Influence of Seasonal Variation and Anthropogenic Activities on Elemental Compositions in Zooplankton: A Year-Long Case Study from the Jeddah Coast of the Red Sea

Zooplankton, one of the most important groups in the ocean, serves as a pivotal connection in food webs that sustain a variety of marine life, making it imperative to investigate their spatial–temporal variations in elemental concentrations. Here we measured the concentrations of 20 common elements (including those trace/heavy metals) in the zooplankton population along the Jeddah Coast of the Saudi Arabian Red Sea over a year from October 2013 to September 2014. Our results indicated that mean concentrations of elements were broadly consistent between coastal and offshore areas within a 2 km range, with notable exceptions being higher Zn and lower Cd levels at coastal sites. A decline in concentrations of total organic carbon (TOC), total nitrogen (TN), and Cd was observed from the south to the north in offshore areas ( R