Joana Cruz

• PhD in Marine Sciences
• Researcher at Centro de Ciências do Mar

Estimates of copepod secondary production are of great importance to infer the global organic matter fluxes in aquatic ecosystems and species-specific responses of zooplankton to hydrologic variability. However, there is still no routine method to determine copepods secondary production in order to eliminate time consuming experimental analyses. Th...

Coastal lagoons are often exposed to intense short-term environmental changes and strong anthropogenic pressures influencing zooplanktonic communities and production. However, most works focus on long-term temporal scales using monthly or seasonal sampling strategies. The present study analysed the structure of the mesozooplanktonic assemblages, th...

Microplastics, nanoplastics and related products have been recently found in marine ecosystems worldwide, calling for new analytical methods for rapid detection and risk assessment. Fluorescence is a sensitive technique that when used with polarity probes can potentially detect low-polarity plastic particles in environments. Here, we evaluated the...

The occurrence of scyphozoan blooms is frequently reported in coastal areas, suggesting a need to assess its impacts on trophic webs. However, many scyphozoan species remain understudied with regard to their feeding ecology. Here, feeding selectivity experiments were conducted to learn about the possible prey preference of Catostylus tagi among mes...

The seasonal occurrence of the Black Sea jellyfish Blackfordia virginica Mayer, 1910 blooms is a reason of concern in the Guadiana estuary in South of Portugal (South-West Europe), causing considerable economic and ecological impacts to fisheries. Due to jellyfish biochemical properties, they may represent an opportunity as an alternative food sour...

This cover illustrates the contamination of coastal environments by molecules or fragments released after degradation of plastics and microplastics. Many of the released molecules are uniquely related to specific polymer classes. Using these specific molecules as markers allows analysis for the presence of specific microplastics in the environment....

The intricate interplay among atmospheric CO 2 concentrations, surface ocean pH dynamics, and their profound impact on marine ecosystems is of paramount importance in the context of contemporary climate change. Pre-industrial atmospheric CO 2 concentrations oscillated in phase with glacial-interglacial cycles, showcasing low levels during glacial p...

The rivers of São Tomé Island are colonized by the little fish, endemic species with an amphidromous life cycle. The adults live upstream in the rivers, the larvae hatch and migrate to the ocean with the river flow, where they will remain for a few months until they transform into post-larvae and migrate back to the rivers, several of them with wa...

Marine plastic litter, originating from land-based sources, enters the marine environment by passing through coastal ecosystems such as lagoons and estuaries. As early life history stages (ELHS) of many commercially important fish species rely on these transitional areas as nursery grounds, we hypothesized that they encounter a spatial gradient of...

Content Paleodata of environmental responses to climate change from the Last Glacial Maximum (LGM) and the Holocene provide a useful performance test for climate models' sensitivity, contributing to better forecasts. Temporal high resolution data for both periods is important to reduce the uncertainties of models regionally. The Portuguese margin,...

DNA metabarcoding is particularly helpful for monitoring taxonomically complex communities and hard to identify morphologically, such as several zoo and ichthyoplankton, which contain eggs and larval stages of unknown species. However, the efficiency of metabarcoding in diversity recovery is dependent on the targeted genetic markers and primers emp...

Discontinuities and density gradients in the ocean may guide fish larva towards estuarine nursery grounds. However, recreating the ocean in a box is a challenge, particularly when scientists aim to test the preferences of fish larvae when water treatments have different temperatures and salinities, as highlighted by Gouraguine et al. (2021). These...

The rivers of São Tomé Island are colonized by Sicydium bustamantei (Greeff 1882), an amphidromous fish that spawns in those areas. After hatching, larvae drift to the ocean with the river flow. In the marine realm, the planktonic larvae develop and migrate to freshwater as post-larvae. The migrations of post-larvae support important local fisherie...

Individual animals across all taxa differ consistently in behaviour, i.e. they show personality traits. This inter-individual variability has significant ecological and evolutionary consequences, since it affects a range of population-level processes. Here, we focus on the selection and recruitment of nursery habitats in temperate fish larvae. The...

A low-cost citizen science campaign increased the knowledge on two invasive marine species in south Portugal. In just six months, citizen scientists extended in more than 80 km the known distribution of the invasive Atlantic blue crab. New records of weakfish in the Guadiana estuary where reported in 2019 since the last ones in 2017.

The Sense Acuity and Behavioral (SAAB) Hypothesis proposes that the swimming capabilities and sensorial acuity of temperate fish larvae allows them to find and swim towards coastal nursery areas, which are crucial for their recruitment. To gather further evidence to support this theory, it is necessary to understand how horizontal swimming capabili...

Climate change and the overall increase of seawater temperature are causing a poleward shift in species distribution, which includes a phenomenon described as the tropicalization of temperate regions. This work aims to report the first records of four species off the southwestern Iberian Peninsula, namely, the oceanic puffer Lagocephalus lagocephal...

Climate change and the overall increase of seawater temperature are causing a poleward shift in species distribution, which includes a phenomenon described as the tropicalization of temperate regions. This work aims to report the first records of four species off the southwestern Iberian Peninsula, namely, the oceanic puffer Lagocephalus lagocephal...

The Atlantic blue crab Callinectes sapidus Rathbun, 1896 is native in the western Atlantic, however it is a non-indigenous species across Europe since 1900, among other world regions. In this paper, we report the first occurrences of this species in the Ria Formosa lagoon and in the Guadiana estuary (SW-Iberian Peninsula, Europe) which occurred in...

This study evaluated the impacts of submarine groundwater discharges (SGD) on a rocky intertidal community of South Portugal, during April-November 2011. Chlorophyll-a concentration was higher at the SGD site in respect to the Reference site. Epibenthic community structure differed between sites, with an increase in Chthamalus spp. and a decrease i...

This work aims to undertake a preliminary characterization of winter fish assemblages in the salt marsh areas of Guadiana lower estuary (South-East Portugal) and discusses the potential risks of habitat dominance by a non-indigenous species (NIS). To this effect, six field campaigns were carried out in four sampling sites during winter season targe...

Jellyfish modulate the energy fluxes between compartments of aquatic ecosystems and the period that energy remains within each compartment. However, the contribution of different sources of organic matter (OM) to the production of most estuarine jellyfish species is unknown. Therefore, this study aimed to identify and quantify the putative sources...

This work updates the characterization of winter fish communities in salt marsh areas of Guadiana estuary (SE-Portugal) and discusses the potential risks of habitat dominance by a non-indigenous species (NIS). To this effect, six field campaigns were carried out during winter season targeting the collection of fish species. Individuals from seven d...

The feeding ecology of Blackfordia virginica was evaluated concurrently with their ecophysiological condition in a temperate estuary. The diet of B. virginica is composed not only of metazooplankton, as commonly observed for other jellyfish species, but also of phytoplankton, ciliates and detritus. This feeding behavior might explain their good nut...

The abundance of the calanoid copepod Centropages chierchiae has increased at the northern limits of its distribution in recent decades, mainly due to oceanic climate forcing, suggesting this as a key species in monitoring climate change. Laboratory experiments were conducted to study the combined effect of temperature, food type and concentration...

Several studies have documented effects of hydrological conditions influencing fish and benthonic communities in estuaries and coastal areas, but only few evidences of freshwater discharge on zooplankton assemblages are found. The major finding of our study in an estuary under climate variability with regulated flow by dams is that increased annual...

Laboratory experiments were conducted to study the combined effect of temperature (8, 13, 19 and 24°C), food type and food concentration on the grazing rates of the adult stages of the calanoid copepod Centropages chierchiae. As prey, the diatom Phaeodactylum tricornutum and the dinoflagellate Gymnodinium sp. (both ca. 15 µm cell diameter) were use...

Herbivory is a key factor in regulating plant biomass, thereby driving ecosystem performance. Algae have developed multiple adaptations to cope with grazers, including morphological and chemical defences. In a series of experiments we investigated whether several species of macroalgae possess anti-herbivore defences and whether these could be regul...

Square mesh traps placed under natural boulder cover were used to obtain in situ settlement rates of intertidal brachyurans along a rocky coast within the Cascais area, Central Portugal. Megalopae of all intertidal species known to occur in this region were present in the samples. The settlement variability within different spatial scales, i.e. hun...