Ulva intestinalis

Take a close look at the long strands of this seaweed, then there is no doubt where it got its name from: long, thin, inflated tubes. Its appearance can vary depending upon where it grows. There are lots of species of gutweed, often growing at the foot of a sea dike, on tidal flats and beaches. Some even grow in fresh water. You can find around ten different species in the Netherlands, which are only possible to identify with the help of a microscope.

 Ulva intestinalis is a conspicuous bright grass-green seaweed, consisting of inflated irregularly constricted, tubular fronds that grow from a small discoid base. Fronds are typically unbranched. Fronds may be 10-30 cm or more in length and 6-18 mm in diameter, the tips of which are usually rounded. Like other members of the genus, Ulva intestinalis is a summer annual, decaying and forming masses of bleached white fronds towards the end of the season.

Origin of species name
Adjective (Latin), relating to or found in the intestines (Guiry & Nic Dhonncha, 2002).

 Identification
 A recent molecular study suggested that the genus Enteromorpha is synonymous with the genus Ulva (Hayden et al., 2003). Species within the genus Ulva are difficult to identify. Identification is heavily reliant on cell detail and cell arrangement, in addition to gross morphology, but complicated by the fact that the morphology of a single species can vary in response to environmental conditions. For instance, Ulva intestinalis and Ulva compressa (as Enteromorpha) are two distinct, genetically divergent and reproductively isolated species (Blomster et al., 1998). They are, however, difficult to distinguish. The presence or absence of branching fronds was the most useful gross morphological characteristic distinguishing these two species (Ulva intestinalis being unbranched). But ambiguity exists because low salinity or salinity shock can induce branching in Ulva intestinalis. However, if environmental factors, such as salinity are taken into account, branching can be used to identify the great majority of thalli correctly (Blomster et al., 1998).

Azores Exclusive Economic Zone, Belgian Exclusive Economic Zone, Gulf of Mexico, Irish Exclusive economic Zone, Polish Exclusive Economic Zone

Known from the nearshore.

Depth range based on 49 specimens in 1 taxon.
Water temperature and chemistry ranges based on 1 sample.

Environmental ranges
  Depth range (m): 0 - 9.37
  Temperature range (°C): 21.061 - 21.061
  Nitrate (umol/L): 1.956 - 1.956
  Salinity (PPS): 35.349 - 35.349
  Oxygen (ml/l): 5.197 - 5.197
  Phosphate (umol/l): 0.384 - 0.384
  Silicate (umol/l): 5.808 - 5.808

Graphical representation

Depth range (m): 0 - 9.37
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

 Occurs in a wide range of habitats on all levels of the shore. Where suitable support is available, it will grow on rocks, mud, sand and in rock pools. It is abundant in brackish water areas, where there is appreciable fresh water run off and in wet areas of the splash zone. It is also a common epiphyte on other algae and shells. The seaweed may become detached from the substratum, and buoyed up by gas, rises to the surface, where it continues to grow in floating masses.

The following is a representative barcode sequence, the centroid of all available sequences for this species.

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 100
Specimens with Barcodes: 109
Species With Barcodes: 1