Effect of sinking spring phytoplankton blooms on lipid content and composition in suprabenthic and benthic invertebrates in a cold ocean coastal environment

Abstract

Lipids were measured in 19 suprabenthic and benthic invertebrate taxa from 5 phyla to determine their responses to a sinking spring diatom bloom. In Conception Bay, as in many areas of coastal Newfoundland, Canada, benthic organisms experience sub-zero temperatures year round. Among specimens collected at depths between 210 and 220 m, the small mysid Erythrops erythrophtalma had, on average, the highest lipid concentration (6% of wet weight), while a holothurian (Order Apodida) had the lowest (0.3%). In E. erythrophtalma, 73% of the lipids were found in the neutral fraction, while in the sea cucumber 68% were polar lipids. The euphausiid Thysanoessa raschii had the highest proportion of essential ω3 fatty acids (41% total fatty acids) while the holothurian had the lowest (21%). Pseudocalanus spp. showed the highest mean value for the C 16 polyunsaturated fatty acid (PUFA) ratio indicative of lipids from nutrient-replete diatoms. The amphipods Acanthostepheia malmgreni and Anonyx spp. responded immediately to each spring bloom with increased total and neutral lipid contents. The mysid Pseudomma truncatum also showed a transient increase in total lipid content, but this occurred much later in the summer. However, P. truncatum, together with the decapod Pandalus borealis, the mysid Mysis mixta, and the polar bivalve Yoldia hyperborea, did respond immediately based on increased proportions of ω3 fatty acids, while the asteroid Ctenodiscus crispatus showed increased ω3 fatty acid proportions in its gonads much later. The chaetognath Parasagitta elegans differed from most other species in that it maintained very similar total lipid and C 16 PUFA proportions throughout the sampling period, suggesting little direct response to the bloom. Thus, we found a variable response to the bloom with respect to phenology, even within orders, which depended upon feeding behaviour and gonadogenesis. KEY WORDS:Fatty acids · Bacillariophyceae · Polychaeta · Copepoda · Malacostraca · Protobranchia · Echinodermata · Chaetognatha Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 391: [33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51] 2009 survival and growth (Ackman & Kean-Howie 1994, Xu et al. 1994. They are precursors of highly bioactive metabolites and are required for normal membrane structure and function, especially at low temperatures (Hall et al. 2002). Thus, the Arctic marine realm, in which Newfoundland is located (Spalding et al. 2007), is an area of particular interest for work with marine fatty acids and lipid classes. Indeed, the study of food web lipids in the cold waters off the coast of Newfoundland is important and timely given current problems with the ground fishery (e.g. Parsons 2005, Martínez-Murillo & Haedrich 2007) and the increasing interest in aquaculture in this area (e.g. Tlusty et al. 2005, Parrish et al. 2007a.In the present study, we examined the responses of suprabenthic and benthic invertebrates at > 200 m depth near, on ...

Fatty acids as dietary tracers in benthic food webs

“…These microalgae also contribute to benthic food webs, and in some cases the presence of their characteristic FAs in benthic organisms indicates a trophic connection between pelagic and benthic food webs (Kharlamenko et al 1995, Graeve et al 1997, Parrish et al 2009). Benthic food webs also rely on macroalgae, vascular plants (such as mangroves and seagrass), and bacteria, and these food sources also have characteristic FA compositions that can be used to identify their contributions to higher trophic levels (Dalsgaard et al 2003).…”

Lipids in Marine Ecosystems

“…The rationale behind the use of these 9/ 7 ratios is elongation of the diatom 16:1 7 to 18:1 7, but they could be biased if there was a significant intake of bacterial 18:1 7. Low and seasonally highly variable ratios have been observed in echinoderm gonads [102,103].…”

“…This multivariate technique handles a large amount of variables simultaneously, and has been used by organic geochemists to determine organic matter sources and degradation of suspended and sinking particles in the oceans [110,111]. We have used PCA to determine marine, terrestrial, and anthropogenic organic inputs, and trophic relationships (e.g., [100,102,104,[112][113][114]). Fatty acid PCA continues to have a strong following [115][116][117], but more sophisticated multivariate statistical analyses are emerging too (see below).…”

Tissue-specific fatty acid profiles of vent-obligate tonguefishes (Symphurus spp.) on volcanic arcs in the western Pacific Ocean

“…In terms of MUFA, the polychaete was characterized by relatively elevated levels of 17:1 (1 isomer; 7.1 %), 20:1 (4 isomers; 10.3 %) and 22:1ω7 (6.6 %). This fatty acid composition is intermediate between that of polychaetes at deep hydrothermal vents (Phleger et al 2005) and those found in cold coastal benthos (Parrish et al 2009). …”

“…The crustacean was rich in PUFA (40 % of total fatty acids), principally 20:5ω3 (10.1 %) and 22:6ω3 (18.5 %), and was characterized by moderate 16:1ω7 (6.8 %), 18:1ω7 (6.4 %) and 18:1ω9 (9.1 %) levels. This combination of fatty acids, in particular 18:1ω9, 20:5ω3 and 22:6ω3 together, is typical of crustaceans (Parrish et al 2009). Although the polychaete was less rich in ΣPUFA (30.2 %), and contained very little 22:6ω3 (0.5 %), a large relative amount of 20:5ω3 (16.5 %) was present.…”