PROFILPELAJAR.COM

Metridia gerlachei
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Copepoda
Order:	Calanoida
Family:	Metridinidae
Genus:	Metridia
Species:	M. gerlachei
Binomial name
	Metridia gerlachei; Giesbrecht, 1902

Metridia gerlachei is a copepod found primarily in Antarctic and sub-Antarctic waters.

Description

In length, the female M. gerlachei is between about 3.25 and 4.3 millimetres (0.128 and 0.169 in) with a mean of 3.8 millimetres (0.15 in). The male is smaller, between about 2.15 and 2.7 millimetres (0.085 and 0.106 in) and averaging 2.55 millimetres (0.100 in) in length.^[1]

Distribution

Metridia gerlachei is found primarily in Antarctic and sub-Antarctic waters, in addition to records from the southern Atlantic, Pacific, and Indian Oceans.^[1]

Ecology

Life cycle and reproduction

Metridia gerlachei may start to reproduce during late winter^{[note 1]} or early spring and stops during mid-winter (although a more conservative estimate gives from December to April^[2]).^[3] Breeding peaks in December and January due to the abundance of phytoplankton.^[2] It has a relatively low egg production rate of about 6 eggs per day at saturated food concentrations.^[4]

Vertical distribution

During summer, most of the population is found from the surface to 300 metres (980 ft) in depth. The population is evenly distributed throughout the water column in autumn and winter. It then becomes concentrated between 200 and 1,000 metres (660 and 3,280 ft) in depth during spring.^[3] During the day, M. gerlachei is concentrated below 200 metres (660 ft). It starts to ascend to the surface when the decrease in light is maximal, reaching the surface a few hours later. The most feeding occurs at this point. The descent starts right after this, and ends when the increase in light reaches its maximum. The population is usually concentrated within 50 metres (160 ft) of depth during this diel vertical migration.^[5]

Feeding

Metridia gerlachei is omnivorous, eating mainly phytoplankton,^[5] but also copepod eggs,^[6] Oncaea curvata,^[7] and other animal matter.^[8]

Notes and references

Notes

^ All seasons are for the Southern Hemisphere.

References

^ ^a ^b Razouls C.; de Bovée F.; Kouwenberg J.; Desreumaux N. (2018). "Diversity and Geographic Distribution of Marine Planktonic Copepods". Sorbonne Université, CNRS. Retrieved 29 September 2018.
^ ^a ^b Niehoff, Barbara; Schnack-Schiel, Sigrid; Cornils, Astrid; Brichta, Mauricio (2002). "Reproductive activity of two dominant Antarctic copepod species, Metridia gerlachei and Ctenocalanus citer, in late autumn in the eastern Bellingshausen Sea". Polar Biology. 25 (8): 583–590. doi:10.1007/s00300-002-0378-7. ISSN 1432-2056.
^ ^a ^b Schnack-Schiel, Sigrid B.; Hagen, Wilhelm (1995). "Life-cycle strategies of Calanoides acutus, Calanus propinquus, and Metridia gerlachei (Copepoda: Calanoida) in the eastern Weddell Sea, Antarctica". ICES Journal of Marine Science. 52 (3–4): 541–548. doi:10.1016/1054-3139(95)80068-9. ISSN 1054-3139.
^ Calbet, Albert; Irigoien, Xabier (1997). "Egg and faecal pellet production rates of the marine copepod Metridia gerlachei northwest of the Antarctic Peninsula". Polar Biology. 18 (4): 273–279. doi:10.1007/s003000050188. ISSN 0722-4060.
^ ^a ^b Lopez, M.D.G.; Huntley, M.E. (1995). "Feeding and diel vertical migration cycles of Metridia gerlachei (Giesbrecht) in coastal waters of the Antarctic Peninsula". Polar Biology. 15 (1). doi:10.1007/BF00236120. ISSN 0722-4060.
^ Huntley, Mark E.; Escritor, Florence (1992). "Ecology of Metridia gerlachei Giesbrecht in the western Bransfield Strait, Antarctica". Deep Sea Research Part A. Oceanographic Research Papers. 39 (6): 1027–1055. doi:10.1016/0198-0149(92)90038-U. ISSN 0198-0149.
^ Metz, C; Schnack-Schiel, SB (1995). "Observations on carnivorous feeding in Antarctic calanoid copepods". Marine Ecology Progress Series. 129: 71–75. doi:10.3354/meps129071. ISSN 0171-8630.
^ Hopkins, T. L. (1985). "Food web of an Antarctic midwater ecosystem". Marine Biology. 89 (2): 197–212. doi:10.1007/BF00392890. ISSN 0025-3162.