A 5-year study (2014–2018) of the relationship between coastal phytoplankton abundance and intertidal barnacle size along the Atlantic Canadian coast

Benthic–pelagic coupling refers to the ecological relationships between benthic and pelagic environments. Studying such links is particularly useful to understand biological variation in intertidal organisms along marine coasts. Filter-feeding invertebrates are ecologically important on marine rocky shores, so they have often been used to investigate benthic–pelagic coupling. Most studies, however, have been conducted on eastern ocean boundaries. To evaluate benthic–pelagic coupling on a western ocean boundary, we conducted a 5-year study spanning 415 km of the Atlantic coast of Nova Scotia (Canada). We hypothesized that the summer size of intertidal barnacles (Semibalanus balanoides) recruited in the preceding spring would be positively related to the nearshore abundance (biomass) of phytoplankton, as phytoplankton constitutes food for the nauplius larvae and benthic stages of barnacles. Every year between 2014 and 2018, we measured summer barnacle size in clearings created before spring recruitment on the rocky substrate at eight wave-exposed locations along this coast. We then examined the annual relationships between barnacle size and chlorophyll-a concentration (Chl-a), a proxy for phytoplankton biomass. For every year and location, we used satellite data to calculate Chl-a averages for a period ranging from the early spring (when most barnacle larvae were in the water) to the summer (when barnacle size was measured after weeks of growth following spring benthic recruitment). The relationships were always positive, Chl-a explaining nearly half, or more, of the variation in barnacle size in four of the five studied years. These are remarkable results because they were based on a relatively limited number of locations (which often curtails statistical power) and point to the relevance of pelagic food supply to explain variation in intertidal barnacle size along this western ocean boundary coast

Collecting dogwhelks (Nucella lapillus) for Field Experiments

This video shows a collection of dogwhelks (<i>Nucella lapillus</i>) on the Atlantic coast of Nova Scotia, Canada. It was recorded in May 2016.<br

Installation of experimental cages to examine predator nonconsumptive effects on prey

This video shows the installation of experimental cages to examine predator nonconsumptive effects on prey. It was recorded in Deming Island (45°12'45.60''N, 61°10'26.65''W), Nova Scotia, Canada during May 2016.<br

Predator nonconsumptive effects on prey demography (B)

This lecture is based on the article Ehlers, S. M., R. A. Scrosati & J. A. Ellrich. 2018. Predator nonconsumptive effects on prey demography: dogwhelk cues decrease benthic mussel recruitment. Journal of Zoology <a href="https://doi.org/10.1111/jzo.12555">https://doi.org/10.1111/jzo.12555</a><strong><br></strong

Submerged experimental cages to examine predator cue effects on mussel recruitment

This video shows experimental cages to examine nonconsumptive effects of predatory dogwhelks (Nucella lapillus) on blue mussel (Mytilus spp) recruitment. It was recorded in Deming Island, Nova Scotia, Canada during 2016

Freshwater pearl mussel (Margaritifera margaritifera) glochidium

This video shows a hatching glochidium larvae of the endangered freshwater pearl mussel <i>Margaritifera margaritifera</i> (L. 1758). It was recorded during a freshwater mussel conservation project in the Westerwald (Germany) during August 2008. <br

Predator nonconsumtive effects on prey demography (A)

This lecture is based on the article: Ellrich et al. 2015. Predator nonconsumptive effects on prey recruitment weaken with recruit density. Ecology 96(3): 611-616.<br

Mesh scourers measuring mussel recruitment in Tor Bay Provincial Park, Nova Scotia, Canada

Mesh scourers measuring benthic recruitment of blue mussels in Tor Bay Provincial Park, Nova Scotia, Canada. <br

Predator nonconsumptive effects on prey behavior

This lecture is based on the article: Johnston, B. R., M. Molis & R. A. Scrosati. 2012. Predator chemical cues affect prey feeding activity differently in juveniles and adults. Canadian Journal of Zoology 90: 128-132.<br