Habitat point records from 1983 Collins Selsey Bill to East Solent sublittoral survey

This report contains the results of 15 days diving (May-September 1983) between the East Solent and Selsey Bill. Observations from previous years are also included. The underwater geology of this area has been studied extensively by Wallace. Recently members of the Oceanography Department, Southampton University (Hall 1982) have worked with Wallace to further map bottom features in order to determine the coastline structure following recent glaciations. The seabed has been studied remotely by echosounding, side scan sonar and seismic profiling. Decca navigation has been used for this work and the study described here. Linked to this has been a diving programme to examine interesting features. The authors have been involved with the geological studies since 1981. An abundance of life on the various features compared to the surrounding sand and gravel seabed was noted, hence this study. Published information on the marine life of the study area is limited. The review of the Solent Estuarine System (NERC 1980), covering most fields of study, extends into the north-west corner of the region. The marine life off the Sussex coast east of Selsey Bill has been studied by members of the South-East Underwater Conservation Society (SEUCS 1983). Studies of the alien alga Sargassum muticum and associated species by workers at the Portsmouth Polytechnic Marine Laboratory, Hayling Island, include the East Solent and Bembridge (Knight-Jones et al, 1975; Gray, 1978; Critchley, 1981). Chamberlain (1977) has studied coralline red algae on the Isle of Wight including Bembridge. The description of the role of seaward in shingle transport by Joliffe and Wallace (1973) covers both sides of Selsey Bill. There is much archaeological evidence that the original northern shore of the area extended from Horse Tail, south of the Medmery Bank to the Mixon (Longcroft, 1856). Wallace concludes that in the 13th century, the sea broke through and rapidly established the existing shoreline. Roman Selsey and Church Rocks, Hayling Bay have been described by McKee and Wallace (McDonald, 1968). Working in collaboration with geologists, a number of seabed features, identified from side-scan sonar and echo sounder surveys, have been examined. The bottom is mainly sand and gravel. Limestone outcrops to the west and south of Selsey Bill and also to the east of Bembridge are present. Ridges of clay bedrock are found to the south and east of Chichester Harbour entrance. There are many mounds of cobbles and boulders, e.g. Bullock Patch, north and west Medmery Bank and New Grounds which are probably glacial moraines. An interesting feature of the area is the widely scattered rectangular limestone sarcens up to 5 m across. Light penetration is generally poor due to the presence of fine muddy silts from the East Solent and harbours to the north as well as the clay outcrops. Underwater photography was used extensively to aid identification of species and define habitats. The principal habitats described are sand, gravel, cobble, boulder, clay bedrock and limestone bedrock. There is a clear increase in species diversity and abundance with substrate particle size. Shallow limestone outcrops have the richest flora and fauna. Any stable surface from gravel upwards is normally covered with an extensive growth of ascidians, hydroids and bryozoans. Visually dominant species at many sites below 8 m were Dendrodoa grossularia, Nemertesia antennina, Tubularia indivisa, Flustra foliacea and Alcyonidium gelatinosum. Smaller hydroid and bryozoan species (e.g. Halecium halecinum, Obelia spp, Bugula turbinata, Epistomia bursaria) contribute to a thick turf on prominant surfaces. Tube dwelling worms are common, Sabellaria sp. on most surfaces and Lanice conchilega in sand and gravel. Algal growth is limited over much of the area due to depth. However, the shallow limestone reefs support a rich flora. Exposed clay and limestone outcrops are extensively bored by the bivalves, Pholas dactylus and Barnea sp. respectively. Large beds of Crepidula fornicata are found in the approaches to the East Solent and, to a lesser extent, Mytilus edulis south of Selsey Bill. Gravel extraction and fishing are the main commercial uses of the area. Sewage disposal and hydrocarbon exploration are noted.The area is important for recreation, principally sailing and angling. Scientific and archaeological interest is reviewed. Recommendations for further work are made, including reefs, algae and boulder habitats. Records currently considered sensitive have been removed from this dataset.

本报告收录了1983年5月至9月间（为期15天）在东索伦特与塞尔斯比之间的潜水观测结果。同时，亦纳入了往年之相关观察资料。此区域之水下地质结构已由华莱士进行了广泛的研究。近期，南安普顿大学海洋学系的成员（霍尔，1982年）与华莱士合作，进一步绘制海底特征图，以确定近期冰川作用后的海岸线结构。海底地形通过回声测深、侧扫声纳和地震剖面法进行远程研究。在此工作中，使用了Decca导航系统，并描述了本研究。与潜水项目相结合，旨在研究有趣的地貌特征。自1981年起，作者便参与地质研究。与周围沙砾质海底相比，该区域各种地貌上生物种类繁多，故开展此项研究。关于研究区海洋生物的出版信息极为有限。对索伦特河口系统（NERC，1980年）的综述，涵盖研究领域的多数方面，并延伸至该区域西北角。塞尔斯比以东的萨塞克斯海岸海洋生物由东南水下保护协会（SEUCS，1983年）的成员进行研究。朴次茅斯理工学院海洋实验室（黑林岛）的工作人员对外来藻类Sargassum muticum及其相关物种进行了研究，包括东索伦特和贝布里奇（Knight-Jones等，1975年；Gray，1978年；Critchley，1981年）。查默林（1977年）研究了怀特岛上的珊瑚红藻，包括贝布里奇。Joliffe和Wallace（1973年）对砾石运输中向海方向的角色的描述涵盖了塞尔斯比的两边。大量考古证据表明，该区域原始的北岸从Medmery Bank南边的马尾巴延伸至Mixon（Longcroft，1856年）。华莱士得出结论，在13世纪，海水突破并迅速形成了现有的海岸线。罗马时期的塞尔斯比和Hayling Bay的教堂岩石由McKee和Wallace（McDonald，1968年）进行了描述。与地质学家合作，对由侧扫声纳和回声测深调查确定的多个海底特征进行了研究。海底主要由沙砾组成。塞尔斯比以南和以西，以及贝布里奇以东存在石灰岩露头。在奇切斯特港入口的南边和东边发现了粘土基岩的脊。在该区域有许多由漂砾和巨砾构成的隆起，例如Bullock Patch、Medmery Bank的北部和西部以及New Grounds，这些可能是冰川漂砾。该区域一个有趣的特征是广泛分布的矩形石灰岩柱，直径可达5米。由于来自东索伦特和北边港口的细泥质淤泥以及粘土露头的存在，光线穿透性普遍较差。水下摄影被广泛用于帮助识别物种和确定栖息地。所描述的主要栖息地包括沙、砾石、卵石、巨砾、粘土基岩和石灰岩基岩。随着底质颗粒大小的增加，物种多样性和丰富度明显增加。浅层石灰岩露头拥有最丰富的生物群落。从砾石以上的任何稳定表面通常覆盖着大量的海鞘、水螅和苔藓动物的生长。在8米以下的许多地点，视觉上占主导地位的物种是Dendrodoa grossularia、Nemertesia antennina、Tubularia indivisa、Flustra foliacea和Alcyonidium gelatinosum。较小的水螅和苔藓动物物种（例如Halecium halecinum、Obelia spp、Bugula turbinata、Epistomia bursaria）在显著表面形成厚厚的草坪。管栖虫类在多数表面都很常见，Sabellaria sp.在大多数表面，Lanice conchilega在沙和砾石中。由于深度，该区域大部分地区的藻类生长受限。然而，浅层石灰岩礁支持丰富的植被。暴露的粘土和石灰岩露头被双壳类动物Pholas dactylus和Barnea sp.广泛钻孔。在东索伦特入口附近发现大量Crepidula fornicata床，在塞尔斯比以南的较小程度上，也发现了Mytilus edulis。该区域的主要商业用途是砾石开采和捕鱼。提到废物处理和烃类勘探。该区域对休闲活动，尤其是帆船和钓鱼活动具有重要意义。科学和考古价值也得到了回顾。提出了进一步工作的建议，包括礁石、藻类和巨砾栖息地。目前认为敏感的记录已从该数据集中移除。