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Abiotic conditions drive significant variability in nutrient processing by a common Caribbean sponge, Ircinia felix
Author(s) -
Archer Stephanie K.,
Stevens Julia L.,
Rossi Ryann E.,
Matterson Kenan O.,
Layman Craig A.
Publication year - 2017
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.1002/lno.10533
Subject(s) - nutrient , abiotic component , sink (geography) , nutrient cycle , sponge , biogeochemical cycle , nitrogen cycle , nitrate , ecology , environmental chemistry , biology , environmental science , nitrogen , botany , chemistry , cartography , organic chemistry , geography
Coral reefs typically occur in oligotrophic waters, where tight recycling of energy and nutrients is essential in order to support their high productivity. Sponges are efficient filter feeders that host diverse and abundant microbial communities that often contain members capable of carrying out complex nutrient transformations. Consequently, sponges often act as significant sources of bioavailable forms of nitrogen and phosphorus while acting as sinks for dissolved organic carbon (DOC). However, little attention has focused on variability of nutrient release by sponges and no studies have reported how abiotic conditions may impact sponge‐driven changes in nutrient concentrations. Here, we show that a common Caribbean sponge, Ircinia felix , is capable of being both a source and a sink for DOC, ammonium, nitrate/nitrite (NO x −), and phosphate (PO 4 3 −). Additionally, we show that abiotic conditions, particularly ambient nutrient availability, seem to explain a significant amount of the variability ( R 2 range from 0.40 to 0.65). Interestingly, as ambient nutrient concentrations increased, I. felix transitioned from acting as a source to serving as a sink for all nutrient forms measured. We also found I. felix ‐associated bacteria exhibit a significantly higher abundance of predicted nitrogen metabolism, carbon fixation, and photosynthetic genes relative to ambient water and sediment. These results suggest that sponges play an important and dynamic role in biogeochemical cycling on reefs, particularly as human activities alter natural nutrient dynamics in coastal systems.