Royal Netherlands Institute for Sea Research
Royal Netherlands
Institute for Sea Research
Phone number
+31 (0)222 369 389
Location
Texel
Function
Senior Scientist

Dr. Andi Haas

Senior Scientist

‘Coral is deteriorating due to fast food’

Biogeochemist Andreas Haas studies changes in coral reef ecosystems as a consequence of human influence. ‘The infamous bleaching of coral, due to the loss of associated symbiotic algae under warm seawater conditions is well known. That often happens in a relatively short time and yields shocking images that capture our attention. A lesser-known threat for corals comes from other algae. Macroalgae, or filamentous turf algae, can emerge if there is an excess of nutrients in the water - for example from wastewater, or when the ecosystem is disrupted due to overfishing or pollution.’

Quick snack

‘A coral reef system is a complex community comprising a multitude of organisms that coexist in a delicate and co-dependent balance. For instance, when algae increase, then the bacteria seize their chance too. Most algae release sugars that provide a tasty and readily available food source for them. Subsequently, the entire balance shifts and ultimately, algae and other non-calcifying organisms like sponges emerge that can even decompose the calcium carbonate of the corals. We see this effect occurring throughout the world and mainly at locations that are exposed to much human influence. In a comparative study of coral reefs across the pacific, including some exposed to significant human influence, and some of the most pristine reefs on this planet (e.g., Millennium Atoll, 3000 kilometres south of Hawai’i), we could see clear evidence of this fast-food effect.’

Exchange

‘In my research, I am primarily trying to understand exactly how the balance between algae, corals and bacteria works. Currently we are quantifying tens of thousands of different organic molecules in seawater. That will hopefully provide starting points to tackle the underlying chemical causes of this problem. In addition, we are examining how the negative effects of people on coral can possibly be reduced. For example, it seems the corals experience less damage from harmful algae if the water around a reef is refreshed more often. We can take something like that into account during the design of new waterfronts and harbours. Ultimately we need to understand the biogeochemical mechanisms of coral reefs in detail to save the immense biodiversity and ecosystem services that coral reefs provide.’

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Linked news

Wednesday 24 June 2020
Microbes decisive in battle between coral and turf algae
Corals worldwide are threatened due to climate change and local stressors. The front line of the battle, however, is microscopic in scale. In the competition between coral and turf algae, microbes can be decisive in the outcome.
Tuesday 03 December 2019
Onderzoekers verkennen diepste en grootste onderwater-zinkgaten ter wereld
Van 5 tot 20 december organiseren het Koninklijk Nederlands Instituut voor Onderzoek der Zee (NIOZ) en Wageningen Marine Research een expeditie naar de Sababank, vlakbij het Nederlandse eiland Saba in het Caribisch gebied. Experts hopen aan boord van…
Friday 23 August 2019
Caribbean coral reefs, between resilience and warmer climates
A group of scientists from NIOZ, MARUM and ZMT are heading to Curacao to gather data on the modern and fossil reefs surrounding the island. Their expedition will last from August 23rd until September 3rd, and they will use state-of-the-art approaches…
Friday 12 April 2019
Pristine coral reefs show remarkable differences in microorganisms depending on the time of day
Nature communication published a study today which captures for the first time the high variability between day and night in microbes living on pristine coral reefs. The here described dramatic changes have never been witnessed before as these reefs…

Linked blogs

Wednesday 04 December 2019
NIOZ@SEA | Sinkhole expedition to the Sababank
From 5 to 18 December, NIOZ and Wageningen Marine Research (WMR) are organizing an expedition to the Saba Bank, near the Dutch island of Saba in the Caribbean. Experts on board the research vessel Pelagia hope to gain more knowledge about the…
Friday 23 August 2019
NIOZ@SEA | Curacao mapping
A group of scientists from NIOZ, MARUM and ZMT are heading to Curacao to gather data on the modern and fossil reefs surrounding the island. Their expedition will last from August 23rd until September 3rd, and they will use state-of-the-art approaches…

NIOZ publications