Groundwater survey reveals new records and species

shrimp-like groundwater animal

Detail of the shrimp like groundwater animal Niphargus kochianus irlandicus: Head and front legs. Structures of eyes are still visible, but eyes are non-functional due to lack of pigment. Quanta SEM scan by Barry O’Hagan

A systematic survey of groundwater crustaceans in the Republic of Ireland has yielded a number of first records and species new to science.

Groundwater is an increasingly important commodity, which is facing rising demands from agriculture and for the production of drinking water. While there has been increasing public awareness of the existence of groundwater microbes, other subterranean water organisms have remained largely obscure, because access remains a challenge. As a result legislation usually fails to attribute ecosystem qualities to groundwater.

Whilst, on a worldwide scale, groundwater biodiversity and biogeography data remain sketchy, crustaceans emerge as the most successful faunal group in this environment, contributing ca 40% of known groundwater species.

Groundwater crustaceans have evolved remarkable adaptations in order to survive on very scarce food resources

Endemism is common, because individual groundwater bodies are confined by hydrological, geological or chemical barriers which impede faunal migration. As a consequence, unique groundwater animals are often extremely vulnerable to extinction threats from habitat degradation or contamination.

Compared to related species in surface water environments, groundwater crustaceans have evolved remarkable adaptations (blindness, lack of pigmentation, sleek and small body shapes, long and slow lifecycles and low numbers of offspring) in order to survive on very scarce food resources.

Biogeographic divide

The Republic of Ireland is one of the very few countries which has recently undertaken a systematic survey of its groundwater crustaceans, with a focus on boreholes and wells. It may have just come in time, before many of the old dug wells without water pumps disappear. By 2008 fewer than 4,500 households remained without provision of piped water.

Site records in Ireland

Sites with records for the shrimp like groundwater animal Niphargus kochianus irlandicus from the Ireland surveys since 2006. The Northern limit of its biogeographic distribution is near Upper Lough Erne

There is a biogeographic divide in Ireland, as the largest Irish groundwater animals, Niphargus species, appear to be absent from the North, which remained under icecover for much longer. Niphargus kochianus irlandicus is genetically discrete from morphologically similar Niphargus in Britain. We interpret its high interregional genetic diversity as evidence for a long sustained presence in Ireland.

So far the Irish groundwater survey for subterranean crustaceans has yielded six first records (Microniphargus leruthi, Parastenocaris vicesima, Speocyclops sp, Fabaeformiscandona breuili. Fabaeformiscandona wegelini and Cavernocypris subterraneana) and one species new to science (Moraria nov.sp.). The collected biological material has scope for more, eg Diacyclops languidoides is investigated for cryptic diversity and blind Gammarus and Asellus specimens indicate the existence of discrete subterranean populations.

Considering that Ireland is a well researched area with low aquatic biodiversity, our survey results would seem to indicate that there is great potential for similar groundwater surveys to uncover enormous subterranean biodiversity in countries without a history of glaciation.

Acknowledgement: The groundwater ecology survey was funded by the EPA Ireland.

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