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Globally, habitat loss in coastal marine systems is a major driver of species decline, and estuaries are particularly susceptible to loss. Along the United States Pacific coast, monospecific eelgrass (Zostera marina) beds form the major estuarine vegetated habitat. In Morro Bay, California, eelgrass experienced an unprecedented decline of > 95%, from 139 ha in 2007 to < 6 ha by 2017. Fish populations were compared before and after the eelgrass decline using trawl surveys. Beach seines surveys were also conducted during the post-decline period to characterize species within and outside of remnant eelgrass beds. While the estuary-wide loss of eelgrass did not result in fewer fish or less biomass, it led to changes in species composition. The post-eelgrass decline period was characterized by increases in flatfish (mainly Citharichthys stigmaeus) and staghorn sculpin (Leptocottus armatus), and decreases in habitat specialists including bay pipefish (Syngnathus leptorhynchus) and shiner perch (Cymatogaster aggregata). There were similar trends inside and outside of remnant eelgrass patches. These findings support evidence across multiple ecosystems suggesting that the predominance of habitat-specialists predicts whether or not habitat loss leads to an overall decline in fish abundance. In addition, loss of critical habitats across seascapes can restrict population connectivity and lead to range contraction. For bay pipefish, the loss of eelgrass in Morro Bay is likely to create a population biogeographic divide. Currently, Morro Bay is dominated by flatfish and sculpins, and the longevity of this new ecosystem state will depend on future eelgrass recovery dynamics supported by ecosystem-based management approaches.

In contemplating better ways to manage, Stafford Beer says the big problem is that you are not determining absolute facts: you are establishing a set of conventions. Hence his view, that a model is neither true nor false: it is more or less useful. And while this paper suggests Beer’s Viable Systems Model (VSM) is overwhelmingly more, rather than less useful, that the VSM and its founding theories are virtually unknown at the level of everyday management begs the question, why? Over time we have learned about the usefulness of the VSM compared to other management theories, when used in the contest of the organisational strategic planning process. Thus through a sequence of diagrams based on Beer’s original drawings, we show how the VSM came to underpin a process for strategic planning in one organisation. The paper has three aims; to attach an everyday ‘common speak’ understanding to some of Beer’s work, to demonstrate how we have learned to appreciate the usefulness of the VSM and its associated diagrams and conventions and to suggest a link between the Action Research change methodology and Beer’s work.

Measurements over an annual cycle of longitudinal and vertical salinity distributions in a small sub-estuary, the Tavy Estuary, UK, are used to illustrate the dependence of salt intrusion and stratification on environmental variables. The interpretations are aided by vertical profiling and near-bed data recorded in the main channel and on the mudflats. Generally, high water (HW) salt intrusion at the bed is close to the tidal limit and is dominated by runoff and winds, with decreasing salt intrusion associated with increasing runoff and increasing up-estuary winds (or vice versa). Tidal effects are not statistically significant because of two compensating processes: the long tidal excursion, which is comparable with the sub-estuary length for all but the smallest neap tides, and the enhanced, near-bed, buoyancy-driven salt transport that occurs at small neap tides close to the limit of saline intrusion. The effect of wind on HW surface salt intrusion in the main channel is not statistically significant, partly because it is obscured by the opposing local and estuary-wide effects of an up-estuary or down-estuary wind stress. These processes are investigated using a simple tidal model that incorporates lateral, channel–mudflat bathymetry and reproduces, approximately, observed channel and mudflat velocities. Surface salinity at HW increases with tidal range because of enhanced spring-tide vertical mixing—a process that also reduces salinity stratification. Stratification increases with runoff because of increased buoyancy inputs and decreases with up-estuary winds because of reduced near-bed salt intrusion. Stratification and plume formation are interpreted in terms of the bulk and estuarine Richardson Numbers, and processes at the confluence of the sub-estuary and main estuary are described.

This paper considers those interpretations of action research that can be traced to Kurt Lewin at the Research Center for Group Dynamics at the University of Michigan, and the work in social ecology by Emery and Trist at the Tavistock Institute. It locates the logical basis of these interpretations in the philosophy of pragmatism, particularly as it relates to Peirce’s inferential logic and inquiry system. Drawing on this argument, and on the significant developments in approaches to systemic thinking over the past 40–50 years, a normative set of criteria is established for action research. The paper concludes that both positivist science (which relates to closed systems thinking) and action research (which relates to open systems thinking) are essential to any complete scientific approach.

Scientific Methodology (SM) has long suited those who favour analytical and quantitative research in management. Thus the dilemma between the rigour and relevance of contemporary management research methods is fuelled by action researchers who keep wanting to contrast Action Research (AR) with SM. This paper presents a Western philosophical view on the development of belief systems and theory-based methods over time. It thus links the progressive and cumulative development of SM with the contemporary AR methodology. In doing this it presents a different point of view—that the traditions of SM and AR have much closer relationships than people often give them credit for.

Despite its importance to ocean–climate interactions, the metabolic state of the oligotrophic ocean has remained controversial for >15 years. Positions in the debate are that it is either hetero- or autotrophic, which suggests either substantial unaccounted for organic matter inputs, or that all available photosynthesis (P) estimations (including 14C) are biased. Here we show the existence of systematic differences in the metabolic state of the North (heterotrophic) and South (autotrophic) Atlantic oligotrophic gyres, resulting from differences in both P and respiration (R). The oligotrophic ocean is neither auto- nor heterotrophic, but functionally diverse. Our results show that the scaling of plankton metabolism by generalized P:R relationships that has sustained the debate is biased, and indicate that the variability of R, and not only of P, needs to be considered in regional estimations of the ocean's metabolic state., Whether the oligotrophic ocean is net heterotrophic or net autotrophic has been a matter of debate for many years. Here Serret et al. show that, rather than being one or the other, the oligotrophic ocean is functionally diverse, with different metabolic states in different gyres.

Measurements are presented of the properties of suspended particulate matter (SPM) in the estuarine turbidity maximum (ETM) of the upper Humber and Ouse estuaries during transient, relatively low freshwater inflow conditions of September 1995. Very high concentrations of near-bed SPM (more than 100 g l−1) were observed in the low-salinity (less than 1), upper reaches. SPM within the ETM consisted largely of fine sediment (silt and clay) that existed as microfloc and macrofloc aggregates and individual particles. Primary sediment particles were very fine grained, and typically, about 20–30% was clay-sized at high water. The clay mineralogy was dominated by chlorite and illite. There was a pronounced increase in particle size in the tidal river, up-estuary of the ETM. The mean specific surface area (SSA) of near-bed SPM within the ETM was 22 m2 g−1 on a spring tide and 24 m2 g−1 on a neap tide. A tidal cycle of measurements within a near-bed, high concentration SPM layer during a very small neap tide gave a mean SSA of 26 m2 g−1. The percentage of silt and clay in surficial bed sediments along the main channel of the estuary varied strongly. The relatively low silt and clay percentage of surficial bed sediments (about 10–35%) within the ETM’s region of highest near-bed SPM concentrations and their low SSA values were in marked contrast to the overlying SPM. The loss on ignition (LOI) of near-bed SPM in the turbid reaches of the estuary was about 10%, compared with about 12% for surface SPM and more than 40% in the very low turbidity waters up-estuary of the ETM. Settling velocities of Humber–Ouse SPM, sampled in situ and measured using a settling column, maximized at 1.5 mm s−1 and exhibited hindered settling at higher SPM concentrations.

This paper considers the philosophical background of Stafford Beer's Viable Systems Diagnosis (VSD) as profoundly influenced by Charles Peirce. In a general sense, our work discusses the VSD theory base in the development of a model for actionable theory in organizations. This paper examines VSD theory in the Beer trilogy ‘Brain of the Firm,’ ‘The Heart of the Enterprise’ and ‘Diagnosing the System’ and we propose that a sound set of VSD action principles can be derived from this trilogy. We contend that the philosophical background underpinning these principles is important. Using Beer’s ‘Decision and Control,’ we consider that philosophical background and link Operational Research and the interdisciplinary learning within Cybernetics to modern general systems theory. We explore Beer’s viewpoint on the Peirce depiction of four main methods of fixing belief; tenacity, authority, a priori and finally the scientific to assist in that expansion. We consider how knowledge of Beer’s perspective on making sense of the world is important in the linkage of VSD theory to the managerial problem arena. We relate the Peirce methods to previously reported problem solving exercises involving the VSD ideology, which we will develop individually at a later date. This paper reflects our desire to express the interpretation of VSD theory in a language that the well-informed manager may readily translate into the third step of testing theory in practice.

This paper uses Stafford Beer's Viable Systems Diagnosis (VSD) to suggest that the development of a model for actionable theory in organizations would take the form of a three-step process. The first step involves the definition and explanation of an appropriate theory base, the second theory interpretation into a coherent set of action principles and the third contextual action in organizations. We contend that even for a well-informed and widely read manager gleaning the theoretical basis for this process from the recognized Beer trilogy “Brain of the Firm,” “The Heart of the Enterprise” and “Diagnosing the System” is difficult to justify in terms of time, understanding, and action. We maintain that a sound set of action principles emanating from Beer's primary work must be considered before tackling the noted trilogy. We use Beer's initial text “Cybernetics and Management” to trace some fundamental operational research and the interdisciplinary tripartite science of cybernetics. We commence our action model process with some introductory thoughts into operational research, cybernetics, VSD, and contextual action. Our first step toward action involves some primary definitions and principles of cybernetic theory and the prospect of controlling overwhelming variety. Our second step provides our set of coherent potential action principles fundamental to cybernetic theory. The paper is written in a journalistic rather than academic style reflecting the need to couch the interpretation of the theory in a language that the well-informed manager may readily translate into third step contextual practice.

Results are presented from a 1-year campaign to measure the seasonal variability of some key physical and biological properties of intertidal mudflats over a section of the central Tamar Estuary and to relate these to the physical environment. Seasonal variations in “physical” mudflat properties, such as grain size, density and moisture content were relatively small. With the exception of the particulate organic carbon content in the upper 0.002 m of surface sediment, biological variations were large. Redox potential exhibited considerable seasonal variation and showed that the sediments were less reduced in winter and more reduced in summer. Chlorophyll a and extracellular polymeric substances (EPS) within the surface 0.002 m of sediment (due to the presence of benthic diatoms) were strongly correlated and exhibited a pronounced seasonal pattern, with smallest values during winter and greatest values during late summer and early autumn. EPS had a dominating influence on sediment erosion, as determined from annular flume measurements. Velocity measurements and velocity modelling indicated that during the flood, and for much of the time during benthic diatom “bloom” conditions of high chlorophyll a and EPS sediment contents, the stresses exerted by tidal currents were too small to cause significant suspension of sediments over much of the middle and upper mudflats. Suspended fine sediment in the turbidity maximum zone was transported down-estuary and deposited in the main channel at low-water (LW) slack. Some of this sediment, in the form of relatively large aggregates, was subsequently transported onto the mudflats during the flooding tide, where slack currents and fast settling velocities may have enhanced sediment deposition there.

The Action Research (AR) PhD program at Monash University had its genesis in Systems Thinking and Organizational Learning. This paper discusses the role of the university in AR projects in business and the central role that AR projects can have in a Faculty's strategic positioning. The issues that have emerged in the project to date are discussed.

The objectiveof this paper is to provide “practitioner researchers” with insights into the initial findings around the challenges of conducting “business action research in practice” in “commercial” settings on the basis of experiences of a PhD cohort at Monash University in the first 18 months of candidature. In performing the role of a concluding paper, it sets out a generic framework for action research that the cohort has come to embrace. In doing so, it draws on emergent themes spread across the six diverse topics that are the subject of action research interventions of the cohort members. The paper then identifies and analyses the common patterns that have emerged and offers observations and conclusions for those involved in practitioner research.

This paper investigates action learning as a “maintenance of mindset.” It is an account of a personal evolution from a 4-year work in progress Action Research (AR) study exploring organizational viability. That study, involving two separate organizations and four cycles of AR, has seen the researcher and to some extent the organizations develop action-learning mindsets. The paper is an attempt to step outside the study and its associated learning from an organizational perspective and to link the threads of learning from the mindset of an action researcher. The paper suggests that adopting the mindset of an action researcher favors the transfer of learning from one organizational situation to another. Advocating that action researchers do not restart their initial methodologies, it is contended that the second organization has gained advantage of learning from the first. It is concluded that action learning mindsets articulate cumulative wisdom from organizational and methodological perspectives.

Over the past three decades the annual mean latitude of the Gulf Stream off the coast of the United States has been forecastable from the intensity of the North Atlantic Oscillation (NAO)1, the predictions accounting for more than half the variance. Here we show that much of the unexplained variance can be accounted for by the Southern Oscillation in the Pacific, the Gulf Stream being displaced northwards following El Nino-Southern Oscillation (ENSO) events. This provides a link between events in the equatorial Pacific and the circulation and weather conditions of the North Atlantic.

Data are presented from several experiments in the freshwater-saltwater interface (FSI) region of the Tamar Estuary. Longitudinal surveys of salinity and suspended particulate matter (SPM) at high water showed that the location of the FSI could be predicted in terms of a power-law regression with freshwater runoff. Longitudinal transects also were surveyed over periods of several hours. The FSI was observed to advect into the region on the flood with strong vertical mixing. After high water, stratification became intense as fresher water ebbed in the surface layers. The near-bed water in the stratified region began to ebb between 2 h and 3 h before low water. A model of the vertical structure of longitudinal currents showed that the enhanced stratification on the ebb, coupled with the longitudinal density gradient, partly produced this long period of slack, near-bed currents following high water. A strong turbidity maximum (TM) occurred during spring tides and was located slightly up-estuary of the FSI at high water. Longitudinal transects during a period of low freshwater runoff and large neap tide showed that at the start of the flood the TM was associated with the FSI region. As the FSI advected up-estuary on the flood there was considerable resuspension of sediment at the FSI. Some of this SPM moved with the FSI and reached the limit of saline intrusion, where it formed a slowly-eroding TM as particles settled during the long, high-water slack period. As the near-bed currents increased on the ebb and the FSI moved down-estuary, strong vertical mixing and resuspension of recently deposited sediment occurred in the unstratified water behind the FSI and the associated TM advected down-estuary. Additional effects were present with stronger tides and increased runoff.

Measurements of velocity, salinity, and suspended solids concentration have been used to investigate the intra-tidal variation of vertical and transverse shear-induced dispersion. For the study research the interaction of the longitudinal density gradient and vertical shear during the early part of the ebb tide accounted for much of the net longitudinal dispersion of solute landward. The same mechanism also is shown to lead to a net particulate transport landward. The landward flux, however, takes place during the flood tide. The field data are also used to elucidate the tidally averaged tidal pumping mechanism.

A one-dimensional, hydrodynamical model of the Tamar Estuary shows good agreement with measured tidal elevations and currents. Computed currents are used to drive a one-dimensional moving-element model of the salt balance. The moving-element model overcomes the numerical difficulties associated with strong tidal advection. Axial distributions of salinity at high water, computed using the moving-element model, compare well with measurements. The modelled and observed high water salinity distributions in this macrotidal estuary show little dependence on tidal range. The major variability in salinity is due to runoff. This strong and rapid dependence on runoff is a consequence of short residence (or flushing) times. Typically, residence times are less than one day throughout the year in the upper 10 km of estuary. The residence times maximize in summer, reaching 14 d for the whole estuary. During high runoff winter periods residence times are less than 5 d. Mixing coefficients for the moving-element salinity model are deduced from salinity measurements. Dispersion coefficients at fixed locations along the estuary are deduced from solutions of the salinity model. The spatially-averaged coefficients at mean spring and neap tides are 180 and 240 m2 s−1, respectively, for average runoff. Therefore, spring-neap variations in dispersion are fairly small and show a negative correlation with tidal range. The spatially-averaged dispersion coefficients at mean tides vary from 150 to 300 m2 s−1 for typical summer and winter runoff, respectively. The increase in dispersion with runoff and the decrease with tidal range implies that buoyancy-driven currents generate an important component of the shear dispersion in this estuary.

Twitch potentiation and the associated changes in contraction time and 1/2 relaxation time have been studied in a sample of 78 medial gastrocnemius motor units from 8 cats. Potentiation was produced by repetitive stimulation of the motor units every 10 sec with a brief tetanus followed 2 sec later by a twitch. Fast twitch fatigue resistant units were found to potentiate more strongly than either slow twitch (contraction time greater than 45 msec) or fast twitch fatigable units. It is concluded that Type C muscle fibres are more susceptible to potentiation than either Type A or Type B fibres. In a sample of 88 motor units from the same experiments, values for twitch/tetanus ratio were compared amongst units sharing similar mechanical properties. Slow contracting units developed small tetanic tensions and had small twitch/tetanus ratios. Fast twitch non fatigable units had intermediate values for contraction strength and twitch/tetanus ratio overlapping the ranges found for both the slow twitch and the more powerful fast twitch fatigable units. It is concluded that differences in twitch/tetanus ratio for medial gastrocnemius motor units are primarily related to motor unit contraction strength rather than differences in muscle fibre type.

The static force sensitivity of soleus tendon organ (Ib) afferents has been studied by noting their responses to graded force development produced by isometric contractions of either the whole muscle or single motor units. Data included responses of 23 Ib afferents to contraction of 8 whole muscles (8 experiments) and 16 Ib afferents to contraction of 30 motor units (5 experiments). Tendon organ responses of varying magnitude to contraction of the whole muscle or several of its individual motor units could be explained by differences in the number of muscle fibers that insert into each receptor's capsule and by differences in the contraction strength of these fibers. This finding suggests that soleus tendon organs have similar absolute sensitivities to static force development. An estimate was made of this absolute sensitivity and the value obtained (314 pps/g of force actually coupled to the receptor) is 2 orders of magnitude greater than those previously reported indices that simply relate Ib firing rate to force as measured at the tendon. The relationship between force exerted on a tendon organ's capsule and Ib firing rate is whown to be curvilinear and in keeping with a possible saturation effect that reduces the receptor's responsiveness to active contractions at relatively long muscle lengths.