Interdisciplinary approaches to advancing anti-racist pedagogies in ecology, evolution, and conservation biology.

Racism permeates ecology, evolution, and conservation biology (EECB). Meaningfully advancing equity, inclusion, and belonging requires an interdisciplinary anti-racist pedagogical approach to educate our community in how racism shaped our field. Here, we apply this framework, highlight disparities and interdisciplinary practices across institutions globally, and emphasize that self-reflection is paramount before implementing anti-racist interventions.

RAPID NITRATE UPTAKE RATES AND LARGE SHORT-TERM STORAGE CAPACITIES MAY EXPLAIN WHY OPPORTUNISTIC GREEN MACROALGAE DOMINATE SHALLOW EUTROPHIC ESTUARIES1.

We quantified the effects of initial macroalgal tissue nitrogen (N) status (depleted and enriched) and varying pulses of nitrate (NO3- ) concentration on uptake and storage of nitrogen in Ulva intestinalis L. and Ulva expansa (Setch.) Setch. et N. L. Gardner using mesocosms modeling shallow coastal estuaries in Mediterranean climates. Uptake of NO3- (µmol · g dry weight [dwt]-1 · h-1 ) was measured as loss from the water after 1, 2, 4, 8, 12, and 24 h and storage as total tissue nitrogen (% dwt) and nitrate (ppm). Both species of algae exhibited a high affinity for NO3- across all N pulses and initial tissue contents. There was greater NO3- removal from the water for depleted than enriched algae across all time intervals. In the low-N-pulse treatment, U. intestinalis and U. expansa removed all measurable NO3- within 8 and 12 h, respectively, and in the medium and high treatments, removal was high and then decreased over time. Maximum mean uptake rates of nitrate were greater for U. expansa (∼300 µmol · g dwt-1 · h-1 ) than U. intestinalis (∼100 µmol · g dwt-1 · h-1 ); however, uptake rates were highly variable over time. Overall, U. expansa uptake rates were double those of U. intestinalis. Maximum tissue NO3- for U. expansa was >1,000 ppm, five times that of U. intestinalis, suggesting that U. expansa has a greater storage capacity in this cellular pool. These results showed that opportunistic green algae with differing tissue nutrient histories were able to efficiently remove nitrate from the water across a wide range of N pulses; thus, both are highly adapted to proliferate in estuarine environments with pulsed nutrient supplies.

Spatial refuges and associational defenses promote harmful blooms of the alga Caulerpa sertularioides onto coral reefs.

Extreme population fluctuations, or outbreaks, are driven by interacting processes that are often more complex than isolated changes in consumer or resource control. Blooms of the macroalga Caulerpa sertularioides in the eastern tropical Pacific overgrew and killed reef-building corals, with blooms onto reefs corresponding to cool La Niña phases of inter-decadal fluctuations of the El Niño-Southern Oscillation. We quantified factors responsible for the maintenance of C. sertularioides patches in off-reef areas, namely an associational mutualism with an epiphytic cyanobacteria (Lyngbya majuscula), coupled with spatial refuges at the scales of individual thalli and habitat. Maintenance of near reef algal populations with a strong response to nutrient addition showed that these populations were primed to bloom onto reefs in response to enhanced nutrient delivery, such as those potentially associated with La Niña conditions. However, our experiments demonstrated that no single factor related to consumer or resource control was likely to stimulate bloom formation in isolation. Rather, we propose a novel model of reef bloom formation where off-reef blooms are sustained by processes reducing consumer control, and then bloom onto reefs through an interaction between increased allochthonous nutrient input and an uncoupling of consumer control by an association with epiphytic cyanobacteria.