TY - JOUR
T1 - Sponge and mollusk associations in a benthic filter-feeding assemblage in the middle and lower Xingu River, Brazil
AU - Volkmer-Ribeiro, Cecilia
AU - Mansur, Maria Cristina Dreher
AU - Pereira, Daniel
AU - Tiemann, Jeremy S
AU - Cummings, Kevin S.
AU - Sabaj, Mark Henry
N1 - Funding Information:
The Brazilian authors are indebted to Paulo Eduardo Aydos Bergoncci, M.Sc. biologist and coordinator of the lab of analysis and environmental research of the Lotica enterprise, Porto Alegre, for free access to its facilities. The authors acknowledge three anonymous referees for carefully reviewing the manuscript and providing valuable suggestions. Thanks to Priscila Madoka M. Ito for information on trawl otter boards. Special thanks to Lúcia Rapp Py-Daniel, Leandro Sousa, Alany Gonçalves, Daniel Fitzgerald, and the other members of the iXingu Project for fieldwork and logistical support. Study funded in part by NSF DEB-1257813 (PI Sabaj).
PY - 2020/11/1
Y1 - 2020/11/1
N2 - During a pilot survey, sponges and mollusks were sampled from the bottom of the middle Xingu River (rapids) and lower Xingu River (ria) via hand-picking in shallows and trawling and surface-supplied dives in deeper waters. The survey revealed a benthic community composed of eight sponge species in four genera and three families, and added six species to the Xingu Basin fauna. Sponges exhibited distinct variation in body shape corresponding to local environmental conditions such as water depth, current velocity and available substrates. Sponges inhabiting rocky bottoms in swift currents (rapids) typically formed crusts. Those in the deeper, calmer waters of the ria attained massive and elaborate forms while attached to infaunal bivalves. Oncosclera navicella and Drulia cristata exhibited crusts and massive forms as adaptations to rapids and ria, respectively. In the middle to lower Xingu, sponges encrusted the shells of eleven species of bivalves (seven infaunal, three epifaunal, and one infaunal/epifaunal) and one infaunal/epifaunal gastropod. Bivalves provide key substrates for supporting sponges above the sand, mud and detritus of the Xingu ria. Potential impacts of the Belo Monte Dam complex on the sponge fauna of the middle Xingu rapids are discussed.
AB - During a pilot survey, sponges and mollusks were sampled from the bottom of the middle Xingu River (rapids) and lower Xingu River (ria) via hand-picking in shallows and trawling and surface-supplied dives in deeper waters. The survey revealed a benthic community composed of eight sponge species in four genera and three families, and added six species to the Xingu Basin fauna. Sponges exhibited distinct variation in body shape corresponding to local environmental conditions such as water depth, current velocity and available substrates. Sponges inhabiting rocky bottoms in swift currents (rapids) typically formed crusts. Those in the deeper, calmer waters of the ria attained massive and elaborate forms while attached to infaunal bivalves. Oncosclera navicella and Drulia cristata exhibited crusts and massive forms as adaptations to rapids and ria, respectively. In the middle to lower Xingu, sponges encrusted the shells of eleven species of bivalves (seven infaunal, three epifaunal, and one infaunal/epifaunal) and one infaunal/epifaunal gastropod. Bivalves provide key substrates for supporting sponges above the sand, mud and detritus of the Xingu ria. Potential impacts of the Belo Monte Dam complex on the sponge fauna of the middle Xingu rapids are discussed.
KW - benthic communities
KW - epizoic interactions
KW - filter feeding
KW - fluvial substrates
KW - reservoirs
KW - run-of-the-river dams
KW - sessile macroinvertebrates
KW - sponge morphology
KW - INHS
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U2 - 10.1635/053.166.0113
DO - 10.1635/053.166.0113
M3 - Article
SN - 0097-3157
VL - 166
SP - 1
EP - 24
JO - Proceedings of the Academy of Natural Sciences of Philadelphia
JF - Proceedings of the Academy of Natural Sciences of Philadelphia
IS - 1
ER -