Mesozooplankton dynamics in the Benguela ecosystem, with emphasis on the herbivorous copepods

Verheye, HM; Hutchings, L.; Huggett, Jenny A.; Painting, S. J.

doi:10.2989/02577619209504725

Cited by 81 publications

(33 citation statements)

References 23 publications

(40 reference statements)

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“…Zooplankton must cope with these advective forces to maintain their populations near phytoplankton-rich upwelling zones. Among the mechanisms proposed to help zooplankton retention, diel vertical migration (DVM) and ontogenetic layering have often been invoked (Pillar et al 1984, Verheye et al 1992. Calanus chilensis, however, show little or restricted DVM, possibly limited by the shallow OML (Escribano 1998.…”

Section: Discussionmentioning

confidence: 99%

Spatial distribution of Calanus chilensis off Mejillones Peninsula (northern Chile): ecological consequences upon coastal upwelling

Giraldo¹,

Escribano²,

Marı́n³

2002

Mar. Ecol. Prog. Ser.

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The Mejillones Peninsula upwelling system (northern Chile) appears to be a natural laboratory, suitable to test hypotheses concerning variability of copepod growth in nature. In this zone, in January 2000, we collected zooplankton samples inside and outside of an upwelling plume to assess differential responses of copepodid Calanus chilensis to spatial distribution of temperature, chlorophyll a (chl a), current field and dissolved oxygen (DO). We studied variability of prosome length (PL), dry weight (DW), oil sac volume (OSV), ovary development (GI) and a condition index (CI) of females, and PL and OSV of Copepodid Stage C5. The sea temperature ranged between 14 and 20°C in the upper 10 m, whereas chl a varied between 3 and 14 mg m -3. We distinguished 2 zones according to temperature and the current field: a cold retention area coinciding with the upwelling plume, and a warmer highly advective zone, outside the plume. Abundance of most copepodids was associated with cold and chl a-rich waters, and positively correlated to current speeds. DW and CI of females and PL of Stage C5 were negatively correlated to temperature, but not to chl a. Within the cold retention zone, copepodids were more abundant, females and C5 copepodids were larger and heavier, and females had more developed ovaries, but there were no differences in lipid content or CI. We concluded that resulting circulation may act as an efficient mechanism to maintain copepodids within the chl a-rich upwelling center, but this also implies spatial heterogeneity in temperature and food, giving rise to variability in growth and development of copepods, which is then reflected in different-sized individuals in the late stages of development.

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Section: Discussionmentioning

confidence: 99%

Spatial distribution of Calanus chilensis off Mejillones Peninsula (northern Chile): ecological consequences upon coastal upwelling

Giraldo¹,

Escribano²,

Marı́n³

2002

Mar. Ecol. Prog. Ser.

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“…Similar dominant copepods including Calanoides, Centropages, Metridia and various small calanoids were found by De Decker (1973). Calanoides, most abundant in this region, is known to be an upwelling specialist (Verheye et al 1992). It stores lipids, and undergoes diapause and ontogenetic migrations allowing populations to maintain themselves within the system during periods of low productivity (Verheye et al 1991).…”

Section: Community Structurementioning

confidence: 99%

Large-scale patterns in diversity and community structure of surface water copepods from the Atlantic Ocean

Woodd-Walker¹,

Ward²,

Clarke³

2002

Mar. Ecol. Prog. Ser.

117

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Diversity and structure of copepod assemblages were investigated using 259 WP2 zooplankton samples collected from the top 200 m of the Atlantic Ocean between 60°N and 63°S. Whilst richness at a number of taxonomic levels (genera-superfamily) demonstrated a smooth latitudinal cline from the tropics towards the poles, other diversity indices such as evenness and taxonomic distinctness showed abrupt changes around 40°N and 40°S, coincident with sea surface temperatures of 17 to 20°C. In the tropics and subtropics, copepod communities were characterised by high stable taxonomic diversity and a relatively even distribution of genera within samples. In contrast, at high latitudes and low temperatures communities showed large variation in overall diversity, evenness and distinctness. Multidimensional scaling and cluster analysis of transformed generic abundances, pooled into 5°latitudinal means, produced ordinations consistent with the recent subdivision of the oceans into 4 primary biomes based on temporal and spatial patterns of primary production. The copepod community corresponding to the Trades biome, where primary production is broadly continuous, exhibited high generic richness and evenness. In contrast, community structure in the Polar biome, where primary production is highly seasonal, was highly variable and dominated by a few genera. These genera tended to be herbivorous or omnivorous and stored lipid. The Westerlies biome and the Benguela province had intermediate copepod community characteristics. We therefore suggest that copepod diversity and community structure are closely tied not to temperature or energy input, but to the temporal patterns of primary and secondary production.

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“…-1 d -1 in the Benguela upwelling system (Peterson et al 1988, in Verheye et al 1992. In northern Chile, off Antofagasta, González et al (2000) estimated an ingestion rate of 5 to 22 µg C ind.…”

Section: Comparative Total Carbon Ingestion Of Copepods and Appendicumentioning

confidence: 99%

Plankton community structure and carbon cycling in a coastal upwelling system. I. Bacteria, microprotozoans and phytoplankton in the diet of copepods and appendicularians

Vargas¹,

González²

2004

Aquat. Microb. Ecol.

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Copepod and appendicularian grazing experiments using naturally occurring planktonic assemblages from a coastal embayment (Mejillones Bay, northern Chile upwelling system at 23º S) were conducted between October 2000 and October 2001. Total carbon ingestion rates based on sizefractioned chlorophyll data showed that dominant copepods (Acartia tonsa, Centropages brachiatus, Oithona similis and Paracalanus parvus) ingested between 2 and 8 µg C ind.-1 d -1, while appendicularians (Oikopleura dioica and O. longicauda) ingested ~3 to 4 µg C ind.-1 d -1 . Even when most copepods were feeding on larger cells (> 23 µm) at high rates, the smaller copepods also grazed at similar rates on nanoplankton (5 to 23 µm) and picoplankton (< 5 µm). In contrast, chain-forming diatoms were cleared at very low rates by copepods. Bacteria were cleared only by appendicularians (~170 tõ 400 ml ind.) but not by any copepod, while heterotrophic protists constituted a substantial proportion in the diet of both copepods and appendicularians (~10 to 100% body carbon d -1 ), particularly during austral spring. Occasionally, copepod C-specific ingestion on heterotrophs was similar to that on autotrophic cells. Large ciliates and dinoflagellates were cleared but not ingested by the appendicularian O. dioica, suggesting a mechanism of trapping large cells in their houses and implying a rapid export of fresh material. Since heterotrophs are a common component in the diet of these 2 groups (omnivory by copepods and bacterophagy by appendicularians), they can potentially affect microbial food webs in this upwelling system and thus carbon export.KEY WORDS: Carbon flux · Omnivory · Microzooplankton · Clearance rate · Copepods · Appendicularians Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 34: [151][152][153][154][155][156][157][158][159][160][161][162][163][164] 2004 Acartia (e.g. Gonzalez et al. 2000, Grünewald et al. 2002. It is often assumed that copepods feed mostly on phytoplankton, mainly diatoms; therefore, trophic coupling between copepods and protists such as ciliates, dinoflagellates and heterotrophic nanoflagellates has been less thoroughly examined in this region. Predation by omnivorous copepods on other components of the phytoplankton and microzooplankton, especially small heterotrophic nanoflagellates and ciliates, may be important. For other coastal areas it has been suggested that protists occasionally constitute the main food source for calanoid and cyclopoid copepods (Kleppel et al. 1991, Pierce & Turner 1992, Levinsen et al. 2000, which would have important implications for food web dynamics.On the other hand, some attention has been given to the role of large-sized microphages, e.g. appendicularian tunicates. Appendicularians may play an important role in channeling carbon from bacteria and small-sized phytoplankton into downward export (Fortier et al. 1994). In contrast with copepods, which have long been considered the major component of secondary production in the ...

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Mesozooplankton dynamics in the Benguela ecosystem, with emphasis on the herbivorous copepods

Cited by 81 publications

References 23 publications

Spatial distribution of Calanus chilensis off Mejillones Peninsula (northern Chile): ecological consequences upon coastal upwelling

Spatial distribution of Calanus chilensis off Mejillones Peninsula (northern Chile): ecological consequences upon coastal upwelling

Large-scale patterns in diversity and community structure of surface water copepods from the Atlantic Ocean

Plankton community structure and carbon cycling in a coastal upwelling system. I. Bacteria, microprotozoans and phytoplankton in the diet of copepods and appendicularians

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