Climate Change Adaptations

 Dr Anjani Ganase reports from the front lines of science looking for solutions to our rapidly warming ocean.

 

Coastal defences are better when nature is involved.

 

In Trinidad and Tobago, a common solution to any flooding or erosion event is the installation of a box drain or retention wall. Pouring concrete or straightening a riverbed ignores the downstream negative impacts, the loss of ecological systems and the prevention of any future adaptation. Box drains, concrete walls and such permanent constructs do not respond to climate impacts and require high-cost maintenance in the long run. This is a common problem worldwide with 40 % of Japan’s coastlines hardened by coastal defences. These engineered solutions are referred to as hard defences – directly referring to the hardening of the coastline or the riverbed.

 

In contrast, soft - also known as ecosystem-based - solutions aim to mimic natural ecosystem functions - mangroves, back beach habitats, coral reefs - to provide defensive services. In some scenarios, hybrid defences were designed to combine the two (hard and soft) for the best of both worlds. Hybrids aim to provide immediate barrier to further erosion while maintaining the ecological form and adaptability of the area for any further changes especially climate change. While both soft and hybrid solutions are likely to be made more cost effective and adaptable, they can be designed on par with the natural measures – namely existing coral reefs, mangroves etc that protected the coastline.  A review by the University of Tokyo based on 304 published articles for studies done in 55 countries around the world found that hybrid solutions had the largest reduction in hazard and were cost effective when compared to the hard solutions. It must be noted that most of the observations were undertaken in conditions of low-level threats, as few studies investigated effectiveness during extreme storm events.

 

Mangroves and coral reefs are natural defences against sea-level rise and storm events.  Mangroves and coral, Kimbe Bay, Papua New Guinea. Credit: Matt Curnock / Ocean Image Bank

 

Jellification of the Arctic Ocean?

 

The first scenarios of climate change by researchers in the early 2000s anticipated an ocean dominated by jellyfish with expanded ranges across the world as warming extended the range of suitable habitats. This is hastened by overfishing which removes natural predators, and nutrient polluted water which encourages the blooming of some algae species. However, while there are examples of jellyfish populations increasing in some places around the world, resulting in issues such as inundating fish nets, clogging intakes of power plants in coastal areas, there is no global consensus for jellyfish invasions or expanding their range.

 

A group for researchers from Bremen University, Germany modelled the potential spread of jellyfish species into the Arctic with climate change. The results revealed that most species may be likely to occupy new spaces in the Arctic open ocean and coastal areas, which would have been limited by the presence of sea ice otherwise. Sea ice is critical for the environmental condition and the food web of the Arctic as it regulates light availability, nutrient mixing, both of which are important for the phytoplankton that forms the base of the food web in the region.

 

Warming conditions also regulate the ocean circulation and current patterns, and the mixing of the water column. The alteration of the sea ice and the warming temperature might promote a shift toward jellyfish compatibility, and, the scientist noted, a potential for some species to migrate north from the Atlantic basin once the temperatures permit survival and reproduction in the polar region. The potential of the jellyfish expansion to this region poses a threat to fish communities – those that compete with the predacious jellyfish for food as well as impact to spawning grounds, especially of species with ecological and commercial importance, such as the polar cod. However, there needs to be more monitoring in the region focussed on the jellyfish communities. Jellyfish are still not well researched and their importance or threat to the ocean food web still needs to be assessed.

 

Yellow lion’s mane jellyfish passes through a moon jellyfish bloom in Prince William Sound in Alaska Credit: Ron Watkins / Ocean Image Bank

 

Playing the long game with coral preservation

 

It is projected that climate change will result in the mass die off of up to 99% of corals worldwide by mid-century. Recognising the importance of coral species to the fisheries, ocean health and humans, scientists have been conducting research into the cryo-preservation of corals – sperm and eggs, embryos, and larvae – over the last decade. While we’re not there yet, the scientists are getting closer to the possibility of viable re-introduction of coral species to the environment in the post- warming era. The challenge with cryo-preservation is the method of freezing and thawing cells without damage. Freezing results in the formation of ice: for persons exposed to the extreme cold this resembles frost bite. The process of vitrilisation is where the freezing of the cells occurs without the formation of ice crystals and produces a “glass-like solidification” below -80 C. This is done with the use of a concoction of cryo-preservation agents to protect the cells and has been tested on mice, embryos, plants, fish, and now corals.

 

The second danger is the warming process to bring the organisms “back to life”. Today, lasers are used to warm samples. In the latest study, scientist have successfully been able to revive coral larvae from a species – Stylophora pistillata – common to the Indo-Pacific region. Previous attempts resulted in the larvae being able to swim freely but with no settlement, cell division and skeleton formation. However, by tweaking the chemical composition of the cryopreservation agents, the latest experiment revealed that 11 % of the larvae successfully thawed, swam, and settled and formed coral skeleton. While 11 % sounds low, in nature successful recruitment of corals ranges between 5 to 10 %. This technology along with controlled coral husbandry to rear coral to adults might result in successful reintroduction of corals.

 

In all scenarios, time is not on our side. We can all do something. As a species, we must be mindful of nature, of our place in the natural world. As societies and communities, we can preserve natural systems, conserve water and land resources. As individuals, we can consume conservatively, create less waste.

 

 

 

References:

 

Huynh, Lam Thi Mai, et al. "Meta-analysis indicates better climate adaptation and mitigation performance of hybrid engineering-natural coastal defence measures." Nature Communications 15.1 (2024): 2870.

 

Pantiukhin, Dmitrii, Gerlien Verhaegen, and Charlotte Havermans. "Pan‐Arctic distribution modeling reveals climate‐change‐driven poleward shifts of major gelatinous zooplankton species." Limnology and Oceanography (2024).

 

Narida, Arah, et al. "First successful production of adult corals derived from cryopreserved larvae." Frontiers in Marine Science 10 (2023): 1172102.