Sinking Jelly-Carbon Unveils Potential Environmental Variability along a Continental Margin

Abstract

Particulate matter export fuels benthic ecosystems in continental margins and the deep sea, removing carbon from the upper ocean. Gelatinous zooplankton biomass provides a fast carbon vector that has been poorly studied. Observational data of a large-scale benthic trawling survey from 1994 to 2005 provided a unique opportunity to quantify jelly-carbon along an entire continental margin in the Mediterranean Sea and to assess potential links with biological and physical variables. Biomass depositions were sampled in shelves, slopes and canyons with peaks above 1000 carcasses per trawl, translating to standing stock values between 0.3 and 1.4 mg C m2 after trawling and integrating between 30,000 and 175,000 m2 of seabed. The benthopelagic jelly-carbon spatial distribution from the shelf to the canyons may be explained by atmospheric forcing related with NAO events and dense shelf water cascading, which are both known from the open Mediterranean. Over the decadal scale, we show that the jelly-carbon depositions temporal variability paralleled hydroclimate modifications, and that the enhanced jelly-carbon deposits are connected to a temperature-driven system where chlorophyll plays a minor role. Our results highlight the importance of gelatinous groups as indicators of large-scale ecosystem change, where jelly-carbon depositions play an important role in carbon and energy transport to benthic systems.

Sinking of Gelatinous Zooplankton Biomass Increases Deep Carbon Transfer Efficiency Globally

“…Large amounts of jelly-C biomass that are reported from coastal areas of open shelves and semienclosed seas of North America, Europe, and East Asia come from coastal stranding data (e.g., http://www.jellywatch.org/). Large amounts of jelly-C are quickly transferred to and remineralized on the seabed in coastal areas, including estuaries, lagoons and subtidal/intertidal zones (reviewed in Lebrato et al, 2012), shelves and slopes (Billett et al, 2006;Lebrato & Jones, 2009;Sweetman & Chapman, 2011), the deep sea , and even entire continental margins such as in the Mediterranean Sea (Lebrato, Molinero, et al, 2013). Jelly-C transfer begins when gelatinous zooplankton die at a given "death depth" (exit depth), continues as biomass sinks through the water column, and terminates once biomass is remineralized during sinking or reaches the seabed, and then decays.…”

Spatial and temporal variation of seasonal synchrony in the deep-sea shrimp Aristeus antennatus in the Western Mediterranean

“…Wavelet clustering showed three clear patterns that correspond to different spatial regimes of primary production (D'Ortenzio and d'Alcala, 2009) and feeding pathways. First, the northern locations of the Catalan coast are more productive and experience a comparatively larger influx of seasonal primary production exported from upper layers to the seabed (Lebrato et al, 2013). Second, a canyon-dependent pattern differentiates the two fisheries operating in large submarine canyons, in which the complex current systems govern the hydrography of each canyon promoting the bottom re-suspension of seabed organic matter producing conditions suitable for the occurrence of red shrimp (Canals et al, 2013;Sardà et al, 2009).…”

“…In the Mediterranean Sea, surface oceanographic processes and productivity dynamics have been shown to impact organisms at the deep sea (Hidalgo et al, 2011;Lebrato et al, 2013), including red-shrimp (Cartes et al, 2009;Company et al, 2008). Thus, for each population subunit we evaluated the potential influence of climate on the strength of seasonal covariation of red-shrimp investigating the link between North Atlantic climate and the regional scale hydroclimatology at CA and MA varies over time and space.…”

“…Our study examined how monthly CPUE covaried spatially and how the strength of this covariation changed with time, rather than evaluating the covariation of time series with environmental variables (e.g., Lebrato et al, 2013;Maynou, 2008a,b;Sardà et al, 2009). Potential drivers of the observed results are hereafter suggested.…”

Bloom or bust: synchrony in jellyfish abundance, fish consumption, benthic scavenger abundance, and environmental drivers across a continental shelf

“…The episodic events of benthic scavenging by fishes and other fauna in response to ‘jelly falls’ after blooms has been recently documented (e.g., Sweetman and Chapman, ; Sweetman et al ., ). These events provide localized surges of energy and transport carbon to benthic systems (Lebrato et al ., ,b) with rates of removal akin to other carrion falls (e.g., fishes; Sweetman et al ., ). Scavenging is an important ecosystem process whereby energy can be recycled in the food web by upper trophic levels – a fundamental response to sudden, dramatic increases in faunal abundance such as with GZ.…”