Pushkar M. Wadke, Michael T. Burrows, David Meldrum and Andrew J. Davies
Published in the conference proceedings of Oceans 2007, Vancouver (2007)

Magnetic sensors have existed for many years and are widely used in different applications such as navigation systems, automation, position detection and current detection (amongst others). In this paper we explore a unique application of underwater magnetic sensing using a magneto-resistive sensor to monitor animal behaviour. Animal behaviour researchers have used several different techniques to study the behaviour of limpets. Most common are motographic methods using time-lapse photography. This technique is limited by low resolution, time consuming data analysis and sometimes an obscured field of view. Here, we present preliminary results from the use of a magneto-resistive sensor attached to the common limpet Patella vulgata. The (Honeywell HMC1052) 2-axis anisotropic magneto-resistive (AMR) sensor was fixed using epoxy putty to the shell of a limpet. The sensor has the capability to capture the limpet’s orientation with a resolution of 0.05°. This high resolution allows us to describe a range of behavioural responses which was not possible using earlier techniques. Limpet movement was truthed using time-lapse infra-red videography. Magneto-resistive sensors can quantify orientation behaviour, be used in extreme environments and provide superior data to qualitative and interpreted observations obtained from previous techniques. Several future developments may increase the applicability of this technique, such as using an artificial magnetic field to precisely locate animals at sub-GPS resolution.

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Wadke, P.M., Burrows, M.T., Meldrum, D. & Davies, A.J. (2007) “Using magneto-resitive sensors to monitor animal behaviour: a case study using limpets” Proceedings, Oceans 2007 MTS/IEEE Vancouver.

I’m in Carvoerio, Portugal presenting work done on the EU FP7 project HERMES regarding food supply mechanisms to a coral reef. Read the abstract below:

Internal waves provide a food supply mechanism for cold-water coral reefs

Andrew J. Davies, Marc Lavaleye, Magda Bergman, J. Murray Roberts, Hans Van Haren and Gerard Duineveld

The cold-water coral Lophelia pertusa forms large biogenic reefs throughout the North Atlantic Ocean. The mechanics of food supply to these areas have been largely hypothesised, with topographical focussing of currents, breaking internal waves and retained matter above banks all put forward as potential mechanisms. However, at present, there has only been limited description of these processes from detailed in situ observations. During several HERMES cruises, numerous physical and biological observations have been made in the Mingulay Reef complex. Located between the Outer Hebridean Island chain and the Scottish Mainland, this reef complex is situated within a dynamic area with semi-diurnal tides and currents of up to 80 cm s^-1. In 2006 and 2007, multiple deployments of landers, recording moorings, ship mounted ADCP and CTDs were used to record the food supply processes and the physical habitat of the L. pertusa reefs in the area. The complex topography of the area retains a solitary internal wave which breaks as direction of the tide changes. The wave drives surface productivity and warmer waters to the reef in a regular pattern. This mechanism has a strong resemblance with the theory of Frederiksen et al (1992) that coral distribution could be in areas where the bottom slope is critical to semi-diurnal internal waves.

http://www.anddavies.co.uk/downloads/DaviesetalHERMES.pdf