Flocculation is a key process for controlling the fate and transport of suspended particulate matter (SPM) in water environments and has received considerable attention in the field of water science (e.g., oceanography, limnology, and hydrology), remaining an active area of research. The research on flocculation has been conducted to elucidate the SPM dynamics and to diagnose various environmental issues. The flocculation, sedimentation, and transportation of SPM are closely linked to the compositional and structural properties of flocs. In fact, flocs are highly heterogeneous in terms of composition. However, the lack of comprehensive research on floc composition and structure has led to misconceptions regarding the temporal and spatial dynamics of SPM. This review summarizes the current understanding of the heterogeneous composition of flocs (e.g., minerals, organic matter, metals, microplastic, engineered nanoparticles) and its effect on their structure and on their fate and transport within aquatic environments. Furthermore, the effects of human activities (e.g., pollutant discharge, construction) on floc composition are discussed.
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RBINS Staff Publications 2022
The seasonal variation in concentration of transparent exopolymer particles (TEPs), particulate organic carbon (POC) and particulate organic nitrogen (PON) were investigated together with floc size and the concentration of suspended particulate matter (SPM) along the cross-shore gradient, from the high turbid nearshore toward the low-turbid offshore waters in the Southern Bight of the North Sea. Our data demonstrate that biophysical flocculation cannot be explained by these heterogeneous parameters, but requires a distinction between a more reactive labile (“fresh”) and a less reactive refractory (“mineral-associated”) fraction. Based on all data, we separated the labile and mineral-associated POC, PON, and TEP using a semi-empirical model approach. The model's estimates of fresh and mineral-associated organic matter (OM) show that great parts of the POC, PON, and TEP are associated with suspended minerals, which are present in the water column throughout the year, whereas the occurrence of fresh TEP, POC, and PON is restricted to spring and summer months. In spite of a constantly high abundance of total TEP throughout the entire year, it is its fresh fraction that promotes the formation of larger and faster sinking biomineral flocs, thereby contributing to reducing the SPM concentration in the water column over spring and summer. Our results show that the different components of the SPM, such as minerals, extracellular OM and living organisms, form an integrated dynamic system with direct interactions and feedback controls.
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RBINS Staff Publications 2022
Today, the so-called taxonomic impediment, i.e., the lack of taxonomic (inclusive of genetic) information, taxonomic and curatorial expertise, and infrastructure in many parts of the world, means that accessing and generating taxonomic information remains extremely difficult. To alter this trend, the Convention on Biological Diversity installed the Global Taxonomy Initiative (GTI) and endorsed it with an operational program of work. Its objectives are to remedy the knowledge gaps in our taxonomic system, increase the number of well-trained taxonomists and curators, optimize the infrastructure needed to do sound taxonomic research, significantly improve access to taxonomic collections, data, and metadata, and, thereby, to improve decision- making in conservation of biodiversity. To speed up taxonomic capacity building the Belgian GTI Focal Point has established the series Abc Taxa (www.abctaxa.be), a toll-free information highway between experts and novices. It is believed that this artery will speed up the construction of taxonomic capacity, as it does not evoke the expensive, long-term teacher-apprentice relationships previously utilized to install operational, high-quality taxonomists and collection managers. Since 2005, 19 volumes have been released with subjects as diverse as taxonomy of sea cucumbers of the Comoros, good practices in collection management of mollusc collections, taxonomy of the amphibians of Cuba and of Guyana, taxonomy of algae of Sri Lanka, bee taxonomy in sub-Saharan Africa, mushroom taxonomy of Central Africa, introduction to the taxonomy of mites, taxonomy of invasive succulents of South Africa, taxonomy of the sawflies of southern Africa, taxonomy of the diatoms of the Congo, taxonomy of fish parasites of African Freshwater fishes and taxonomy of the brittle and basket stars of South Africa. This contribution briefly details the scope and aims of Abc Taxa, demonstrates the value of the series for development, and acts as a call for future manuscripts.
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RBINS Staff Publications 2021
