Publication Date:
2017-05-12
Description:
In species with complex life cycles, laboratory studies have shown that variations in
the traits of settling larvae can affect post-settlement survival and influence recruitment and
benthic− pelagic coupling. However, we still know little about the magnitude and spatial scale of
natural trait variation. We studied spatial variation in body size and nutritional reserves (carbon,
nitrogen and lipids) of settled cyprids of the barnacle Semibalanus balanoides along the coast of
West Scotland. We quantified variation among regions (north vs. south: range ~700 km), locations
(~50 km), shores (~10 km) and within shores (~10 m). We also evaluated trait responses to gradients
in chlorophyll and shore openness and compared swimming vs. settled cyprids in order to
infer the likely influence of costs of substratum search on trait variation. Variability between
regions was large, with higher trait values (e.g. carbon cyprid−1: 35 to 50% higher) in the north.
Most traits correlated negatively with pelagic chlorophyll a (a proxy for larval/juvenile food availability);
this counter-gradient pattern suggests an adaptive role of increased reserves, buffering
benthic juveniles from low food availability during the critical early post-settlement period. Body
size and nitrogen content correlated positively with shore openness; lower than expected carbon
content suggest increased costs of substratum search on open shorelines. Higher nitrogen content
but lower percent carbon was found in settled vs. swimming larvae, suggesting costs of sub -
stratum search at the time of settlement. Overall, we uncovered the spatial scales at which trait
variation, shaped by pelagic processes, can affect post-metamorphic survival, recruitment and
benthic−pelagic coupling.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
peerRev
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