Penny Stirling

Foraging behaviour of Patella vulgata L. in an Irish sea-lough

Abstract The foraging movements of limpets Patella vulgata L. were studied on a vertical rock face at Lough Hyne, County Cork, Ireland. Rhythms on two adjacent grids were similar, but showed some differences in timing. Distance moved and speed of movement were related to limpet size. Feeding excursions were more regular and prolonged on spring tides than on neaps. Limpets high on the shore were active ony at night, at low water, when they moved vertically up the rock face. They fed in habitats unlike those surrounding their homes, mainly on rock that was either bare, or covered by lichens. Limpets near mid-tide level did not move preferentially in any one direction, and they appeared to show no choice of feeding area. Limpets low on the shore were active near the times of low water both at night and during the day. They tended to move horizontally and, at least on some occasions, they chose areas of low barnacle density in which to feed. The feeding patterns seen at different tidal heights are discussed in relation to growth rates.

Patterns of foraging activity in the limpet Patellavulgata L. — A preliminary study

Abstract Activity of limpets was studied at Lough Ine, Co. Cork, Ireland. The small tidal range allowed long periods of continuous observation over consecutive tidal cycles. All activity was associated with the time of low water, but showed varying relations to it depending on vertical height on the shore and on the time in the spring/neap cycle. Low-water limpets were predominantly active in the day, but also showed a minor activity peak on the low water at night. Limpets higher on the shore were active only at night. It is possible that these differences reflect different behaviour in relation to the effects of desiccation and predation at different levels on the shore. The activity periods were shown to be exclusively concerned with feeding: radula rasping was almost continuous while the limpets were away from the home scar. Limpets at different levels had, however, different behaviour patterns in terms of the areas that they used for grazing.

The developmental cycle of Chlamydia trachomatis in McCoy cells treated with cytochalasin B.

The growth of a genital trachoma-inclusion conjunctivitis agent strain of Chlamydia trachomatis in McCoy cells treated with cytochalasin B was studied by quantitative infectivity estimations and by light and electron microscopy. Provided that infection of the monolayer was initiated by centrifuging the infectious particles on to the cells before incubation, this chlamydial strain grew as fast and to as high a titre [approximately 10(7) inclusion-forming units (i.f.u.) per culture] as those chlamydiae which infect cell cultures in vitro without centrifugation. Each i.f.u. inoculated yielded approximately 600 i.f.u., and extracellular infectivity was detected soon after intracellular infectivity appeared. Inclusions were recognized by fluorescent antibody staining techniques early in the developmental cycle when cultures were not infectious and when only reticulate bodies were seen by electron microscopy. Inclusions were recognized in Giemsa-stained preparations examined by dark ground microscopy only when elementary bodies appeared in the inclusions. Iodine staining was not a reliable indicator either of the number of inclusions present or of their infectivity.

Decadal-scale changes in the shallow subtidal benthos of an Irish marine reserve.

Abstract Long-term annual monitoring of rocky intertidal and shallow subtidal shores of an Irish sea lough (1990–2010) documented major regime shifts in the past decade. When population densities of the purple urchin Paracentrotus lividus plummeted in Lough Hyne Marine Reserve in southwestern Ireland, the warm-water fucalean alga Cystoseira foeniculacea and ephemeral algae proliferated shortly after. We discuss the possible influences of release from herbivory and climate change on this algal proliferation, which blanketed the benthos. Smothering of the benthos led to high levels of shallow subtidal anoxia. Furthermore, the invasive fucalean alga Sargassum muticum has made repeated incursions into the reserve. Although being reduced by persistent eradication efforts (2003–2011), Sargassum is spreading within the lough. Limited seawater flushing and propagule dispersal within the lough and eutrophication in coastal waters may have contributed to community-level changes. Whether the regime change is cyclical (contingent on re-establishment of urchins within the lough and continued eradication of S. muticum) or irreversible (the result of critical transitions) remains unclear.

Changes in brown seaweed distributions in Lough Hyne, SW Ireland: a long-term perspective

Abstract Distributions of brown seaweeds (Phaeophyceae: Fucales, Laminariales and Tilopteridales) were surveyed in 2011 in Europe’s first marine reserve, Lough Hyne in SW Ireland, and compared with distributions from three historical surveys (1930, 1955 and 1980). The most salient phycological differences were the incursion of the low intertidal and shallow subtidal species Fucus serratus, Himanthalia elongata and Saccharina latissima into the north basin of the marine reserve after the recent mass mortality of the purple urchin (Paracentrotus lividus). Monitoring surveys (1990–2012) at ten sites in the lough indicated that populations of S. latissima peaked in 1994, abruptly crashed in 1996 and then slowly recovered. As well as documenting the expansion of kelp, our annual, whole-lough snorkel surveys (2004–2012) demonstrated the recent proliferation of the introduced Sargassum muticum and native Cystoseira foeniculacea. Although the causal role of top-down factors (fishing ban and/or urchin population crash), bottom-up factors (nutrient enhancement), climatic variables (warming vs. episodic cooling) and pathogens (urchin and algal) is being widely debated, decadal-scale and inter-annual changes are clearly detectable and most consistent with a release from herbivory within the marine protected area.

Shallow subtidal octocorals in an Irish marine reserve

Alcyonacean octocorals are anthozoans which are found in many coastal benthic habitats, where they can be sensitive to environmental and/or anthropogenic stress. As part of a two-decade monitoring study of Lough Hyne (Europe’s first marine reserve and Ireland’s only one), we documented benthic communities at rocky-shore sites. As a fully marine, semi-enclosed, tidal ‘lake’ connected to the Atlantic Ocean via tidal rapids, Lough Hyne has long been noted for its high species and habitat diversity. One of the noteworthy guilds we report here was the alcyonacean octocorals: (1) the soft coral Alcyonium hibernicum under shallow subtidal rocks at monitoring sites in the lough from 2002 to 2015 and (2) the first known records (2013 to present) of the red soft coral A. glomeratum inside the lough (above the rapids). Furthermore, in August/September 2014 and 2015, we rediscovered the stoloniferous octocoral Sarcodictyon catenatum, last reported in the lough in the 1930s. We documented the distribution and abundance of these species in shallow subtidal areas of the lough as a baseline in the face of rapidly degrading conditions due to extreme oxygen fluctuations from eutrophication.

Lusitanian nemertean species in Lough Hyne Marine Reserve: Paradrepanophorus crassus and Punnettia splendida

The warm-water nemertean species Paradrepanophorus crassus, described from Mediterranean shores, was first recorded in Lough Hyne, County Cork, Ireland in 1931 by Renouf. This large nemertean that forms membranous tubes under low intertidal to shallow subtidal rocks has increased in frequency, particularly from 2009 to 2012 with peak values of 0.26 specimens per metre of shoreline. Eggs were noted within the membranous tube of one specimen collected in June 2012. Furthermore, based on digital photographs of specimens, the striped nemertean species Punnettia splendida was also noted in September 2011; this is a new species record for Lough Hyne.

Osilinus lineatus: Incursion and Proliferation in Lough Hyne Marine Reserve, SW Ireland

Abstract: Changes in the distributional ranges of marine indicator species have been used to support hypotheses of climate change on NE Atlantic shores. One such indicator species, Osilinus lineatus (da Costa, 1778) (a trochid gastropod), recently colonized the Lough Hyne Marine Reserve in SW Ireland and spread around the lough shores in the last two decades. The incursion and local spread of O. lineatus was documented during annual intertidal community surveys of the lough from 1994 to 2010. This species is presently an abundant member of the loughs biota. Although the tidal rapids connecting the lough to the open ocean may have acted as a partial barrier to incursion, substantial populations of the trochid have been noted within the lough from 2003 to the present. Climate change may have enabled this primarily Lusitanien species to penetrate and flourish in the lough. However, based on environmental variables measured and other species surveyed, changes in the semi-enclosed lough may be more complex.

Nemerteans in an Irish marine reserve: synopsis of current and historical records

The under-rock guild of nemerteans from Lough Hyne, south-west Ireland was recorded during a long-term benthic survey of the marine reserve. From 2004 to 2014, common nemerteans were recorded annually in late summer for ten historical monitoring sites (each 10 m of shoreline); more comprehensive surveys were completed in 2012 (4126 low-intertidal to shallow-subtidal rocks were turned) and 2014 (1289 rocks turned) with supplementary information in 2015. The bootlace worm, Lineus longissimus, was the most abundant nemertean species. It was significantly more abundant at the extremely shallow East Castle site than the other nine sites; peak populations (across all ten sites) occurred in 2012. The Lusitanian nemertean Paradrepanophorus crassus was abundant after 2007. To date, 13 nemertean species were recorded with numerous new records for the lough, including Tubulanus annulatus, Micrura purpurea, Ramphogordius sanguineus, Micrella rufa and Emplectonema gracile . Three additional nemertean species were previously recorded, indicating that at least 16 species occur in the lough. Given the low densities and paucity of comprehensive earlier records, we are not able to ascertain definitely whether these species are new incursions or if sparsely distributed residents have increased.