International Journal of Marine Science, 2016, Vol.6, No.21, 1-20
1
Research Article Open Access
Decoupled seasonal stress as an indication of chronic stress and site dependent
responses in
Montastraea cavernosa
and
Porites astreoides
inhabiting the Florida
Reef Tract
Joshua A Haslund
1
, Briana Hauff
1
, Kevin B. Strychar
2
, James M. Cervino
3
1 Department of Zoology, Michigan State University, East Lansing, Michigan, United States of America
2 Annis Water Resources Institute, Grand Valley State University, Muskegon, Michigan, United States of America
3 Woods Hole Oceanographic Institution, Woods Hole, Maine, United States of America
Corresponding email
International Journal of Marine Science 2016, Vol.6, No.21 doi
Received: 21 Jan., 2016
Accepted: 25 May, 2016
Published: 25 May, 2016
Copyright
© 2016 This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use,
distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article
:
Haslund J.A., Hauff B., Strychar K.B., and Cervino J.M., 2016, Decoupled seasonal stress as an indication of chronic stress and site dependent responses in
Montastraea caverno
sa and
Porites astreoides
inhabiting the Florida Reef Tract, International Journal of Marine Science, 6(21): 1-20
(do
Abstract
Although mass mortality from disease and climate anomalies are largely to blame for rapid losses in coral cover along the
Florida reef tract, the failure of extant populations to recolonize the offshore zone is puzzling given improvements to water quality
and narrower range in seawater temperature compared to the inshore patch reef zone. Using existing data from the Coral Reef
Environmental Monitoring Program (CREMP) and from an inshore and offshore site established to compliment this dataset we
identified significantly increased abundance and diversity of scleractinian coral from inshore to offshore across the Florida reef tract.
Applying exploratory statistical methods we identified two abundant species,
Montastraea cavernosa and Porites astreoides
,
inhabiting both zones to varying degrees. Following reciprocal transplantation of conspecifics between a representative offshore and
inshore reef (6 m depth), we monitored monthly coral colony brightness (a measurement related to endosymbiotic dinoflagellate
density) over a two-year period to examine symbiont loss, a common stress response in scleractinian corals. Although
species-specific stress patterns were not identified, zone-specific variation was evident. Trigonometric regression of stress level by
month revealed a significant relationship supporting an annual stress and recovery period at the inshore patch reef zone. Contrary to
this result, conspecifics transplanted to the offshore zone did not display recovery resulting in a continued chronically bleached state
over the two-year period. Our results implicate alleviation or decreased stress at inshore sites and the importance of extending greater
protection to reefs within this zone.
Keywords
Acclimation; Coral; Florida Keys; Patch Reef; Symbiodinium
Introduction
The Florida reef tract has experienced dramatic decreases in coral cover (Aronson and Precht, 2001), shifts in reef
communities (Pandolfi et al., 2005; Ruzicka et al., 2013), and decreases in reef architectural complexity
(Alvarerz-Filip et al., 2009), which have all resulted in decreased biodiversity. This trend is most apparent along
the 15 offshore reef preservation areas of the Florida Keys National Marine Sanctuary (FKNMS). Located
between 1 and 8 m depths and 5 to 7 km offshore, these once highly productive reef crest and fore reef ecosystems
no longer support accreting scleractinian coral communities and can be considered relict in comparison to
historical baselines (Palandro et al., 2008). This imperiled status of the offshore reef zone is not a result of a single
stressor. Diseases and macro-algal overgrowth arising from human interaction, decreased coral resilience
following destructive hurricanes and anomalous hypothermic (Hudson et al., 1976; Walker et al., 1982; Shinn et
al., 2003) and hyperthermic seawater temperature events have all greatly affected this region. Presently, conditions
are such at offshore reefs that corals should display net accretion, however reef building coral populations remain
at low abundances. Observing transects extending from inshore to offshore, coral abundance decreases to the
offshore bank reef zone (Roberts et al., 1982; Lirman and Fong, 2007; Schutte et al., 2010) with approximately
two-times lower abundance at offshore reefs. In contrast, sustained growth has been observed throughout the
inshore patch reef system despite far fewer protected areas in contrast to offshore reefs, increased frequency of
