The Gelatinous Zooplankton communities of Godthåbsfjorden, West Greenland
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The Gelatinous Zooplankton communities of Godthåbsfjorden, West Greenland Russell R. Hopcroft 1,3 , Cornelia Jaspers 2 , Torkel G. Nielsen 2,3 [email protected] 1 Institute of Marine Science, University of Alaska Fairbanksm, USA National Institute of Aquatic Resources, Technical University of Denmark, Copenhagen Greenland Climate Research Centre, Greenland Institute of Natural Resources, Nuuk, Greenland Methods: Zooplankton collections were taken vertically with a 0.25 m 2 Multinet MIDI equipped with 505 µm nets from near bottom to surface, as well as a 2 m diameter MIK net of 1300 µm mesh hauled obliquely to 100m depth. Gelatinous zooplankton were identified and measured soon after collection on unpreserved material with the aid of a light table. The only non-crustaceans that were left for processing after preservation were chaetognaths and larvaceans. For all other taxa considered, samples were processed in their entirety. Introduction: The zooplankton communities of high latitude fjords remains poorly know. This is particularly true for those that are seasonally ice-covered and/or containing tide-water glaciers such as most fjords in Greenland and other polar archipelagos. Their gelatinous fauna remains virtually ignored. We conducted a survey of the composition, abundance, and distribution of non-copepod groups along a transect leading from the furthest inland extend of Godthåbsfjorden into the offshore waters of Fyllas Bank, West Greenland. Acknowledgements: This contributes to the Greenland Climate Research Centre project 6505, and the Arctic Ocean Diversity (ArcOD) project of the Census of Marine Life . Preliminary Results: In total we collected 17 species of hydromedusae, 3 species of siphonophores, 3 species of scyphomedusae, 3 species chaetognaths, 5 species of ctenophore, 3 species of pteropods, 1 species of pelagic polychaete, and 3 species of larvaceans (=appendicularians), for a total of 38 species. Ctenophores were unexpectedly abundant during the cruise with Fyllas Bank communities dominated by the ctenophore Mertensia ovum, with lesser contributions by Bolinopsis infundibulum. Inside the fjord, Mertensia abundance declined precipitously with the community becoming dominated by at least 2 species of Beroe. Table 1. Average abundance (numbers m -2 ) of gelatinous species Fig.1. Abundance per square meter of the most dominant gelatinous zooplankton in Godthåbsfjorden, West Greenland Thoughts: Although the numbers of many taxa appear low, this is compensated for by the generally large size of most species, particularly so for the ctenophores. The grazing impact of these communities must be substantial. -53.5 -53 -52 .5 -52 -5 1.5 -51 -50.5 -50 -49 .5 Longitude S ta n d a rd sta tio n s D a n a cru ise Ju n e 2010 63.8 64 64.2 64.4 64.6 64.8 Latitude Species Species Mertens ia ovum 300.24 Halis tema rubra ( nectophore) trace Dimophyes arctica (eudoxid) 76.95 Melic erc um oc toc os tatum trace Dimophyes arctica (nectophore) 57.39 Mitroc omella polydiademata trace A glantha digitale 72.78 S ars ia princ eps trace C yanea c apillata 70.12 E uphys a aurata tarce B olinops is infundubulum 30.90 Limac ina helic ina 25.64 N otQ uantified R athk eha oc topunc tata 11.28 Oik opleura labradoriens is Beroe cucumis 7.40 Oik opleura vanhoeffeni Beroe abyssicola 6.44 F ritillaria borealis Limac ina retrovers a 3.05 E uk rohnia hamata Obelia longis s ima 2.65 P aras agitta elegans Nanomia cara (nectophore) 2.13 P s eudos agitta maxima B ouganvillia s uperc iliarus 1.90 P antac hogon haec k eli 1.25 C atablema ves ic arium 1.22 S ars ia tubulos a 0.96 C lione limac ina 0.75 T omopterus s eptentrionalis 0.62 T iarops is multic irrata 0.62 A urelia aurita 0.59 A eginops is laurentii 0.27 P lotoc nide borealis 0.07 P tycogena lactea 0.05 Halitholus c irratus 0.05 P eriphylla periphylla 0.02 Mertensia ovum -54° -53° -52° -51° -50° 63.6° 63.8° 64.0° 64.2° 64.4° 64.6° 64.8° 65.0° Beroe cucumis -54° -53° -52° -51° -50° 63.6° 63.8° 64.0° 64.2° 64.4° 64.6° 64.8° 65.0° Beroe abyssicola -54° -53° -52° -51° -50° Bolinopsis infundibulum -54° -53° -52° -51° -50° 2000 200 200 20 25 2.5 25 2.5 Aglantha digitale -54° -53° -52° -51° -50° 63.6° 63.8° 64.0° 64.2° 64.4° 64.6° 64.8° 65.0° R athkea octopunctata -54° -53° -52° -51° -50° 63.6° 63.8° 64.0° 64.2° 64.4° 64.6° 64.8° 65.0° Obelia longissima -54° -53° -52° -51° -50° Dimophyes arctica -54° -53° -52° -51° -50° 500 50 500 50 100 10 25 2.5 Bougainillia supercilliaris -54° -53° -52° -51° -50° 63.6° 63.8° 64.0° 64.2° 64.4° 64.6° 64.8° 65.0° S ars ia tubulosa -54° -53° -52° -51° -50° 63.6° 63.8° 64.0° 64.2° 64.4° 64.6° 64.8° 65.0° Tiariopsis multicirrata -54° -53° -52° -51° -50° C atablema vesicarium -54° -53° -52° -51° -50° 20 2 20 2 5 0.5 5 0.5 Limacina helicina -54° -53° -52° -51° -50° 63.6° 63.8° 64.0° 64.2° 64.4° 64.6° 64.8° 65.0° Limacina retroversa -54° -53° -52° -51° -50° 200 20 25 2.5 FB5 FB4 FB 3.5 FB3 FB 2.5 FB2 FB 1.5 FB1 G F1A G F2 G F3 G F4 G F5 G F6 G F8 G F10 G F11 G F12 2D Stress:0.08 Fig.2. Cluster analysis and Multidimensional Scaling of Bray-Curtis similarity coefficients showing clear zonation of gelatinous zooplankton communities in Godthåbsfjorden FB2 FB1 FB1.5 FB3 FB2.5 FB3.5 FB4 FB5 G F1A G F2 G F4 G F3 G F5 G F6 G F8 G F10 G F11 G F12 Sam ples 100 80 60 40 20 B ray-C urtis S im ilarity
description
The Gelatinous Zooplankton communities of Godthåbsfjorden, West Greenland Russell R. Hopcroft 1,3 , Cornelia Jaspers 2 , Torkel G. Nielsen 2,3 [email protected] 1 Institute of Marine Science, University of Alaska Fairbanksm, USA - PowerPoint PPT Presentation
Transcript of The Gelatinous Zooplankton communities of Godthåbsfjorden, West Greenland
The Gelatinous Zooplankton communities of Godthåbsfjorden, West Greenland
Russell R. Hopcroft1,3, Cornelia Jaspers2, Torkel G. Nielsen2,3
1Institute of Marine Science, University of Alaska Fairbanksm, USANational Institute of Aquatic Resources, Technical University of Denmark, Copenhagen
Greenland Climate Research Centre, Greenland Institute of Natural Resources, Nuuk, Greenland
Methods:Zooplankton collections were taken vertically with a 0.25 m2 Multinet MIDI equipped with 505 µm nets from near bottom to surface, as well as a 2 m diameter MIK net of 1300 µm mesh hauled obliquely to 100m depth. Gelatinous zooplankton were identified and measured soon after collection on unpreserved material with the aid of a light table. The only non-crustaceans that were left for processing after preservation were chaetognaths and larvaceans. For all other taxa considered, samples were processed in their entirety.
Introduction: The zooplankton communities of high latitude fjords remains poorly know. This is particularly true for those that are seasonally ice-covered and/or containing tide-water glaciers such as most fjords in Greenland and other polar archipelagos. Their gelatinous fauna remains virtually ignored. We conducted a survey of the composition, abundance, and distribution of non-copepod groups along a transect leading from the furthest inland extend of Godthåbsfjorden into the offshore waters of Fyllas Bank, West Greenland.
Acknowledgements:This contributes to the Greenland Climate Research Centre project 6505, and the Arctic Ocean Diversity (ArcOD) project of the Census of Marine Life .
Preliminary Results:In total we collected 17 species of hydromedusae, 3 species of siphonophores, 3 species of scyphomedusae, 3 species chaetognaths, 5 species of ctenophore, 3 species of pteropods, 1 species of pelagic polychaete, and 3 species of larvaceans (=appendicularians), for a total of 38 species. Ctenophores were unexpectedly abundant during the cruise with Fyllas Bank communities dominated by the ctenophore Mertensia ovum, with lesser contributions by Bolinopsis infundibulum. Inside the fjord, Mertensia abundance declined precipitously with the community becoming dominated by at least 2 species of Beroe.
Table 1. Average abundance (numbers m-2) of gelatinous species
Fig.1. Abundance per square meter of the most dominant gelatinous zooplankton in Godthåbsfjorden, West Greenland
Thoughts: Although the numbers of many taxa appear low, this is compensated for by the generally large size of most species, particularly so for the ctenophores. The grazing impact of these communities must be substantial.
-53.5 -53 -52.5 -52 -51.5 -51 -50.5 -50 -49.5
Longitude
Standard stations Dana cru ise June 2010
63.8
64
64.2
64.4
64.6
64.8
Latit
ude
Species Species
Mertensia ovum 300.24 Halistema rubra (nectophore) traceDimophyes arctica (eudoxid) 76.95 Melicercum octocostatum traceDimophyes arctica (nectophore) 57.39 Mitrocomella polydiademata traceAglantha digitale 72.78 Sarsia princeps traceCyanea capillata 70.12 Euphysa aurata tarceBolinopsis infundubulum 30.90Limacina helicina 25.64 Not QuantifiedRathkeha octopunctata 11.28 Oikopleura labradoriensisBeroe cucumis 7.40 Oikopleura vanhoeffeniBeroe abyssicola 6.44 Fritillaria borealisLimacina retroversa 3.05 Eukrohnia hamataObelia longissima 2.65 Parasagitta elegansNanomia cara (nectophore) 2.13 Pseudosagitta maximaBouganvillia superciliarus 1.90Pantachogon haeckeli 1.25Catablema vesicarium 1.22Sarsia tubulosa 0.96Clione limacina 0.75Tomopterus septentrionalis 0.62Tiaropsis multicirrata 0.62Aurelia aurita 0.59Aeginopsis laurentii 0.27Plotocnide borealis 0.07Ptycogena lactea 0.05Halitholus cirratus 0.05Periphylla periphylla 0.02
Mertensia ovum
-54° -53° -52° -51° -50°
63.6°
63.8°
64.0°
64.2°
64.4°
64.6°
64.8°
65.0°
Beroecucumis
-54° -53° -52° -51° -50°
63.6°
63.8°
64.0°
64.2°
64.4°
64.6°
64.8°
65.0°
Beroeabyssicola
-54° -53° -52° -51° -50°
Bolinopsisinfundibulum
-54° -53° -52° -51° -50°
2000200
20020
252.5
252.5
Aglanthadigitale
-54° -53° -52° -51° -50°
63.6°
63.8°
64.0°
64.2°
64.4°
64.6°
64.8°
65.0°
Rathkeaoctopunctata
-54° -53° -52° -51° -50°
63.6°
63.8°
64.0°
64.2°
64.4°
64.6°
64.8°
65.0°
Obelialongissima
-54° -53° -52° -51° -50°
Dimophyesarctica
-54° -53° -52° -51° -50°
50050
50050
10010
252.5
Bougainilliasupercilliaris
-54° -53° -52° -51° -50°
63.6°
63.8°
64.0°
64.2°
64.4°
64.6°
64.8°
65.0°
Sarsiatubulosa
-54° -53° -52° -51° -50°
63.6°
63.8°
64.0°
64.2°
64.4°
64.6°
64.8°
65.0°
Tiariopsismulticirrata
-54° -53° -52° -51° -50°
Catablemavesicarium
-54° -53° -52° -51° -50°
202
202
50.5
50.5
Limacinahelicina
-54° -53° -52° -51° -50°
63.6°
63.8°
64.0°
64.2°
64.4°
64.6°
64.8°
65.0°
Limacinaretroversa
-54° -53° -52° -51° -50°
20020
252.5
Transform: Fourth rootResemblance: S17 Bray Curtis similarity
4thfgbcdea
FB5
FB4
FB3.5
FB3FB2.5
FB2 FB1.5
FB1
GF1A
GF2
GF3
GF4
GF5
GF6GF8
GF10
GF11GF12
2D Stress: 0.08
Fig.2. Cluster analysis and Multidimensional Scaling of Bray-Curtis similarity coefficients showing clear zonation of gelatinous zooplankton communities in Godthåbsfjorden
FB
2
FB
1
FB
1.5
FB
3
FB
2.5
FB
3.5
FB
4
FB
5
GF
1A
GF
2
GF
4
GF
3
GF
5
GF
6
GF
8
GF
10
GF
11
GF
12
Samples
100
80
60
40
20
Bra
y-C
urt
is S
imila
rity
Transform: Fourth rootResemblance: S17 Bray Curtis similarity
4thfgbcdea
