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Article: Effects of Eutrophication, Seasonality and Macrofouling on the Diversity of Bacterial Biofilms in Equatorial Coral Reefs

Sawall, Yvonne

PLOS ONE, 7(7):e39951

2012

Abstract: Biofilms play an important role as a settlement cue for invertebrate larvae and significantly contribute to the nutrient turnover in aquatic ecosystems. Nevertheless, little is known about how biofilm community structure generally responds to ... ...

Institution	Leibniz-Zentrum für Marine Tropenforschung
Abstract	Biofilms play an important role as a settlement cue for invertebrate larvae and significantly contribute to the nutrient turnover in aquatic ecosystems. Nevertheless, little is known about how biofilm community structure generally responds to environmental changes. This study aimed to identify patterns of bacterial dynamics in coral reef biofilms in response to associated macrofouling community structure, microhabitat (exposed vs. sheltered), seasonality, and eutrophication. Settlement tiles were deployed at four reefs along a cross-shelf eutrophication gradient and were exchanged every 4 months over 20 months. The fouling community composition on the tiles was recorded and the bacterial community structure was assessed with the community fingerprinting technique Automated Ribosomal Intergenic Spacer Analysis (ARISA). Bacterial operational taxonomic unit (OTU) number was higher on exposed tiles, where the fouling community was homogenous and algae-dominated, than in sheltered habitats, which were occupied by a variety of filter feeders. Furthermore, OTU number was also highest in eutrophied near-shore reefs, while seasonal variations in community structure were most pronounced in the oligotrophic mid-shelf reef. In contrast, the macrofouling community structure did not change significantly with seasons. Changes in bacterial community patterns were mostly affected by microhabitat, seasonal and anthropogenically derived changes in nutrient availability, and to a lesser extent by changes in the macrofouling community structure. Path analysis revealed a complex interplay of various environmental and biological factors explaining the spatial and temporal variations in bacterial biofilm communities under natural conditions.
Keywords	Community ecology ; Community structure ; Coral reefs ; Algae ; Bacteria ; Bacterial biofilms ; Biodiversity ; Seasonal variations
Language	English
Document type	Article
Database	Repository for Life Sciences

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Article: Extensive phenotypic plasticity of a Red Sea coral over a strong latitudinal temperature gradient suggests limited acclimatization potential to warming

Sawall, Yvonne / Hohn, Sönke

Scientific reports, 5: 8940

2015

Abstract: Global warming was reported to cause growth reductions in tropical shallow water corals in both, cooler and warmer, regions of the coral species range. This suggests regional adaptation with less heat-tolerant populations in cooler and more thermo- ... ...

Institution	Leibniz-Zentrum für Marine Tropenforschung
Abstract	Global warming was reported to cause growth reductions in tropical shallow water corals in both, cooler and warmer, regions of the coral species range. This suggests regional adaptation with less heat-tolerant populations in cooler and more thermo-tolerant populations in warmer regions. Here, we investigated seasonal changes in the in situ metabolic performance of the widely distributed hermatypic coral Pocillopora verrucosa along 12° latitudes featuring a steep temperature gradient between the northern (28.5°N, 21–27°C) and southern (16.5°N, 28–33°C) reaches of the Red Sea. Surprisingly, we found little indication for regional adaptation, but strong indications for high phenotypic plasticity: Calcification rates in two seasons (winter, summer) were found to be highest at 28–29°C throughout all populations independent of their geographic location. Mucus release increased with temperature and nutrient supply, both being highest in the south. Genetic characterization of the coral host revealed low inter-regional variation and differences in the Symbiodinium clade composition only at the most northern and most southern region. This suggests variable acclimatization potential to ocean warming of coral populations across the Red Sea: high acclimatization potential in northern populations, but limited ability to cope with ocean warming in southern populations already existing at the upper thermal margin for corals.
Language	English
Document type	Article
Database	Repository for Life Sciences

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Article ; Online: Physiological responses and adjustments of corals to strong seasonal temperature variations (20-28°C).

Sawall, Yvonne / Nicosia, Anna M / McLaughlin, Kathryn / Ito, Maysa

The Journal of experimental biology

2022 Volume 225, Issue 13

Abstract: Temperature is a key driver of metabolic rates. So far, we know little about potential physiological adjustments of subtropical corals to seasonal temperature changes (>8°C) that substantially exceed temperature fluctuation experienced by their ... ...

Abstract	Temperature is a key driver of metabolic rates. So far, we know little about potential physiological adjustments of subtropical corals to seasonal temperature changes (>8°C) that substantially exceed temperature fluctuation experienced by their counterparts in the tropics. This study investigated the effect of temperature reductions on Montastraea cavernosa and Porites astreoides in Bermuda (32°N; sea surface temperature ∼19-29°C) over 5 weeks, applying the following treatments: (i) constant control temperature at 28°C, and (ii) temperature reduction (0.5°C day-1) followed by constant temperature (20 days; acclimatization period) at 24°C and (iii) at 20°C. Both species decreased photosynthesis and respiration during temperature reduction as expected, which continued to decrease during the acclimatization period, indicating adjustment to a low energy turnover rather than thermal compensation. Trajectories of physiological adjustments and level of thermal compensation, however, differed between species. Montastraea cavernosa zooxanthellae metrics showed a strong initial response to temperature reduction, followed by a return to close to control values during the acclimatization period, reflecting a high physiological flexibility and low thermal compensation. Porites astreoides zooxanthellae, in contrast, showed no initial response, but an increase in pigment concentration per zooxanthellae and similar photosynthesis rates at 24°C and 20°C at the end of the experiment, indicating low acute thermal sensitivity and the ability for thermal compensation at the lowest temperature. Respiration decreased more strongly than photosynthesis, leading to significant build-up of biomass in both species (energy reserves). Results are important in the light of potential poleward migration of corals and of potential latitudinal and species-specific differences in coral thermal tolerance.
MeSH term(s)	Acclimatization/physiology ; Animals ; Anthozoa/physiology ; Coral Reefs ; Hot Temperature ; Seasons ; Symbiosis/physiology ; Temperature
Language	English
Publishing date	2022-07-08
Publishing country	England
Document type	Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
ZDB-ID	218085-6
ISSN	1477-9145 ; 0022-0949
ISSN (online)	1477-9145
ISSN	0022-0949
DOI	10.1242/jeb.244196
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Diel versus time-integrated (daily) photosynthesis and irradiance relationships of coral reef organisms and communities.

Sawall, Yvonne / Hochberg, Eric J

PloS one

2018 Volume 13, Issue 12, Page(s) e0208607

Abstract: The most important source of energy to tropical shallow water coral reefs is light, the transformation of which ultimately limits reef biomass and growth. Therefore, measurements of productivity (primary production, P) for benthic reef organisms and ... ...

Abstract	The most important source of energy to tropical shallow water coral reefs is light, the transformation of which ultimately limits reef biomass and growth. Therefore, measurements of productivity (primary production, P) for benthic reef organisms and communities are critical to understand reef functioning. Short-term (minutes to hours) P measurements of reef photosynthesizers virtually always produce the classic hyperbolic tangent (or similar) P-E (irradiance) relationship, with P rapidly rising to a saturation point as E increases. Longer-term (days to weeks), larger-scale investigations of natural reef communities typically do not explore P-E relationships, but the few that do show no saturation of time-integrated P with high time-integrated E. In this paper we present a modeling study to reconcile this apparent contradiction. We used 52 published short-term (instantaneous) P-E curves of organisms (corals, algae) and communities (corals, mixed corals and algae) from different reefs in the Indo-Pacific and the Caribbean, each coupled with 928 diel light curves comprising a wide range of cloud cover scenarios. The diel light curves provided instantaneous E at 1-minute intervals, from which we calculated corresponding instantaneous P using the different published P-E relationships. We integrated both variables to calculate time-integrated E and P. Time-integrated E varied up to 18-fold due to changes in cloud cover and season. We found that, despite routine saturation of instantaneous P, day-scale P-E relationships were near linear in all cases, with slightly decreased linearity in cases where instantaneous light saturation occurred very early during the day. This indicates that the Functional Convergence Hypothesis (FCH) developed by terrestrial ecologists may also apply for reef photosynthesizers. The FCH states that despite short-term light saturation, plants on average do not absorb more light than they can use, since resource allocations are strictly coordinated and tailored towards an optimal use. Thus, there is no contradiction: At the growth time scale (≥ day), P should be expected to be a near linear function of E. One implication is that reef P can be estimated using rapid optical measurements, as opposed to traditional, laborious respirometry methods. The requirement going forward is to derive appropriate values for light-use efficiency, which is the rate at which the plant or community converts absorbed light into fixed carbon.
MeSH term(s)	Animals ; Anthozoa/growth & development ; Anthozoa/metabolism ; Biomass ; Coral Reefs ; Cyanobacteria/growth & development ; Cyanobacteria/metabolism ; Light ; Models, Biological ; Photosynthesis
Language	English
Publishing date	2018-12-17
Publishing country	United States
Document type	Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
ISSN	1932-6203
ISSN (online)	1932-6203
DOI	10.1371/journal.pone.0208607
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article ; Online: Chronically elevated sea surface temperatures revealed high susceptibility of the eelgrass Zostera marina to winter and spring warming

Sawall, Yvonne / Ito, Maysa / Pansch, Christian

2021

Abstract: While it is well known that severe marine summer heatwaves can cause acute and dramatic die-offs of seagrass meadows, the effect of trans-seasonal warming and winter/spring heatwaves are yet poorly understood. This study simulated a 9-months warming ... ...

Abstract	While it is well known that severe marine summer heatwaves can cause acute and dramatic die-offs of seagrass meadows, the effect of trans-seasonal warming and winter/spring heatwaves are yet poorly understood. This study simulated a 9-months warming scenario on the common seagrass Zostera marina from winter into summer, using outdoor mesocosms, which provided near-natural conditions. The relevance of the natural temperature pattern, as well as the 3.6°C warming, and their implications were further discussed in the context of a 22-yr temperature time series of the study region. Survival of plants was high in winter independent of temperature. In spring, however, heat-treated Z. marina flowered 1.5 months earlier and experienced high mortalities. Thereafter, plant survival, growth, and pigmentation were largely comparable between temperature regimes. Yet, a comparatively high mortality occurred in ambient plants, after an abnormally warm June. Final biomass was reduced by ~ 50% in heat-treated plants. These results imply that warm winter-to-spring conditions can have severe effects on vital seagrass traits. Warming accelerates consumption of energy reserves triggering advanced flowering, similar to many terrestrial plants. Although, surviving heat-treated plants were not able to re-stock energy reserves throughout the high-light summer as inferred from low plant biomass, these seemed rather resistant to summer heatwave events.
Subject code	580
Language	English
Publisher	Wiley
Publishing country	de
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Physiological responses and adjustments of corals to strong seasonal temperature variations (20–28°C)

Sawall, Yvonne / Nicosia, Anna M. / McLaughlin, Kathryn / Ito, Maysa

2022

Abstract	Temperature is a key driver of metabolic rates. So far, we know little about potential physiological adjustments of subtropical corals to seasonal temperature changes (>8°C) that substantially exceed temperature fluctuation experienced by their counterparts in the tropics. This study investigated the effect of temperature reductions on Montastraea cavernosa and Porites astreoides in Bermuda (32°N; sea surface temperature ∼19–29°C) over 5 weeks, applying the following treatments: (i) constant control temperature at 28°C, and (ii) temperature reduction (0.5°C day−1) followed by constant temperature (20 days; acclimatization period) at 24°C and (iii) at 20°C. Both species decreased photosynthesis and respiration during temperature reduction as expected, which continued to decrease during the acclimatization period, indicating adjustment to a low energy turnover rather than thermal compensation. Trajectories of physiological adjustments and level of thermal compensation, however, differed between species. Montastraea cavernosa zooxanthellae metrics showed a strong initial response to temperature reduction, followed by a return to close to control values during the acclimatization period, reflecting a high physiological flexibility and low thermal compensation. Porites astreoides zooxanthellae, in contrast, showed no initial response, but an increase in pigment concentration per zooxanthellae and similar photosynthesis rates at 24°C and 20°C at the end of the experiment, indicating low acute thermal sensitivity and the ability for thermal compensation at the lowest temperature. Respiration decreased more strongly than photosynthesis, leading to significant build-up of biomass in both species (energy reserves). Results are important in the light of potential poleward migration of corals and of potential latitudinal and species-specific differences in coral thermal tolerance.
Subject code	541
Language	English
Publishing date	2022-07-08
Publisher	The Company of Biologists
Publishing country	de
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Disparate population and holobiont structure of pocilloporid corals across the Red Sea gradient demonstrate species‐specific evolutionary trajectories

Buitrago‐López, Carol / Cárdenas, Anny / Hume, Benjamin C. C. / Gosselin, Thierry / Staubach, Fabian / Aranda, Manuel / Barshis, Daniel J. / Sawall, Yvonne / Voolstra, Christian R.

Molecular Ecology. 2023 May, v. 32, no. 9 p.2151-2173

2023

Abstract: Global habitat degradation heightens the need to better understand patterns of genetic connectivity and diversity of marine biota across geographical ranges to guide conservation efforts. Corals across the Red Sea are subject to pronounced environmental ... ...

Abstract	Global habitat degradation heightens the need to better understand patterns of genetic connectivity and diversity of marine biota across geographical ranges to guide conservation efforts. Corals across the Red Sea are subject to pronounced environmental differences, but studies so far suggest that animal populations are largely connected, excepting evidence for a genetic break between the northern‐central and southern regions. Here, we investigated population structure and holobiont assemblage of two common pocilloporid corals, Pocillopora verrucosa and Stylophora pistillata, across the Red Sea. We found little evidence for population differentiation in P. verrucosa, except for the southernmost site. Conversely, S. pistillata exhibited a complex population structure with evidence for within‐reef and regional genetic differentiation, in line with differences in their reproductive mode (P. verrucosa is a broadcast spawner and S. pistillata is a brooder). Analysis for genomic loci under positive selection identified 85 sites (18 of which were in coding sequences) that distinguished the southern P. verrucosa population from the remainder of the Red Sea population. By comparison, we found 128 loci (24 of which were residing in coding sequences) in S. pistillata with evidence for local adaptation at various sites. Functional annotation of the underlying proteins revealed putative roles in the response to stress, lipid metabolism, transport, cytoskeletal rearrangement, and ciliary function (among others). Microbial assemblages of both coral species showed pervasive association with microalgal symbionts from the genus Symbiodinium (former clade A) and bacteria from the genus Endozoicomonas that exhibited significant differences according to host genotype and environment. The disparity of population genetic and holobiont assemblage patterns even between closely related species (family Pocilloporidae) highlights the need for multispecies investigations to better understand the role of the environment in shaping evolutionary trajectories. It further emphasizes the importance of networks of reef reserves to achieve conservation of genetic variants critical to the future survival of coral ecosystems.
Keywords	Symbiodinium ; corals ; cytoskeleton ; genetic variation ; genomics ; genotype ; habitat destruction ; lipid metabolism ; microalgae ; population genetics ; population structure ; stress response ; symbionts ; Red Sea
Language	English
Dates of publication	2023-05
Size	p. 2151-2173.
Publishing place	John Wiley & Sons, Ltd
Document type	Article ; Online
Note	JOURNAL ARTICLE
ZDB-ID	1126687-9
ISSN	1365-294X ; 0962-1083
ISSN (online)	1365-294X
ISSN	0962-1083
DOI	10.1111/mec.16871
Database	NAL-Catalogue (AGRICOLA)

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Book ; Online ; Thesis: Coral resistance to natural and anthropogenic disturbances

Sawall, Yvonne

2011

Abstract: Coral resistance, recruitment, metabolism, eutrophication, physical destruction, acclimatization, biofilm. - The effects of natural (upwelling, tsunami) and human induced (eutrophication, overfishing, bomb fishing) disturbances to corals were ... ...

Author's details	by Yvonne Sawall
Abstract	Coral resistance, recruitment, metabolism, eutrophication, physical destruction, acclimatization, biofilm. - The effects of natural (upwelling, tsunami) and human induced (eutrophication, overfishing, bomb fishing) disturbances to corals were investigated in highly diverse reefs of SE Asia. Firstly, coral recruitment patterns and their contribution to reef recovery and secondly, the corals metabolic flexibility in various environments were investigated. In addition, the bacterial community structure in biofilms was assessed in relation to environmental changes. In summary, the investigated coral reefs seem to be very dynamic visible in recruitment patterns and bacterial community structure being highly responsive to seasonal changes and being able to support reef recovery in most cases. The widely distributed coral species P. lutea and S. subseriata feature a highly flexible metabolism allowing their distribution even to environmental extremes. However, these corals belong to the minority as indicated by the loss of coral diversity in strongly polluted reefs, but it also shows a high interspecific variability, which provides high diversity reefs with a certain buffer capacity to environmental changes.
Language	English
Size	Online-Ressource (PDF-Datei: 130 S., 8,6 MB)
Publisher	Staats- und Universitaetsbibliothek Host
Publishing place	Bremen
Document type	Book ; Online ; Thesis
Thesis / German Habilitation thesis	Univ., Diss.--Bremen, 2011
Database	Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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Conference proceedings ; Online: Der Seestern - ein wunderschöner und wichtiger Räuber im Meer

Sawall, Yvonne

2011

Publishing country	de
Document type	Conference proceedings ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article: Computational Characterization of the mtORF of Pocilloporid Corals: Insights into Protein Structure and Function in

Banguera-Hinestroza, Eulalia / Ferrada, Evandro / Sawall, Yvonne / Flot, Jean-François

Genes

2019 Volume 10, Issue 5

Abstract: More than a decade ago, a new mitochondrial Open Reading Frame (mtORF) was discovered in corals of the family Pocilloporidae and has been used since then as an effective barcode for these corals. Recently, mtORF sequencing revealed the existence of two ... ...

Abstract	More than a decade ago, a new mitochondrial Open Reading Frame (mtORF) was discovered in corals of the family Pocilloporidae and has been used since then as an effective barcode for these corals. Recently, mtORF sequencing revealed the existence of two differentiated
MeSH term(s)	Animals ; Anthozoa/genetics ; Computational Biology ; DNA, Mitochondrial/genetics ; Ecosystem ; Indian Ocean ; Mitochondria/genetics ; Open Reading Frames/genetics ; Phylogeny ; Phylogeography ; Protein Conformation ; Tandem Repeat Sequences/genetics
Chemical Substances	DNA, Mitochondrial
Language	English
Publishing date	2019-04-27
Publishing country	Switzerland
Document type	Journal Article ; Research Support, Non-U.S. Gov't
ZDB-ID	2527218-4
ISSN	2073-4425
ISSN	2073-4425
DOI	10.3390/genes10050324
Database	MEDical Literature Analysis and Retrieval System OnLINE

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