Publication Date:
2023-06-21
Description:
Larval dispersal is a fundamental process responsible for colonization and connectivity of benthic invertebrate
populations. It is difficult to study larval dispersal in polar environments because weather and climate conditions
restrict sample collection to certain seasons. In this study, we leveraged oceanographic moorings as long-term
scientific platforms for collecting larvae and recruits of benthic invertebrate species in the Fram Strait and
along the continental slope north of Svalbard in 2017–2021. Larval traps and fouling panels were deployed at
various depths on 15 moorings at 8 locations, and additional specimens of biofouling were obtained opportunistically
from moored instruments. Our results showed a significant difference in species composition between
samples collected in Atlantic Water in the West Spitsbergen Current (WSC) and samples collected in Arctic Water
near the seafloor and in the East Greenland Current (EGC) in the western part of the Fram Strait. There was also a
stark difference between Atlantic Water species in the Fram Strait and on the north Svalbard slope. Most
specimens collected in the WSC belonged to species with long-duration planktotrophic larvae, such as the
ubiquitous bivalve Hiatella arctica, the bryozoan Alcyonidium mamillatum, and two nudibranchs. Samplers
exposed primarily to Arctic water at their given depth and location were dominated by hydrozoans. We observed
medusae budding off of the hydroids Stegopoma plicatile and Rhizoragium roseum. Our study demonstrates that the
WSC is an important vector for larval dispersal into the central Arctic Ocean. Integration of biological samplers
on oceanographic moorings holds great promise for monitoring efforts as climate change progresses, especially in
environments where research is challenging and seasonally limited, such as the Arctic.
1. Introduction
For benthic invertebrates, especially those with sessile adult stages
(e.g., sponges, anemones), larval dispersal is the primary mechanism of
dispersal to new habitats (Pechenik, 1999). The patterns and mechanisms
of larval dispersal are difficult to study in the Arctic Ocean, where
weather and climate conditions restrict sample collection to summer
months. As a result, larval dispersal and the subsequent processes of
settlement and recruitment in benthic invertebrates are poorly understood
in the Arctic Ocean, despite their importance.
Oceanographic moorings provide excellent platforms for studying
larval dispersal, recruitment, and growth of organisms (Chava et al.,
2021; Schiaparelli and Aliani, 2019). Instruments and floats on a
mooring are deployed in the water column by design, so the
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
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