Nitrogen eutrophication particularly promotes turf algae in coral reefs of the central Red Sea

Show full item record



Permalink

http://hdl.handle.net/10138/316997

Citation

Karcher , D B , Roth , F , Carvalho , S , El-Khaled , Y C , Tilstra , A , Kürten , B , Struck , U , Jones , B H & Wild , C 2020 , ' Nitrogen eutrophication particularly promotes turf algae in coral reefs of the central Red Sea ' , PeerJ , vol. 8 , 8737 . https://doi.org/10.7717/peerj.8737

Title: Nitrogen eutrophication particularly promotes turf algae in coral reefs of the central Red Sea
Author: Karcher, Denis B.; Roth, Florian; Carvalho, Susana; El-Khaled, Yusuf C.; Tilstra, Arjen; Kürten, Benjamin; Struck, Ulrich; Jones, Burton H.; Wild, Christian
Contributor: University of Helsinki, Tvärminne Zoological Station
Date: 2020-04-02
Language: eng
Number of pages: 25
Belongs to series: PeerJ
ISSN: 2167-8359
URI: http://hdl.handle.net/10138/316997
Abstract: While various sources increasingly release nutrients to the Red Sea, knowledge about their effects on benthic coral reef communities is scarce. Here, we provide the first comparative assessment of the response of all major benthic groups (hard and soft corals, turf algae and reef sands-together accounting for 80% of the benthic reef community) to in-situ eutrophication in a central Red Sea coral reef. For 8 weeks, dissolved inorganic nitrogen (DIN) concentrations were experimentally increased 3-fold above environmental background concentrations around natural benthic reef communities using a slow release fertilizer with 15% total nitrogen (N) content. We investigated which major functional groups took up the available N, and how this changed organic carbon (C-org) and N contents using elemental and stable isotope measurements. Findings revealed that hard corals (in their tissue), soft corals and turf algae incorporated fertilizer N as indicated by significant increases in delta N-15 by 8%, 27% and 28%, respectively. Among the investigated groups, C-org content significantly increased in sediments (+24%) and in turf algae (+33%). Altogether, this suggests that among the benthic organisms only turf algae were limited by N availability and thus benefited most from N addition. Thereby, based on higher C-org content, turf algae potentially gained competitive advantage over, for example, hard corals. Local management should, thus, particularly address DIN eutrophication by coastal development and consider the role of turf algae as potential bioindicator for eutrophication.
Subject: 1181 Ecology, evolutionary biology
Coral reefs
Nutrients
Stable isotopes
Nitrogen cycling
Eutrophication
Turf algae
Zooxanthellae
Phase shifts
PERMEABLE CARBONATE
BUILDING CORALS
ORGANIC-MATTER
CLIMATE-CHANGE
NUTRIENT ENRICHMENT
SCLERACTINIAN CORAL
POCILLOPORA-DAMICORNIS
STYLOPHORA-PISTILLATA
PRIMARY PRODUCTIVITY
WATER-QUALITY
Rights:


Files in this item

Total number of downloads: Loading...

Files Size Format View
peerj_8737.pdf 5.121Mb PDF View/Open

This item appears in the following Collection(s)

Show full item record