Disappearing Prey Spurs Leopard Attacks

Abstract

sea-surface microlayer (SML), the uppermost 1-1000 |xm of the ocean, is a distinct ecosystem, providing important habitat for fish larvae and microorganisms. Unfortunately, in areas with high industrial, agricultural, and ship? ping activities, pollutants can build up in the SML, to an average of 500 times the concentrations in the underlying water column, accord? ing to Oliver Wurl (National University of Singapore). Wurl and co-author Jeffrey Obbard (National University of Singapore) reviewed studies on major SML pollutants, including persistent organic pollu? tants (POPs) such as pesticides and polychlorinated biphenyls (PCBs), organotin compounds, and heavy metals (Mar Pollut Bull 2004; 48: 1016-30). Like most environmental bound? ary layers, the SML has high biologi? cal activity, says Wurl. The metab? olism of marine organisms leads to an enrichment of proteins and lipids in the SML. Proteins and lipids, because of their hydrophobic nature, are also transported to the SML on bubbles from the subsurface layers, increasing this enrichment. Zooplankton, larval and juvenile fish, and bacteria there? fore collect in the SML, because they find alotof food. POPs, however, are notoriously drawn to hydrophobic compounds such as lipids, and are known to adversely affect the endocrine sys? tems of many marine organisms, including mammals. Many of the organisms feeding in the SML form the basis of the marine food webs. We know that even low concentrations of POPs can lead to significant bioaccumulation in higher animals, continues Wurl. POP concentrations have been reported to be 10 to 40 times higher in the SML over the subsurface water of coastal areas com?