Coral Reef Ecosystems

Danian cool-water coral reefs in southern Scandinavia localised over seafloor highs

by Nicolas Thibault

Morten Bjerager, Finn Surlyk, Holger Lykke-Andersen, Nicolas Thibault, Lars Stemmerik, "published in 'Marine and Petroleum Geology', 2010, v. 27, p. 455-466"

Danian (Paleocene) reefs formed by ahermatypic scleractinian corals in relatively deep water are known in a few... more Danian (Paleocene) reefs formed by ahermatypic scleractinian corals in relatively deep water are known in a few localities in southern Scandinavia. Reflection and shallow seismic profiles, and samples from drilling and scuba diving in bridge pier excavations in Øresund, the strait between Denmark and Sweden, for the first time allow interpretation of the factors that controlled the localisation of the reefs. After the mass-extinction at the K/T boundary, reef-building scleractinian corals were absent in the Boreal early Danian in the Danish basin. Faunal evolution after the biotic crisis and a rise in relative sea level are interpreted to have favoured formation of deep-water coral reefs in the Øresund region in mid-Danian time. The reefs were 6–20 m high and 20–200 m long on the seafloor and have a patchy distribution within a bryozoan mound-dominated setting in an area of about 10 km2. They are composed of the framework-building ahermatypic scleractinian coral Dendrophyllia candelabrum with minor occurrences of bryozoans, echinoderms, gastropods and bivalves. It has been suspected that the reefs were located over contemporaneous seafloor highs but this notion was only based on comparison with similar modern deep-water reefs offshore Norway. The data from Øresund indicate that the Danian reef complex was formed over a late Maastrichtian palaeo-seafloor high, the Saltholm-Malmø High, supporting this interpretation and thus adding fundamentally to the understanding of the factors controlling the formation and localisation of these deep and cool-water coral reefs. Individual reefs were initiated and grew on eroded crests and steep south-dipping flanks of bryozoan mounds and were predominantly situated on the southern part of the high and are interpreted as growing towards NW-flowing bottom currents rich in particulate nutrients.

Reef response to sea-level and environmental changes during the last deglaciation: Integrated Ocean Drilling Program Expedition 310, Tahiti Sea Level

by Elizabeth Abbey

Camoin G, Seard C, Deschamps P, Webster J, Abbey E, Braga JC, Iryu Y, Durand N, Bard E, Hamelin B, Yokoyama Y, Thomas A, Hendersone G, Dussouillez P. Geology. DOI: 10.1130/G32057

Ciliate and bacterial communities associated with White Syndrome and Brown Band Disease in reef building corals.

by Michael Sweet

White Syndrome (WS) and Brown Band Disease (BrB) are important causes of reef coral mortality for which causal agents... more White Syndrome (WS) and Brown Band Disease (BrB) are important causes of reef coral mortality for which causal agents have not been definitively identified. Here we use culture-independent molecular techniques (DGGE and clone libraries) to characterise ciliate and bacterial communities in these diseases. Bacterial (16S rRNA gene) and ciliate (18S rRNA gene) communities were highly similar between the two diseases. Four bacterial and nine ciliate ribotypes were observed in both diseases, but absent in non diseased specimens. Only one of the bacteria, Arcobacter sp. (JF831360) increased substantially in relative 16S rRNA gene abundance and was consistently represented in all diseased samples. Four of the eleven ciliate morphotypes detected contained coral algal symbionts, indicative of the ingestion of coral tissues. In both WS and BrB, there were two ciliate morphotypes consistently represented in all disease lesion samples. Morph1 (JN626268) was observed to burrow into and underneath the coral tissues at the lesion boundary. Morph2 (JN626269), previously identified in BrB, appears to play a secondary, less invasive role in pathogenesis, but has a higher population density in BrB, giving rise to the visible brown band. The strong similarity in bacterial and ciliate community composition of these diseases suggests that they are actually the same syndrome.

Kimirei, IA 2012 Importance of mangroves and seagrass beds as nurseries for coral reef fishes in Tanzania. PhD Thesis, Radboud Universiteit Nijmegen, 204 p

by Ismael Kimirei

Spatial Analyses of Benthic Habitats to Define Coral Reef Ecosystem Regions and Potential Biogeographic Boundaries along a Latitudinal Gradient

by Brian Walker

Marine organism diversity typically attenuates latitudinally from tropical to colder climate regimes. Since the... more Marine organism diversity typically attenuates latitudinally from tropical to colder climate regimes. Since the distribution of many marine species relates to certain habitats and depth regimes, mapping data provide valuable information in the absence of detailed ecological data that can be used to identify and spatially quantify smaller scale (10 s km) coral reef ecosystem regions and potential physical biogeographic barriers. This study focused on the southeast Florida coast due to a recognized, but understudied, tropical to subtropical biogeographic gradient. GIS spatial analyses were conducted on recent, accurate, shallow-water (0–30 m) benthic habitat maps to identify and quantify specific regions along the coast that were statistically distinct in the number and amount of major benthic habitat types. Habitat type and width were measured for 209 evenly-spaced cross-shelf transects. Evaluation of groupings from a cluster analysis at 75% similarity yielded five distinct regions. The number of benthic habitats and their area, width, distance from shore, distance from each other, and LIDAR depths were calculated in GIS and examined to determine regional statistical differences. The number of benthic habitats decreased with increasing latitude from 9 in the south to 4 in the north and many of the habitat metrics statistically differed between regions. Three potential biogeographic barriers were found at the Boca, Hillsboro, and Biscayne boundaries, where specific shallow-water habitats were absent further north; Middle Reef, Inner Reef, and oceanic seagrass beds respectively. The Bahamas Fault Zone boundary was also noted where changes in coastal morphologies occurred that could relate to subtle ecological changes. The analyses defined regions on a smaller scale more appropriate to regional management decisions, hence strengthening marine conservation planning with an objective, scientific foundation for decision making. They provide a framework for similar regional analyses elsewhere.

eReefs - A New Perspective on the Great Barrier Reef

by Klaus Joehnk

Chen, Y., Minchin, S., Seaton, S., Jöhnk, K.D., Robson, B., Qifeng, B., 2011. eReefs – Towards a New Perspective on a Sustainable Future of the Great Barrier Reef. In: Chan, F., Marinova, D. and Anderssen, R.S. (eds) MODSIM2011, 19th International Congress on Modelling and Simulation. Modelling and Simulation Society of Australia and New Zealand, December 2011. ISBN: 978-0-9872143-1-7, pp. 1195-1201.

High street cleaners

by Magnus Johnson

Published online 1/2/2012

A light-hearted look at the ecology of the bluestreak cleaner fish (Labroides dimidiatus) and the parasitic mimic... more A light-hearted look at the ecology of the bluestreak cleaner fish (Labroides dimidiatus) and the parasitic mimic (Plagiotremus rhinorhynchos).

Twenty-five years of change in scleractinian coral communities of Daya Bay (northern South China Sea) and its response to the 2008 AD extreme cold climate event

by Gilbert Price

Chen, T., Yu, K., Shi, Q., Li, S., Price, G., Wang, R., Zhao, M., Chen, T., Zhao, J., 2009. Twenty-five years of change in scleractinian coral communities of Daya Bay (northern South China Sea) and its response to the 2008 AD extreme cold climate event. Chinese Science Bulletin 54, 2107-2117.

Coral reefs worldwide are becoming increasingly and detrimentally impacted upon by a variety of factors including... more Coral reefs worldwide are becoming increasingly and detrimentally impacted upon by a variety of factors including significant climate changes, such as global warming and increased El Nino-Southern Oscillation activity. Generally, the persistence of coral reefs, especially at low-latitudes, is governed, in part, by sea surface temperatures not exceeding the critical limit (∼30°C) at which mass mortality can occur. Thus, it is thought that corals living at high-latitudes (i.e., currently cooler sea surface temperatures) will likely respond more favourably to hypothesized future temperature increases than corals living at low-latitudes (i.e., currently warmer sea surface temperatures). Consequently, high-latitude coral communities may have the potential to act as regions of refugia for many coral species in the face of potential future global warming. The Daya Bay (22°31′–22°50′N), northern South China Sea, contains several high-latitude non-reefal coral communities and represents one of the most northerly distributions of scleractinian corals within the region. Significantly, Daya Bay has experienced dramatic warming in both air and sea surface temperatures throughout the past 50 years. In this paper, we analyze 25 years of change in the Daya Bay coral communities, based both on historic surveys and our latest 2006–2008 regional ecological surveys. Our results suggest that, contrary to predictions, there have been significant declines in coral cover within the Daya Bay during the past 25 years (i.e., 76.6% coral cover in 1983/1984 to only 15.3% coral cover by 2008). Such changes also reflect a significant shift in the most abundant coral species, from Acropora pruinosa to Favites abdita. Most of the modern coral communities became established between 15 and 30 years ago, corresponding to a period of increased winter sea surface temperature. However, very few colonies have become established within the last 15 years, despite a more intense period of warming. By taking into account additional factors, we hypothesize that direct anthropogenic impacts, rather than climatic events, have both restricted the development, and drove the decline, of Daya Bay coral communities in the last 15 years. The Daya Bay has also been subjected to occasional extreme cold events during the past 50 years, with the most recent occurring in early 2008 (13 January–13 February). During the 2008 cold event, the lowest air temperature reaches only 6.6°C, and the mean sea surface temperature for February fall to < 14°C, including six continuous days at 12.3°C. Significantly, the sea surface temperatures fall below the hypothesized critical lower temperature threshold (∼13°C) that commonly leads to mass mortality in scleractinian coral communities. Surprisingly, our coral community surveys, conducted both before (August 2007) and after (late February 2008) the extreme 2008 cold event, demonstrate that the Daya Bay coral ecosystems are barely impacted upon during the cold period. Those observations suggest that the Daya Bay scleractinian coral communities have developed adaptations to low sea surface temperatures. Overall, our data support the hypothesis that high-latitude coral communities, such as Daya Bay, have the potential to act as areas of refugia for scleractinian corals in the advent of potential future global warming.

Heavy metal pollution recorded in Porites corals from Daya Bay, northern South China Sea

by Gilbert Price

Chen, T.-R., Yu, K.-F., Li, S., Price, G.J., Shi, Q., Wei, G.-J., 2010. Heavy metal pollution recorded in Porites corals from Daya Bay, northern South China Sea. Marine Environmental Research 70, 318-326.

We examined metal-to-calcium ratios (Fe/Ca, Mn/Ca and Zn/Ca) in the growth bands of two Porites corals from Daya Bay,... more We examined metal-to-calcium ratios (Fe/Ca, Mn/Ca and Zn/Ca) in the growth bands of two Porites corals from Daya Bay, South China Sea, in order to trace long-term trends in local ambient pollution levels. Although Fe and Mn did not show any obvious increasing trends over 32 years in the period 1976–2007, peak values of Fe/Ca and Mn/Ca occurred in the mid-late 1980s, temporally-coeval with the local construction of a nuclear power station. Furthermore, both corals showed rapid increases in Zn concentrations over the past 14 years (1994–2007), most likely due to increases in domestic and industrial sewage discharge. The Daya Bay corals had higher concentrations of metals than other reported corals from both pristine and seriously polluted locations, suggesting that acute (Fe and Mn) and chronic (Zn) heavy metal contamination has occurred locally over the past 32 years.

Was enhanced riverine input responsible for the demise of Central Adriatic cold water reefs in historical times?

by Alessandro Ceregato

A review of community ecology of mesophotic coral ecosystems

by Rob Toonen

Co-authored with SE Kahng, H Spalding, R Garcia, E Brokovich, D Wagner, E Weil, & L Hinderstein

Microbial diversity associated with four functional groups of benthic reef algae and the reef‐building coral Montastraea annularis

by Kristen Marhaver

Controls on Coral-Ground Development along the Northern Mesoamerican Reef Tract

by Paul Blanchon

Rodrıguez-Martınez RE, Jordan-Garza AG, Maldonado MA, Blanchon P (2011) Controls on Coral-Ground Development along the Northern Mesoamerican Reef Tract. PLoS ONE 6(12): e28461. doi:10.1371/journal.pone.0028461

Coral-grounds are reef communities that colonize rocky substratum but do not form framework or three-dimensional reef... more Coral-grounds are reef communities that colonize rocky substratum but do not form framework or three-dimensional reef structures. To investigate why, we used video transects and underwater photography to determine the composition, structure and status of a coral-ground community located on the edge of a rocky terrace in front of a tourist park, Xcaret, in the northern Mesoamerican Reef tract, Mexico. The community has a relatively low coral, gorgonian and sponge cover (10%) and high algal cover (40%). We recorded 23 species of Scleractinia, 14 species of Gorgonacea and 30 species of Porifera. The coral community is diverse but lacks large coral colonies, being dominated instead by small, sediment-tolerant, and brooding species. In these small colonies, the abundance of potentially lethal interactions and partial mortality is high but decreases when colonies are larger than 40 cm. Such characteristics are consistent with an environment control whereby storm waves periodically remove larger colonies and elevate sediment flux. The community only survives these storm conditions due to its slope-break location, which ensures lack of burial and continued local recruitment. A comparison with similar coral-ground communities in adjacent areas suggests that the narrow width of the rock terrace hinders sediment stabilization, thereby ensuring that communities cannot escape bottom effects and develop into three- dimensional reef structures on geological time scales.

Reef Morphology and Community Structure Along a Fluvial Gradient, Rio Bueno, Jamaica

by Jennie Mallela

Geomorfología y unidades ecológicas del complejo de arrecifes de las Islas del Rosario e Isla Barú (Mar Caribe, Colombia)

by Maria Helena Cendales

An assessment of an environmental gradient using coral geochemical records, Whitsunday Islands, Great Barrier Reef, Australia

by Jennie Mallela

Lewis SE, Brodie JE, McCulloch MT, Mallela J, Jupiter SD, Williams HS, Lough JM, Matson EG (2011) An assessment of an environmental gradient using coral geochemical records, Whitsunday Islands, Great Barrier Reef, Australia. Marine Pollution Bulletin doi:10.1016/j.marpolbul.2011.09.030

► First study to use coral proxy records to examine the Whitsunday Islands gradient. ► First study to show a regional GBR-scale change in the coral Ba/Ca ratio after 1860. ► Research provides new insights into the environmental influences on coral proxies. ► Research shows a change in the environmental gradient since European settlement.

Coral cores were collected along an environmental and water quality gradient through the Whitsunday
Island group,... more Coral cores were collected along an environmental and water quality gradient through the Whitsunday
Island group, Great Barrier Reef (Australia), for trace element and stable isotope analysis. The primary aim
of the study was to examine if this gradient could be detected in coral records and, if so, whether the gradient
has changed over time with changing land use in the adjacent river catchments. Y/Ca was the trace
element ratio which varied spatially across the gradient, with concentrations progressively decreasing
away from the river mouths. The Ba/Ca and Y/Ca ratios were the only indicators of change in the gradient
through time, increasing shortly after European settlement. The Mn/Ca ratio responded to local disturbance
related to the construction of tourism infrastructure. Nitrogen isotope ratios showed no apparent
trend over time. This study highlights the importance of site selection when using coral records to record
regional environmental signals.

Isolation by distance across the Hawaiian Archipelago in the reef building coral Porites lobata

by Rob Toonen

There is an ongoing debate on the scale of pelagic larval dispersal in promoting connectivity among populations of... more There is an ongoing debate on the scale of pelagic larval dispersal in promoting connectivity among populations of shallow, benthic marine organisms. The linearly arranged Hawaiian Islands are uniquely suited to study scales of population connectivity and have been used extensively as a natural laboratory in terrestrial systems. Here we focus on the lobe coral Porites lobata, an ecosystem engineer of shallow reefs throughout the Pacific. Patterns of recent gene-flow and population structure in P. lobata samples (n = 310) from the Hawaiian Islands (n = 10 sites) and from their nearest neighbor Johnston Atoll, were analyzed with 9 microsatellite loci. Despite its massive growth form, ~ 6% of the samples from both locations were the product of asexual reproduction via fragmentation. Cluster analysis and measures of genetic differentiation indicated that P. lobata populations from the Hawaiian Islands are strongly isolated from those on Johnston Atoll (FST = 0.311; P < 0.001), with recent migrants (n=6) being clearly identifiable. Within Hawai’i, two geographically overlapping genetic lineages were present. Here, over > 37% (P = 0.001) of the variation in genetic distance was explained by geographic distance, consistent with a pattern of isolation by distance.  This isolation by distance pattern suggests indicates that while the majority of ongoing gene-flow in Hawaiian P. lobata occurs among geographically proximate populations, inter-island distances are insufficient to generate strong population structure across the archipelago.

An assessment of coral reefs in Tobago.

by Jennie Mallela

Mallela J, Parkinson R, Day O (2009) An assessment of coral reefs in Tobago. Caribbean Journal of Science in press 45

The coral reefs of Tobago represent some of the southernmost reefs in the Caribbean and have developed under the... more The coral reefs of Tobago represent some of the southernmost reefs in the Caribbean and have developed under the influence of runoff (e.g. terrestrial sediment and nutrients) from South American rivers. Local terrestrial runoff resulting from poor land management practices have also impacted reef development.
Benthic surveys were conducted at 11 sites around the island in order to assess reef status. Mean (±SD) coral cover across Tobago was 14.9 (±7.6) % and macroalgae cover was highly variable ranging between 65 % at Bulldog Reef (Atlantic Coast), to 1.2 % at Mt Irvine (Caribbean coast). Montastrea faveolata (Ellis) and Diploria strigosa (Dana) dominated scleractinian coral communities and gorgonians accounted for 12.3 (±7.1) % of total
benthic cover. Yellow band disease was observed on the major reef builders, M. faveolata, at most sites. The
grazing urchin, Diadema antillarum (Philippi), have not recovered since their demise in the 1980’s. However despite limited grazing, the majority of monitoring sites were still dominated by coral communities.

Key words: Coral reef . Tobago . Diadema, river runoff. coral cover. sedimentation.

Available at:
http://caribjsci.org/June10/46_83-87.pdf

Status of Coral Reefs of the Lesser Antilles: The French West Indies, The Netherlands Antilles, Anguilla, Antigua, Granada, Trinidad and Tobago

by Jennie Mallela

Chapter 19. Status of Coral Reefs of the Lesser Antilles:
The French West Indies, The Netherlands Antilles, Anguilla, Antigua, Grenada, Trinidad and Tobago

Book: Wilkinson C (2008) Status of coral reefs of the world 2008, Townsville, Australia

Defenses of Caribbean sponges against predatory reef fish. I. Chemical deterrency

by Rob Toonen

Survey of anti-predatory defenses of marine sponges across the Caribbean