Langstone Harbour Research Articles

Insights into PFAS contaminants before and after sewage discharges into a marine protected harbour

Per and polyfluoroalkyl substances (PFAS) and their degradation products are a concern to human and ecosystem health. Wastewater treatment plants are not efficient at removing PFAS compounds and are thought to be a major source of these compounds to marine environments. The sewerage infrastructure in the UK, has over 20,000 combined stormwater overflows (CSOs). These CSOs are relief values whereby untreated wastewater can discharge under permit from the Environment Agency with exceptional rain/snowfall conditions. CSOs discharged 3.6 million monitored hours of untreated wastewater into English rivers and coasts in 2023. Concerns have been raised about the proximity of these CSO discharges to highly protected marine habitats. This study is the first to determine that PFAS concentrations are elevated in a highly protected marine bay (Langstone Harbour, England) following recent sewage releases compared to an extended period without discharge. Analysis was carried out into a suite of 54 PFAS compounds of which only one (PFHpA) was detectable above LOD prior to discharges but 8 afterwards. These included banned PFOS (Linear and Branched 8.6 ng/L ∓ 0.90) and PFOA (2.9 ng/L ∓ 0.29) which were above annual average EQS for inland and ‘other’ surface waters. Most of the PFAS compounds detected doubled in concentration above LODs. These two-fold increases we discuss are likely conservative estimates based on the use of LODs and tidal conditions. Additional Oysters (Crassostrea gigas) and Seaweed (Fucus vesiculosus) were taken revealing high concentrations of the shorter chain PFBA (6.99μg/kg ∓ 2.42 ww) in seaweed samples. These seaweeds were calculated to have conservative bioaccumulation factors (BAF) > 6000 for PFBA indicating these algae might be an important reservoir of some PFAS contamination. We discuss these results in the context of the largescale discharges of untreated wastewater nationally and globally, and call upon a need for a better understanding of the transfer of PFAS contaminants into marine food chains.

Corrosion of Copper, Cupronickel, Nickel Aluminium Bronze and Super-Duplex Stainless Steel Rotating Cylinder Electrodes in Seawater under Turbulent Flow Conditions

The corrosion of uncoated metals in a marine environment restricts the choice of suitable engineering metals and alloys. Anodic dissolution of metal and cathodic reduction of oxygen are important processes and formation of a surface oxide film can affect both electrode reactions. Charge transfer and mass transfer data can provide information on corrosion rate and mechanism. Several metals and alloys having a history of use in marine engineering are considered, including copper, two copper alloys (cupronickel and nickel aluminium bronze) plus a more recent addition to strong, corrosion resistant alloys (a super duplex stainless steel). The rotating cylinder electrode offers the benefits of a controlled, turbulent flow of electrolyte, facilitating controlled mass transfer in a compact cell geometry which is well-suited to bench-top operation. These features are illustrated using a variety of electrochemical techniques, including open-circuit potential vs time monitoring, linear sweep voltammetry, rotation speed step- or potential step current transients and linear polarisation resistance measurements. Seawater taken from Langstone Harbour, Hampshire, UK, was filtered, air-saturated, pH 8.0 and maintained at 25 °C. Dimensionless group correlations and graphical plots (using an analogous approach to the Koutecky-Levich equation for an RDE) enabled contributions of charge transfer-, mixed- and mass transfer- controlled data to be appreciated, allowing the Tafel slopes of electrode reactions, the diffusion coefficient of dissolved oxygen, the mass transfer coefficient for oxygen reduction and the mean corrosion rate to be estimated.

Increasing numbers of harbour seals and grey seals in the Solent.

Harbour seals (Phoca vitulina) and grey seals (Halichoerus grypus) both occur within the UK, but display regional contrasting population trends. While grey seals are typically increasing in number, harbour seals have shown varying trends in recent decades following repeated pandemics. There is a need for monitoring of regional and local populations to understand overall trends. This study utilized a 20‐year dataset of seal counts from two neighboring harbours in the Solent region of south England. Generalized additive models showed a significant increase in the numbers of harbour (mean 5.3–30.5) and grey (mean 0–12.0) seals utilizing Chichester Harbour. Conversely, in Langstone Harbour there has been a slight decrease in the number of harbour seals (mean 5.3–4.0). Accompanying photographic data from 2016 to 18 supports the increase in seal numbers within Chichester Harbour, with a total of 68 harbour and 8 grey seals identified. These data also show evidence of site fidelity of harbour seals in this area, with almost a quarter of animals resighted within the past three years. Overall, this long‐term study indicates an increasing number of both harbour and grey seals within the Solent. However, more research is required to identify the drivers of this trend.

Unusual male size vs sperm count relationships in a coastal marine amphipod indicate reproductive impairment by unknown toxicants

Sperm quantity/quality are significant reproductive endpoints with clear links to population level dynamics. Amphipods are important model organisms in environmental toxicology. Despite this, field monitoring of male fertility in invertebrates has rarely been used in monitoring programs. The aim of this study was to compare sperm quality/quantity in an amphipod collected at six UK locations with differing water quality. Due to low sperm counts and an observed lack of relationship between sperm count and weight in amphipods collected from a nationally protected conservation area (Langstone Harbour, England), we also compared datasets from this site over a decade to determine the temporal significance of this finding. One collection to evaluate a female reproductive endpoint was also performed at this site. Interestingly, this harbour consistently presented some of the lowest sperm counts comparable to highly industrial sites and low eggs number from females. Amphipods collected from all the sites, except from Langstone Harbour, presented strong positive correlations between sperm count and weight. Given Langstone Harbour has several international and national protected statutes primarily for marine life and birds, our results indicate that E. marinus, one important food component for wading birds, might be impacted by unknown reproductive stressors. These unknown stressors maybe related to agricultural runoff, leachate from historical landfills and effluent from storm water overflows. This study highlights the importance of exploring new reproductive endpoints such as sperm quantity/quality in marine monitoring programs.

Infaunal Community Responses to the Gradient of Heavy-metals in Langstone Harbour, UK

The complex nature of the marine environments including a broad array of factors seems inconvenient to have specific indicator organisms alerting the changes in ecological quality based on pollutant inputs to water bodies. Benthic infauna, however, may respond to the pollution-induced spatial quality changes in a tidal inlet as they are incapable to avoid from the pollution sources and hence, from low quality of sediment and water. This research suggested that the interaction of sediment metal stressors and the possible associated factors finer grain fractions, estuary position and depth is likely to encounter with a specific distributional pattern of infauna. The communities of macroinfauna in Langstone Harbour were studied spatially from 36 samples collected across four subtidal stations, two each to the upper northern and the southern of the platform. The distinct variations in communities between and within stations and the most contributed species to variations were determined using multivariate analysis techniques. The structured model showed that the measured environmental factors explained 29.4% of infaunal community structure in the harbour with the highest contribution of chromium (6.6%). Environmental patterns suggested the increasing metal deposition in the finergrained muddy sediments towards the innermost basin with stagnant and shallower waters.

A novel marine genus, Halobyssothecium (Lentitheciaceae) and epitypification of Halobyssothecium obiones comb. nov.

A novel marine genus, Halobyssothecium (Lentitheciaceae), is introduced to accommodate Byssothecium obiones (= Halobyssothecium obiones) with evidence from phylogenetic analyses of concatenated LSU, SSU, ITS rDNA, and TEF1 sequence data. We could not locate any type material for this species and there is no molecular data available for the type of this species. Therefore, an epitype is designated for the precise delineation of this taxon. A detailed morphological description and DNA characterization based on LSU, SSU, ITS rDNA, and TEF1 sequence data are provided for the epitype, obtained from Spartina culms in Eastney, Langstone Harbour, Hampshire, UK.

Development and evaluation of a new diffusive gradients in thin-films technique for measuring organotin compounds in coastal sediment pore water

Organotins present a toxicological risk to biota in the aquatic environment. Understanding the behaviour of these compounds in sediment is challenging, with sophisticated analytical techniques required for their measurement. We investigated the use of silica-bound sorbents for diffusive gradients in thin-films (DGT) adsorption gels to pre-concentrate five organotins (monobutlytin (MBT), dibutyltin (DBT), tributyltin (TBT), diphenyltin (DPhT), triphenyltin (TPhT)) found frequently in coastal sediment. C8 sorbent showed optimum performance in uptake and recovery of organotins for pH and ionic strength ranges typical of coastal waters. Recoveries from adsorption gels deployed in filtered sea water were MBT = 123 ± 20%, DBT = 75 ± 12%, TBT = 81 ± 16%, DPhT = 72 ± 30%, TPhT = 58 ± 10% respectively. Devices were used to investigate DGT fluxes and pore water concentrations of organotins in coastal sediment collected from a contaminated site. DGT fluxes measured in sediment cores for the five organotins ranged between 4.3 × 10−8 and 1.6 ×10−5ngcm2s−1. The depletion of organotin species within pore waters at the interface with DGT devices was measured over a series of deployment times (2, 7, 14, 21 and 28 days) and provided estimates of the concentration of organotins in pore waters at Langstone Harbour, UK, prior to depletion by the DGT device and information on their spatial heterogeneity. The novel in situ DGT device developed can pre-concentrate organotins from pore waters in coastal sediment core samples and allows their detection at low environmental concentrations using conventional gas chromatographic/mass spectrometric instrumentation. Use of the DGT device overcomes many problems associated with the conventional pore water sampling of organotins. Our preliminary data suggests it has potential in the future to be a useful tool in investigating the environmental fate of these pollutants. The use of the C8 gel will also allow for the simultaneous sequestration of other semi- and non-polar analytes present in the pore water.

Reproductive biology and population ecology of the marine fan worm Sabella pavonina (Savigny) (Polychaeta: Sabellidae)

The reproductive biology and population ecology of the sabellid polychaete, Sabella pavonina (Savigny) inhabiting an intertidal sand bank in Langstone Harbour, Portsmouth, was investigated between February 2007 and June 2009. ‘Blind’ thrown quadrats and sediment cores were used to characterise population distribution patterns at the site, and monthly coelomic fluid samples from 30 individuals were used to investigate the reproductive biology of the population, sex of the specimen, the presence of coelomocytes and the development of oocytes. Highest population densities (30.58 m−2 ± 8.05) were recorded on the low shore (0.4 m above chart datum) where the largest size particle fractions and lowest percentage organic content were found. Poisson distribution analysis showed the population was ‘clumped’ at the shore level, with a maximum number of 188 individuals in a 0.25 m2 quadrat, and within individual quadrats with up to 23 individuals in a 100 cm2 subsection. Sabella pavonina has an annual reproductive cycle which culminates in May/June spawning period. Oogenesis was a long process, first observed by the presence of small eggs (20 µm) from September onwards and maximum oocyte diameters were recorded (270 µm) between May and June prior to spawning. Between- and within-individual synchronicity was greatest in the early stages of oogenesis (October to February) when oocyte diameters ranged from 50–100 µm; however, increasing oocyte diameters were observed from March when rapid growth was initiated. Day length and sea temperature are candidates for exogenous cues controlling gametogenesis and possible mechanisms concerning fertilization in the species are discussed.

Colonisation and modification of soft substratum habitats by the invasive macroalga Sargassum muticum

Sargassum muticum is an invasive brown macroalga that originates from Japan. In the introduced range, thalli can grow in soft substratum habitats attached to embedded rock fragments and shells. Within Strangford Lough, Northern Ireland, S. muticum has rapidly colonised large areas of soft substrata, where dispersal by peripatetic or 'stone-walking' plants is very effective. Sediment cores were collected under and outside canopies of S. muticum in Strangford Lough (S. muticum first recorded there in 1995) and Langstone Harbour, English Channel (S. muticum first found there in 1974) to investigate modification of the infaunal assemblages. At both study sites, community analy- ses highlighted significant differences between the assemblages under the canopies and those in adjacent unvegetated areas. In Strangford Lough, the invertebrate community under the canopy con- tained a higher abundance of smaller, opportunistic, r-selected species than outside the canopy. By contrast, the communities under and outside the canopy at Langstone Harbour were similar in spe- cies composition, diversity and dominance, but overall faunal abundance was greater under the canopy. Sediment characteristics were not affected by S. muticum canopies, but the infaunal changes may be related to environmental modification; shading, flow suppression and temperature stratifica- tion were also investigated. The differences between these 2 sites indicate that localised conditions and/or the duration of colonisation of S. muticum are important in determining the nature of habitat modification.

Effects of Chromated Copper Arsenate (CCA) Wood Preservative on Early Fouling Community Formation

The effects of the anti-marine-borer timber preservative CCA (a pressure impregnated solution of copper, chromium and arsenic compounds) on early fouling community formation were investigated during a number of field trials. The formation of a biofilm on the surface of CCA-treated and untreated timber panels of Scots pine was examined by scanning electron microscopy following submersion in Langstone Harbour, Portsmouth, UK for periods of 2, 7, 14 and 28 days. Results indicated a slightly faster rate of biofilm formation after 2 and 7 days of exposure on untreated timber compared to CCA-treated timber, although no differences were visible between panels after 14 and 28 days exposure, or between panels treated to different CCA loadings after all exposure periods. Settlement of the serpulid Ficopomatus enigmaticus and two species of barnacles ( Elminius modestus and Balanus crenatus) onto the surface of untreated and CCA-treated panels of Scots pine was examined following 4 weeks exposure in a brackish water millpond at Emsworth, West Sussex. Numbers of individuals were higher on CCA-treated panels than on untreated panels, and in the case of F. enigmaticus abundance of individuals increased with increasing preservative loadings. Early colonization by macroalgal species on the surface of CCA-treated and untreated panels of Scots pine was examined following submersion of panels in Langstone Harbour for a period of 4 weeks. Percentage cover of most species of algae was similar on the surface of CCA-treated and untreated panels, with the exception of Hincksia granulosa and Ceramium nodulosum which had significantly higher percentage cover on untreated panels. Possible explanations for the recruitment patterns are discussed.

Toxicity of Chromated Copper Arsenate (CCA)-Treated Wood to Non-Target Marine Fouling Communities in Langstone Harbour, Portsmouth, UK

The effect of the anti-marine-borer timber preservative chromated copper arsenate (CCA) (a pressure impregnated solution of copper, chromium and arsenic compounds) on non-target marine fouling animals was investigated during a subtidal exposure trial. Panels of Scots pine treated to target retentions of 12, 24 and 48 kg CCA per m −3 of wood, plus untreated controls were submerged at a coastal site on the south coast of the UK for 6, 12 and 18 months. After each exposure period the fouling communities that formed on the surface of panels were assessed both qualitatively and quantitatively. Community structure was similar on panels treated to the three CCA loadings, but was significantly different from community structure on untreated panels. The total number of species (species richness) was similar on all panels, although the number of individual organisms attached to the surface of panels was significantly higher on CCA-treated panels than on untreated panels. k-dominance curves revealed that the difference in numbers of individuals between CCA-treated and untreated panels was caused by higher numbers of the dominant species ( Elminius modestus, Hydroides ezoensis, and Electra pilosa) on CCA-treated panels. Other species were present in similar numbers on panels of all treatments. Results indicate that there are no detrimental toxic effects to epibiota caused by the presence of CCA preservative within the matrix of the wood at any of the treatment levels. Differences in community structure between CCA-treated and untreated panels may be due to enhanced larval settlement on CCA-treated timber by some species as a result of modifications to the surface properties of the timber by the CCA preservative.

The use of historical photography in environmental studies

The time-scales over which significant environmental changes take place can vary from a few hours on highly mobile coastal sediments to tens or even hundreds of years on exposed stone surfaces. Studies of rapidly changing features can be carried out using traditional field monitoring techniques, perhaps aided by airborne or satellite imagery if the scale of change is sufficiently large. Less dynamic surfaces do not lend themselves to such methods since, over the time-scale of traditional research projects, the amount of change will be less than the known errors in the measurement techniques. This paper describes the use of historical aerial photographs to study changes in an inter-tidal environment, around Langstone Harbour and Chichester Harbour (U.K.), and discusses the advantages and limitations of this data source.

Langstone oysterbeds restoration

This paper describes a major environmental enhancement project to remove builders' rubble from the internationally important but sensitive waters of Lang-stone Harbour in Havant, Hampshire. The civil engineering work was carried out at no cost to the borough council in an innovate partnership scheme whereby the contractor retained income from the sale of the recycled aggregate which resulted from the work. The problems encountered in carrying out such a project are described, together with the unexpected opportunities. The success of the project was a direct result of the teamwork approach to management which involved a significant number of non-contractual but carefully chosen parties within the management team, working together with a single overall aim but each willing to consider views of the rest. The future of the site as a local nature reserve and recipient of subsequent European Community ‘Life’ funding is also considered.

LANGSTONE OYSTERBEDS RESTORATION.

This paper describes a major environmental enhancement project to remove builders' rubble from the internationally important but sensitive waters of Lang-stone Harbour in Havant, Hampshire. The civil engineering work was carried out at no cost to the borough council in an innovate partnership scheme whereby the contractor retained income from the sale of the recycled aggregate which resulted from the work. The problems encountered in carrying out such a project are described, together with the unexpected opportunities. The success of the project was a direct result of the teamwork approach to management which involved a significant number of non-contractual but carefully chosen parties within the management team, working together with a single overall aim but each willing to consider views of the rest. The future of the site as a local nature reserve and recipient of subsequent European Community ‘Life’ funding is also considered.

The green tide threat in the UK — a brief overview with particular reference to Langstone Harbour, south coast of England and the Ythan Estuary, east coast of Scotland

Summary World-wide, our coastal waters have been subject to an increased nutrient input since the latter part of the nineteenth century. This has led to the eutrophication or ‘nutrient pollution’ of many coastal sites, including Langstone Harbour and the Ythan Estuary here in the UK. Eutrophication at these and, indeed, at other nutrient enriched sites is evident by the appearance of large blooms of fast-growing opportunistic macroalgae. Blooms of macroscopic species of green algae (Chlorophyta: Ulvophyceae) are particularly common and the phenomenon is often referred to as the occurrence of green tides. Green tides may have a dramatic environmental impact, causing much damage to the local ecosystem. Numerous strategies have hence been employed in order to combat the problem, but to date there has been limited success. For this reason, current research in the UK is aimed at increasing our knowledge of green tide algae in terms of their ecophysiology, whilst further investigation of the nutrient pathways and fluxes within specific ecosystems has been deemed necessary. It is anticipated that this ‘backto basics’ approach will ultimately contribute to the development of new, successful eutrophication management strategies.

A geophysical investigation of saline intrusion and geological structure beneath areas of tidal coastal wetland at Langstone Harbour, Hampshire, UK

Abstract Experiments are described that test how tide and geological structure affect saline intrusion beneath an area of coastal wetland in Hampshire, southern England. Resistivity tomography and time-dependent ground conductivity surveys were carried out at two closely located survey sites. Resultant maps and sections show clear geophysical anomalies that can be attributed to tidal saline intrusion and to the position of geological structures. Results suggest that migration of saline groundwater is, in places, out of phase with the tidal cycle, and is concentrated along sub-surface tidal channels, gravel aquifers and depressions in Chalk bedrock topography. We conclude that the seawater-fresh-water boundary in the studied wetland environment is complicated by shallow-level saline flow along geologically definable routes within the Quaternary deposits above the less permeable Chalk bedrock.

Observations on the mechanisms of attachment of some marine fouling blue‐green algae

Using scanning electron microscopy (SEM), differential interference contrast microscopy (DICM) and cytochemical staining techniques, preliminary observations have been made on the mechanisms of attachment of some common, marine, benthic fouling blue-green algae ("cyanobacteria") isolated into culture from various toxic and non-toxic surfaces in Langstone Harbour, south coast of England. Blue-green algae investigated included species of Calothrix, Dermocarpa, Plectonema, Phormidium and Xenococcus. The blue-green algae are rapid colonisers and can make an important contribution to the pioneering communities on both toxic and non-toxic surfaces. A characteristic feature of the colonization process is the production of variable quantities of extracellular polymeric substances (EPS) which appear to function as adhesives. Cytochemical staining revealed the EPS to be an acidic polysaccharide and, therefore, chemically similar to the EPS produced by sessile diatoms. It is suggested that the EPS additionally assists in cell motility, acts as an antidesiccant and may influence the fouling process by combining with antifouling paint toxins and modifying the surface energy of substrata.

GIS mapping of Langstone Harbour for an integrated ecological and archaeological study

The work discussed in this paper aims to develop a Geographic Information System (GIS) to hold and display environmental and archeological data for the analysis of an inter-tidal zone. Langstone Harbour on the south coast of Hampshire, England, forms the study area. The work is being carried out with the support of The Royal Society for the Protection of Birds (RSPB) and Hampshire County Council. As it was found that existing topographic mapping would not provide a suitable topographic base for such an inter-tidal area, metric aerial photography and analytical photogrammetry were employed to create a detailed topographic base. The photogrammetric models were fitted within a control network established using a high precision differential Global Positioning System (GPS). Recorded three dimensional coordinates of archaeological finds and structures will allow the comparison between environmental and locational contexts of coastal archaeological structures. This will greatly enlarge the available archaeological data set, adding value to the data, as well as assisting the study of sea level change and wider coastal processes. Conversion and integration of other environmental data is adding further data layers of the GIS.

GIS mapping of Langstone Harbour for an integrated ecological and archaeological study

The work discussed in this paper aims to develop a Geographic Information System (GIS) to hold and display environmental and archeological data for the analysis of an inter-tidal zone. Langstone Harbour on the south coast of Hampshire, England, forms the study area. The work is being carried out with the support of The Royal Society for the Protection of Birds (RSPB) and Hampshire County Council. As it was found that existing topographic mapping would not provide a suitable topographic base for such an inter-tidal area, metric aerial photography and analytical photogrammetry were employed to create a detailed topographic base. The photogrammetric models were fitted within a control network established using a high precision differential Global Positioning System (GPS). Recorded three dimensional coordinates of archaeological finds and structures will allow the comparison between environmental and locational contexts of coastal archaeological structures. This will greatly enlarge the available archaeological data set, adding value to the data, as well as assisting the study of sea level change and wider coastal processes. Conversion and integration of other environmental data is adding further data layers of the GIS.

Tidal Inlet Equilibrium, in Relation to Cross-sectional Area and Sediment Transport Patterns

Equilibrium cross-sectional area is a crucial parameter in the assessment of the stability of tidal inlets; it has been related to tidal prism, through the empirical O'Brien method. Analyses presented here, based upon equations associated with equilibrium, show that other factors (i.e. not tidal prism alone) are also important: (1) flood and ebb tidal durations; (2) freshwater discharges; and (3) sediment transport through the entrance. Analytical approaches are suggested for evaluating tidal inlet equilibrium conditions. The method can be applied to analyse the equilibrium of individual inlets, reducing errors in the application of the O'Brien method. Equilibrium conditions for inlet systems at Langstone Harbour (southern England) and Yangpu Harbour (southern China) are compared, suggesting some deviation from the conclusion that maximum cross-sectional mean current speed for a stable inlet should be around 1·0 m s -1.