Records of adventive marine algae in New Zealand: Antithamnionella ternifolia, Polysiphonia senticulosa (Ceramiales, Rhodophyta), and Striaria attenuata (Dictyosiphonales, Phaeophyta)

Three species of introduced marine macroalgae are reported for Wellington Harbour (North Island, New Zealand). One of these, Polysiphonia senticulosa (Ceramiales, Rhodophyta) is illustrated from New Zealand for the first time, and the known distributional ranges of two species, Striaria attenuata (Dictyosiphonales, Phaeophyta) and Antithamnionella ternifolia (Ceramiales, Rhodophyta), are extended to the North Island.

Ages of 24 widespread tephras erupted since 30,000 years ago in New Zealand, with re-evaluation of the timing and palaeoclimatic implications of the Lateglacial cool episode recorded at Kaipo bog

Tephras are important for the NZ-INTIMATE project because they link all three records comprising the composite inter-regional stratotype developed for the New Zealand climate event stratigraphy (NZ-CES). Here we firstly report new calendar ages for 24 widespread marker tephras erupted since 30,000 calendar (cal.) years ago in New Zealand to help facilitate their use as chronostratigraphic dating tools for the NZ-CES and for other palaeoenvironmental and geological applications. The selected tephras comprise 12 rhyolitic tephras from Taupo, nine rhyolitic tephras from Okataina, one peralkaline rhyolitic tephra from Tuhua, and one andesitic tephra each from Tongariro and Egmont/Taranaki volcanic centres. Age models for the tephras were obtained using three methods: (i) C-based wiggle-match dating of wood from trees killed by volcanic eruptions (these dates published previously); (ii) flexible depositional modelling of a high-resolution C-dated age-depth sequence at Kaipo bog using two Bayesian-based modelling programs, Bacon and OxCal's P_Sequence function, and the IntCal09 data set (with SH offset correction-44±17yr); and (iii) calibration of C ages using OxCal's Tau_Boundary function and the SHCal04 and IntCal09 data sets. Our preferred dates or calibrated ages for the 24 tephras are as follows (youngest to oldest, all mid-point or mean ages of 95% probability ranges): Kaharoa AD 1314±12; Taupo (Unit Y) AD 232±10; Mapara (Unit X) 2059±118cal.yrBP; Whakaipo (Unit V) 2800±60cal.yrBP; Waimihia (Unit S) 3401±108cal.yrBP; Stent (Unit Q) 4322±112cal.yrBP; Unit K 5111±210cal.yrBP; Whakatane 5526±145cal.yrBP; Tuhua 6577±547cal.yrBP; Mamaku 7940±257cal.yrBP; Rotoma 9423±120cal.yrBP; Opepe (Unit E) 9991±160cal.yrBP; Poronui (Unit C) 11,170±115cal.yrBP; Karapiti (Unit B) 11,460±172cal.yrBP; Okupata 11,767±192cal.yrBP; Konini (bed b) 11,880±183cal.yrBP; Waiohau 14,009±155cal.yrBP; Rotorua 15,635±412cal.yrBP; Rerewhakaaitu 17,496±462cal.yrBP; Okareka 21,858±290cal.yrBP; Te Rere 25,171±964cal.yrBP; Kawakawa/Oruanui 25,358±162cal.yrBP; Poihipi 28,446±670cal.yrBP; and Okaia 28,621±1428cal.yrBP.Secondly, we have re-dated the start and end of the Lateglacial cool episode (climate event NZce-3 in theNZ-CES), previously referred to as the Lateglacial climate reversal, as defined at Kaipo bog in eastern North Island, New Zealand, using both Bacon and OxCal P_Sequence modelling with the IntCal09 data set. The ca1200-yr-long cool episode, indicated by a lithostratigraphic change in the Kaipo peat sequence to grey mudwith lowered carbon content, and a high-resolution pollen-derived cooling signal, began 13,739±125cal.yrBP and ended 12,550±140cal.yrBP (mid-point ages of the 95% highest posterior density regions, Bacon modelling). The OxCal modelling, generating almost identical ages, confirmed these ages. The Lateglacial cool episode (ca 13.8-12.6cal.kaBP) thus overlaps a large part of the entire Antarctic Cold Reversal chronozone (ca 14.1-12.4cal.kaBP or ca 14.6-12.8cal.kaBP), and an early part of the Greenland Stadial-1 (Younger Dryas) chronozone (ca 12.9-11.7cal.kaBP). The timing of the Lateglacial cool episode at Kaipo is broadly consistent with the latitudinal patterns in the Antarctic Cold Reversal signal suggested for the New Zealand archipelago from marine and terrestrial records, and with records from southern South America. © 2012 Elsevier Ltd.

A composite pollen-based stratotype for inter-regional evaluation of climatic events in New Zealand over the past 30,000 years (NZ-INTIMATE project)

Our review of paleoclimate information for New Zealand pertaining to the past 30,000 years has identified a general sequence of climatic events, spanning the onset of cold conditions marking the final phase of the Last Glaciation, through to the emergence to full interglacial conditions in the early Holocene. In order to facilitate more detailed assessments of climate variability and any leads or lags in the timing of climate changes across the region, a composite stratotype is proposed for New Zealand. The stratotype is based on terrestrial stratigraphic records and is intended to provide a standard reference for the intercomparison and evaluation of climate proxy records. We nominate a specific stratigraphic type record for each climatic event, using either natural exposure or drill core stratigraphic sections. Type records were selected on thebasis of having very good numerical age control and a clear proxy record. In all cases the main proxy of the type record is subfossil pollen. The type record for the period from ca 30 to ca 18 calendar kiloyears BP (cal. ka BP) is designated in lake-bed sediments from a small morainic kettle lake (Galway tarn) in western South Island. The Galway tarn type record spans a period of full glacial conditions (Last Glacial Coldest Period, LGCP) within the Otira Glaciation, and includes three cold stadials separated by two cool interstadials. The type record for the emergence from glacial conditions following the termination of the Last Glaciation (post-Termination amelioration) is in a core of lake sediments from a maar (Pukaki volcanic crater) in Auckland, northern North Island, and spans from ca 18 to 15.64±0.41 cal. ka BP. The type record for the Lateglacial period is an exposure of interbedded peat and mud at montane Kaipo bog, eastern North Island. In this high-resolution type record, an initial mild period was succeeded at 13.74±0.13 cal. ka BP by a cooler period, which after 12.55±0.14 cal. ka BP gave way to a progressive ascent to full interglacial conditions that were achieved by 11.88±0.18 cal. ka BP. Although a type section is not formally designated for the Holocene Interglacial (11.88±0.18 cal. ka BP to the present day), the sedimentary record of Lake Maratoto on the Waikato lowlands, northwestern North Island, is identified as a prospective type section pending the integration and updating of existing stratigraphic and proxy datasets, and age models. The type records are interconnected by one or more dated tephra layers, the ages of which are derived from Bayesian depositional modelling and OxCal-based calibrations using the IntCal09 dataset. Along with the type sections and the Lake Maratoto record, important, well-dated terrestrial reference records are provided for each climate event. Climate proxies from these reference records include pollen flora, stable isotopes from speleothems, beetle and chironomid fauna, and glacier moraines. The regional composite stratotype provides a benchmark against which to compare other records and proxies. Based on the composite stratotype, we provide an updated climate event stratigraphic classification for the New Zealand region. © 2013 Elsevier Ltd.

North/South Infrastructure Development via Cross-border PPP Mechanism

Both Northern Ireland and Republic of Ireland governments recognise the current infrastructural deficits in their respective jurisdictions which, if not addressed, will undermine the future economic prosperity of both regions. This paper considers the adoption of a collaborative approach on the island to addressing the deficit, using public private partnerships (PPP) as the delivery vehicle. It presents a critical perspective of the challenges and opportunities posed by adopting such a cross-border approach. Whilst PPPs have the potential to bring about North-South co-operation, bridge gaps in infrastructure capacity and facilitate the advancement of sectoral knowledge, their adoption on a cross border basis will require significant reorganisation and change at administrative and sectoral levels. This review concludes that governments and construction sector representatives in Northern Ireland and the Republic of Ireland have still some work to do in order to enhance the capability and readiness of public and private partners to evolve an all-island PPP infrastructure development approach.

Problems with identifying the '8200-year cold event' in terrestrial records of the Atlantic seaboard: a case study from Dooagh, Achill Island, Ireland.

The Northern Hemisphere cooling event 8200 years ago is believed to represent the last known major freshwater pulse into the North Atlantic as a result of the final collapse of the North American Laurentide ice sheet. This pulse of water is generally believed to have occurred independently of orbital variations and provides an analogue for predicted increases in high-latitude precipitation and ice melt as a result of anthropogenically driven future climate change. The precise timing, duration and magnitude of this event, however, are uncertain, with suggestions that the 100-yr meltwater cooling formed part of a longer-term cold period in the early Holocene. Here we undertook a multiproxy, high-resolution investigation of a peat sequence at Dooagh, Achill Island, on the west coast of Ireland, to determine whether the 8200-year cold event impacted upon the terrestrial vegetation immediately downwind of the proposed changes in the North Atlantic. We find clear evidence for an oscillation in the early Holocene using various measures of pollen, indicating a disruption in the vegetation leading to a grassland-dominated landscape, most probably driven by changes in precipitation rather than temperature. Radiocarbon dating was extremely problematic, however, with bulk peat samples systematically too young for the North Atlantic event, suggesting significant contamination from downward root penetration. The sustained disruption to vegetation over hundreds of years at Dooagh indicates the landscape was impacted by a long-term cooling event in the early Holocene, and not the single century length 8200-year meltwater event proposed in many other records in the North Atlantic region.

ANTITHAMNION-DENSUM (SUHR) HOWE FROM CLARE ISLAND, IRELAND - A MARINE RED ALGA NEW TO THE BRITISH-ISLES

The diminutive marine red alga Antithamnion densum (Suhr) Howe (Ceramiales, Rhodophyta), previously known in the north Atlantic from three sites in north-western France, is reported from the subtidal of a wave-exposed site at Clare I., Co. Mayo, Ireland, where it grows epiphytically on various macroalgae. The previously restricted distribution of this species in the North Atlantic gave rise to speculation that it represented an introduced plant. The geographical isolation of the Irish locality and the restricted habitat in which plants were found suggests that A. densum may be native to the north eastern Atlantic. However, the finding of the Trailliella-phase of the adventive red alga Bonnemaisonia hamifera Hariot at Clare I. in 1911, shortly after it had been discovered on the south coast of England, indicates the potential for the transport of introduced species to the west coast of Ireland.

Ancient manuring practices pollute arable soils at the St Kilda World Heritage Site, Scottish North Atlantic

The impact of ancient fertilization practices on the biogeochemistry of arable soils on the remote Scottish island of Hirta, St Kilda was investigated. The island was relatively unusual in that the inhabitants exploited seabird colonies for food, enabling high population densities to be sustained on a limited, and naturally poor, soil resource. A few other Scottish islands, the Faeroes and some Icelandic Islands, had similar cultural dependence on seabirds. Fertilization with human and animal waste streams (mainly peat ash and bird carcases) on Hirta over millennia has led to over-deepened, nutrient-rich soils (plaggen). This project set out to examine if this high rate of fertilization had adversely impacted the soil, and if so, to determine which waste streams were responsible. Arable soils were considerably elevated in Pb and Zn compared to non-arable soils. Using Pb isotope signatures and analysis of the waste streams, it was determined that this pollution came from peat and turf ash (Pb and Zn) and from bird carcases (Zn). This was also confirmed by (13)C and (15)N analysis of the profiles which showed that soil organic matter was highly enriched in marine-derived C and N compared to non-arable soils. The pollution of such a remote island may be typical of other 'bird culture' islands, and peat ash contamination of marginal arable soils at high latitudes may be widespread in terms of geographical area, but less intense at specific locations due to lower population densities than on Hirta.

Mantle flow, volatiles, slab-surface temperatures and melting dynamics in the north Tonga arc-Lau back-arc basin

The Fonualei Spreading Center affords an excellent opportunity to evaluate geochemical changes with increasing depth to the slab in the Lau back-arc basin. We present H2O and CO2 concentrations and Sr, Nd, Pb, Hf and U-Th-Ra isotope data for selected glasses as well as new Hf isotope data from boninites and seamounts to the north of the Tonga arc. The Pb and Hf isotope data are used to show that mantle flow is oriented to the southwest and that the tear in the northern end of the slab may not extend east as far as the boninite locality. Along the Fonualei Spreading Center, key geochemical parameters change smoothly with increasing distance from the arc front and increasing slab surface temperatures. The latter may range from 720 to 866 degrees C, based on decreasing H2O/Ce ratios. Consistent with experimental data, the geochemical trends are interpreted to reflect changes in the amount and composition of wet pelite melts or super-critical fluids and aqueous fluids derived from the slab. With one exception, all of the lavas preserve both U-238 excesses and Ra-226 excesses. We suggest that lavas from the Fonualei Spreading Center and Valu Fa Ridge are dominated by fluid-fluxed melting whereas those from the East and Central Lau Spreading Centers, where slab surface temperatures exceed similar to 850-900 degrees C, are largely derived through decompression. A similar observation is found for the Manus and East Scotia back-arc basins and may reflect the expiry of a key phase such as lawsonite in the subducted basaltic crust.

Homogenization and analysis of an expanded long-term monthly rainfall network for the Island of Ireland (1850–2010)

Long-term precipitation series are critical for understanding emerging changes to the hydrological cycle. To this end we construct a homogenized Island of Ireland Precipitation (IIP) network comprising 25 stations and a composite series covering the period 1850–2010, providing the second-longest regional precipitation archive in the British-Irish Isles. We expand the existing catalogue of long-term precipitation records for the island by recovering archived data for an additional eight stations. Following bridging and updating of stations HOMogenisation softwarE in R (HOMER) homogenization software is used to detect breaks using pairwise and joint detection. A total of 25 breakpoints are detected across 14 stations, and the majority (20) are corroborated by metadata. Assessment of variability and change in homogenized and extended precipitation records reveal positive (winter) and negative (summer) trends. Trends in records covering the typical period of digitization (1941 onwards) are not always representative of longer records. Furthermore, trends in post-homogenization series change magnitude and even direction at some stations. While cautionary flags are raised for some series, confidence in the derived network is high given attention paid to metadata, coherence of behaviour across the network and consistency of findings with other long-term climatic series such as England and Wales precipitation. As far as we are aware, this work represents the first application of HOMER to a long-term precipitation network and bodes well for use in other regions. It is expected that the homogenized IIP network will find wider utility in benchmarking and supporting climate services across the Island of Ireland, a sentinel location in the North Atlantic.