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IAG Working Group REEForm – Reef and reef landform responses to environmental and

climatic change

Report from First Scientific Meeting, Maldives 21st- 26th June 2010

The First Scientific Meeting of REEForm took place between 21st – 26th June 2010 on the island of

Lankanfinolhu (Paradise Island), Maldives. The meeting was generously supported by the Ministry of Housing,

Transport and Environment (Government of Maldives) and by Paradise Resort, Malé Atoll, Maldives, and we

extend our sincere thanks for their support and assistance during the meeting. The primary aims of this first

meeting of the REEForm Working Group were as follows:

1) to define the priority research areas for REEForm over the next 4 + years;

2) to develop plans for a series of synthesis papers relating to key research themes and that will underpin future

work in these research areas;

3) to establish a research programme and to agree on the operational activities of REEForm; and

4) at this meeting, to examine the high profile issues facing reef islands in the Maldives.

Scientific programme

The first two days of the meeting comprised a series of scientific workshops, each focused on different aspects

of reef and reef island geomorphology relevant to the wider interests of REEForm. Each workshop took the form

(A) REEForm members at the official opening ceremony of the 1st Working Group Meeting in the Maldives which was attended by the Minister of Housing, Transport and Environment, the Minister of Fisheries, and the Minister of Tourism. (B) Participants in more informal dress mode on the island of Bodukaashihurra, Ari Atoll.

B

A

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of a research presentation that provided a review of the current state of scientific knowledge, and a review of

major research gaps and key research questions. Each session was followed by a discussion session aimed at

highlighting key issues around which REEForm’s future activities might focus. The following provides a brief

overview of each workshop:

Reef Islands (lead by Paul Kench)

Paul Kench gave a review of the current state of knowledge regarding reef island formation and change.

This included an overview of reef island settings and types, of island-building process and of the data that

exists with regard our understanding of sediment transport processes around islands, and of island

morphodynamics. Useful case studies were provided from some of the detailed, integrated studies recently

undertaken in The Maldives. Evident from the talk was the fact that quite fundamental research gaps

remain in many areas of reef island geomorphology, and that these seriously compromise our ability to

accurately predict future reef island states and morphodynamic responses to changing marine and

environmental baselines. The paucity of existing data enabling us to link ecological changes with sediment

supply pathways was also discussed. Arising from subsequent group discussions were a number of key

areas where the group felt more geomorphic and process data was most urgently needed to inform

assessment of future island trajectories.

- The need for more process-based and temporal datasets to improve understanding of island

morphodynamics. In particular, the styles and rates of morphological change on reef islands.

- The need for an improved spatial coverage and understanding of the timing and chronology of island

formation and the interactions between island-building and past sea level states.

- The need for more case studies of islands in different reef regions.

- The need for data on the links between island fringing reef ecology, sediment supply (including types,

and rates) – and how these may vary temporally and influence styles of island evolution.

There was a strong commitment by the group to target reef islands in future field-based research activities.

Holocene reef growth (lead by Scott Smithers)

Scott Smithers provided a useful review of the current data that exists in relation to understanding

Holocene coral reef accretion rates. Recent published reviews were discussed and these provided a

context from which key research gaps were identified. An interesting overview of the number of reef sites

from which core records are presently available was provided, and which emphasised the relative paucity

of data on this key topic. Inherent within this, and occurring in large part as a function of past constraints of

dating, was the relatively low resolution of many reef chronostratigraphic records. New U-series methods

provide opportunities for these to be significantly improved. Scott also discussed the important issue of

temporal variations in reef-building through the Holocene – and it is clear that in many regions rates of reef

accretion probably peaked several 1000 years before present. A key point arising from this was that of reef

accretion in relation to the lower (or even regressive) rates of sea-level rise evident in the mid-late

Holocene. The interesting issue of intrinsic marginality for reefs through reduced accommodation space

was discussed. Arising from the group discussions that followed were a number of key areas which the

group felt represented major research priorities.

- The need for much greater coverage of reef accretion rate data, especially in relation to the most

recent phases of reef accretion in specific setting – something perhaps most easily achieved by an

emphasis on multiple shallow coring programmes.

- The need to generate data of contemporary reef growth rates.

- The need for more data from shallow fore-reef settings.

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- The need for data from submerged reefs that may represent new (juvenile) phases of reef

development.

- The need for more data to allow expanded regional scale assessments of peak periods of Holocene

reef accretion, and whether cyclical patterns of reef development, such as those recently delineated on

the inner-shelf of the GBR, are more widespread.

Reef carbonate production (lead by Chris Perry)

Chris Perry provided a review of the current state of research in the area of reef carbonate production,

dealing with both reef framework components and detrital carbonate sediments. It is evident that our

understanding of the organisms and processes involved in framework and sediment production is generally

good, and that there is a generally good understanding of the spatial/bathymetric distribution of these

processes/components. In addition, our conceptual understanding of how these processes interact to drive

reef accretion and/or generate sediment facies is also reasonably good, but attempts to quantify the rates

of production either cumulatively or for individual components is far more poorly constrained. Reef

carbonate budget methodologies do exist and the on-going ReefBudget project (aligned to REEForm’s

interests) is helping to develop standardized approaches to this topic. Similar approaches, in terms of

standardized sediment budget methodologies, do not yet exist. Major research gaps were identified in

terms of linking reef ecological states (and changes therein) to sediment and framework carbonate

production rates and styles. In relation to reef islands numerous major gaps in our understanding of

sediment production were identified; i) how does sediment production and supply to islands change

through time as islands evolve? ii) what are the major environmental factors than can trigger changes in

sediment production, and with what implications? iii) are sediments of appropriate type and grade being

produced today to maintain island structures? Arising from the group discussions that followed were a

number of key areas which the group felt represented major research priorities.

- The need for reef framework carbonate budget studies from a wider variety of sites, including an

emphasis on carbonate budget data from reefs that exist across a gradient of evolutionary states.

- The need to develop standardized approaches to quantify rates of carbonate sediment production.

- The need to improve understanding of island sediment records, especially where these can be linked

both to estimates of contemporary production and to records of recent morphodynamic change.

Reefs under present and future marginal states (lead by Bernhard Riegl)

Bernhard Riegl provided a very interesting review on reef marginality and, as a major potential driver of

future marginal states, coral bleaching. Concepts of marginality and examples of different drivers of

marginality (bathymetric, latitudinal, ecological) were discussed, along with the typical characteristics of

marginal reef systems with respect to issues such as sediment production/retention and reef-building

capacity. The issue of increased marginality of reef systems under changing environmental and climatic

conditions was a central theme of the presentation. This included wide-ranging consideration of

temperature as a potential future driver of marginal states and a review of the current state of knowledge

regarding ecological responses to bleaching and how this may impact on the sedimentary components of

reef systems – aspects that are very poorly constrained. Furthermore, the marginality of corals and reefs

was only considered critical to the working group goals where it impacts on geomorphic products. This was

followed by a very thought provoking discussion on approaches to modelling ecological transitions in reef

systems as community components respond to external drivers of change, and concepts around the

opening and closing of ‘windows of marginality’. Arising from the group discussions a number of interesting

research areas were identified by the group.

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- The potential to examine changes in carbonate production states in systems with established long-

term environmental records – local sediment depocentres may, for example, record associated subtle

shifts in carbonate production.

- The potential to develop ecologically-based models and to link these to conceptual ideas about

changes in carbonate production and sediment generation states.

Tropical coastal management and the role of geomorphology (lead by Arthur Webb)

Arthur Webb gave a very interesting presentation on key geomorphic research requirements from the

perspective of those directly involved in tropical coastal management (primarily in the Pacific). Underlying

these needs are poor landuse practices which, in the vicinity of many Pacific islands, include coastal

dredging, poorly considered coastal engineering, on-going water quality change, and widespread beach

sand and gravel extraction. Many urbanised islands in the Pacific (and elsewhere) are thus highly disturbed

environments that have limited potential for natural morphodynamic change as environmental baselines

shift. This has become a pressing issue where island development impinges upon the island fringes –

essentially those areas of islands where natural shoreline changes should be expected. Much of the talk

revolved around the key areas where geomorphological data can support the demands being placed on

coastal managers. In particular, in was noted that there is an increasing need for managers to be able to: i)

respond to the increased demands being placed on coastal zone development; ii) ensure appropriate

responses to coastal adaptation projects (mainly, but probably incorrectly, linked to climate change); and

iii) provide guidance on island responses to sea-level rise and climate change stresses. Sea-level rise was

reported as the key climate change related issue for most islands, but models to predict island response

are clearly inadequate at present, and natural shoreline changes are rarely factored into most

assessments. Arising from the group discussions were a number of priority research areas.

- A need for an improved understanding of the links between sea-level rise and shoreline change and,

linked to this, a need for improved monitoring of shorelines.

- A need for an improved approach to modelling island dynamics and change to inform management.

- A need for improved understanding and monitoring of sea level variability.

- A need for improved monitoring in both natural and disturbed island environments and, linked to this,

improved data on sediment production and supply pathways in these systems.

Lessons from the past – the last interglacial (lead by Mick O’Leary)

Mick O’Leary presented a review of the current state of research knowledge relating to the peak of the last

interglacial (Marine Isotope Stage 5e) as an analogue for examining reef behaviour under conditions of

higher sea levels and sea-surface temperatures. The context for research on reef development during

MIS5e is that this was a period of the Earth’s history when sea levels and sst’s appear to have been

comparable to those projected in the near-future. Problems with using Holocene reef growth records to

interpret reef response modes to rapid rises in sea level were discussed and the opportunities to address

these problems using data from the last interglacial exposure along the Western Australian coastline

considered. However, whilst these analogues appear to have considerable value for examining both reef

ecological and geomorphic responses, a number of major constraints remain, especially with regard to the

timing and duration of the sea-level highstand at that time. Arising from the group discussions that followed

were a number of key areas which the group felt represented major research priorities.

- The need for improved constraints on the timing of the MIS5e highstand.

- The need for better constraints on the timing and duration of the ‘lower’ and ‘upper’ highstands.

- Data on the ecological and geomorphic responses of reefs following the late MIS5e ‘jump’ in sea level.

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Field excursions

In addition to the formal science sessions, Working Group members participated in a series of field excursions

around Ari and Malé Atolls. These provided an opportunity to visit a range of reef islands that exist across a

spectrum of states; from natural uninhabited islands, through to highly modified/engineered systems. These

trips, led by Dr Paul Kench (Auckland) provided a fascinating insight not only into the natural geomorphic

processes that operate on the reef islands of the Maldives, but also an opportunity to see the major landform

modifications that have occurred on some of the most densely populated islands.

Bodukaashihurra – an uninhabited island in Ari Atoll. (A) REEForm members examining sediment and reef samples from around the island and discussing island sediment generation processes. (B) Western margins of the island where erosion of the island flanks, linked in part to seasonal wind reversals, has lead to under-cutting of vegetation and scarping of the island margins. Significant recent sediment accumulation has occurred on the opposite (S to SE) sides of the island, probably linked to a change in island position on the reef platform top.

A

B

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Vabbinfaru (Banyon Tree) – a resort island in Malé Atoll. (A) Management practices around the island – sand bag type groynes and, dredging and pumping of lagoon sediment for shoreline nourishment. (B) Thriving coral communities along the margins of the perimeter reef. (C) Examining experimental substrates established by researchers from The University of Auckland for reef carbonate budget studies.

A

B

C

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Huraa – an inhabitated island in Malé Atoll. (A) Reclaimed land (previously reef flat) on the southern side of the island. The line of palm trees in the foreground marks the original island margin. (B) View landward showing wave reworking and scarping of the reclaimed land. This new land provides protection for nearby infrastructure, but also houses the islands de-salination plant . (C) Sand bags and cement bag style seawalls (which have a typically short lifespan) ‘protecting’ the island flanks.

C

B

A

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Malé. (A) View along tetrapod wall on the western side of Malé. This is constructed right along the seaward edges of the islands former reef flats. Note area in foreground has been reclaimed by infilling of the former reef-flat up to the tetrapod wall. (B) Wave-overtopping during high water on a high spring tide. (C) Sediment overwash during the high spring tides. It is interesting that despite the proximity of the terapod walls and the narrow, restricted nature of the active reef, significant amounts of sediment still seem to be being produced on the remaining reef flats.

C

B

A

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Key outcomes from the June 2010 Meeting

Thematic programmes: As outlined above a key aim of this first WG meeting was to agree on the primary

scientific themes on which REEForm will focus its research efforts. There was a strong consensus that a major

priority for REEForm should be on promoting the science required to understand and inform reef and reef island

management and adaptation strategies, and that any field research activities undertaken by REEForm should

be guided by this commitment. Arising from this was an agreement to structure REEForm’s activities around a

series of Thematic Programmes, each dealing with different aspects of reef and reef island geomorphology, but

which directly link back to this central guiding principle. The four identified themes are:

Thematic programme 1 - Reef islands

Thematic programme 2 - Reef growth

Thematic programme 3 - Reef carbonate production

Thematic programme 4 - Modelling reef and reef island morphodynamics

The research remits of each programme will appear in due course on the REEForm website.

Outputs and publications:

A further outcome of the meeting was a commitment towards producing a series of review/synthesis papers

relating to the key areas of research interest discussed above. Initial planning of these papers took place during

the meeting and will be followed up over the next 12 months. A decision was also taken to establish a formal

REEForm contribution series for publications arising from both REEForm’s specific activities and those

undertaken by REEForm members.

Future research activities and conferences sessions:

The group spent some time discussing potential future field-based research data collection programmes and

conference sessions to support and promote our key areas of research. There was a general consensus that

our immediate group-based field research would focus on aspects of reef island development and change, and

a plan for a research expedition to the Maldives in 2011 was discussed.

2011 Maldives research expedition (North Maalhosmaduulu (Raa) Atoll)

2012 ICRS Meeting, Cairns (planned thematic session)

Great Barrier Reef/Coral Sea research expedition ?

2013 IAG Meeting, Paris (planned thematic session)

Pacific Islands research expedition ?

Funding and promotion:

A discussion was also held regarding the general issues of: 1) promoting the activities of REEForm; and 2)

securing funding for future field-based research. In the first instance an improved website will be developed,

with content expanded to reflect the developments arising from the Maldives meeting. Efforts are also underway

to identify potential sources of longer-term funding both from national funding bodies and through corporate

groups.

Chris Perry, July 2010