Map of Seattle circa 1851
Historical Context

Seattle before urbanization

This illustration from the Seattle Times (link to article) provides a fascinating window into what Seattle’s marine ecosystem might have looked like prior to urbanization. It’s a map of the Seattle area circa 1851, the year that the first white settlers arrived in the area.

There are some amazing distinctions here between the geography of the area at that time, and that of Seattle as we see it today. The entire area that was once a mud flat at the mouth of the Duwamish River is now filled in and inhabited. Harbor Island, a massive man-made structure where large cargo ships now dock and unload, did not yet exist. Without dredging, the southern parts of Elliott Bay were shallower than they are today. A cove exists on the north side of the bay where cruise ships now dock.

Here’s the same illustration next to a satellite map of modern day Seattle (click on it to make it bigger):

Map of Seattle circa 1851 next to satellite image of Seattle today

Left: Seattle circa 1851 (Source: Seattle Times). Right: Satellite image of Seattle today (Source: Google Earth)

With so much more soft sediment and so much less rocky habitat, I find myself wondering whether the rocky habitat species that are so common today – octopus, lingcod, rockfish – were barely present prior to urbanization. The area may have instead been dominated by seagrass beds and tidal mud flats, which support a very different biological community. With no long-term data sets spanning the length of the urbanization process, it may be hard to really know how the ecosystem has changed and what it looked like before the city of Seattle existed.  It’s fun to think about though!


Photo of Seattle from Don Armeni Boatramp
Background, Ecosystem Services, Historical Context

Urban Marine Environments as Coupled Human and Natural Systems

Over the last decade, a growing faction of scientists in the world of ecology and conservation biology has pushed the idea that most ecosystems on Earth are now comprised of coupled human and natural components.  They’ve come up with a variety of different names of these entities, but the one that I like most is “Coupled Human and Natural Systems,” or CHANS.  The idea is that although we’ve spent decades studying natural ecosystems, we have to take a step back and include humans before we can really understand how ecosystems function.

The literature describes several key qualities of coupled human and natural systems.  They are structured in a hierarchical manner and consist of complex networks of interactions.  These interactions are commonly reciprocal, with humans acting in ways that influence natural components, and natural components in turn influencing humans.  They also may involve positive or negative feedback loops that can accelerate or decelerate key processes.  Coupled human and natural systems exhibit emergent properties, which differ from the properties of individual system parts.  They exhibit nonlinearity in their dynamics, and may shift between multiple states or equilibria when certain thresholds are exceeded or system resilience is reduced.

If that sounds like Greek, don’t worry, I’m not here to drone on about models or theories.  I simply wanted to introduce the idea of CHANS.  By definition, CHANS are systems in which natural and human components interact. It’s undeniable then that urban marine ecosystems qualify.  Graphical model of human and natural interactions in urban marine ecosystemsThey are created out of long, intense interactions between humans and nature. Does the theory above then  give us insight into how urban marine ecosystems function? Do urban marine ecosystems evolve over time according to the theoretical framework for CHANS?

As I explore urban marine ecology in posts and research, I will do my best to highlight the coupled human and natural components of the system.  This may come in the form of historical information about interactions between humans and urban marine environments, explorations of the ecosystem services urban marine environments provide, and evaluations of these systems through the lens of resilience theory.  It may seem tangential at times, but the bottom line is that urban marine ecosystems are not just comprised of the marine organisms we encounter underwater.  Humans are very much a part of the ecological processes in urbanized marine habitats, and we may not be able to understand these processes or habitats until we have fully integrated ourselves into the ecological picture.