Coral recruits are highly sensitive to heavy fuel oil exposure both in the presence and absence of UV light

F Mikaela Nordborg; Diane L Brinkman; Andrew P Negri

doi:10.1016/j.envpol.2022.119799

Coral recruits are highly sensitive to heavy fuel oil exposure both in the presence and absence of UV light

Environ Pollut. 2022 Sep 15:309:119799. doi: 10.1016/j.envpol.2022.119799. Epub 2022 Jul 18.

Authors

F Mikaela Nordborg¹, Diane L Brinkman², Andrew P Negri³

Affiliations

¹ AIMS@JCU, Division of Research & Innovation, James Cook University and Australian Institute of Marine Science, Townsville, 4810, Queensland, Australia; College of Science & Engineering, Division of Tropical Environments and Societies, James Cook University, Townsville, 4810, Queensland, Australia; Australian Institute of Marine Science, Townsville, 4810, Queensland, Australia. Electronic address: mikaela.nordborg@my.jcu.edu.au.
² Australian Institute of Marine Science, Townsville, 4810, Queensland, Australia.
³ AIMS@JCU, Division of Research & Innovation, James Cook University and Australian Institute of Marine Science, Townsville, 4810, Queensland, Australia; Australian Institute of Marine Science, Townsville, 4810, Queensland, Australia.

PMID: 35863709
DOI: 10.1016/j.envpol.2022.119799

Abstract

Oil pollution remains a prominent local hazard to coral reefs, but the sensitivity of some coral life stages to oil exposure remains unstudied. Exposure to ultraviolet radiation (UVR), ubiquitous on coral reefs, may significantly increase oil toxicity towards these critical habitat-forming taxa. Here we present the first data on the sensitivity of two distinct post-settlement life stages of the model coral species Acropora millepora to a heavy fuel oil (HFO) water accommodated fraction (WAF) in the absence and presence of UVR. Assessment of lethal and sublethal endpoints indicates that both 1-week-old and 2-month-old recruits (1-wo and 2-mo) were negatively affected by chronic exposures to HFO (7 and 14 days, respectively). Relative growth (1-wo and 2-mo recruits) and survival (1-wo recruits) at end of exposure were the most sensitive endpoints in the absence of UVR, with no effect concentrations (NEC) of 34.3, 5.7 and 29.3 μg L^-¹ total aromatic hydrocarbons (TAH; ∑39 monocyclic- and polycyclic aromatic hydrocarbons), respectively. On average, UVR increased the negative effects by 10% for affected endpoints, and latent effects of exposure were evident for relative growth and symbiont uptake of recruits. Other sublethal endpoints, including maximum quantum yield and tissue colour score, were unaffected by chronic HFO exposure. A comparison of putative species-specific sensitivity constants for these ecologically relevant endpoints, indicates A. millepora recruits may be as sensitive as the most sensitive species currently included in oil toxicity databases. While the low intensity UVR only significantly increased the negative effects of the oil for one endpoint, the majority of endpoints showed trends towards increased toxicity in the presence of UVR. Therefore, the data presented here further support the standard incorporation of UVR in oil toxicity testing for tropical corals.

Keywords: Coral reef; Heavy fuel oil; Oil pollution; PAH; Phototoxicity; Ultraviolet radiation.

MeSH terms

Animals
Anthozoa*
Coral Reefs
Fuel Oils*
Petroleum Pollution* / analysis
Petroleum* / toxicity
Ultraviolet Rays
Water Pollutants, Chemical* / metabolism

Substances

Fuel Oils
Petroleum
Water Pollutants, Chemical