Identification

Title

Species point records from 1978 NCC Loch Obisary survey

Abstract

A preliminary survey was made of Loch Obisary, the largest brackish water loch in North Uist, Outer Hebrides. The loch has a single narrow connection to the sea, through which sea water enters at high tides. Salinity, temperature and depth measurements were taken throughout the loch and revealed the presence of a distinct halocline and thermocline in the north basin of the loch at about 4 m depth, neither of which were present in the south basin. The salinity of the water above the halocline in the north basin and throughout the south basin was 13 - 14 ppt whilst that below the halocline had a maximum of 28.5 ppt. Temperature decreased by approximately 1 degree Centigrade at the level of the halocline and rose again by approximately 0.5 degree Centigrade near the bottom of the loch. The flora and fauna were investigated both by diving and by shore collections. Two distinct communities of plants and animals were found in the loch: i) A 'freshwater ' marginal component consisting of freshwater euryhaline species and true brackish water species found above the halocline in the north basin and throughout the south basin of the loch. ii) A marine component consisting of marine euryhaline species numerically dominated by the red alga Phyllophora pseudoceranoides and the tunicates Ciona intestinalis and Ascidiella aspersa. Comparisons are made with other studies of brackish lochs and waters and it is concluded that Loch Obisary is an interesting and unusual example of this scarce habitat type.

Resource type

dataset

Resource locator

http://data.jncc.gov.uk/data/0a2495e7-6ebf-4883-a5f3-2e3ab7b69dd8-1978-NCC-Loch-Obisary-survey.csv

name: 1978-NCC-Loch-Obisary-survey.csv

Unique resource identifier

code

0a2495e7-6ebf-4883-a5f3-2e3ab7b69dd8

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Additional information source

Mitchell, Dipper, Earll, Rowe (1980) Loch Obisary: a preliminary survey

Classification of spatial data and services

Topic category

oceans

Keywords

Keyword set

keyword value

Marine

Marine Recorder

JNCCMNCR10000200

MNCR

Species

Geographic location

West bounding longitude

-7.229043798

East bounding longitude

-7.152251725

North bounding latitude

57.56071656

South bounding latitude

57.51255964

Temporal reference

Temporal extent

Begin position

1978-05-01

End position

1978-05-28

Dataset reference date

date type

publication

effective date

2001-08-29

Frequency of update

Quality and validity

Lineage

This survey was extracted from a Marine Recorder snapshot.

Conformity

Data format

name of format

Comma Separated Values

version of format

Unknown

Constraints related to access and use

Constraint set

Use constraints

Open Government Licence v3.0

Limitations on public access

no limitations

Responsible organisations

Responsible party

organisation name

Digital and Data Solutions, JNCC

email address

data@jncc.gov.uk

responsible party role

custodian

Metadata on metadata

Metadata point of contact

organisation name

Digital and Data Solutions, JNCC

email address

data@jncc.gov.uk

responsible party role

pointOfContact

Metadata date

2018-05-17

Metadata language