MarineGEO partners were central to a recent study published in Science that revealed that higher ocean temperatures lead to greater predation pressure. Scientists from 36 sites across 110 degrees of latitude ran the same experiment to assess the intensity and impact of predators on local marine invertebrate communities. By including sites across latitudes that span almost from pole to pole along the Americas, and on both Atlantic and Pacific coasts, the study was able to detect broadscale trends that were obscured in smaller scale studies.
The foundation of the study included developing PanAmEx (The Pan-American Experimental Initiative in Marine Macroecology), an experimental network established to examine broad-scale ecological patterns and processes across coastal marine ecosystems of North, Central, and South America. PanAmEx was coordinated and supported by the Smithsonian Institution (including the Smithsonian Environmental Research Center, Smithsonian Tropical Research Institute, and the Smithsonian-led MarineGEO program) and Temple University. The network brings together collaborators from 11 countries in the Americas.
The first PanAmEx project, initiated in 2018 and 2019, was an experiment to measure gradients in interaction strength among marine benthic organisms, focusing on how predation affects assembly of communities of fouling organisms. The experiment compared development of fouling communities (sessile invertebrates) on PVC panels that were either exposed or protected from predators (mainly fishes) using cages. The PVC panels were deployed from (preferably floating) docks, providing a simple and standardized substratum for colonization of marine organisms. Results revealed higher predator consumption rates and consistently stronger impacts on biomass and species composition of marine invertebrate communities in warmer tropical waters. The strength of the trends were variable among regions within the study (e.g., North Pacific vs South Atlantic) but by including sites across such a large latitudinal range, the large scale patterns were revealed.
The findings imply that predators will have an increasing impact on prey communities with future ocean warming. This may be particularly noticeable in colder water regions where (fish) predators are not currently an important determinant of invertebrate communities.