Table 10.5. Samples Within Study areas Study Area


Grab samples


The East Anglia THREE site


43 (38 from the Zone survey and five from the East Anglia THREE / FOUR survey)


The offshore cable corridor


126 grabs (47 from the Zone surveys 38 from the East Anglia THREE / FOUR survey and 41 from East Anglia ONE cable corridor survey)


Trawl samples


7 trawls (Four from the Zone survey and three from the East Anglia THREE / FOUR survey)


17 trawls (11 from the Zone Survey and six from the THREE / FOUR survey)


Video samples


50 (42 from the Zone survey and eight from the EA THREE / FOUR survey)


143 (58 from the Zone Surveys, 44 from the East Anglia THREE / FOUR Survey and 41 fromthe East Anglia ONE Cable corridor survey)


31. Detailed methodology for how the samples were collected is presented in the reporting of each survey (see Appendix 10.2, Appendix 10.3 and Appendix 10.4) however, a brief summary is provided below.


10.4.2.2.1 Using Video Footage 32.


To minimise the environmental impact of the surveys, a video camera was dropped to the sea bed prior to the use of any potentially destructive sampling techniques (grab or beam trawl sampling). The “drop down” digital video and stills cameras were mounted within a frame and towed astern of a vessel over the sea bed surface, at a speed of approximately 0.5knots for circa ten minutes. Following the completion of an ecological review of the geophysical data, the sea bed imagery acquired during all surveys was inspected on the vessel in ‘real time’ in order to assess the presence, or otherwise, of important benthic habitats at stations which were indicated as being of possible importance.


33.


This technique also aided characterisation of the sea bed sediments and habitat types.


10.4.2.2.2 Sampling for infauna 34.


Throughout all three benthic survey campaigns the positions of all benthic grab stations were recorded using dGPS with a nominal accuracy of within 2m. All benthic samples were obtained using a standard 0.1m² mini-Hamon grab deployed from the survey vessel. At each station the grab was lowered to the sea bed and, once


Preliminary Environmental Information May 2014


East Anglia THREE Offshore Windfarm


Chapter 10 Benthic Ecology Page 24


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104