Spawning research in the National Sea Simulator

2017

The following projects are being conducted in the National Sea Simulator in 2017:

Dredging and coral reproduction

A juvenile coral removes coarse sediment from its surface during an experiment in the National Sea Simulator. Image: G. Ricardo

Elevated sediments from natural events and dredging activities can impact corals by reducing light and smother coral surfaces. Sediments may also affect many aspects of coral reproduction and subsequent early life history stages. This project aims to understand the impact of sediments on coral settlement and post-settlement processes.

This research is supported by:
AIMS, National Environment Science Program

Researchers
Dr Gerard Ricardo
Dr Andrew Negri
Dr Ross Jones
Dr Nicole Webster

 

Oil spills and coral spawning

A researcher prepares oil samples for ecotoxicology experiments

Oil from spills and leaks can interact with corals at both the water's surface and beneath the ocean.  In this study, millimetre-long coral embryos, larvae and recruits will be exposed to oils under controlled conditions to measure the sensitivity of this critical stage in a coral's life history. 

Coral reefs in clear waters are also naturally exposed to high levels of UV radiation but this can increase the toxicity of some components in oil. We will also therefore investigate the effects of UV radiation on toxic thresholds of oils to corals.  These results can be used by industry and regulators to assess the risks posed to corals by spills and leaks.

This research is supported by:
AIMS and King Abdullah University of Science and Technology (KAUST)

Researchers
Dr Andrew Negri
Dr Diane Brinkman
PhD Student: Mikaela Nordborg
Florita Flores
Prof. Carlos M. Duarte
Prof.  Susana Agustí


Evolution in the 21st century: Can coral reef organisms adapt to climate change?

'Evolution21' is a five year project examining the genetic and non-genetic responses of various reef organisms to today’s climate conditions, and those predicted for the years 2050 and 2100.

Understanding how animals and plants adapt is required to predict the health and resilience of coral reef populations under continued ocean change. Evolution 21 is a five-year mesocosm project assessing how three climate scenarios (today, and predicted for years 2050 and 2100) will impact the health and adaptation of reef organisms such as corals, sponges, foraminifera, seagrasses and sea urchins.

We study a range of attributes in animals and their microbial symbionts – diverse microscopic communities essential for the health of the animal.

Evolution 21 has been running in the National Sea Simulator since mid-2016. Some sponges, sea urchins and corals are now potentially acclimatised to future conditions and are reproducing through spawning this season. We will investigate if the offspring from these acclimatised adults are more resilient to future ocean conditions.

This research is supported by:
AIMS, Marsden Fund and Victoria University of Wellington

Researchers:
Dr Nicole Webster
Dr Line Bay
Prof Madeleine van Oppen
Dr Sven Uthicke
Dr Heidi Luter
Dr James Bell
Ms Veronique Mocellin
Ms Frances Patel
Mr Jose Montalvo-Proano (AIMS@JCU PhD student)
Ms Nora Kandler (VUW PhD student)
Ms Maria Andersen
Ms Mikayla Huizer
 

Does climate change affect the sensitivity of juvenile corals to sediment stress?

Successful clearance of sediments by a Pocillopora actua coral recruit 3 days after it was exposed to a single fine sediment (~50 μm) deposition event under current climate conditions. Image: G. Ricardo

Corals are threatened globally due to increasing sea surface temperatures and ocean acidification related to anthropogenic climate change. In addition, corals are periodically exposed to high sediment concentrations during storm events and dredging. When these sediments deposit on the seafloor they are particularly harmful for the early life stages of corals.

To test how climate and sediment stressors interact, we will rear and grow juvenile corals at SeaSim under current and future climate conditions.

Experimentally, they will be exposed to multiple realistic sediment depositions. By comparing how the juvenile corals from each climate treatment cope with the sediment stress we will determine whether climate-adjusted thresholds for sediments will be needed to improve water quality management for the Great Barrier Reef and its catchments.

This research is supported by:
AIMS
James Cook University
AIMS@JCU
National Environmental Science Programme

Researchers:
PhD student Christopher Brunner
Dr Andrew Negri
Dr Sven Uthicke
Dr Mia Hoogenboom
Dr Gerard Ricardo

 

Understanding crown-of-thorns starfish (COTS) outbreaks

The early life stages of a crown-of-thorns starfish - from single cell, to swimming larvae and settlement.

The crown-of-thorns starfish (COTS) is a natural predator of corals in the Indo‐Pacific region, including the Great Barrier Reef (GBR). While they are native to the region, COTS are a leading cause of coral loss on the GBR. Since the 1960’s, the Reef has experienced three recorded major outbreaks of COTS, with populations erupting approximately every 15 years. A fourth outbreak is now in progress on the northern GBR.

During the spawning season, we conduct multiple experiments in which we raise COTS larvae until they can move onto the reef surface (a stage called settlement). Most of these experiments test the importance of food (small algae) in the survival of the COTS larvae, but we also test global change-related factors.

With help of SeaSim staff, we have developed a flow through larval culture system which allows raising larvae under more natural conditions. Larvae cultured in the SeaSim also assist in other COTS research, such as developing eDNA approaches to monitor COTS larvae and adults.

This research is supported by:
AIMS and the University of Otago

Researchers:
Dr Charlotte Johansson
Dr Sven Uthicke
Dr Miles Lamare

 

Survivors of coral bleaching: are their offspring more temperature tolerant?

A staghorn coral that has survived a bleaching event sits next to a dead plate coral on the Great Barrier Reef. Image: C. Brunner

The Great Barrier Reef (GBR) has experienced two years of back-to-back bleaching from elevated sea temperatures. Encouragingly, some coral colonies survive these bleaching events. Some of their bleaching tolerance is potentially due to the presence of genes involved in thermal tolerance.

We are investigating whether the young of the bleaching survivors from warm waters of the far northern GBR are more stress tolerant than young from the cooler central GBR. This research will test whether these offspring may fare better in a changing climate.

This study is an important first step in providing baseline data to assess the effectiveness of novel interventions such as assisted translocation or gene flow for restoration on coral reefs.  

This research is supported by:
AIMS

Researchers:
Dr Kate Quigley
Dr Carly Randall
Dr Line Bay
Dr Andrew Negri
Dr Madeleine van Oppen

 

Genetic markers of climate change adaptation in corals

A colony of the coral Platygyra daedalea. 

If coral species are to persist into the future, they will need to adapt to increased temperatures. Current models suggest that a 1.5°C increase in heat tolerance is required for their survival in the immediate future. Heat tolerance can be increased in coral populations if genes or gene regions associated with thermal tolerance are present in parents and inherited by their offspring.

Using SeaSim facilities, this team are rearing a large number of coral larvae from controlled crosses of parental colonies of the coral species Platygyra daedalea. Building on research from 2016 where we successfully identified genomic markers of heat tolerance in larvae, our experiments this year focus on the juvenile stage of this coral.

Understanding the biological tradeoffs and interactions that determine thermal tolerance in reef building corals will allow us to understand their capacity to adapt and persist in rapidly warming oceans. This information is required for conventional management and to underpin novel interventions to maintain coral reef ecosystems into the future.

This research is supported by:
AIMS and Oregon State University USA

Researchers:
Dr Line Bay
Ms Holland Elder (National Geographic Early Career Grant)
Prof Eli Meyer

 

Testing candidate gene function involved in coral skeleton and larval development

Microinjecting single-celled larvae of Acropora millepora with CRISPR/Cas9 to modify targeted genes. Image: P. Cleaves

In this project, we are testing the function of several key genes thought to be involved in skeleton development and larval metamorphosis in the coral Acropora millepora. We will test the function of these genes by modifying them using the cutting-edge method for gene editing, CRISPR-Cas9.

This project builds on our results from 2016 where, as a proof-of-concept, we made targeted mutations in genes that make coral larvae glow green and red. Our work will provide important foundational knowledge for the molecular basis for skeleton formation, which is ecologically important for this species of corals on the Great Barrier Reef.

This research is supported by:
AIMS, University of Texas and Stanford University

Researchers:
Dr Phil Cleaves
Prof Mikhail Matz
Dr. John Pringle
Dr Line Bay

 

Assisted evolution

Wing Chan and Lesa Peplow examine one year-old Acropora coral purebreds and hybrids growing in the National Sea Simulator.

This project will use 'assisted evolution' approaches to increase the rate of naturally occurring evolutionary processes to enhance the growth, survival and heat tolerance of corals under present day and predicted future conditions.

During this year's spawning event, three approaches will be followed:

  • Creation of coral hybrids (formed when the eggs of one species are fertilised by the sperm of another). The hybrid colonies will be reared through to reproductive maturity and the performance of later generations will be tested for increased heat tolerance.
  • Proof-of-concept experiments to examine whether the bacterial community of corals can be altered by inoculating the early life stages with with specific bacterial cocktails.
  • Coral photosymbionts bred in the lab for increased heat tolerance will be offered to coral larvae and their impact on coral bleaching tolerance will be examined.

This research is fundamental to determine whether assisted evolution approaches can be used to enhance the tolerance of corals to climate change.

This research is supported by:
AIMS and the University of Melbourne

Researchers:

Prof Madeleine van Oppen
Prof Ary Hoffman
Prof Linda Blackall
Dr Patrick Buerger (CSIRO, University of Melbourne)
Mr Carlos Alvarez-Roa
Ms Lesa Peplow