Ampelisca mississippiana is a small (less than 6 mm long), colorless amphipod that was discovered only recently from sediment samples taken in the Mississippi Canyon of the Northern Gulf of Mexico (Soliman & Wicksten 2007). At the head of the canyon, at a depth of about 480 m, these crustaceans were found to be the dominant benthic animals forming dense mats of up to 12,000 individuals per m² in the muddy ocean floor (Soliman & Wicksten 2007).

Like other ampeliscid amphipods, Ampelisca mississippiana probably feed on detritus and build tubes in the sediment. High density mats of tube-dwelling organisms are thought to be of great ecological significance because they stabilize the soft mud while capturing particulate matter flowing from the continental shelf to the deeper regions of the gulf (Soliman & Wicksten 2007). It has also been suggested that ampeliscid tube mats may have a positive effect on certain fish populations by reducing the accumulation of silt in the water, by facilitating the settlement of fish larvae, and by deterring predation (Mackenzie et al. 2006).

Ampelisca mississippiana populations may be threatened by the Gulf of Mexico oil slick resulting from the Deep Water Horizon Incident of 20 April 2010 (Robertson & Krauss 2010). By mid-May 2010, aerial views show the oil within 100 km of the type locality at the head of the Mississippi Canyon (see Map). The effects of oil spills and associated remediation efforts on deep ocean communities are poorly understood (Biella 2010).

Gulf of Mexico

Holotype for Ampelisca mississippiana Soliman & Wicksten, 2007
Catalog Number: USNM 1080602
Collection: Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology
Sex/Stage: Female;
Preparation: Alcohol (Ethanol)
Year Collected: 2000
Locality: United States, Gulf of Mexico, North Atlantic Ocean
Depth (m): 480 to 480
Vessel: Gyre R/V

Paratype for Ampelisca mississippiana Soliman & Wicksten, 2007
Catalog Number: USNM 1080603
Collection: Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology
Sex/Stage: Female;
Preparation: Alcohol (Ethanol)
Collector(s): G. Rowe
Year Collected: 2002
Locality: United States, Gulf of Mexico, North Atlantic Ocean
Depth (m): 476 to 476
Vessel: Gyre R/V

Paratype for Ampelisca mississippiana Soliman & Wicksten, 2007
Catalog Number: USNM 1080604
Collection: Smithsonian Institution, National Museum of Natural History, Department of Invertebrate Zoology
Sex/Stage: Female;
Preparation: Alcohol (Ethanol)
Collector(s): G. Rowe
Year Collected: 2001
Locality: United States, Gulf of Mexico, North Atlantic Ocean
Depth (m): 490 to 490
Vessel: Gyre R/V

Depth range based on 3 specimens in 1 taxon.
Water temperature and chemistry ranges based on 3 samples.

Environmental ranges
  Depth range (m): 476 - 490
  Temperature range (°C): 8.578 - 8.578
  Nitrate (umol/L): 27.441 - 27.441
  Salinity (PPS): 35.006 - 35.006
  Oxygen (ml/l): 2.904 - 2.904
  Phosphate (umol/l): 1.653 - 1.653
  Silicate (umol/l): 20.944 - 20.944

Graphical representation

Depth range (m): 476 - 490
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.