|Intrepid scientists hard at work....
The proposed indicator focuses on sponge and other epifauna (e.g. coral and anemone) species and is designed to spot changes in the number and type of species present in response to natural variability and human-induced pressures. Sponges and other epifauna are sensitive to environmental variability such as changes in the amount of sediment in the water column and damage from physical impacts such as fishing gear or oil and gas industry infrastructure. Ocean acidification and climate change are also likely to affect the type and quantity of species present.
The proposed indicator we are testing on this survey has two main parts:
- Sponge morphological (body shape) diversity: Identifying individual sponge species can be very difficult due to the vast number and variation in sponges that occur in the UK and further afield. As such, spotting changes in the number and type of species present could be very time-consuming and costly. However, recognising different body shapes or ‘morphological diversity’ of sponges (see image below) is much more straightforward and quicker to do. Therefore, this could be used to detect changes in response to variations in the environment. This method has mainly been tested during inshore dive surveys and so one of the key objectives for this offshore survey is to collect data on sponge body-shapes using a drop-down camera, to test whether this approach will work in deeper waters.
- Species composition and abundance of other epifauna communities: Epifauna is the collective term for animals that live on the surface of a substrate, in this case the sea floor and the rocky outcrops emerging from it. We can measure epifauna species composition and abundance in two ways: either by counting the total number of epifauna species or by measuring the area occupied by epifauna.
|The many shapes of sponges (Berman et al 2013)
The location for our study is Solan Bank Site of Community Importance (SCI). Bedrock and stony reef are present at the site, which is fantastic habitat for sponges and other epifaunal species. Solan Bank is located approximately 50km north of Cape Wrath on the Scottish mainland. Extensive areas of bedrock outcrops with cliffs rising up to 10 metres from the surrounding seabed are found across the site. Away from the cliffs, habitat ranges from sands through to highly fissured bedrock reefs. Hopefully there will be some interesting photos of sponges and other epifaunal species to come in the next blog.
Bye for now! Joey, Declan, Megan, Graeme and Becca.