Nessletter - No 105 - 1991

Magazine Overview

This issue of NESSLETTER, number 105, dated June 1991 (with a 'Dec '91' notation), published by NESS INFORMATION SERVICE, focuses heavily on the ongoing scientific research conducted by the Loch Ness Project. The ISSN is 0264-7001. The main cover headline highlights the "Loch Ness Project Hydrographic and Seismic Survey."

Morphometry

The morphometry of Loch Ness is described as a steep-walled, glaciated tectonic faultline. Its maximum recorded depth is 754ft (230m) by a Kelvin wire sounding machine, though a water gauge reading of 820ft (250m) during trials of a mini-sub has disputed this. A 1979 Loch Ness Project survey using calibrated hydrographic equipment vindicated the 754ft depth. Recent developments in 'swathe' sounders, like the Simrad E.M. 100 used in a 1987 survey of Urquhart Bay, are significantly reducing survey times. A planned future survey will use the Bentech Topas 3-D Topography and Seismic Profiling Sonar with a 45-beam system and Star Track Differential G.P.S. for accuracy within 5m, aiming to produce a 3-D hydrographic chart and a simultaneous seismic profile of the sedimentary structures beneath the loch bed.

Sub-Bottom and Seismic Work

Sediment studies are crucial for understanding the history of Loch Ness and selecting locations for the Project's Long-Core Programme, designed to penetrate sediments back to the last ice age. The first shallow seismic survey will use the Topas swathe system, with data analyzed by Dr. Julian Dowdeswell of the Scott Polar Research Institute to shed light on deglaciation processes. A complete survey of the loch's sediment composition is planned over two years, involving collaboration with Dr. Andrew Dugmore and Jane Boyale from the University of Edinburgh. Particle size analysis will be conducted.

Post Glacial Depositional Processes

A second survey, to be carried out by Dr. R.J. Whittington of the Institute of Earth Studies, U.C.W. Aberystwyth, will map Quaternary sediment thickness, the bedrock surface, and establish seismic stratigraphy to relate individual seismic facies to specific glacial/interglacial environments. It will also define the style and importance of side wall mass transfer of sediment into the central basins.

Sediments and Coring

Lake sediments hold historical evidence of events within and around the catchment. A multi-disciplinary programme is underway using coring equipment to acquire information over a range of time scales. Physical deposition processes are being investigated through a complete survey of deposits, with sedimentation rates and particle size analysis. The formation of 'flocks' in the sediment will be studied, and a study of organic chemistry will provide insights into past environments through the identification of source organisms. This work is being conducted by Dr. Martin Jones.

Decomposition in Sediments

Decomposition in sediments is vital for nutrient recycling. Redox zones are being investigated by Dr. Andy C. Aplin. Loch Ness is considered a useful site for studying biogeochemical behaviour in artificial compounds like PCBs and nuclear fission products, due to its long hydraulic residence time which traps pollutants. Dr. Hamilton-Taylor is leading work on this, requiring a special wide bore corer. The mud/water interface is also being studied by Dr. Bill Davison.

Industrial Revolution and Pollution

Changes in trace elements since the Industrial Revolution are being studied, with cores distributed to a number of workers. The aim is to determine if the lake is being polluted by sewage, fertilizer inputs, soil erosion, or acid rain. Loch Ness is of particular interest as the Great Glen appears to mark a boundary in a strong air pollution gradient leading to lake acidification. Publications on this aspect are expected. This work includes lead-210 dating and analysis of carbonaceous particles from fossil fuel burning. Diatoms are indicators of acidification or enrichment, while pore water chemistry is also being studied.

Paleomagnetism and Geochemistry

Further studies include paleomagnetism and trace metal geochemistry by Dr. John Smith and Kate Farr, and pollen and sediment laminations by Dr. Paddy O'Sullivan.

Physical Studies

Loch Ness has a tradition of physical studies, with internal seiches first described in 1964. The use of the loch as a marine surrogate was explored by Dr. Mortimer and later by Dr. Thorpe. Studies have focused on the unique uniformity of the basin and its orientation, which amplifies thermal effects like internal seiches and waves. Acoustic techniques are used to reveal thermoclines and other structures, and a study of acoustic scattering layers is underway. Temperature/depth profiles accumulated over ten years are being used to develop mathematical models of internal wave behaviour. The project aims to discover the effects of physical water movements and temperature on nutrient supply, distribution, and biomass, and how these affect acoustic techniques. Observations are planned on four scales: Kelvin Helmholz Billows, Surges, and Internal Seiches.

Plankton

The larger Scottish lochs are relatively unpolluted, making them valuable for biological studies. Dr. P. Maitland's 1977/80 study revealed the basic structure of the plankton. The current project focuses on short-term events like zooplankton migrations and requires a more integrated approach to understand primary production, energy flow, and nutrient cycling. A fixed sampling station has been established in collaboration with the Institute of Freshwater Ecology and universities. The study involves intensive sampling of the plankton community and physical conditions. Carbon tracing is used to identify carbon flux through the plankton. Acoustic techniques are being used simultaneously to study internal structures and their relationship to the distribution of plankton types. The epilimnion is monitored for effects of external energy inputs. Diel migration of plankton and fish is also planned.

Benthos

Littoral benthos of Loch Ness have been examined, with less work done on profundal regions. Macro benthos in profundal and side wall regions have been studied, with attention paid to smaller organisms like ostracods, which are important food for Arctic charr. Efforts are underway to extend the species list into micro-benthos, including an examination of nematodes. Changes in sub-littoral fauna due to fish farming are also being monitored.

Fish

Loch Ness contains few coarse fish but is rich in salmonids, particularly brown trout and Arctic charr. Studies have defined basic habitats and communities using underwater photography and sonar. Discoveries include a layer of pelagic Arctic charr and profundal populations feeding on benthos. Netting locations from the 200m profundal to mid-loch pelagic zones aim to produce material representative of specific habitat niches for population ecology and genetic studies. Material from approximately 200 trout and a number of charr has been accumulated. Morphological, aging, and feeding studies are being conducted on both species. Genetic research on Scottish charr populations and Loch Ness material aims to place them in a broader context. Trout genetics are also being examined, with observations of plankton-feeding trout in shallow offshore areas and 'ferox' feeding on deep charr. Parasitology of different species is also being investigated.

Loch Ness Project Hydrographic and Seismic Survey

Throughout the week commencing December 1st, 1991, a hydrographic and seismic survey of the deep basins of Loch Ness was conducted. This aims to reveal depth contours and probe sediments beneath the loch bed. The lake is described as Britain's largest body of freshwater and an under-researched resource, unusual for its geological fault line and 'trench-like' form with two basins over 200m deep. The survey is co-ordinated by David Siviter of Subtechnique, with the Official Loch Ness Exhibition Centre as the operational base. The survey utilizes a new research tool, the TOPAS 3-D Topography and Seismic Profiling sonar, which significantly reduces survey time. Navigational data is provided by Marconi UDI's Star-Track Differential GPS system, accurate to 5m. The survey aims to resolve controversies about the maximum depth and produce a new chart, revealing the shape of the bedrock and the pattern of sedimentation at the end of the last ice age (10,000 years ago). The sediments provide a time capsule of historical change, from post-industrial revolution acidification to climate change cycles. Scientists from Wolverhampton Polytechnic are also involved in the coring programme.

The Navigation System

The Marconi UDI GPS Navigation System uses an on-board transmitter and satellite network to provide accurate positioning. It links to a shore-based Master Reference Station and Goonhilly tracking station. The system can determine the transmitter's position with an accuracy of within 15 feet, ideal for charting depths.

The Survey

Adrian Shine reported that the survey achieved nearly 300 kilometers of hydrographic line survey and seismic profiles covering both deep basins of the loch.

Facts Contributing to Success

Factors contributing to the survey's success included the willingness of personnel to work long hours, the effectiveness of the Marconi UDI GPS system allowing work in darkness, and calm, cold weather providing a stable temperature gradient for reliable depth accuracy calculations.

Hydrographic Survey Data

The hydrographic survey data, recorded on magnetic tape, will require at least two months of post-processing to complete a definitive new chart. No water as deep as reported during the Vickers Pisces submersible trials in 1969 was found. Shallow trenches were noted near the sides of the northern basin, causing the silt plain to rise away from the wall.

Seismic Profiles

Seismic profiles revealed rocky slopes continuing beneath the sediments, with about 45 meters of total penetration, followed by another 20 meters of layered sediment. This is speculated to be organic lake sediment overlying glacial clays, providing invaluable information for future coring programmes.

Comment

The commentator expresses interest in hearing the outcome of the survey once the data is processed. He notes that Adrian Shine mentioned avoiding shores but covering deep areas well. The commentator supports the idea of interdisciplinary studies on Loch Ness, emphasizing that the research is not 'monster-hunting' but rather about understanding the unknown aspects of the loch. He hopes the two planned scientific programmes will work in conjunction.

Recurring Themes and Editorial Stance

The recurring theme is the extensive and scientifically rigorous research being conducted on Loch Ness, moving beyond popular notions to focus on paleolimnology, geology, ecology, and physics. The editorial stance is supportive of this scientific endeavor, emphasizing the value of understanding the loch's complex environment and history. There is a clear distinction made between 'monster-hunting' and genuine scientific investigation, with a preference for the latter.