Distribution of Macroalgae in the area of Calvi (Corsica, Mediterranean Sea)
This dataset describes the occurrences of 19 species of macroalgae along standardized transects in the Bay of Calvi (Corsica). This dataset was based on 2 different campaigns (one in 2016 and one in 2019) in the Bay of Calvi. In both campaigns, an underwater remotely operated vehicle (ROV) was deployed in the Bay and navigated along straight transects perpendicular to the coastline. The ROV was equipped with a down-looking GoPro camera, to capture footage of the bottom, and a built-in front-looking camera to capture a general view of the landscape and navigation. Algae were identified and their coverage was quantified using the down-looking videos.
The species of macroalgae are the following : Acetabularia acetabulum, Amphiroa rigida, Caulerpa prolifera, Caulerpa cylindracea, Codium bursa, Colpomenia sinuosa, Corralinales (order), Cystoseira brachycarpa, Cystoseira crinita, Cystoseira spinosa, Cystoseira zosteroides, Dictyota (genus), Flabellia petiolata, Halopteris (genus), Halopteris scoparia, Jania (genus), Osmundaria volubilis, Padina pavonica, Peyssonnelia squamaria.
In this project, each of the "events" represent different transects navigated by the ROV. The points on the map are the location of the beginning of each transect (located on the coast). From this point, the ROV navigated perpendicularly to the coast until the end of the rocky shore. The actual geographic position of each algae is not recorded, but only the presence of each algae species along this transect.
Katz L, Sirjacobs D, Danis B (2021): Distribution of Macroalgae in the area of Calvi (Corsica, Mediterranean Sea). v1.7. Université Libre de Bruxelles (ULB). Dataset/Samplingevent. https://ipt.biodiversity.be/resource?r=macroalgae_of_calvi&v=1.7
此資料的發布者及權利單位為 Université Libre de Bruxelles (ULB)。 This work is licensed under a Creative Commons Attribution (CC-BY) 4.0 License.
Occurrence; Macroalgae; Corsica; Calvi; biodiversity; benthic communities; ROV; underwater imagery; invasive species; coverage; photogrammetry
The area of interest is the Bay of Calvi. Total coverage of the dataset is the extent of 17 ROV transects (12 carried out in 2016, 5 in 2019), perpendicular to coast line. Transects are distributed in the whole Bay of Calvi, Corsica (Mediterranean Sea). More specifically, the area between Punta Revellata and Punta Spano was the focus of our study.
|界定座標範圍||緯度南界 經度西界 [42.553, 8.709], 緯度北界 經度東界 [42.617, 8.83]|
Most algae were identified to genus or species, encrusting algae were identified as “Corralinales”.
|Genus||Dictyota, Halopteris, Jania|
|Species||Acetabularia acetabulum, Amphiroa rigida, Caulerpa prolifera, Caulerpa cylindracea, Codium bursa, Colpomenia sinuosa, Cystoseira brachycarpa, Cystoseira crinita, Cystoseira spinosa, Cystoseira zosteroides, Flabellia petiolata, Halopteris scoparia, Osmundaria volubilis, Padina pavonica, Peyssonnelia squamaria|
|起始日期 / 結束日期||2016-07-17 / 2016-07-21|
|起始日期 / 結束日期||2019-06-05 / 2019-06-07|
|計畫名稱||Evaluation of ROV imagery for the study of macroalgae communities in the Bay of Calvi, Corsica. Master Thesis|
|經費來源||This project was driven by Lea Katz's master thesis, co-supervised by Damien Sirjacobs and Sylvie Gobert (Université de Liège) and by Bruno Danis (Université Libre de Bruxelles). The project received logistics support from the STARESO station, Université de Liège (Pierre Lejeune).|
|研究區域描述||The area of interest was the near-shore area of the Bay of Calvi. In particular, rocky bottoms, areas around Posidonia meadows and few bare sediment areas. Analyzed area covered the 0-40m depth layer.|
|研究設計描述||The goal of this Master’s thesis was to evaluate underwater ROV imagery for the study of macroalgae communities and to assess the current state of macroalgae diversity in the Bay of Calvi. We also compared the current diversity data with older macroalgae diversity data. A secondary goal was to assess the invasion of Caulerpa cylindracea (an invasive macroalgae in the region).|
Each transect was filmed by GoPro cameras attached to an underwater Remotely Operated Vehicle (ROV). Videos were visualised and annotated using the software "COVER" (Carré 2010). For each transect, species were identified and relative cover and abundance were estimated.
|研究範圍||The study is based on 2 sampling campaigns. Both campaigns covered the same area (see "geographic coverage"). The lenght of the transects is variable but is around 100m in general. The first one occurred in july 2016 and was performed over several days. Each transect was observed 1 time. The second campaign took place in june 2019. Again, several days were needed to observe the different transects. Each transect was observed 1 time.|
|品質控管||In some videos, species identification was validated by another algae specialist (Damien Sirjacobs, Université de Liège). We also replicated one transect with a team of divers who did their own identifications. This proved that our ROV/video method was strong and provided similar results.|
- For each transect : - an underwater ROV was navigated at approximately 1m from the bottom in a straight line perpendicular to the shore. It was equipped with cameras filming the bottom and the surroundings. - in the lab, down-looking video was analysed and annotated. Species are identified. Information about depth, salinity, temperature and cover were retrieved for each algae observation. - abundances of different macroalgae were compared between transects (spatial comparisons) and between different years (temporal comparisons).