Polysiphonia brodiei

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Herbarium specimen

Polysiphonia brodiei - herbarium specimen.

Kate Neill

Identity

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Preferred Scientific Name

Polysiphonia brodiei (Dillwyn) Sprengel, 1827

Other Scientific Names

Ceramium brodiei (Dillwyn) C.Agardh, 1811
Conferva brodiei Dillwyn, 1809
Hutchinsia brodiei (Dillwyn) Lyngbye, 1819
Hutchinsia penicillata C.Agardh, 1828
Polysiphonia brodiei f. densa Holmes & Batters, 1890
Polysiphonia penicillata (C.Agardh) Sprengel, 1827

Local Common Names

Denmark: knippeledtang
Norway: penseldokke

Summary of Invasiveness

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P. brodiei is a filamentous red alga which has been introduced to the Pacific and Atlantic coasts of North America, as well as to Japan, Australia, and New Zealand.

In analyses of the potential impacts of introduced marine species in Australian waters, P. brodiei has been assessed as one of the 10 most damaging species (Hayes et al., 2005) based on a combination of human health, economic and environmental criteria. P. brodiei is listed as one of 66 marine species on the Global Invasive Species Database managed by the Invasive Species Specialist Group (ISSG).

Taxonomic Tree

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Domain: Eukaryota
Kingdom: Plantae
Phylum: Rhodophyta
Class: Rhodophyceae
Order: Ceramiales
Family: Rhodomelaceae
Genus: Polysiphonia
Species: Polysiphonia brodiei

Notes on Taxonomy and Nomenclature

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Polysiphonia brodiei (Dillwyn) Spreng. is a red alga belonging to the family Rhodomelaceae within the order Ceramiales (Rhodophyta). The specific name, recognizing the Scottish botanist James Brodie, was initially and incorrectly spelt “brodiaei”. Silva et al. (1996) noted that in forming the epithet the genitive inflection should be added to the unmodified name in accordance with Rec. 60C.3 of the International Code of Botanical Nomenclature.

The type locality is Bantry Bay, Cork, Ireland (Womersley, 1979: 497). The type specimen is Lectotype BM-K; Probable Syntype: LD – 24.vi.1807, Hutchins. (Maggs and Hommersand, 1993). The basionym is Conferva brodiaei Dillwyn 1809: 81, pl.107, and recorded synonyms include: Ceramium brodiaei (Dillwyn) C.Agardh; Hutchinsia brodiaei (Dillwyn) Lyngbye; Hutchinsia penicillata C.Agardh; and Polysiphonia penicillata (C.Agardh) Spreng.

Description

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Species of Polysiphonia are generally distinguished by the number of pericentral cells present (ranging from 4 to 12 or more), the degree of cortication of the axes, the growth habit and robustness of plants, as well as on the basis of particular features of vegetative and reproductive cells e.g. presence/absence of trichoblasts, shape of the cystocarp, size and shape of spermatangial branches (e.g. Womersley, 1979).

P. brodiei is a red alga, generally 5-25 cm in height although they may be as tall as 40 cm, dark reddish brown to crimson purple in colour, and profusely and irregularly branched. The plants are attached to the substrate by numerous rhizoids and a mat of interwoven, branched prostrate axes that develop from the base of young axes. The axes are extremely soft and flaccid when young, becoming firmer and flexible when older. There are several main percurrent axes that are generally 0.6-0.9 mm in diameter, and which bear numerous, spirally arranged laterals. The lower axes are heavily corticated by several layers of small cells. Only the new growth of the upper axes are ecorticate, with well-defined segments visible. There are (6)7-8 pericentral cells. Trichoblasts or scar cells are on every segment, and the trichoblasts are slender and 2-4 times furcate. Branches are formed in the axils of the trichoblasts. Plants are dioecious.

Cystocarps have short stalks, and are urceolate with the ostiolar cells slightly inflated. The spermatangial branches develop as a branch of a trichoblast, and are cylindrical with a rounded to pointed apex. Tetrasporangia are formed in long spiral series, with a divergence of 1/6 to 1/7. When mature, the tetrasporangia occupy about half the segment width resulting in a slight distortion of the segments. Maggs and Hommersand (1993) noted that the morphology of this species varies greatly with environmental conditions. Plants found on lower intertidal shores or floating structures are elongate and flaccid with a cylindrical outline to the laterals, whereas in upper shore pools the plants are densely tufted and have a pyramidal outline.

Distribution

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Within its native range, P. brodiei has been reported from northern Europe (the UK and Scandinavia) through to western Africa and nearby islands, and in the Mediterranean from Morocco to Turkey.

It has been reported as introduced to the Pacific coast of North America (Alaska to California), Japan and Australasia (southern Australia and Tasmania, New Zealand). It is also present in Atlantic Canada in Newfoundland (South and Hooper, 1980) and Nova Scotia (Lauret, 1971), and is reported as introduced in these localities (NIMPIS, 2002). P. brodiei is also recorded from India (both western and eastern coasts), Iran, Kuwait, Qatar and Saudi Arabia (Silva et al., 1996), however, it is not clear whether the species is native or introduced to these areas.

Distribution Table

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The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

Last updated: 10 Jan 2020

Continent/Country/Region	Distribution	Origin	Invasive	Reference	Notes
Africa
Cabo Verde	Present	Native		Lawson et al. (1995); John et al. (2004)
Morocco	Present	Native		Gómez Garreta et al. (2001); Benhissoune et al. (2003)
Asia
India	Present	Introduced		Silva et al. (1996)
-West Bengal	Present	Introduced		Biswas (1926)
Iraq	Present	Introduced		Silva et al. (1996)
Japan	Present			Segi (1960); Yoshida et al. (1990)
Kuwait	Present	Introduced		Silva et al. (1996)
Qatar	Present	Introduced		Silva et al. (1996)
Saudi Arabia	Present	Introduced		Silva et al. (1996)
Turkey	Present	Native		Gómez Garreta et al. (2001)
Europe
Denmark	Present, Widespread	Native		Kapraun and Rueness (1983); Athanasiadis (1996)
Faroe Islands	Present, Widespread	Native		Irvine (1982); Kapraun and Rueness (1983); Nielsen and Gunnarsson (2001)
France	Present, Widespread	Native		Feldmann (1943); Feldmann (1954); Gómez Garreta et al. (2001)
Greece	Present, Widespread	Native		Gerloff and Geissler (1974); Gómez Garreta et al. (2001)
Ireland	Present, Widespread	Native		Maggs and Hommersand (1993); Morton (1994)
Italy	Present, Widespread	Native		Giaccone (1969); Furnari et al. (1999); Gómez Garreta et al. (2001)
Netherlands	Present, Widespread	Native		Stegenga and Mol (1983); Stegenga et al. (1997)
Norway	Present, Widespread	Native		Kapraun and Rueness (1983); Rueness (1997)
Portugal	Present, Widespread	Native		Ardré (1970)
-Azores	Present	Native		Neto (1994)
-Madeira	Present	Native		John et al. (2004)
Romania	Present, Widespread	Native		Caraus (2002)
Spain	Present, Widespread	Native		Gómez Garreta et al. (2001); Gorostiaga et al. (2004); Bárbara et al. (2005)
-Canary Islands	Present	Native		Lawson et al. (1995); John et al. (2004)
Sweden	Present, Widespread	Native		Kylin (1944)
United Kingdom	Present, Widespread	Native		Maggs and Hommersand (1993); Hardy and Guiry (2003)
North America
Canada	Present	Introduced		Maggs and Hommersand (1993)
-British Columbia	Present	Introduced		Scagel et al. (1989)
-Newfoundland and Labrador	Present	Introduced		South and Hooper (1980); South and Tittley (1986)
-Nova Scotia	Present	Introduced		Lauret (1971)
United States	Present			CABI (Undated)	Present based on regional distribution.
-Alaska	Present	Introduced		Scagel et al. (1989)
-California	Present	Introduced		Hollenberg (1944); Abbott and Hollenberg (1976); Scagel et al. (1989)
-Oregon	Present	Introduced		Hansen (1997)
-Washington	Present	Introduced		Scagel et al. (1989)
Oceania
Australia	Present			CABI (Undated)	Present based on regional distribution.
-South Australia	Present	Introduced	Invasive	Womersley (1979); Womersley (2003)
-Tasmania	Present	Introduced	Invasive	Womersley (1979); Womersley (2003)
-Victoria	Present	Introduced	Invasive	Womersley (1979); Womersley (2003)
New Zealand	Present	Introduced	Invasive	Adams (1991); Nelson (1999)
Sea Areas
Atlantic - Northeast	Present			Nielsen et al. (1995)	Baltic Sea, UK, Denmark, Faroes, France, Ireland, Netherlands, Norway, Portugal, Scandinavia, Spain, Sweden
Mediterranean and Black Sea	Present			Giaccone (1978); Gómez Garreta et al. (2001)	Adriatic, Black Sea, France, Greece, Italy, Morocco, Romania, Spain, Turkey

History of Introduction and Spread

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P. brodiei was first reported in Australia in 1979 as a species that had probably been introduced via shipping (Womersley, 1979), based on specimens collected from 1940 onwards. In New Zealand P. brodiei was reported for the first time by Adams (1983) based on a specimen collected in 1940 from Wellington Harbour, (North Island). This species has been subsequently reported from sites in the North, South and Stewart Islands, primarily in busy ports growing on harbour structures (Adams, 1991; Nelson, 1999). However, the record of Harvey (1855:230) of Conferva brodiaei Dillwyn from Port Pegasus, Stewart Island, New Zealand, was incorrect and based on material of P. muelleriana. J.Agardh (Adams, 1991:423).

It appears to increasing in abundance even in its native range. In a study comparing the macroalgal vegetation of the Swedish Skagerrak coast in 1960-61 with the flora present in 1997, it was found that P. brodiei increased in abundance, and this was considered to be a response to increased eutrophication at the study sites (Johansson et al., 1998).

Introductions

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Introduced to	Introduced from	Year	Reason	Introduced by	Established in wild through		References	Notes
Introduced to	Introduced from	Year	Reason	Introduced by	Natural reproduction	Continuous restocking	References	Notes
Alaska					Yes		Scagel et al. (1989)
British Columbia					Yes		Scagel et al. (1989)
California					Yes		Hollenberg (1944)
Japan					Yes		Yoshida et al. (1990)
New Zealand		pre 1940			Yes		Adams (1983)
Newfoundland and Labrador					Yes		South and Hooper (1980)
Nova Scotia					Yes		Lauret (1971)
Oregon					Yes		Hansen (1997)
South Australia		pre 1973			Yes		Womersley (1979)
Tasmania		pre 1940			Yes		Womersley (1979)
Victoria		pre 1959			Yes		Womersley (1979)
Washington					Yes		Scagel et al. (1989)

Risk of Introduction

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P. brodiei is tolerant of a wide range of environmental conditions as demonstrated by its distribution in its native range from higher latitudes in Scandinavia through to western Africa, and it is able to grow on a wide variety of substrates such as rock, rope, wood, concrete and metal.

Habitat

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In its native range, P.brodiei is typically found growing epilithically as well as on mussels and limpets, and as an epiphyte on non-geniculate corallines and smaller algae in mid-shore pools through to the upper subtidal zone (Maggs and Hommersand, 1993). It is less frequently found in the subtidal zone with some records to 8 m depth [e.g. www.weedseen.co.uk]. In the UK, it is reported from extremely exposed intertidal sites through to sheltered subtidal sites [www.weedseen.co.uk]. In Scandinavia, it is reported to grow mainly on rocks in the littoral in somewhat exposed localities (Kapraun and Rueness, 1983).

In its introduced range, P. brodiei has been recorded primarily from port environments. Itcolonises wooden surfaces such as jetties and pylons, as well as ropes, buoys, boat ramps, barges, slow moving vessels such as barges (Abbott and Hollenberg, 1976; Womersley, 1979; Adams, 1991).

Habitat List

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Category	Habitat	Presence	Status
Littoral
	Intertidal zone	Principal habitat	Natural
	Intertidal zone	Principal habitat	Productive/non-natural
Marine

	Benthic zone	Principal habitat	Natural
	Benthic zone	Principal habitat	Productive/non-natural

Biology and Ecology

Top of page Genetics

The haploid chromosome number for P. brodiei has been reported to be 29-31 (Magne, 1964).

Reproductive Biology

P. brodiei has a tri-phasic life history typical of red algae. The macroscopic diploid tetrasporophyte plant bears many tetrasporangia each of which release 4 microscopic spores that settle to form macroscopic, haploid male and female gametophyte plants. Male gametes are called spermatia (plural) or spermatium (singular) and are not motile. Fusion with carpogonia (reproductive structures of the female plant) takes place via a trichogyne – a hair-like receptive surface. The resulting zygote develops into a cystocarp (borne on the female plant) that produces and releases diploid carpospores which in turn settle and develop into tetrasporophyte plants.

Phenology

Maggs and Hommersand (1993) noted that the seasonal behaviour of this species varies with habitat. Populations of P. brodiei growing in rock pools develop between February and April, becoming conspicuous and reproducing when still very small. In these rock pool populations, the plants reach their maximum size in June-July after which they die back or may become overgrown by epiphytes. However, large fertile plants of P. brodiei can be found year round in populations that are submerged or growing on floating structures in sheltered waters. In the UK, spermatangia have been recorded from March to October and December, cystocarps in April-October and tetrasporangia from March to October and December (Maggs and Hommersand, 1993). In Scandinavia, this species is reported to be a summer annual (Kapraun and Rueness, 1983).

Nutrition

P. brodiei is photosynthetic. Observations by Johansson et al. (1998) suggest that it may be able to out-compete other species in the presence of nutrient enrichment or eutrophication.

Environmental Requirements

P. brodiei appears to be tolerant of a wide range of growing conditions in terms of habitat type, substrate, and environmental conditions. In addition, in parts of its native range it has a demonstrated ability to reproduce throughout the year, indicating that growth and reproductive maturity are not under strict temperature and photoperiod control (Maggs and Hommersand, 1983).

Climate

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Climate	Status	Description	Remark
C - Temperate/Mesothermal climate	Preferred	Average temp. of coldest month > 0°C and < 18°C, mean warmest month > 10°C
D - Continental/Microthermal climate	Preferred	Continental/Microthermal climate (Average temp. of coldest month < 0°C, mean warmest month > 10°C)

Water Tolerances

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Parameter	Minimum Value	Maximum Value	Typical Value	Status	Life Stage	Notes
Salinity (part per thousand)				Optimum		found in harbours - may be tolerant of lowered salinity

Notes on Natural Enemies

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Although there are no specific known consumers of P. brodiei, fish, crabs and small crustaceans are known to feed on other Polysiphonia spp. (NIMPIS, 2002).

Means of Movement and Dispersal

Top of page Natural Dispersal (Non-Biotic)

It may be considered possible, if not likely, that P. brodiei is spread at least locally by tides and currents.

Vector Transmission (Biotic)

There are no recorded instances of spread via biotic agents.

Accidental Introduction

P. brodiei is considered to have been introduced to Australia, New Zealand, North America and Japan through shipping/vessel movements. As a small filamentous species, with a broad natural distribution range both geographically and ecologically, as well as the capacity to grow on a wide range of substrata, P. brodiei is an “ideal” fouling species. This species can be distributed long distances through vessel-hull fouling involving large and small commercial vessels as well as recreational craft. In addition this species can be translocated shorter distances via vessels as well as contaminated marine equipment, e.g. ropes, pontoons and marine farming equipment.

Intentional Introduction

There is no known example of intentional introduction of this species.

Pathway Vectors

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Vector	Notes	Long Distance	Local	References
Ship hull fouling	this has been speculated as the means of introduction by	Yes	Yes	Adams, 1983; Womersley, 1979

Impact Summary

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Category	Impact
Cultural/amenity	Negative
Environment (generally)	Negative

Impact

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In a study conducted in Australia to identify and rank introduced marine species found within Australian waters, P. brodiei was considered to be a “medium priority species” based on its invasion potential from infected to uninfected bioregions. Based on its impact potential, both economic and environmental, P. brodiei was identified as one of the 10 most damaging potential domestic target species in Australia (Hayes et al., 2005). However, the nature of the impacts caused by P. brodiei are not clear. P. brodiei may have impacts on the settlement of other marine species as it may be able to colonise surfaces more effectively/competitively than native species. There is no information on either the palatability of this species or its nutritional value for grazers, relative to other equivalent filamentous/turfing red algae.

Risk and Impact Factors

Top of page Invasiveness

Proved invasive outside its native range
Has a broad native range
Abundant in its native range
Highly adaptable to different environments
Is a habitat generalist
Has high reproductive potential

Impact outcomes

Modification of natural benthic communities
Negatively impacts aquaculture/fisheries
Reduced amenity values

Impact mechanisms

Competition - shading
Competition - smothering
Competition (unspecified)
Fouling

Likelihood of entry/control

Highly likely to be transported internationally accidentally
Difficult to identify/detect in the field

Prevention and Control

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Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.

Eradication

This is unlikely to be a viable option given the small stature of this species and the wide range of potential habitats and environmental conditions in which it can survive.

Containment/zoning

Restricting the movement of vessels, rafts and pontoons from infected areas to uninfected areas is an option to reduce the likelihood of spread. Controlling the deployment of marine equipment which has been used in infected areas and requiring hull cleaning prior to movement from infected to uninfected regions are also methods which can be employed to minimize spread.

Control

There are no recorded instances of attempts to control P. brodiei where it has become established and/or invasive.

Gaps in Knowledge/Research Needs

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Little is known about the ecology of P. brodiei in either its native or non-native range with respect to herbivores or associated fauna, and there are no data on its palatability, growth rates, or generation times, and there has been no detailed examination of the life history of this species in the field and how this might vary throughout its geographic and ecological range. Also, there is no information available about its competitive ability relative to other taxa living in shared habitats.