Greetings from Down Under

Greetings from down under! I’ve just arrived in Sydney to work with one of my all-time top science heroes, Dr. Emma Johnston, at University of New South Wales (UNSW). It’s all thanks to support from the National Science Foundation and the Australian Academy of Science, through a program they jointly fund called EAPSI – East Asia Pacific Summer Institute.

Twitter post following rocky landing in Sydney

My Twitter post after landing amidst Sydney’s 100-year storm

Of course, it’s not at all summer here in Australia. My approach into Sydney Airport was among the most exciting aviation experiences I can recall due to a 100-year winter storm that was pounding the coast of New South Wales. Upon deplaning, I discovered a usually fair-weather city deep in the throes of winter weather chaos. City buses were rerouted, sirens of emergency vehicles chirped persistently in the distance, and Hassan, my Uber driver, had to turn around on three different occasions to avoid downed power lines.

Of course, my first reaction as a wise American tourist was to instantly flock to the water’s edge to watch. Here was the scene above iconic Bondi Beach in East Sydney:

Zaza Silk (pictured) lost her swimming pool and her mother’s ashes as the sea gobbled up her yard and home. Photo credit – top: © Seven/Sunrise, bottom: Peter Rae.

Harrowing stories from the storm’s victims have since emerged. Storm surge and wave action seized up to 50 horizontal meters of shoreline in a single night in some locations, wreaking havoc for residents and businesses.

Of course, the fact that the sea poses such a risk to coastal communities (both in Australia and around the world) is a small part of why I am here conducting research. I study the artificial structures we build to protect shorelines from seawater inundation, also known as shoreline armoring. As climate change raises sea levels and human populations migrate towards the coasts (Neumann et al. 2015), the need for shoreline armoring is more critical than ever. Yet, we must balance this need with the potential negative consequences of armoring. Previous research suggests that artificial structures such as seawalls and breakwaters alter the composition of marine ecosystems (Bulleri and Chapman 2010). These changes could influence the goods and services that marine ecosystems provide to coastal communities, such as pollution processing and recreational fishing.

Over the next few months, I will work closely with researchers at UNSW to examine how marine trophic (feeding) relationships compare between natural and armored shorelines in Sydney Harbour. Sydney is the epicenter for research on urban marine ecosystems, and researchers here have unparalleled knowledge of the species that live on artificial structures locally. This knowledge will enable me to use stable isotope analysis and next generation sequencing to identify the position of each species in the food chain and its original source of photosynthetic energy. By comparing these characteristics between organisms living on altered and natural shorelines, we will gain insight into how the structure and function of marine communities may be influenced by shoreline armoring.



Research Blitz – Science for Adaptation Planning

I’m en route to the Friday Harbor Labs for a much anticipated research blitz – a 72 hour research intensive with fellow graduate students in the IGERT Program on Ocean Change (IPOC). Over the course of the coming weekend, we hope to make considerable progress on an interdisciplinary collaboration we started last fall. Our objective: Use a case study approach to identify how scientists can best support the planning process undertaken by coastal cities as they adapt to rising sea level.

From the IPCC's 2013 Report (see link in text)

From the IPCC’s 2013 Report (see link in text)

For many years now, the Intergovernmental Panel on Climate Changes (IPCC) and concerned scientists have warned of the impending rise of global sea level and the risks it poses to coastal communities, particularly in high density, urban areas. Projections published by the IPCC in 2013 suggest that sea level could increase by more than 3 feet by the end of the century. But more recent research suggests that the threat may be much more extreme and immediate in some locations due to geographic unevenness in the rate at which sea level is rising. Cities like Miami are already beginning to experience periodic inundation from the surrounding ocean, and record-breaking storm surge events like that from Hurricane Sandy now pose considerable risks to New York and other low-lying metropolitan areas. For many coastal cities, sea level rise is no longer a possibility in the distant future; it’s a process that is already underway, with very real social and economic consequences.

The question many coastal cities therefore face is not how to prevent sea level from rising, but how to adapt to the additional increase we’re already fairly certain will occur. Adaptation plans are under development in most major coastal cities, with the Dutch leading the pack. Many of these plans employ both traditional engineering solutions, like the construction or reinforcement of seawalls and dikes, as well as “soft engineering” approaches, such as restoring wetlands that serve as barriers from encroaching seas. Though economists, social scientists, policy buffs, and the design and urban planning community have already made extensive research contributions to the field of adaptation planning, we’d like to know what more natural scientists (climatologists, oceanographers, biologists, ecologists) could do to help.

Adapting to sea level rise will most certainly require creative approaches that draw on expertise from a wide range of disciplines. What better way to learn about adaptation planning and the science behind it than with an interdisciplinary group of IPOC fellows!


Photograph of ocean and riprap at dusk
Big Ideas, Ecosystem Services, Recent Research

Climate change and the proliferation of shoreline armoring

Louise Firth and colleagues recently published this article in Environmental Science Processes & Impacts: Climate change and adaptational impacts in coastal systems: the case of sea defences. It provides a brief exploration of shoreline armoring in the face of climate change. The general idea is this: as sea levels rise, coastal cities and developments are requiring increases in coastal defense structures (breakwaters, riprap, etc). These structures carry negative and potentially positive impacts for marine ecosystems. Why not construct them with these impacts in mind?

Photo of coastline with riprap and seawall

(c) Nigel Chadwick

“There is no doubt,” Firth and colleagues state in their paper, “that [armoring structures] modify the natural environment and can have deleterious impacts…” They cite research that has demonstrated how armoring structures act as stepping stones for species undergoing range expansions and how they have facilitated biological invasions. However, they may have potentially beneficial impacts as well, by supporting species of conservation importance and increasing habitat heterogeneity, as Firth et al. (2013) note.

So what does this mean for the construction of coastal defense structures? If the objective is to enhance intertidal biodiversity, Firth et al. (2013) provide these guidelines:

  • ”Build structure lower in the intertidal zone.”  Areas that are submerged for longer tend to support a greater number of species. Would this alter habitat that would otherwise be unaltered? That’s a discussion for another day I suppose.
  • Avoid smooth rocky material“, as these types of surfaces tend to be to be colonized by fewer species.  Specifically, they suggest a mixture of hard and soft rock to create greater surface roughness.
  • Create rock pools,” which should provide refuges for some species at low tide and support greater diversity.
  • Create pits” and crevices.  These provide hiding places and habitat heterogeneity.
  • Deploy precast habitat enhancement units.” Firth et al. (2013) note that a variety of such units are currently being tested around the world at the moment.  More on this soon in future posts!