News » National Marine Week Ocean Hero - Dr Nikki James

Our Ocean Hero for National Marine Week 2020 - Dr Nikki James

In celebration of National Marine Week, the Marine Stewardship Council (MSC) ran an Ocean Health blog, with QA-style guest content to put a spotlight on the main threats our oceans are facing – and on the organisations that are doing something about it. NRF-SAIAB scientists contributed to this blog, sharing information about their marine research projects on climate change and how they are addressing this issue.

This is what our Ocean Hero and Senior Scientist, Dr Nikki James had to say about Climate Change:


Dr Nikki James – Senior Scientist at SAIAB

  1. 1.       Provide us with a context of our marine resources in South Africa.

Africa has been identified as being one of the region’s most vulnerable to the impacts of climate change, yet our understanding of the impact of climate change on coastal and estuarine ecosystems is limited. Recent studies have shown that surface waters along the subtropical East Coast are warming significantly and this has been linked to warming and strengthening of the Agulhas Current. In contrast, some sections of the south and west coast are cooling seasonally as winds that favour the upwelling of cold bottom water to the surface increase.

  1. 2.       Explain to us the impacts of climate change on our oceans and marine life.

Marine species are more susceptible to changes in temperature than many land-based animals. This is because many marine species cannot maintain a constant body temperature and cannot survive in temperatures too far out of their normal or preferred range. Consequently, of all of the physical stressors associated with climate change, temperature is considered to have the most impact on marine species. As water temperatures increase the metabolism of fishes increases. They need more and more oxygen to fuel this high metabolism and if not enough food is available then all the fishes' energy goes into fuelling their high metabolism, with no energy left for growth and reproduction. There may also not be enough oxygen available as the amount of oxygen dissolved in water decreases as temperature increases. As a consequence, worldwide, species are moving out of their normal ranges to more favourable habitats as waters get warmer. In response to warming waters, changes in the distribution and abundance of tropical and temperate fish species have already been recorded in South African waters.

  1. 3.       Provide an overview of the projects led by SAIAB to address, study or mitigate the impacts of climate change on the marine ecosystem.
  • Evaluating the tolerance of common coastal fishes and invertebrates to extreme temperatures (Rhodes University).
  • Assessing the vulnerability of estuarine biota to climate change through the response of organisms to changes in temperature, flood regime, and habitat loss.
  • Coastal ocean acidification in Algoa Bay and its impact on the physiology and behaviour of a common coastal fish.
  • The role of mangrove habitat complexity in shaping the thermal physiology of invertebrate and fish larvae.
  1. 4.       List some simple ways in which consumers/ South Africans can help minimise or mitigate the impacts of climate change on the coastal and marine environment.

The five main environmental threats to our oceans and coastal ecosystems are: overfishing, pollution, invasive species, habitat destruction and climate change. The combined effects of these environmental threats reduce the ability of species and ecosystems to adapt to change. South Africans can play their part through buying sustainable seafood, reducing pollution and reducing carbon emissions. 

  1. 5.       What does ocean sustainability/ ocean health mean to you?

Ocean sustainability and ocean health means maintaining healthy fish populations, maintaining habitat for species and keeping our oceans clean (no pollution). 

  1. 6.       In your opinion, and within the context of climate change, what role can/is sustainable fishing (and seafood) playing in mitigating the impacts on our oceans?

Sustainable fishing (and seafood) plays a major role in mitigating the impacts of climate change on our oceans. Groundbreaking research conducted by a Rhodes University/SAIAB PhD student has shown that fisheries species from marine protected areas are more resilient to ocean warming than the same species from heavily fished areas. This is because overfishing removes the fitter, larger individuals from heavily fished populations.

  1. 7.       As an Ocean Hero this Marine Month, please provide us with a quote or educational tip in celebration of our oceans and ocean heritage.

Healthy ecosystems are more resilient and able to adapt to change. 

 

The following imagery show climate change impacting the marine environment and the work that our research teams are doing to address the impacts.

 
Extreme high seas surge into the West and East Kleinemonde estuaries.

  
Image 1                                                                                           Image 2

Image 1: PhD students Carla Edworthy and Melissa Pollard catching larval fish to determine the tolerance of fishes to ocean acidification in Algoa Bay.

Image 2: Specialized equipment in NRF-SAIAB’s ecophysiology platform allows scientists to determine the physiological response of organisms to climate change.

 
Dusky kob and spotted grunter trapped in a draining shallow water body
(Photo: Paul Cowley).