Open AccessA halo of reduced dinoflagellate abundances in and around eelgrass beds
Author(s) -
Emily Jacobs-Palmer,
Ramón Gallego,
Ana RamónLaca,
Emily Kunselman,
Kelly Cribari,
Micah Horwith,
Ryan P. Kelly
Publication year - 2020
Publication title -
peerj
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.927
H-Index - 70
ISSN - 2167-8359
DOI - 10.7717/peerj.8869
Subject(s) - zostera marina , seagrass , dinoflagellate , abundance (ecology) , ecology , habitat , zostera , foundation species , transect , biology , algal bloom , ecosystem , callinectes , bay , environmental science , fishery , oceanography , phytoplankton , geology , nutrient , crustacean
Seagrass beds provide a variety of ecosystem services, both within and outside the bounds of the habitat itself. Here we use environmental DNA (eDNA) amplicons to analyze a broad cross-section of taxa from ecological communities in and immediately surrounding eelgrass ( Zostera marina ). Sampling seawater along transects extending alongshore outward from eelgrass beds, we demonstrate that eDNA provides meter-scale resolution of communities in the field. We evaluate eDNA abundance indices for 13 major phylogenetic groups of marine and estuarine taxa along these transects, finding highly local changes linked with proximity to Z. marina for a diverse group of dinoflagellates, and for no other group of taxa. Eelgrass habitat is consistently associated with dramatic reductions in dinoflagellate abundance both within the contiguous beds and for at least 15 m outside, relative to nearby sites without eelgrass. These results are consistent with the hypothesis that eelgrass-associated communities have allelopathic effects on dinoflagellates, and that these effects can extend in a halo beyond the bounds of the contiguous beds. Because many dinoflagellates are capable of forming harmful algal blooms (HABs) toxic to humans and other animal species, the apparent salutary effect of eelgrass habitat on neighboring waters has important implications for public health as well as shellfish aquaculture and harvesting.