Two offshore coral species show greater acclimatization capacity to environmental variation than nearshore counterparts in southern Belize

Abstract

Coral reefs are enduring decline due to the intensifying impacts of anthropogenic global change. This widespread decline has resulted in increased efforts to identify resilient coral populations and develop novel restoration strategies. Paramount in these efforts is the need to understand how environmental variation and thermal history affect coral physiology and resilience. Here, we assess the acclimatization capacity of Siderastrea siderea and Pseudodiploria strigosa corals via a 17-month reciprocal transplant experiment between nearshore and offshore reefs on the Belize Mesoamerican Barrier Reef System. These nearshore reefs are more turbid, eutrophic, warm, and thermally variable than offshore reefs. All corals exhibited some evidence of acclimatization after transplantation. Corals transplanted from nearshore to offshore calcified slower than in their native habitat, especially S. siderea corals which exhibited 60% mortality and little to no net growth over the duration of the 17-month study. Corals transplanted from offshore to nearshore calcified faster than in their native habitat with 96% survival. Higher host tissue d 15 N in nearshore corals indicated that increased heterotrophic opportunity or nitrogen sources between nearshore and offshore reefs likely promoted elevated calcification rates nearshore and may facilitate adaptation in nearshore populations to such conditions over time. These results demonstrate that offshore populations of S. siderea and P. strigosa possess the acclimatization capacity to survive in warmer and more turbid nearshore conditions, but that local adaptation to native nearshore conditions may hinder the plasticity of nearshore populations, thereby limiting their utility in coral restoration activities outside of their native habitat in the short term.

Environmental stability and phenotypic plasticity benefit the cold-water coral Desmophyllum dianthus in an acidified fjord

“…Population genetic data support the lack of local adaptation with gene flow along both the horizontal and vertical axes of the fjord 49 . Similar results of local acclimatisation have been shown for calcification rates of the gorgonian coral Antillogorgia bipinnata 88 and several tropical coral species 89 , 90 after reciprocal transplantation. The morphological change of the native and novel deep corals on the pulley in the water column is also a sign of acclimatisation to the environmental conditions in deep waters.…”

Global change differentially modulates Caribbean coral physiology

“…Varying levels of plasticity in P. strigosa and P. astreoides from different habitats has been previously reported [47,88]; however, natal reef effects were not evident in either species in this study (Fig 3B and 3C). The small sample size of P. strigosa likely contributed to the lack of differences between habitats, while different measures of plasticity-physiological plasticity (present study) vs. gene expression plasticity [88]-may contribute to the inconsistent responses observed in P. astreoides.…”

“…affects responses to global change. Specifically, the inshore site is known to be more environmentally variable (i.e., diel and seasonal variability) than the offshore location (S1 Fig), potentially diving local adaptation and/or long-term acclimatisation in these species [46][47][48]. This study further investigates the physiological responses of corals assessed in Bove et al [17] and detailed descriptions of experimental setup can be found there.…”

“…This higher plasticity likely comes at a fitness trade-off in corals that are experiencing sub-optimum conditions [42,87]. Indeed, a reciprocal transplant experiment in southern Belize identified higher plasticity of offshore colonies of S. siderea compared to those from a nearshore environment [47]. The offshore colonies grew at a much higher rate when transplanted to the nearshore environment than in their natal environment (generally considered more ideal conditions) [47], suggesting that plasticity in these corals may indeed come at the cost of growth in home or more ideal conditions [42].…”

Endosymbiont strategic shifts inhibit cooperation during coral bleaching recovery

“…Protein concentration in the host fraction was measured on a spectrophotometer (BioTek ELx808, Agilent) using the Bradford method. Total host lipids were measured colorimetrically on a spectrophotometer (BioTek PowerWave XS2, Agilent) as described [51]. Surface area was determined by the single wax dipping method [52].…”