Cross-references
Algal Blooms
Macroalgal Blooms
Toxic Blooms
MACROALGAL BLOOMS
Michael J. Kennish
Department of Marine and Coastal Sciences,
School of Environmental and Biological Sciences,
Rutgers University, New Brunswick, NJ, USA
Synonyms
Seaweed blooms
Definition
Macroalgal blooms are rapid accumulations of macroalgal
populations that form dense canopies in benthic communities of estuaries and coastal lagoons (Valiela et al., 1997;
Anderson et al., 2010). They are manifested by a marked
increase in macroalgal biomass (often >0.5 kg m
À2
;
McGlathery, 2001) that falls outside normal seasonal
cycles of abundance. The percent cover of intertidal/
subtidal benthic habitat is also used as a measure of
macroalgal bloom occurrence. Canopy heights may
exceed 0.5 m (McGlathery, 2001).
Characteristics
The proliferation of bloom-forming “ephemeral”
macroalgae appears to be on the rise in shallow estuarine
and coastal lagoonal environments due to the increase in
nutrient enrichment and eutrophication of these water bodies observed for decades in temperate and tropical regions
(McGlathery, 2001; Kennish and Paerl, 2010). While
macroalgal blooms lack the direct chemical toxicity of
toxic phytoplankton blooms, they have a broader range of
ecological effects and typically last longer (Valiela et al.,
1997). For example, Gordon and McComb (1989) reported
that a bloom of Cladophora lasted for about a dozen years
in Peel Harvey Estuary, Western Australia, and Valiela
et al. (1992) documented blooms of Cladophora and
Gracilaria exceeding 20 years in Waquoit Bay, Massachusetts (USA). Macroalgal “nuisance” blooms are detrimental to seagrass beds because they block or attenuate light
(Burkholder et al., 2007; Kennish et al., 2010). Persistent
macroalgal blooms therefore often result in the displacement and loss of essential seagrass habitat by macroalgal
populations (McGlathery, 2001; Kennish et al., 2010).
These blooms may cause other impacts such as the increase
in sediment organic matter and oxygen depletion (hypoxia/
anoxia), decrease in redox potential, and increase in
sediment sulfide concentrations as the macroalgal layer
decays. Hydrogen sulfide concentrations also typically
increase and can create a hazardous environment to
humans in proximity to the bloom sites.
Bibliography
Anderson, I. C., Stanhope, J. W., Hardison, A. K., and McGlathery,
K. J., 2010. Sources and fates of nitrogen in Virginia coastal
bays. In Kennish, M. J., and Paerl, H. W. (eds.), Coastal
Lagoons: Critical Habitats of Environmental Change. Boca
Raton, FL: Taylor and Francis/CRC Press, pp. 43–72.
Burkholder, J. M., Tomasko, D. A., and Touchette, B. W., 2007.
Seagrasses and eutrophication. Journal of Experimental Marine
Biology and Ecology, 350, 46–72.
Gordon, D. M., and McComb, A. J., 1989. Growth and production
of the green alga Cladophora montagneana in a eutrophic Australian estuary and its interpretation using a computer program.
Water Research, 23, 633–645.
Kennish, M. J., and Paerl, H. W. (eds.), 2010. Coastal Lagoons:
Critical Habitats of Environmental Change. Boca Raton, FL:
Taylor and Francis/CRC Press.
Kennish, M. J., Haag, S. M., and Sakowicz, G. P., 2010.
Seagrass decline in New Jersey coastal lagoons: a response to
increasing eutrophication. In Kennish, M. J., and Paerl, H. W.
(eds.), Coastal Lagoons: Critical Habitats of Environmental
Change. Boca Raton, FL: Taylor and Francis/CRC Press,
pp. 167–201.
McGlathery, K. J., 2001. Macroalgal blooms contribute to the
decline of seagrass in nutrient enriched coastal waters. Journal
of Phycology, 37, 453–456.
McGlathery, K. J., Sundbäck, K., and Anderson, I. C., 2007. Eutrophication in shallow coastal bays and lagoons: the role of plants
in the coastal filter. Marine Ecology Progress Series, 348, 1–18.
Valiela, I., Foreman, K., and LaMontagne, M., 1992. Couplings of
watersheds and coastal waters: sources and consequences of
nutrient enrichment in Waquoit Bay, Massachusetts. Estuaries,
15, 443–457.
Valiela, I., McClelland, J., Hauxwell, J., Behr, P. J., Hersh, D., and
Foreman, K., 1997. Macroalgal blooms in shallow estuaries:
controls and ecophysiological and ecosystem consequences.
Limnology and Oceanography, 42, 1105–1118.
Cross-references
Algal Blooms
Macroalgae
Toxic Blooms
MACROFAUNA
Rolando Bastida-Zavala and Betzabé Moreno-Dávila
Laboratorio de Sistemática de Invertebrados Marinos,
Universidad del Mar Campus Puerto Angel, Puerto Angel,
Oaxaca, Mexico
Definition
Macrofauna are estuarine and marine organisms visible to
the naked eye (> 0.5 mm) that commonly inhabit the benthos, where they can be found buried in sediment or
attached to a fixed substrate (rocks, reefs, rhodolith,
etc.). Some macrofauna may also be observed moving
on the sediment surface as epifauna or in the water column. Macrofauna that are often abundant in the benthos
include flatworms (Platyhelminthes), sipunculids, nematodes, polychaetes, isopods, amphipods, stomatopods,
388
MACROALGAL BLOOMS
Algal Blooms
Macroalgal Blooms
Toxic Blooms
MACROALGAL BLOOMS
Michael J. Kennish
Department of Marine and Coastal Sciences,
School of Environmental and Biological Sciences,
Rutgers University, New Brunswick, NJ, USA
Synonyms
Seaweed blooms
Definition
Macroalgal blooms are rapid accumulations of macroalgal
populations that form dense canopies in benthic communities of estuaries and coastal lagoons (Valiela et al., 1997;
Anderson et al., 2010). They are manifested by a marked
increase in macroalgal biomass (often >0.5 kg m
À2
;
McGlathery, 2001) that falls outside normal seasonal
cycles of abundance. The percent cover of intertidal/
subtidal benthic habitat is also used as a measure of
macroalgal bloom occurrence. Canopy heights may
exceed 0.5 m (McGlathery, 2001).
Characteristics
The proliferation of bloom-forming “ephemeral”
macroalgae appears to be on the rise in shallow estuarine
and coastal lagoonal environments due to the increase in
nutrient enrichment and eutrophication of these water bodies observed for decades in temperate and tropical regions
(McGlathery, 2001; Kennish and Paerl, 2010). While
macroalgal blooms lack the direct chemical toxicity of
toxic phytoplankton blooms, they have a broader range of
ecological effects and typically last longer (Valiela et al.,
1997). For example, Gordon and McComb (1989) reported
that a bloom of Cladophora lasted for about a dozen years
in Peel Harvey Estuary, Western Australia, and Valiela
et al. (1992) documented blooms of Cladophora and
Gracilaria exceeding 20 years in Waquoit Bay, Massachusetts (USA). Macroalgal “nuisance” blooms are detrimental to seagrass beds because they block or attenuate light
(Burkholder et al., 2007; Kennish et al., 2010). Persistent
macroalgal blooms therefore often result in the displacement and loss of essential seagrass habitat by macroalgal
populations (McGlathery, 2001; Kennish et al., 2010).
These blooms may cause other impacts such as the increase
in sediment organic matter and oxygen depletion (hypoxia/
anoxia), decrease in redox potential, and increase in
sediment sulfide concentrations as the macroalgal layer
decays. Hydrogen sulfide concentrations also typically
increase and can create a hazardous environment to
humans in proximity to the bloom sites.
Bibliography
Anderson, I. C., Stanhope, J. W., Hardison, A. K., and McGlathery,
K. J., 2010. Sources and fates of nitrogen in Virginia coastal
bays. In Kennish, M. J., and Paerl, H. W. (eds.), Coastal
Lagoons: Critical Habitats of Environmental Change. Boca
Raton, FL: Taylor and Francis/CRC Press, pp. 43–72.
Burkholder, J. M., Tomasko, D. A., and Touchette, B. W., 2007.
Seagrasses and eutrophication. Journal of Experimental Marine
Biology and Ecology, 350, 46–72.
Gordon, D. M., and McComb, A. J., 1989. Growth and production
of the green alga Cladophora montagneana in a eutrophic Australian estuary and its interpretation using a computer program.
Water Research, 23, 633–645.
Kennish, M. J., and Paerl, H. W. (eds.), 2010. Coastal Lagoons:
Critical Habitats of Environmental Change. Boca Raton, FL:
Taylor and Francis/CRC Press.
Kennish, M. J., Haag, S. M., and Sakowicz, G. P., 2010.
Seagrass decline in New Jersey coastal lagoons: a response to
increasing eutrophication. In Kennish, M. J., and Paerl, H. W.
(eds.), Coastal Lagoons: Critical Habitats of Environmental
Change. Boca Raton, FL: Taylor and Francis/CRC Press,
pp. 167–201.
McGlathery, K. J., 2001. Macroalgal blooms contribute to the
decline of seagrass in nutrient enriched coastal waters. Journal
of Phycology, 37, 453–456.
McGlathery, K. J., Sundbäck, K., and Anderson, I. C., 2007. Eutrophication in shallow coastal bays and lagoons: the role of plants
in the coastal filter. Marine Ecology Progress Series, 348, 1–18.
Valiela, I., Foreman, K., and LaMontagne, M., 1992. Couplings of
watersheds and coastal waters: sources and consequences of
nutrient enrichment in Waquoit Bay, Massachusetts. Estuaries,
15, 443–457.
Valiela, I., McClelland, J., Hauxwell, J., Behr, P. J., Hersh, D., and
Foreman, K., 1997. Macroalgal blooms in shallow estuaries:
controls and ecophysiological and ecosystem consequences.
Limnology and Oceanography, 42, 1105–1118.
Cross-references
Algal Blooms
Macroalgae
Toxic Blooms
MACROFAUNA
Rolando Bastida-Zavala and Betzabé Moreno-Dávila
Laboratorio de Sistemática de Invertebrados Marinos,
Universidad del Mar Campus Puerto Angel, Puerto Angel,
Oaxaca, Mexico
Definition
Macrofauna are estuarine and marine organisms visible to
the naked eye (> 0.5 mm) that commonly inhabit the benthos, where they can be found buried in sediment or
attached to a fixed substrate (rocks, reefs, rhodolith,
etc.). Some macrofauna may also be observed moving
on the sediment surface as epifauna or in the water column. Macrofauna that are often abundant in the benthos
include flatworms (Platyhelminthes), sipunculids, nematodes, polychaetes, isopods, amphipods, stomatopods,
388
MACROALGAL BLOOMS