Benthic invertebrates at Southern California DDT dumpsites
Identifying benthic invertebrates at southern california ddt dumpsites 1 and 2
Principal investigator: Prof. Greg Rouse (SIO-BIC Curator)
Website and specimens managed by: Dr. Charlotte Seid (SIO-BIC Collection Manager)
About the Project | Our Role | Expeditions | Search DNA and Specimen Data | Featured Species | Expedition Images
The deep ocean off southern California has historically been a dumping ground for the pesticide DDT and other industrial wastes. Scripps Institution of Oceanography and collaborators are investigating the extent and impact of these contaminants (read more here).
The seafloor habitats of Dumpsites 1 and 2, located in the Santa Monica and San Pedro Basins off the coast of Los Angeles, contain discarded barrels and DDT-contaminated sediments, which are also home to various bottom-dwelling (benthic) invertebrates. As major links in the marine food web, benthic invertebrates are important for understanding the transfer of DDT to the broader ecosystem, and different species likely play different roles. Yet, simply identifying these benthic invertebrates is challenging, given the small size of the animals, the rarity of high-quality specimens from such deep sites, and fundamental knowledge gaps in invertebrate biodiversity.
Our role in the DDT research is to archive and identify representative benthic invertebrates from Dumpsites 1 and 2. These preserved specimens and their DNA sequences will serve as important reference materials for other research topics, such as the potential spread of DDT+ contamination through the food web.
During research expeditions in 2021-2024, SIO-BIC Curator Greg Rouse, SIO-BIC Collection Manager Charlotte Seid, and collaborators collected benthic invertebrates from sediment cores and barrels at the Santa Monica Basin, San Pedro Basin, and neighboring control sites. They preserved specimens for examination and archival; photographed live animals to capture color, texture, and size; and, critically, collected samples suitable for DNA sequencing. Many benthic invertebrate species reported from southern California in historic publications do not yet have DNA sequences available, so establishing a baseline DNA library for species at the DDT dumpsites will facilitate future identification of these species anywhere in the world.
Using a combination of DNA data and morphological examination by taxonomic specialists, the benthic invertebrates will be identified to the highest possible degree of accuracy and the DNA sequences will be made publicly available. Some specimens have already been determined to represent new species, previously unknown to science!
- August 2021: FK210726, #BiodiverseBorderlands, R/V Falkor with Remotely Operated Vehicle SuBastian, operated by the Schmidt Ocean Institute
- Collected samples, imagery, and video of benthic invertebrates on and around the chemical barrels in the San Pedro Basin
- Cruise overview
- Watch the ROV dives, including Dives 450 and 451 at the barrels
- March 2023: R/V Yellowfin, operated by the Southern California Marine Institute
- Collected benthic invertebrates in sediment samples (multicoring) in the San Pedro Basin
- December 2023: SP2331, R/V Robert Gordon Sproul, operated by Scripps Institution of Oceanography
- Collected benthic invertebrates in sediment samples (multicoring) in the Santa Monica Basin, San Pedro Basin, and control sites off San Diego
- May 2024: SP2407, R/V Robert Gordon Sproul, operated by Scripps Institution of Oceanography
- Collected benthic invertebrates in sediment samples (multicoring) in the Santa Monica Basin and San Pedro Basin
DNA and Specimen Data
- Specimen listings related to this project are tagged #DDTresearch in the SIO-BIC database: https://sioapps.ucsd.edu/collections/bi/search/?q=%23ddtresearch
- DNA sequences are publicly available as an NCBI BioProject.
Featured Species
Annelida (segmented worms)
- Chaetopteridae: Phyllochaetopterus limicolus
Image credit: Charlotte Seid
Phyllochaetopterus limicolus (more about this species)
Common name: parchment worm
Collected from: barrels and sediment cores, San Pedro Basin
Depth: 695-907 m
Remarks: This image shows the animal's head and long palp used for feeding. These worms are fragile and the rest of the body would be hidden in a thin-walled protective tube buried in the sediment.
- Clitellata
Image credit: Greg Rouse
Clitellata
Common name: worm
Collected from: sediment core, San Pedro Basin
Depth: 799 m
- Cossuridae: Cossura sp.
Image credit: Greg Rouse
Cossura sp.
Common name: polychaete worm
Collected from: sediment core, Santa Monica Basin
Depth: 462 m
- Dorvilleidae: Parougia sp.
Image credit: Greg Rouse
Parougia sp.
Common name: polychaete worm
Collected from: barrels and sediment cores, San Pedro Basin and Santa Monica Basin
Depth: 768-885 m
- Fauveliopsidae: Laubieriopsis sp.
Image credit: Greg Rouse
Laubieriopsis sp.
Common name: polychaete worm
Collected from: Santa Monica Basin
Depth: 442 m
- Glyceridae: Glycera sp.
Image credit: Greg Rouse
Glycera sp.
Common name: bloodworm
Collected from: barrels, San Pedro Basin
Depth: 885 m
- Hesionidae: Gyptis sp. W12582
Image credit: Charlotte Seid
Gyptis sp. W12582
Common name: polychaete worm
Collected from: sediment core, San Pedro Basin
Depth: 876 m
Remarks: This is a species new to science. When it is published in a peer-reviewed scientific journal, it will receive an official new name.
- Hesionidae: Neogyptis sp.
Image credit: Greg Rouse
Neogyptis sp.
Common name: polychaete worm
Collected from: sediment cores, San Pedro Basin and Santa Monica Basin
Depth: 759-907 m
- Lumbrineridae
Image credit: Greg Rouse
Lumbrineridae
Common name: polychaete worm
Collected from: sediment cores, Santa Monica Basin
Depth: 442-675 m
- Maldanidae: Maldane cf. sarsi
Image credit: Greg Rouse
Maldane cf. sarsi (more about this species)
Common name: bamboo worm
Collected from: sediment core, Santa Monica Basin
Depth: 442 m
Remarks: This specimen is genetically close to Maldane sarsi, a species originally described from the north Atlantic. Further taxonomic work is required to determine the geographic distribution of this species.
- Maldanidae: Maldanella sp.
Image credit: Greg Rouse
Maldanella sp.
Common name: bamboo worm
Collected from: sediment core, Santa Monica Basin
Depth: 442 m
- Melinnidae: Melinna heterodonta
Image credit: Greg Rouse
Melinna heterodonta (more about this species)
Common name: spaghetti worm
Collected from: sediment core, Santa Monica Basin
Depth: 442 m
- Nereididae
Image credit: Greg Rouse
Common name: polychaete worm
Collected from: sediment core, Santa Monica Basin
Depth: 628 m
- Nephtyidae: Micronephthys sp.
Image credit: Charlotte Seid
Micronephthys sp.
Common name: cat worm
Collected from: sediment core, San Pedro Basin
Depth: 876 m
- Paraonidae
Image credit: Charlotte Seid
Paraonidae (several species)
Common name: polychaete worm
Collected from: barrels and sediment cores, San Pedro Basin and Santa Monica Basin
Depth: 442-886 m
- Polynoidae: Eunoe (new species)
Image credit: Greg Rouse
Eunoe (new species)
Common name: scaleworm
Collected from: barrels, San Pedro Basin
Depth: 883-886 m
Remarks: This scaleworm is a species new to science. When it is published in a peer-reviewed scientific journal, it will receive an official new name.
- Sabellidae
Image credit: Greg Rouse
Sabellidae
Common name: feather-duster worm
Collected from: sediment core, Santa Monica Basin
Depth: 628 m
- Serpulidae: Protis pacifica
Image credit: Greg Rouse
Protis pacifica (more about this species)
Common name: calcareous tubeworm
Collected from: barrels and scallop shells in sediment cores, San Pedro Basin
Depth: 799-900 m
- Sipuncula
Image credit: Greg Rouse
Sipuncula
Common name: peanut worm
Collected from: sediment core, Santa Monica Basin
Depth: 675 m
- Spionidae: Spiophanes anoculata
Image credit: Charlotte Seid
Spiophanes anoculata (more about this species)
Common name: polychaete worm
Collected from: sediment cores, Santa Monica Basin
Depth: 701-768 m
- Syllidae: Myrianida sp.
Image credit: Greg Rouse
Myrianida sp.
Common name: necklace worm
Collected from: barrels, San Pedro Basin
Depth: 883 m
- Terebellidae: Polycirrinae
Image credit: Greg Rouse
Polycirrinae
Common name: spaghetti worm
Collected from: sediment cores, Santa Monica Basin
Depth: 442-462 m
Arthropoda (crustaceans and relatives)
- Amphipoda: Ampeliscidae
Image credit: Charlotte Seid (preserved specimen)
Ampeliscidae
Common name: amphipod crustacean
Collected from: sediment, San Pedro Basin
Depth: 753 m
- Amphipoda: Caprellidae
Image credit: Charlotte Seid (preserved specimen)
Caprellidae
Common name: amphipod crustacean
Collected from: sediment, San Pedro Basin
Depth: 628-698 m
Remarks: The individual in this photo is a female holding eggs in her brood pouch.
- Amphipoda: Liljeborgiidae
Image credit: Charlotte Seid (preserved specimen)
Liljeborgiidae
Common name: amphipod crustacean
Collected from: sediment, San Pedro Basin
Depth: 753 m
- Mysida
Image credit: Charlotte Seid (preserved specimen)
Mysida
Common name: opossum shrimp
Collected from: above sediment, San Pedro Basin
Depth: 874 m
- Tanaidacea
Image credit: Charlotte Seid
Tanaidacea
Common name: tanaid crustacean
Collected from: sediment, San Pedro Basin
Depth: 442 m
Cnidaria (anemones, corals, and relatives)
- Anthozoa: Actiniaria: Calamactis praelonga ?
Image credit: Charlotte Seid
Calamactis praelonga (more about this species)
Common name: burrowing anemone
Collected from: sediment core, Santa Monica Basin
Depth: 675 m
Remarks: Tentative identification, to be confirmed with genetics.
- Anthozoa: Actiniaria: Edwardsia cf. profunda
Image credit: Charlotte Seid
Edwardsia cf. profunda (more about this species)
Common name: burrowing anemone
Collected from: sediment core, San Pedro Basin
Depth: 898 m
Remarks: This anemone is most likely Edwardsia profunda based on its morphology, locality, and depth.
- Anthozoa: Actiniaria: Sagartiogeton cf. californicus
Image credit: Greg Rouse
Sagartiogeton cf. californicus (more about this species)
Common name: anemone
Collected from: barrels, San Pedro Basin
Depth: 886 m
Remarks: This anemone is likely Sagartiogeton californicus based on existing DNA sequences, but further genetic work is warranted.
- Anthozoa: Octocorallia: Pennatuloidea
Image credit: Charlotte Seid (preserved specimen)
Pennatuloidea
Common name: sea pen
Collected from: top of sediment, San Pedro Basin
Depth: 759 m
Remarks: These photos show a wide view of the colony and close-ups of polyps.
- Hydrozoa
Image credit: Charlotte Seid
Hydrozoa
Common name: hydroid (polyp stage)
Collected from: scallop shell in sediment, San Pedro Basin
Depth: 799 m
Remarks: Polyps are the benthic (or sometimes only) phase in the life cycle of hydrozoans.
- Scyphozoa
Image credit: Greg Rouse
Scyphozoa
Common name: jellyfish (polyp stage)
Collected from: barrel, San Pedro Basin
Depth: 885 m
Remarks: Polyps are the benthic phase in the life cycle of some jellyfish.
Echinodermata (brittle stars and relatives)
- Ophiuroidea: Amphipholis pugetana
Image credit: Charlotte Seid (preserved specimen)
Amphipholis pugetana (more about this species)
Common name: brittle star
Collected from: top of sediment, San Pedro Basin
Depth: 698-804 m
- Ophiuroidea: Asteronyx longifissus
Image credit: Charlotte Seid (preserved specimen)
Asteronyx longifissus (more about this species)
Common name: snake star
Collected from: top of sediment, San Pedro Basin
Depth: 698-799 m
- Ophiuroidea: Ophiacantha diplasia
Image credit: Greg Rouse (detail of one arm)
Ophiacantha diplasia (more about this species)
Common name: brittle star
Collected from: top of sediment, San Pedro Basin
Depth: 768 m
- Ophiuroidea: Ophiocten hastatum
Image credit: Charlotte Seid (juvenile specimen)
Ophiocten hastatum (more about this species)
Common name: brittle star
Collected from: top of sediment, San Pedro Basin
Depth: 902 m
ENTOPROCTA (GOBLET ANIMALS)
- Entoprocta: Barentsia sp.
Image credit: Charlotte Seid
Barentsia sp.
Common name: goblet animals or nodding heads
Collected from: sediment cores, San Pedro Basin and Santa Monica Basin
Depth: 846-907 m
Hemichordata (acorn worms)
- Enteropneusta
Image credit: Greg Rouse
Enteropneusta
Common name: acorn worm
Collected from: sediment, San Pedro Basin and Santa Monica Basin
Depth: 628-768 m
Mollusca (clams, snails, etc.)
- Aplacophora: Caudofoveata
Image credit: Greg Rouse
Caudofoveata (maybe multiple species)
Common name: aplacophoran shell-less mollusk
Collected from: sediment, Santa Monica Basin and San Pedro Basin
Depth: 442-799 m
- Aplacophora: Solenogastres: Acanthomeniidae
Image credit: Greg Rouse
Acanthomeniidae
Common name: aplacophoran shell-less mollusk
Collected from: barrel, San Pedro Basin
Depth: 885 m
- Bivalvia: Cuspidariidae: Cardiomya pectinata
Image credit: Charlotte Seid
Cardiomya pectinata (more about this species)
Common name: pectinate cardiomya clam
Collected from: sediment, between San Pedro Basin and Santa Monica Basin
Depth: 442 m
- Bivalvia: Galeommatidae: Axinodon redondoensis
Image credit: Charlotte Seid
Axinodon redondoensis (more about this species)
Common name: elongate axinopsid clam
Collected from: sediment, San Pedro Basin and Santa Monica Basin
Depth: 442-462 m
- Bivalvia: Propeamussiidae: Cyclopecten zephyrus
Image credit: Charlotte Seid
Cyclopecten zephyrus (more about this species)
Common name: thin glass scallop
Collected from: sediment, San Pedro Basin and Santa Monica Basin
Depth: 694-907 m
Remarks: Hydroids and tube worms (Protis pacifica) were attached to the shells.
- Bivalvia: Mytilidae: Dacrydium pacificum
Image credit: Charlotte Seid
Dacrydium pacificum (more about this species)
Common name: Pacific glassy-mussel
Collected from: sediment, San Pedro Basin and Santa Monica Basin
Depth: 442 m
- Bivalvia: Yoldiidae: Yoldiella sp.
Image credit: Charlotte Seid
Yoldiella sp.
Common name: clam
Collected from: sediment core, Santa Monica Basin
Depth: 442 m
- Gastropoda: Heterobranchia: Parvaplustridae: Parvaplustrum sp.
Image credit: Greg Rouse
Parvaplustrum sp.
Common name: bubble snail
Collected from: sediment and whale skeleton, San Pedro Basin
Depth: 885 m
- Gastropoda: Neogastropoda: Columbellidae: Astyris permodesta
Image credit: Charlotte Seid
Astyris permodesta (more about this species)
Common name: dove snail
Collected from: barrels and top of sediment, San Pedro Basin
Depth: 695-900 m
- Gastropoda: Heterobranchia: Nudibranchia: Cuthonidae?
Image credit: Greg Rouse
Cuthonidae?
Common name: aeolid nudibranch
Collected from: barrels, San Pedro Basin
Depth: 885 m
Remarks: This nudibranch is not a close genetic match to known sequences and may be a new species.
- Gastropoda: Heterobranchia: Tjaernoeiidae: Tjaernoeia (new species)
Image credit: Greg Rouse
Tjaernoeia (new species)
Common name: bubble snail
Collected from: barrel, San Pedro Basin
Depth: 885 m
Remarks: This snail is a species new to science. When it is published in a peer-reviewed scientific journal, it will receive an official new name.
- Gastropoda: Heterobranchia: Gastropteridae: Gastropteron pacificum
Image credit: Greg Rouse
Gastropteron pacificum (more about this species)
Common name: Pacific wingfoot snail
Collected from: seawater just above sediment surface, San Pedro Basin
Depth: 799 m
- Scaphopoda
Image credit: Charlotte Seid
Scaphopoda
Common name: tusk shell
Collected from: sediment, San Pedro Basin and Santa Monica Basin
Depth: 409 m
NEMATODA (round WORMS)
- Nematoda: several species
Image credit: Greg Rouse
Nematoda (several species)
Common name: round worms
Collected from: barrels and sediment cores, San Pedro Basin and Santa Monica Basin
Depth: 698-907 m
Remarks: We are collaborating with Dr. Holly Bik's research group at the University of Georgia to study these tiny and diverse worms.
NEMERTEA (RIBBON WORMS)
- Lineidae: Cerebratulus ruber
Image credit: Greg Rouse
Cerebratulus ruber (more about this species)
Common name: red ribbon worm
Collected from: sediment cores, San Pedro and Santa Monica Basins
Depth: 675-893 m
Remarks: Identification to be confirmed.
Porifera (sponges)
- Calcarea: Clathrinidae: Clathrina cf. coriacea
Image credit: Greg Rouse
Clathrina cf. coriacea (more about this species)
Common name: calcareous sponge
Collected from: barrel, San Pedro Basin
Depth: 885 m
Remarks: These tiny sponges were growing on the calcareous tube of the tubeworm Protis pacifica. They are not a close genetic match to known sequences and requires closer comparison to Clathrina coriacea.
- Demospongiae: Suberitidae: Rhizaxinella gadus
Image credit: Greg Rouse
Rhizaxinella gadus (more about this species)
Common name: sponge
Collected from: barrel, San Pedro Basin
Depth: 883 m
Other
- Chordata: Tunicata: Pyrosoma atlanticum
Image credit: Charlotte Seid (preserved specimen)
Pyrosoma atlanticum (more about this species)
Common name: pelagic colonial tunicate
Collected from: above sediment, San Pedro Basin
Depth: 883 m
Remarks: This specimen is a very small colony.
Multicoring in the San Pedro Basin aboard R/V Robert Gordon Sproul in May 2024, cruise SP2407. Image credit: Charlotte Seid.
Multicoring in the San Pedro Basin aboard R/V Robert Gordon Sproul in December 2023, cruise SP2331. Image credit: Charlotte Seid.
Barrel 1 at Dumpsite 1 in the San Pedro Basin, showing microbial growth resembling fried eggs. Credit: model by Greg Rouse using source images from Schmidt Ocean Institute/ROV SuBastian Dive S0451.
Website last updated 2024-08-27