Tomorrow is World Ocean’s day! This week we will share some short articles from current grantees under WIOMSA’s MASMA and MARG programmes.
Understanding sediments accumulations and the importance of regional collaboration in tackling scientific needs.
By Gilbert Owato
The Western Indian Ocean (WIO) region has very rich and diverse marine resources becoming the second Biodiversity hotspot in the world due to its high productivity. For instance, fisheries resources in the WIO region makes an important contribution both to local livelihoods of the poorest sectors of society and national economies. Even with the rich diversity, the WIO region has been impacted by both natural and anthropogenic phenomenon such as the El Nino, riverine input, untreated effluent, dumping of dredged material have all contributed to increasing the sediment load deposited into the ocean. These sediments are known to deposit in areas of minimal ocean currents and tend to accumulate over time.
Sediments have been described as a ready sink of pollutants that are released in the water column for bioavailability purposes. Hence, an increase in accumulated sediment over time can result in an increase in pollutant levels in the overlying waters. Therefore, sediment accumulation rates are an essential tool in understanding processes related to the deposition of organic and inorganic materials in marine environments. Using sediment as a tool for pollution monitoring, a deeper insight into the long-term pollution state of the aquatic environment can be enumerated for a wide expanse of locations and quantification on at least a decadal to century scale, so as to resolve annual variations in the spatial distribution and amount of sediment transferred from the river channel to the ﬂoodplain by giving out a baseline on the histories of radionuclides, the input coefficients with the depths in sediments. Furthermore, sediment accumulation rates are not only a measure of the speed of deposition, but also represent a very useful tool for further paleo-environmental reconstructions of climate history or biotic evolution as seen in the fossil record.
This, therefore, calls for the need of research, where different environmental sample matrix (sediment) to be used so as to understand the biodiversity dynamics associated with the aquatic environments in the WIO.
The use of sediment as a matrix is quite challenging and has brought scientists from different disciplines like chemistry, nuclear sciences to help answer the hypothesis associated with this environment. Though this area has attracted little attention, in the other hand, the approach for research has promoted regional collaboration and partnership in research amongst the experts from the different countries in the WIO through donor-funded projects that have unique approaches to ocean research. These may include and not limited to the use of isotopic techniques to assess coastal and marine Ecosystem. This is achieved through early career scientists, and other professionals who are interested in, or will pursue research and/or management positions that require knowledge of radioactivity and its use in ocean sciences so as to tackle issues related to the basics of radioactivity; natural, anthropogenic, and cosmogenic radioisotopes in the marine environment; radioecology, tracer and dating techniques; and other applications of radionuclides as ocean tracers. Through the initiatives and support from WIOMSA-MARG I programme, studies are being done to determining the sediment accumulation rates and geochronologies using 210Pb dating method, an axiom of the decline in fisheries, Malindi–Ungwana Bay, Kenya. Collaborations are also being received from other organizations like the IAEA in strengthening regional capacities for marine risk assessment using nuclear and related techniques through sample analysis, collaborations and capacity building training.
Investigation of sedimentation processes will aid in for a wide expense of location and quantified on at least a decadal to century scale, so as to resolve the annual variation in the spatial distribution and amount of sediment transferred from the channel to the ﬂoodplain that affects the fish distribution by giving out a baseline on the histories of radionuclides, so as to continue addressing the insufficient knowledge on issues of potential hazards to our rich WIO ecosystem using appropriate techniques.
Gilbert Owato is a researcher at Kenya Marine and Fisheries Research Institute (KMFRI), specialized on Biogeochemistry and Ecotoxicology, he can be reached by email: ow**********@gm***.com