Assessment of Ecological Quality Status of Western Nigeria Offshore Waters (Gulf of Guinea) Using Macrobenthic Assemblage

• Published in: Thalassas : revista de ciencias del mar 2024-03, Vol.40 (1), p.639-651
• Main Authors: Sule, Abiodun Yusuf, Yakub, Ademola Semiu, Nubi, Ayoola Olubunmi, Bassey, Bassey Okon, Mahu, Edem, Igbo, Juliet Kelechi, Bello, Beatrice Omolola, Sohou, Zacharie, Abiodun, Olushola Ayoola, Olapoju, Oluwabukunola Ayokunmi, Nosazeogie, Esther Osayevbovban, Izge, Musa Abdullahi, Brice, Mobio, Adesina, Popoola Atilade
• Format: Article
• Language: English
• Subjects: Adaptability; Alkalinity; Anthropogenic factors; Aquatic animals; Aquatic biota; Benthos; Bioindicators; Biomonitoring; Biota; Bottom sediments; Bottom trawling; Bottom water; Coastal Sciences; Coastal waters; Crude oil; Dissolved oxygen; Drilling rigs; Earth and Environmental Science; Earth Sciences; Environmental impact; Fish & Wildlife Biology & Management; Fisheries; Freshwater & Marine Ecology; Human influences; Indicator species; Macrobenthos; Macrofauna; Macroinvertebrates; Marine & Freshwater Sciences; Marine environment; Marine invertebrates; Marine molluscs; Mollusks; Oceanography; Offshore; Offshore platforms; Parameters; Phosphates; Pollution; Quality assessment; Sediments; Shellfish; Surface water; Trawling; Water analysis; Water depth; Water sampling; Water temperature; Zoobenthos
• ISSN: 0212-5919; 2366-1674
• DOI: 10.1007/s41208-024-00665-7

Benthic macrofauna differs in sensitivity, tolerance, and adaptability to environmental fluctuations and disturbances induced by various anthropogenic activities. These activities pose an environmental threat to aquatic biota; thus, benthic macroinvertebrates are utilized as bioindicators of stressors. This study aimed to assess the ecological quality status (EcoQs) of Nigeria's offshore waters using macrobenthic diversity and ecological biotic indices. Bottom sediments were collected from seven (7) stations using Van-Veen grab, and Niskin water sampler for surface water onboard the RV-BAYAGBONA. The identified macrofauna communities were subjected to AZTI’s Marine Biotic Index (AMBI) to depict the ecological quality status of the environment. The physico-chemical parameters (Water temperature, dissolved oxygen, conductivity, depth, pH, alkalinity, salinity, phosphate, and nitrate) using a multi-parameter checker, HORIBA-U53. The physico-chemical parameters of the bottom water showed significant differences (p  Sipuncula (1.57%) > Porifera (0.78%). The macrofauna community was mostly dominated by Gastropoda (ecological groupings of I and II) and Polychaete (ecological group of III). The biotic indices were ecologically grouped into I (54.3%) and II (42.5%) species that are sensitive and indifferent to pollution and group III (3.2%) tolerant species to excessive organic pollution. The biotic indices were assessed based on the level of sensitivity of the benthic community in response to anthropogenic stressors. Thus, the ecological status using AMBI, M-AMBI, and BI indicated an undisturbed marine environment (healthy EcoQs) with less anthropogenic impacts. Although periodic biomonitoring of the coastal waters is recommended, this is due to the installation of crude oil platforms for exploitation, and fishery activities deploying bottom trawling. Furthermore, complementary use of diverse indices relating to sensitivity/tolerance-based indices is highly recommended to establish a robust database on ecological grouping for diverse benthic species within the western Atlantic Ocean. Graphical Abstract