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Deeply Layered Habitats & Juvenile Colouring Books
Posted by Tony on 17th August 2014 at 23:36:26

Marine Geological and Biological Habitat Mapping (GeoHab)

GeoHab 2014 Conference was held in Lorne in early May. Unexpectedly without my car, my time there had to be trimmed to Monday lunchtime thru Thursday lunchtime. Lets leave the background to my interest until the end and focus on a few key observations:
  • GeoHab sits uncomfortably at the intersection of well-intentioned science and exploitative business models.
  • GeoHab is being revolutionised by big data and big computing, with consequent instrumental biases.
  • GeoHab is an exemplar of Emergence/Systems/Complexity but (like the rest) frames its take on this and on polydisciplinary interplay without wider reference.
  • GeoHab pursues geotope colouring book goals which oversimplify communication with decision intermediaries while extinguishing richness of detail.
Before diving deeper on those points, I should try to neutrally describe the common ground and introduce key differentiators without getting too far into technical details of instrumentation, analysis and modelling capabilities that were central to many of the presentations. It was another common thread which made the presentations more watchable: a spectacular diversity of environments and their inhabitants from across our blue planet. To wrap that introduction, I should also cherry pick a few perceptive observations.

It is bemusing that the depth measurement method used to underpin centuries of marine charts was called "sounding" long before the advent of sonar, the move from sounding lead to echo sounding being relatively recent. Today's challenge starts with trying to extract extra information from returning sonar signals which might say something about the state of the bottom or detect fish mid water. The sea floor can be either rocky or unconsolidated sediment, e.g. mud, sand or gravel. Rock reefs can be encrusted by various invertebrate animals or by macro algae, better known as seaweed, especially kelp. A core goal of GeoHab is to efficiently identify botton dwelling or "benthic" communities, as distinct from far-ranging pelagic populations. The current state of play involves trying to correlate endless sonar data with "ground truthing", mostly in the form of video transects. There is a significant but largely solved technical challenge ensuring proper account is taken of the varied trajectory of vessels gathering data in and on the ocean. Much GeoHab work is concerned with delimiting Marine Protected Areas (MPAs) which are generally seen as the way forward for both conservation and fisheries as highly productive MPAs export fresh stocks to adjacent waters. The preceding is intended as just a top level pointer and vastly understates the range and variety in all these areas.

For benthic critters, "habitat" equals "home", albeit that for many that may involve a staged descent from a planktonic larval form that both gives their own species mobility to (re)colonise and forms much of the base on the food chain. (It is in this territory that confusion between death and suffering most offends, but I digress.) Commercial seafood stocks can be extremely dependent on particularly fragile nursery environments such as seagrass and mangroves. For researchers, the challenge is to usefully model complex fluid environments. Having spent many hours observing the variability of selected near-shore reefs between Lorne and Cape Otway in particular, the detail is overwhelming and the relative significance difficult to judge. In contrast to a computing industry with a habit of placing similarly extreme demands on workers, it was a relief to see much better gender balance in the GeoHab presenters and audience.

We not truly aquatic apes have a long history with the sea, estuaries and inland waters. They supply seafood, transport routes and structural possibilities. Only in very recent times have we started to reflect on our impact on this part of a natural world that for the most part lays (in)conveniently unseen. Suddenly you can hardly touch anything without an environmental effects statement. Would be exploiters and regulators are queuing up for a growing range of GeoHab expertise who can tell them about opportunities and risks. Dredging ports and channels and dumping "spoil", siting oil and gas wells or offshore wind farms, laying cables and pipes all provide commercial justification for people with a love of the sea and some relevant abilities to make an exciting career. Many roles can seem sufficiently removed from the worst of the exploitation by construction and fisheries, but the reality is that GeoHab would not be running to an annual international conference in Lorne without that global demand from industries. This leaves the good girls and guys to do what they can to represent the interests of much loved natural environments in the face of an economic regime still reluctant to accept ecological constraint. But those same exploiters also need to know what is there, at least as well as it can be known through the mostly indirect methods and polydisciplinary interplay of invertebrate biologists, ecologists, geologists, geomorphologists, hydrologists, even in places glaciologists; all backed up by information technologists with expertise in signal processing, statistical analysis, mapping and modelling.

The ongoing information explosion can feel all too unsurprising to those of us with a long history in the technologies and consequent knowledge of how much is hidden behind creeping inefficiencies, but the very existence of current marine habitat mapping depends on the application of Moore's Law–type growth to instrumentation, processing and storage capabilities. With modern sonar navigation aids, remote video capture and more, the amount of data which is at least momentarily captured overwhelms our still impressive capacity to store and process. Residual needs for human intervention at interpretation stage mean both that only a tiny fraction is ever looked at, and that the aim then is very much on reducing further need for such interpretation. So GeoHab cannot escape the common bias of reductionist science towards repeatability. While more than a handful of vendors offer variations on the theme for data capture and processing, there remains an inescapable pressure to try to find signals which translate into a manageably limited set of kinds of bottom which can be delimited, measured and added to provide false assurance to decision makers. Don't mistake this point for any neglect of the spectacular resolution that is being achieved routinely. My concern here is primarily that there is no way such techniques can reveal the kind of knowledge I long ago accumulated by repeated extended visits to particular ledge microhabitats, sticking my face and too rarely a camera in, while dreaming of tiny flexible probes that might be able to look even deeper. As increasingly understood in other contexts, GeoHab's dependence on big data and big processing unavoidably limits what it can see.

Through the mid 1980s, I came to appreciate the potent universality of the then emerging theory of complex systems, initially by chance and soon exploring what had been a gaping hole in my rational understanding of the world, this at the same time as I transitioned from a life which could prioritise diving the east Otway coast to one which made more commercial use of my expertise in information technology. Burdened with that perspective, I've spent the decades since increasingly bemused at how other disciplines come to discover those same principles independently, always reframing them in their own terms without a thought to wider generalities. Sedimentation, tectonic, hydrological and even glaciological processes contribute to the form on the sea floor which a plethora of benthic communities carpet to varying degrees. Wherever there is a gradient of some potential energiser, from solar photons to bubbling methane, novel organisation can self-organise to accelerate dissipation of that gradient in accordance with the second law of thermodynamics. Even when focused on emergence of complexity, we look for simple exemplars. In the ocean, nothing is more basic than wave motion, yet even the interplay of waves remains endlessly fascinating, or frustrating, depending on your objectives. Waves are everywhere in GeoHab, never more so than in digging for data in sonar echoes or amongst the granular sediments of much seafloor. Similarly, the GeoHab community celebrates the wide interdisciplinary collaboration that is essential to any significant project, without a spare thought that the inappropriateness of PhD silos is burdening society much more widely. These are core reasons colleagues and I have set up Kororoit Institute.

In recent years I've become more sensitive to the downside of what I'm calling here a "colouring book" approach to mapping of natural habitats, especially after one privileged lesson in the complexities of Victoria's critically endangered volcanic plains grasslands. These originally extended from longtime home creek valleys NNW of central Melbourne to beyond the South Australian border, on the inland side of the Otways from my favourite diving spots. Such vegetation is traditionally coloured in a flat pale yellow which property developers read as licence to "improve", hiding both the extraordinary small scale complexity of stony rises, watercourses and wildflowers and the 40,000 year history of aboriginal cultivation and land management which provisioned humanity's only truly long term sustainable culture right across this diverse continent. Having looked as deeply as I could into ledges of diverse geological form even within the relative hydrological consistency of Bass Strait, there is simply no way a colouring to represent kelp-weed-covered rocky reef can represent but the smallest fraction of the underlying character. Until we find a way to non-destructively read out the knowledge encoded in the synapses of every territorial marine critter, GeoHab's best efforts at submarine colouring books must leave many fine details in the darkest dark. One particular ledge near the tip of a reef parallel to Wye River's Point Sturt became a regular stop on a tide-dependent dive schedule because of a resident conger eel which gave some species of shrimp never seen elsewhere the confidence to be photographed.

My enchantment with the Otway coast developed across more than fifty years in which Cumberland River and thus Lorne has been a home away from home, mostly but not only in the summer holiday season. In recent years I've become more concerned to try to record a few things I've learnt that may become useful to others in future. I've also organised or helped with a few conferences in my time, including one in Lorne for then Australian computer manufacturers over 30 years ago. While there are emotional rewards in getting such things close enough to right, I can't imagine feeling as buoyant as conference host Daniel Ierodiaconou appeared to be throughout. @Dr_Dan_I remains the only person I can claim to know personally in the GeoHab community, that connection having been made when I became a keen supporter of his @pozible project to raise funds for additional surveying that might correlate with my own memories and photographic records from diving that coast intensively, mostly during and a bit either side of the 1970s. One product of those Deakin surveys is a map used to promote GeoHab which shows extensive reef structures well out from Lorne's Point Grey that supported fishermen friends who operated boats lifted by crane from Lorne Pier in younger days.
detailed survey of reef off Point Grey, conger eel in ledge, shrimp co-inhabitants

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