High Latitude Corals Tolerate Severe Cold Spell

Abstract

Climatically extreme weather events often drive long-term ecological responses of ecosystems. By disrupting the important symbiosis with zooxanthellae, Marine Cold Spells (MCS) can cause bleaching and mortality in tropical and subtropical scleractinian corals. Here we report on the effects of a severe MCS on high latitude corals, where we expected to find bleaching and mortality. The MCS took place off the coast of Perth (32 • S), Western Australia in 2016. Bleaching was assessed before (2014) and after (2017) the MCS from surveys of permanent plots, and with timed bleaching searches. Temperature data was recorded with in situ loggers. During the MCS temperatures dipped to the coldest recorded in ten years (15.3 • C) and periods of <17 • C lasted for up to 19 days. Only 4.3% of the surveyed coral colonies showed signs of bleaching. Bleaching was observed in 8 species where those most affected were Plesiastrea versipora and Montipora mollis. These findings suggest that high latitude corals in this area are tolerant of cold stress and are not persisting near a lethal temperature minimum. It has not been established whether other environmental conditions are limiting these species, and if so, what the implications are for coral performance on these reefs in a warmer future.

Tropicalisation of temperate reefs: Implications for ecosystem functions and management actions

“…The third option for maintaining more desirable ecosystem states than turf is to accelerate adaptation/movement of corals into cooler waters. Naturally recruited corals inhabiting high latitude reefs areas appear tolerant to cooler waters including cold spells (Tuckett & Wernberg, ), but can still be susceptible to bleaching during warm thermal events (Hughes et al, ). Assisting the migration of more thermally tolerant corals may be beneficial to coral persistence at higher latitudes, however, there are still major knowledge gaps including the heritability of traits in corals and/or symbionts (van Oppen et al, ).…”

Warming resistant corals from the Gulf of Aqaba live close to their cold-water bleaching threshold

“…However, the response of these corals to cold stress events has not been tested. The reefs of the GoA are some of the northernmost in the world; limited research has suggested that high latitude corals may have greater tolerance to cold stress than their tropical conspecifics (Tuckett & Wernberg, 2018). In the northernmost part of the GoA, a steep slope from the forereef to a depth of 40-100 m may prevent major cold-water events on the shallow reef since denser cooler water will sink to greater depth.…”

“…Since bleaching severity following cold water stress has previously been shown to be species specific (Coles & Fadlallah, 1991;Zapata, Jaramillo-González & Navas-Camacho, 2011;Kemp et al, 2016;Pontasch et al, 2017;Tuckett & Wernberg, 2018), the responses of two species were compared in this study. Acroporid corals are the most abundant scleractinian genera in Eilat with Stylophora sp.…”

Peer Review #1 of "Warming resistant corals from the Gulf of Aqaba live close to their cold-water bleaching threshold (v0.1)"

“…Manuscript to be reviewed tested. The reefs of the GoA are some of the northernmost in the world; limited research has suggested that high latitude corals may have greater tolerance to cold stress than their tropical conspecifics (Tuckett & Wernberg, 2018). In the northernmost part of the GoA, a steep slope from the forereef to a depth of 40-100 m may prevent major cold-water events on the shallow reef since denser cooler water will sink to greater depth.…”

“…Since bleaching severity following cold water stress has previously been shown to be species specific (Coles & Fadlallah, 1991;Zapata, Jaramillo-González & Navas-Camacho, 2011;Kemp et al, 2016;Pontasch et al, 2017;Tuckett & Wernberg, 2018), the responses of two species were compared in this study. Acroporid corals are the most abundant scleractinian genera in Eilat with Stylophora sp.…”