultant plume, and (iii) development and implementation of a model designed to simulate the disposal characteristics under conditions not observed in the field. The first two approaches involved measurement campaigns, which were undertaken in 2008 and 2010. The 2008 campaign primarily focused on investigation of the hydrodynamic setting through the deployment of a long-term upward facing ADP, which was complemented by hydrological measurements (CTD), and nearby wind records. The 2010 campaign corresponded to the trial disposals at the AMDG, where 4 disposals were monitored using a range of techniques. Stationary water sampling and OBS turbidity measuring stations were positioned in the vicinity of the disposal location with the intention of recording data that could be used to calibrate backscatter data recorded with a vessel mounted ADCP. These data were supplemented by additional pre- and post-disposal measurements, such as sediment cores, MBES backscatter, dynamic penetrometer profiles, and under water video imagery, which provided information on the depositional fate of the disposed material. Therefore, measurements were collected during all stages of the disposal process, providing a unique dataset for a deep-water disposal site. Due to the low number of published studies on disposal plume dispersal and the site specific nature of the process, it was not known in advance what the most efficient and practical techniques for monitoring the plume were. The identification of optimal measuring methods was a secondary outcome of this work. It was found that, due to the transient nature of the plume, stationary sampling techniques were not able to satisfactorily record the plume because its position was difficult to predict. Taking sequential measurements along transects proved to be the optimal approach for tracking the plume. Specifically, backscatter data from the vessel mounted ADCP records provided the best perspective on the spatial and temporal characteristics of the disposal plume. MBES bathymetry data recorded after the completion of all disposals was ultimately inconclusive regarding depositional fate because the deposits were less than 20 cm thick and, therefore, unresolvable at the water depths of the AMDG and the frequency of the system employed. However, a backscatter map, developed from the same MBES dataset, corroborated some of the findings from the plume monitoring surveys by showing the impact locations of the disposed loads, which appeared as lighter gray patches (higher density substrate) amongst the darker gray natural site sediment areas. Analysis of ADCP backscatter data obtained during the trial disposals indicated that the extent of horizontal dispersion was greatest in the surface region (500 800 m) due to stronger current velocities that occur as a result of the decreased influence of friction from the seabed and the increased influence of wind-driven currents. However, in all cases, after the descent of the dredged material to the seabed during the first few minutes, the maximum concentrations were always located near the seabed where horizontal dispersion was low (~200 m). Based on these findings, it was concluded that the weak ambient forcing mechanisms have the potential for the greatest dispersion, rather than the dynamic forces associated with the disposal process. It was found that while generally producing low ambient current velocities, the dominant forcing mechanisms at the AMDG were temporally variable, which could lead to a range of different dispersion characteristics. Tides, wind, and the East Auckland Current (EAUC) were identified as the predominant drivers. Tidal currents were relatively slow (2 10 cm/s), but in general appeared to be more important than wind-driven currents in the surface zone. The influence of the EAUC varied during the field campaigns, where its influence appeared to be weak during the monitored trial disposals, but strong during the long-term deployment of 2008. This variability corresponds to the findings of other studies undertaken on the dynamics of the northeast coast region. The short-term mechanisms of the disposal process, additionally captured in the ADCP backscatter records, showed similar characteristics to those previously described in the literature (i.e., 1 Convective Descent, 2 Dynamic Collapse, and 3 Passive Dispersion). However, through analysis of the rate of dilution throughout the 3 phases, an additional transitional phase was identified. This phase, observed both spatially (with distance from the disposal location) and temporally (with time after disposal), was characterised by a decreased rate of dilution. From the findings, an alternative conceptual model for the disposal process was developed in which the transitional phase was described as a turbulent zone, where water at the interface of the dynamic zone is set in circular motion, therefore, preventing dilution at a particular location or time. After momentum is reduced enough, the turbulent forces give way to the diffusive forces and passive dispersion becomes the dominant mode for dispersion. The main finding of this research was that the potential for dispersion beyond the boundary of the AMDG is low indicating that the site behaves retentively. This finding is partly a result of the low velocities of the ambient currents, but also because of the operational limitations of the tug-towed disposal method employed for disposal. For minimising the dispersion potential of the AMDG for future operations at the site, it is recommended that the disposal method remain unchanged, that material types more susceptible to dispersion not be disposed there, and that disposal not be undertaken when tidal currents are aligned with the wind direction for winds greater than 20 knots

Investigating the build-up of precedence effect using reflection masking

The auditory processing level involved in the build‐up of precedence [Freyman et al., J. Acoust. Soc. Am. 90, 874–884 (1991)] has been investigated here by employing reflection masked threshold (RMT) techniques. Given that RMT techniques are generally assumed to address lower levels of the auditory signal processing, such an approach represents a bottom‐up approach to the buildup of precedence. Three conditioner configurations measuring a possible buildup of reflection suppression were compared to the baseline RMT for four reflection delays ranging from 2.5–15 ms. No buildup of reflection suppression was observed for any of the conditioner configurations. Buildup of template (decrease in RMT for two of the conditioners), on the other hand, was found to be delay dependent. For five of six listeners, with reflection delay=2.5 and 15 ms, RMT decreased relative to the baseline. For 5‐ and 10‐ms delay, no change in threshold was observed. It is concluded that the low‐level auditory processing involved in RMT is not sufficient to realize a buildup of reflection suppression. This confirms suggestions that higher level processing is involved in PE buildup. The observed enhancement of reflection detection (RMT) may contribute to active suppression at higher processing levels

Maine Tidal Power Initiative: Environmental Impact Protocols for Tidal Power

As a result of ongoing climate change, the pressure for the development of new sources of renewable energy has increased. It is extremely likely that climate change is caused by anthropogenic activities. Thus even if dramatic gains are made in energy efficiency; the addition of novel renewable energy sources is critical to reducing fossil fuel emissions. Even current goals for a reduction in the growth of greenhouse gas emissions mean that all possible low-carbon or non-carbon emitting energy sources be considered. In the marine environment, energy in tidal currents, waves, and thermal structure may be extracted to produce electricity. These energy sources are a critical element in the overall renewable portfolio since, unlike wind and solar energy, both marine thermal and tidal energy are reliable additions to the overall electrical grid. In the case of tidal energy, the contribution of periodic but reliable sources of renewable energy becomes increasingly critical as wind and solar penetration in the grid increase. In a high renewable energy penetration grid, a resource like tidal energy does not provide the same base load capacity as, for example, a nuclear power plant. However, tidal energy can have the effect of reducing the size of either storage or peaking capacity that is required for grid stability by providing power for recovery of dispatchable loads. However, as an immature technology, significant questions remain regarding basic questions like the scale of the potential resource, the impact on sediment transport, the effects on fish populations and communities, and the ability to design a system which is acceptable by the people in the associated communities. The objectives of the funded project were to examine tidal power development in Maine from all perspectives: engineering, resource assessment, biological effects, and social dimensions. Resource and environmental research focused on data collection for the Cobscook Bay/Western Passage, possibly the most viable commercial tidal energy site in the US, tidal power sites along with initial evaluation of the suitability of the approach for at least two other tidal development sites in Maine. Concomitantly, alternative energy research is used as a basis of education for a number of graduate and undergraduate students at the University of Maine and Maine Maritime Academy. The Maine Tidal Power Initiative has developed resource and environmental assessment protocols in conjunction with the deployment of a specific marine hydrokinetic device. The protocols are transferrable throughout Maine and the US to evaluate tidal energy resources and better understand the potential impact of this development on the environment. Again, site-specific social science and environmental research focused on the Cobscook Bay/Western Passage area near Eastport Maine. The protocols and methods developed at these sites have also been used to perform initial scoping reviews of locations in Castine Harbor and Wiscasset, Maine that represent a more modest and more typical small scale energy resource. Specific barrier issues which have been addressed for the industry are technologies and protocols for measuring and modeling tidal flows, responses of fishes to those flows, and people interacting in these environments. Measuring tidal flows is critical to the key economic driver for this industry, the size of the potential resource. The second barrier issue is the need for methods for measuring the impact of marine hydrokinetic (MHK) devices on fish. Acoustic methods have been used with ground truth validation from trawls. The protocols developed in this project have already had a significant impact on the approach that has been taken at other sites. Finally the assessment of the human community response to these technologies and impact on community cohesion and participation is perhaps the largest single barrier to the acceptance of the projects. This work also has the potential to be replicated at other sites, although in both the case of the environmental effects and the social response to these projects, details of the species impacted and the economic and social environment are the ultimate determinants of impact and acceptance. The technology focus for most of this work has been the cross-flow turbine developed by Ocean Renewable Power Company. Testing in the University of Maine tow tank has allowed a large design space to be explored for the optimization of the commercial turbine design. The design code developed for the project was validated using this data set. Both the design code and the data will be placed in a public repository. The most important outcome of the turbine design portion of the work is some general design parameters that can be used to assist in the site assessment and for benchmarking of proprietary designs. The design as well as the data is available for resource assessment and design comparisons. The appeal of this turbine design is that the potential exists for a low solidity turbine with lower tip speed ratios, which will have good performance. The low solidity and tip speed ratio is likely to reduce the risk of fish impacts and thus reduce environmental impact and community resistance to these technologies. The need for low carbon energy sources is undeniable. Resistance to large-scale renewable energy development also continues to increase. The overall approach to this project, where the design of the system considers environmental impacts and social acceptance from the initial engineering design stages and continues with an adaptive management scheme, is the only option for addressing energy needs at the scale required

Remote sensing in the coastal and marine environment. Proceedings of the US North Atlantic Regional Workshop

Presentations were grouped in the following categories: (1) a technical orientation of Earth resources remote sensing including data sources and processing; (2) a review of the present status of remote sensing technology applicable to the coastal and marine environment; (3) a description of data and information needs of selected coastal and marine activities; and (4) an outline of plans for marine monitoring systems for the east coast and a concept for an east coast remote sensing facility. Also discussed were user needs and remote sensing potentials in the areas of coastal processes and management, commercial and recreational fisheries, and marine physical processes

Uncovering the role of biomineralisation in otolith trace element uptake by microstructural and microchemical analysis

Otolith biomineralisation was examined in order to uncover its role in trace element uptake within otolith structures by microstructural and chemical analysis. The mechanism of otolith elemental incorporation, the orientation of aragonite and the organic matrix in otoliths of four marine species were investigated in conjunction with the otolith growth patterns and the distribution of trace and minor elemental composition. Results for otoliths of Platycephalus bassensis, Chrysophrys auratus, Trachurus novaezelandiae and Lates calcarifer suggest a common biomineralisation mechanism for marine species, with consistent results across all species. The aragonite orientation, as mapped by electron backscatter diffraction (EBSD), revealed the aragonite c-axis was preferentially aligned parallel with the otolith growth axis and perpendicular to the insoluble organic matrices orientation, as determined by Raman microspectroscopy, in the otoliths of Platycephalus bassensis, Chrysophrys auratus, Trachurus novaezelandiae and Lates calcarifer. The orientation results indicate that otolith mineral growth is directed and controlled by the organic matrix, which acts as a template for the mineral growth, constraining the aragonite orientation and alignment. The organic rich zones (D-zone bands) within the otolith were composed of both insoluble and soluble organic matrices in all four species, with the insoluble matrices bridging the gap between mineral rich zones (L- zone bands) so as to retain crystal orientation across the otolith. Optimisation of electron probe microanalysis (EPMA) quantitative mapping achieved both high spatial resolution (<3 μm) and two dimensional visualisation of the fine scale Sr and S distributions in the otoliths with minimal otolith damage. The otolith growth patterns showed a clear association with the distribution of Sr and S, with D-zone bands exhibiting elevated concentrations of both elements as compared to the L-zone bands. Further examination by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) showed that incorporation of Mg and Ba appears independent of both the S distribution and the growth patterns in all four species. The results suggest that element incorporation into the otolith is linked to the organic composition in the endolymph during mineralisation, and the organic matrices may in part assist the uptake of Sr. The study revealed that whilst the otolith biomineralisation is directed and templated, with aragonite orientation constrained by the insoluble organic matrices, this process has no direct influence over trace element uptake. The association between the distribution of Sr, S and the organic matrices within the otoliths suggests however that the soluble organic matrices may play a role in trace element incorporation, particularly Sr incorporation. These findings may therefore have significant implications for the interpretation of otolith Sr chemistry.Thesis (MPhil) -- University of Adelaide, School of Physical Sciences, 201

Skylab EREP Investigations Summary

The problems in the areas of agriculture, range and forestry; land use and cartography; geology and hydrology; oceans atmosphere, and data analysis techniques were investigated and summarized using Earth Resources Experiment Package (EREP) data