Assessment of the potential impacts of coasteering on rocky intertidal habitats in Wales

The relatively new recreational pursuit of coasteering, which has developed in the St David's area of Pembrokeshire, appears to be expanding rapidly. The majority of local commercial recreation providers (outdoor pursuit centers etc.) now appear to offer this pursuit. The majority of the rocky coastlines where it takes place lie within Pembrokeshire Marine Special Area of Conservation (SAC), and are also Sites of Special Scientific Interest (SSSI). No assessment has yet been undertaken of coasteering's potential impact on the intertidal habitats. Therefore the Countryside Council for Wales (CCW) commissioned the Marine Life Information Network (MarLIN) to undertake a desk study of the likely environmental effects of coasteering on rocky intertidal habitats within the Pembrokeshire marine SAC. The desk study was based on a review of the available literature, and in particular the effects of trampling on rocky intertidal communities. Communities (as biotopes) within the Pembrokeshire marine SAC likely to be exposed to coasteering activities were identified from Phase I biotope data for the area, provided by CCW. Where possible, existing research by MarLIN into the intolerance, recoverability and sensitivity of the biotopes identified, was used to identify their potential vulnerability to trampling. The literature review revealed that: - foliose canopy forming algae (e.g. fucoids) were particularly intolerant and sensitive to trampling impacts; - trampling damaged erect coralline turfs, barnacles, and resulted in an increase in bare space; in some cases paths across the shore were visible; - on brown algae dominated shores, understorey algae could suffer due to increased desiccation but algal turf species, opportunists and gastropod grazers (e.g. limpets) could increase in abundance as an indirect effect of trampling, and that - trampling impacts resulted from physical contact and wear and were dependant on the intensity, duration, and frequency of trampling, and even the type of footwear used. A total of 19 intolerant rocky intertidal biotopes were identified as potentially vulnerable to trampling and hence coasteering within the Pembrokeshire marine SAC, of which six are of Welsh importance and eight are nationally rare or scarce. Trampling is a highly localized impact and it was not possible to identify biotopes, and hence communities, actually impacted by coasteering activities in the Pembrokeshire marine SAC. In addition, the majority of the literature addresses the impacts of trampling on wave sheltered or moderately exposed brown algal dominated shores, while coasteering occurs on more wave exposed, steeply inclined shores. Therefore, direct survey of the routes used by coasteering groups within the Pembrokeshire marine SAC is required to identify the intensity, duration and frequency of trampling impact, together with the communities impacted. Given the paucity of data concerning trampling effects in the rocky intertidal in the UK, a survey of the impacts of coasteering would provide an opportunity to examine the effects of trampling and visitor use in steep rocky, wave exposed shores. The report recognizes the potential to engage coasteerers in contributing to the development of strategies for minimizing adverse impacts, recording impacts and collecting information of use in identifying climate change and the occurrence of non-native species.

Acquisition of continuous plankton recorder data

The Continuous Plankton Recorder has been deployed on a seasonal basis in the north Pacific since 2000, accumulating a database of abundance measurements for over 290 planktonic taxa in over 3,500 processed samples. There is an additional archive of over 10,000 samples available for further analyses. Exxon Valdez Oil Spill Trustee Council financial support has contributed to about half of this tally, through four projects funded since 2002. Time series of zooplankton variables for sub-regions of the survey area are presented together with abstracts of eight papers published using data from these projects. The time series covers a period when the dominant climate signal in the north Pacific, the Pacific Decadal Oscillation (PDO), switched with unusual frequency between warm/positive states (pre-1999 and 2003-2006) and cool/negative states (1999-2002 and 2007). The CPR data suggest that cool negative years show higher biomass on the shelf and lower biomass in the open ocean, while the reverse is true in warm (PDO positive) years with lower shelf biomass (except 2005) and higher oceanic biomass. In addition, there was a delay in plankton increase on the Alaskan shelf in the colder spring of 2007, compared to the warmer springs of the preceding years. In warm years, smaller species of copepods which lack lipid reserves are also more common. Availability of the zooplankton prey to higher trophic levels (including those that society values highly) is therefore dependent on the timing of increase and peak abundance, ease of capture and nutritional value. Previously published studies using these data highlight the wide-ranging applicability of CPR data and include collaborative studies on; phenology in the key copepod species Neocalanus plumchrus, descriptions of distributions of decapod larvae and euphausiid species, the effects of hydrographic features such as mesoscale eddies and the North Pacific Current on plankton populations and a molecularbased investigation of macro-scale population structure in N. cristatus. The future funding situation is uncertain but the value of the data and studies so far accumulated is considerable and sets a strong foundation for further studies on plankton dynamics and interactions with higher trophic levels in the northern Gulf of Alaska.

Monitoring changes in phytoplankton abundance and composition in the Northwest Atlantic: a comparison of results obtained by Continuous Plankton Recorder sampling and colour satellite imagery

Phytoplankton abundance in the NW Atlantic was measured by continuous plankton recorder (CPR) sampling along tracks between Iceland and the western Scotian Shelf from 1998 to 2006, when sea-surface chlorophyll (SSChl) measurements were also being made by ocean colour satellite imagery using the SeaWiFS sensor. Seasonal and inter-annual changes in phytoplankton abundance were examined using data collected by both techniques, averaged over each of four shelf regions and four deep ocean regions. CPR sampling had gaps (missing months) in all regions and in the four deep ocean regions satellite observations were too sparse between November and February to be of use. Average seasonal cycles of SSChl were similar to those of total diatom abundance in seven regions, to those of the phytoplankton colour index in six regions, but were not similar to those of total dinoflagellate abundance anywhere. Large inter-annual changes in spring bloom dynamics were captured by both samplers in shelf regions. Changes in annual (or 8 months) averages of SSChl did not generally follow those of the CPR indices within regions and multi-year averages of SSChl, and the three CPR indices were generally higher in shelf than in deep ocean regions. Remote sensing and CPR sampling provide complementary ways of monitoring phytoplankton in the ocean: the former has superior temporal and spatial coverage and temporal resolution, and the latter provides better taxonomic information.

A method for semi-automated objective quantification of linear bedforms from multi-scale Digital Elevation Models

The increasing availability of large, detailed digital representations of the Earth’s surface demands the application of objective and quantitative analyses. Given recent advances in the understanding of the mechanisms of formation of linear bedform features from a range of environments, objective measurement of their wavelength, orientation, crest and trough positions, height and asymmetry is highly desirable. These parameters are also of use when determining observation-based parameters for use in many applications such as numerical modelling, surface classification and sediment transport pathway analysis. Here, we (i) adapt and extend extant techniques to provide a suite of semi-automatic tools which calculate crest orientation, wavelength, height, asymmetry direction and asymmetry ratios of bedforms, and then (ii) undertake sensitivity tests on synthetic data, increasingly complex seabeds and a very large-scale (39 000km2) aeolian dune system. The automated results are compared with traditional, manually derived,measurements at each stage. This new approach successfully analyses different types of topographic data (from aeolian and marine environments) from a range of sources, with tens of millions of data points being processed in a semi-automated and objective manner within minutes rather than hours or days. The results from these analyses show there is significant variability in all measurable parameters in what might otherwise be considered uniform bedform fields. For example, the dunes of the Rub’ al Khali on the Arabian peninsula are shown to exhibit deviations in dimensions from global trends. Morphological and dune asymmetry analysis of the Rub’ al Khali suggests parts of the sand sea may be adjusting to a changed wind regime from that during their formation 100 to 10 ka BP.